Technical Articles

Technical articles consist of several parts of topics, including pathway research, cytokines, cancer, transmembrane proteins, et al. Among of these topics, such as pathway research, which are divided into various special topics. Click related links to the articles to help you plan and perform your experiment.

CYTOKINES

Cytokines are a large group of proteins that are important in cell signaling. Their release has an effect on the behavior of cells around them. It can be said that cytokines are involved in autocrine signaling, paracrine signaling and endocrine signaling as immunomodulating agents. Cytokines may include growth factors, chemokines, interferons, interleukins, colony-stimulating factors, and tumour necrosis factors(despite some overlap in the terminology). Cytokines are produced by a broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells, as well as endothelial cells, fibroblasts, and various stromal cells; a given cytokine may be produced by more than one type of cell.

The Overview of Chemokines

Chemokines are a series of cytokines with small molecular weight whose main role is the recruitment of leukocyte subsets under homeostatic and pathological conditions. Their name is derived from their ability to induce directed chemotaxis in nearby responsive cells; they are chemotactic cytokines.

Trough interacting with chemokine receptors that are expressed on the cell surface as 7-transmembrane proteins coupled with G-protein for signaling transduction, chemokines can induce firm adhesion of targeted cells to the endothelium and direct the movement of targeted cells to their destination according to the concentration gradient of a given chemokine. In this article, we introduce the family of chemokines and receptors, its key role in the inflammation, and so on.

1. The Function of Chemokines

The major role of chemokines is to act as a chemoattractant to guide the migration of cells. Cells that are attracted by chemokines follow a signal of increasing chemokine concentration towards the source of the chemokine.

The function of chemokines are divided into two sections. One of them is homeostatic, which are constitutively produced in certain tissues and are responsible for basal leukocyte migration. These include: CCL14, CCL19, CCL20, CCL21, CCL25, CCL27, CXCL12 and CXCL13. This classification is not strict; for example, CCL20 can act also as pro-inflammatory chemokine. Another is inflammatory, which are formed under pathological conditions (on pro-inflammatory stimuli, such as IL-1, TNF-alpha, LPS, or viruses) and actively participate in the inflammatory response attracting immune cells to the site of inflammation. Examples are: CXCL-8, CCL2, CCL3, CCL4, CCL5, CCL11, CXCL10

2. The Types of Chemokines and Chemokine Receptors

Chemokines are a group of cytokines with small molecular weight whose main action is the recruitment of leukocyte subsets under homeostatic and pathological conditions.

Through interacting with chemokine receptors that are expressed on the cell surface as 7-transmembrane proteins coupled with G-protein for signaling transduction, chemokine can induce firm adhesion of targeted cells to the endothelium and direct the movement of targeted cells to their destination according to the concentration gradient of a given chemokine. According to behavior and structural characteristics, the chemokine family consists of 50 endogenous chemokine ligands in humans and mice (Table 1) [1][2][3][4][5][6].

Table 1a. CC chemokines

Name Protein Name Other Name(s) Receptor Uniprot ID
CCL1 C-C motif chemokine 1 I-309, TCA-3 CCR8 P22362
CCL2 C-C motif chemokine 2 MCP-1 CCR2 P13500
CCL3 C-C motif chemokine 3 MIP-1a CCR1 P10147
CCL4 C-C motif chemokine 4 MIP-1β CCR1CCR5 P13236
CCL5 C-C motif chemokine 5 RANTES CCR5 P13501
CCL6 C-C motif chemokine 6 C10, MRP-2 CCR1 P27784
CCL7 C-C motif chemokine 7 MARC, MCP-3 CCR2 P80098
CCL8 C-C motif chemokine 8 MCP-2 CCR1, CCR2B, CCR5 P80075
CCL9/CCL10 C-C motif chemokine 9 MRP-2, CCF18, MIP-1? CCR1 P51670
CCL11 Eotaxin C-C motif chemokine 11, Eosinophil chemotactic protein, Small-inducible cytokine A11 CCR2CCR3CCR5 P51671
CCL12 C-C motif chemokine 12 MCP-5 unknown Q62401
CCL13 C-C motif chemokine 13 MCP-4, NCC-1, Ckβ10 CCR2CCR3CCR5 Q99616
CCL14 C-C motif chemokine 14 HCC-1, MCIF, Ckβ1, NCC-2, CCL CCR1 Q16627
CCL15 C-C motif chemokine 15 Leukotactin-1, MIP-5, HCC-2, NCC-3 CCR1CCR3 Q16663
CCL16 C-C motif chemokine 16 LEC, NCC-4, LMC, Ckβ12 CCR1CCR2CCR5CCR8 O15467
CCL17 C-C motif chemokine 17 TARC, dendrokine, ABCD-2 CCR4 Q92583
CCL18 C-C motif chemokine 18 PARC, DC-CK1, AMAC-1, Ckβ7, MIP-4 unknown P55774
CCL19 C-C motif chemokine 19 ELC, Exodus-3, Ckβ11 CCR7 Q99731
CCL20 C-C motif chemokine 20 LARC, Exodus-1, Ckβ4 CCR6 P78556
CCL21 C-C motif chemokine 21 SLC, 6Ckine, Exodus-2, Ckβ9, TCA-4 CCR7 O00585
CCL22 C-C motif chemokine 22 MDC, DC/β-CK CCR4 O00626
CCL23 C-C motif chemokine 23 MPIF-1, Ckβ8, MIP-3, MPIF-1 CCR1 P55773
CCL24 C-C motif chemokine 24 Eotaxin-2, MPIF-2, Ckβ6 CCR3 O00175
CCL25 C-C motif chemokine 25 TECK, Ckβ15 CCR9 O15444
CCL26 C-C motif chemokine 26 Eotaxin-3, MIP-4a, IMAC, TSC-1 CCR3 Q9Y258
CCL27 C-C motif chemokine 27 CTACK, ILC, Eskine, PESKY, skinkine CCR10 Q9Y4X3
CCL28 C-C motif chemokine 28 MEC CCR3CCR10 Q9NRJ3

Table 1b. CXC chemokines

Name Protein Name Other Name(s) Receptor Uniprot ID
CXCL1 Growth-regulated alpha protein C-X-C motif chemokine 1, Gro-a, GRO1, NAP-3, KC CXCR2 P09341
CXCL2 C-X-C motif chemokine 2 Gro-β, GRO2, MIP-2a CXCR2 P19875
CXCL3 C-X-C motif chemokine 3 Gro-?, GRO3, MIP-2β CXCR2 P19876
CXCL4 Platelet factor 4 PF-4, C-X-C motif chemokine 4, roplact, Oncostatin-A CXCR3B P02776
CXCL5 C-X-C motif chemokine 5 ENA-78 CXCR2 P42830
CXCL6 C-X-C motif chemokine 6 GCP-2 CXCR1, CXCR2 P80162
CXCL7 Platelet basic protein NAP-2, CTAPIII, β-Ta, PEP unknown P02775
CXCL8 Interleukin-8 IL-8, NAP-1, MDNCF, GCP-1 CXCR1CXCR2 P10145
CXCL9 C-X-C motif chemokine 9 MIG, CRG-10 CXCR3 Q07325
CXCL10 C-X-C motif chemokine 10 IP-10, CRG-2 CXCR3 P02778
CXCL11 C-X-C motif chemokine 11 I-TAC, β-R1, IP-9 CXCR3CXCR7 O14625
CXCL12 Stromal cell-derived factor 1 SDF-1, PBSF CXCR4CXCR7 P48061
CXCL13 C-X-C motif chemokine 13 BCA-1, BLC CXCR5 O43927
CXCL14 C-X-C motif chemokine 14 BRAK, bolekine unknown O95715
CXCL15 C-X-C motif chemokine 15 Lungkine, WECHE unknown Q9WVL7
CXCL16 C-X-C motif chemokine 16 SRPSOX CXCR6 Q9H2A7
CXCL17 C-X-C motif chemokine 17 DMC, VCC-1 unknown Q6UXB2

Table 1c. C chemokines

Name Protein Name Other Name(s) Receptor Uniprot ID
XCL1 Lymphotactin Lymphotactin a, SCM-1a, ATAC XCR1 P47992
XCL2 Cytokine SCM-1 beta Lymphotactin β, SCM-1β XCR1 Q9UBD3

 

Table 1d CX3C chemokines

Name Protein Name Other Name(s) Receptor Uniprot ID
CX3CL1 Fractalkine Fractalkine, Neurotactin, ABCD-3 CX3CR1 P78423

3. Chemokine Signaling Pathway

Chemokines are a group of cytokines with small molecular weight whose main action is the recruitment of leukocyte subsets under homeostatic and pathological conditions.

Through interacting with chemokine receptors that are expressed on the cell surface as 7-transmembrane proteins coupled with G-protein to transmit cell signals following ligand binding. Activation of G proteins, by chemokine receptors, causes the subsequent activation of an enzyme known as phospholipase C (PLC). PLC cleaves a molecule called phosphatidylinositol (4,5)-bisphosphate (PIP2) into two second messenger molecules known as Inositol triphosphate (IP3) and diacylglycerol (DAG) that trigger intracellular signaling events; DAG activates another enzyme called protein kinase C (PKC), and IP3 triggers the release of calcium from intracellular stores. These events promote many signaling cascades (such as the MAP kinase pathway) that generate responses like chemotaxis, degranulation, release of superoxide anions and changes in the avidity of cell adhesion molecules called integrin’s within the cell harbouring the chemokine receptor[7].

Fig.1. The picture of chemokine signaling pathway

4. Chemokine and Inflammation

Chemokines are chemotactic cytokines that direct the movement of circulating leukocytes to sites of inflammation or injury. Originally studied because of their role in inflammation, chemokines and their receptors are now known to play a crucial part in directing the movement of mononuclear cells throughout the body, engendering the adaptive immune response and contributing to the pathogenesis of a variety of diseases. Chemokine receptors are some of the most tractable drug targets in the huge battery of molecules that regulate inflammation and immunity[8][9]. Here, we survey the properties of chemokines and their receptors and highlight the roles of these chemoattractants in selected clinical disorders.

The chemokine system in innate immune cell homeostasis

Maintenance of hematopoietic stem cells and developing innate immune cells takes place largely in the bone marrow (BM) and is dependent on CXCL12/CXCR4 interactions[10]. As immune cell development progresses past the hematopoietic stem cell, CXCL12/CXCR4 interactions remain essential for BM retention and normal development of multiple immune lineages, including B cells, monocytes, macrophages, neutrophils, natural killer (NK) cells, and plasmacytoid dendritic cells[11]. CXCR4-mediated signaling plays a major role in promoting BM retention of many immune cells. However, exit from the BM may not be entirely passive. In studies examining monocyte development and release from the BM, blockade of CXCR4 induces only a small increase in the number of peripheral blood monocytes[12].

The chemokine system in acute inflammation

Acute Inflammation is a general pattern of immune response to cell injury characterized by rapid accumulation of immune cells at the site of injury. The acute inflammatory response is initiated by both immune and parenchymal cells at the site of injury and is coordinated by a wide variety of soluble mediators.

This coordination starts with the homeostatic prepositioning of innate immune cells throughout the periphery, where they act as local sensors of infection and inflammation through the activation of pattern recognition receptors (PRRs), the inflammasome, and/or RNA and DNA sensors. Neutrophils, monocytes, and basophils, almost all innate immune cells are present to some extent in the periphery under homeostatic conditions. There they lie in wait as sensors of pathogen invasion, via PRRs, or tissue damage, via the interleukin (IL)-33 pathway as one example. MCs and macrophages are classically described as essential immune sensors, based on their expression of a wide variety of PRRs and their broad localization throughout all vascularized tissues. MCs are uniquely capable of responding immediately to infectious or inflammatory stimuli. Lipopolysaccharide (LPS) stimulation of murine peritoneal MCs leads to immediate release of CXCL1 and CXCL2-containing granules, but not histamine-containing granules, as well as transcriptional activation of CXCL1 and CXCL2[13].

Inflammatory Diseases

 

Chemokines have been implicated in a wide range of diseases with prominent inflammatory components. For example, elevated levels of CC chemokines, particularly CCL2, CCL3, and CCL5, in the joints of patients with rheumatoid arthritis coincide with the recruitment of monocytes and T cells into synovial tissues. Inflammation is also a key factor in asthma, in which the chemokine CCL11 (eotaxin) and its receptor, CCR3, contribute to the recruitment of eosinophils to the lung. Psoriasis is another example of chemokine-mediated local cell recruitment and inflammation. Infiltrating effector T cells express CCR4, and its ligands (CCL17 and CCL22) are produced by cutaneous cells. CXCR3 has also been implicated in the recruitment of T cells to inflamed skin[14].

5. The Most Popular Questions about Chemokines

In this part, we enumerate several popular questions about chemokines and hope that may give some help for you.

What is the difference between chemokine and cytokine?

We can differentiate chemokine and cytokines from several aspects. With respect to definition, cytokines are immune-modulating agents which are made up from proteins, while chemokines are a super family of cytokines which mediate chemotaxis. With respect to function, cytokines are involved in both cellular and antibody-mediated immunity in the body, while chemokines are involved in the guiding of cells in the immune system to the site of infection. With respect to types, cytokines include chemokines, ILs, INFs, CSFs, TNFs and TGFs in the body, while chemokines involve CC chemokines, CXC chemokines, C chemokines and CX3C chemokines in the body.

What cells release chemokines?

Some chemokines have roles in development; they promote angiogenesis (the growth of new blood vessels), or guide cells to tissues that provide specific signals critical for cellular maturation. Other chemokines are inflammatory and are released from a wide variety of cells in response to bacterial infection, viruses and agents that cause physical damage such as silica or the urate crystals that occur in gout.

References

[1] Laing KJ, Secombes CJ. Chemokines[J]. Developmental and Comparative Immunology. 2004, 28 (5): 443–60

[2] Villeda SA, Luo J, Mosher KI, et al. The ageing systemic milieu negatively regulates neurogenesis and cognitive function[J]. Nature. 2011, 477 (7362): 90–4

[3] Murdoch C, Finn A. Chemokine receptors and their role in inflammation and infectious diseases[J]. Blood. 2000, 95 (10): 3032–43

[4] Cocchi F, DeVico AL, Garzino-Demo A, et al. Identification of RANTES, MIP-1 alpha, and MIP-1 beta as the major HIV-suppressive factors produced by CD8+ T cells[J]. Science. 1995, 270 (5243): 1811–5

[5] von Recum HA, Pokorski JK. Peptide and protein-based inhibitors of HIV-1 co-receptors[J]. Experimental Biology and Medicine. 2013, 238 (5): 442–9

[6] Garzino-Demo A, Moss RB, Margolick JB, et al. Spontaneous and antigen-induced production of HIV-inhibitory beta-chemokines are associated with AIDS-free status[J]. Proceedings of the National Academy of Sciences of the United States of America. 1999, 96 (21): 11986–91

[7] R. M. Ransohoff. Chemokines and chemokine receptors: standing at the crossroads of immunobiology and neurobiology[J]. Immunity. 2009, 5(31): 711–721

[8] Luster AD. Chemokines — chemotactic cytokines that mediate inflammation[J]. N Engl J Med. 1998, 338:436-45

[9] Israel F. Charo, and Richard M. Ransohoff. The Many Roles of Chemokines and Chemokine Receptors in Inflammation[J]. N Engl J Med. 2006, 354:610-21

[10] Ara T, Tokoyoda K, Sugiyama T, Egawa T, Kawabata K, Nagasawa T. Long-term hematopoietic stem cells require stromal cell-derived factor-1 for colonizing bone marrow during ontogeny[J]. Immunity. 2003, 19: 257–267

[11] Mercier FE, Ragu C, Scadden DT. The bone marrow at the crossroads of blood and immunity[J]. Nat Rev Immunol. 2012, 12: 49–60

[12] Wang Y, Cui L, Gonsiorek W, et al. CCR2 and CXCR4 regulate peripheral blood monocyte pharmacodynamics and link to efficacy in experimental autoimmune encephalomyelitis[J]. J Inflamm (Lond). 2009, 6: 32

[13] Caroline L. Sokol and Andrew D. Luster. The Chemokine System in Innate Immunity[J]. Cold Spring Harb Perspect Biol. 2015, 29:(5)

[14] Flier J, Boorsma DM, van Beek PJ, et al. Differential expression of CXCR3 targeting chemokines CXCL10, CXCL9, and CXCL11 in different types of skin inflammation[J]. J Pathol. 2001, 194:398-405

The Overview of Tumour Necrosis Factor (TNF)

Tumor necrosis factor was reported firstly by Lloyd J. Old as one kind of cytotoxic factor produced by macrophages, from Memorial Sloan-Kettering Cancer Center, New York, in 1975. TNF, also known as TNFα, is a cytokine that can directly kill tumor cells without obvious cytotoxicity to normal cells. It is a 17kDa protein consisting of 157 amino acids and a homotrimer in solution. It is produced chiefly by activated macrophages.

1. Tumor Necrosis Factor function

TNFα is mainly produced by activated macrophages, T lymphocytes, and natural killer (NK) cells, but is also expressed at lower levels by fibroblasts, smooth muscle cells, and tumor cells. The primary role of TNF is in the regulation of immune cells. TNF, being an endogenous pyrogen, is able to induce fever, apoptotic cell death, cachexia, inflammation and to inhibit tumorigenesis and viral replication and respond to sepsis via IL1 & IL6 producing cells.

2. Members

In this section, we present the members of TNF superfamily and the receptors in the table 1(table 1a and 1b).

Tumor Necrosis Factor superfamily

The tumor necrosis factor (TNF) superfamily refers to a superfamily of cytokines that are involved in modulating cell death, survival, proliferation, and differentiation. Nineteen proteins have been identified as part of the TNF family on the basis of sequence, function, and structural similarities (as shown in table 1a).

Table 1a TNF Superfamily-chromosomal location

Chromosomal Location mRNA Accession NO. Uniprot ID
Gene Name/alias Human Human Human Ligand Symbol
TNF/TNFα 6p21.3 NM_000594 P01375 TNFSF1A
Lymphotoxin-alpha/LTα 6p21.3 NM_000595 P01374 TNFSF1B
LTβ 6p21.3 NM_002341 Q06643 TNFSF3
OX40-L 1q25 NM_003326 P23510 TNFSF4
CD40-L, CD154 Xq26 NM_000074 P29965 TNFSF5
Fas-L 1q23 NM_000639 P48023 TNFSF6
CD27-L, CD70 19p13 NM_001252 P32970 TNFSF7
CD30-L, CD153 9q33 NM_001244 P32971 TNFSF8
4-1BB-L 19p13 NM_003811 P41273 TNFSF9
TRAIL 3q26 NM_003810 P50591 TNFSF10
RANK-L, TRANCE 13q14 NM_003701 O14788 TNFSF11
TWEAK 17p13 NM_003809 O43508 TNFSF12
APRIL/TALL2 17P13.1 NM_003808 O75888 TNFSF13
BAFF, BLYS, TALL1 13q32–q34 NM_006573 Q9Y275 TNFSF13B
LIGHT 19p13.3 NM_003807 O43557 TNFSF14
TL1A 9q33 NM_005118 O95150 TNFSF15
GITRL, AITRL 1q23 NM_005092 Q9UNG2 TNFSF18
EDA1 Xq12–q13.1 NM_001399 Q92838 unknown
EDA2 Xq12–q13.1 AF061189 unknown unknown

 

Tumor Necrosis Factor receptors

The portrait of all the receptors in the TNF Superfamily is large and complicated (Table 1b), including the official genome nomenclature site, which introduced the TNFSF and TNFRSF numbering system[1].

Table 1b TNF Receptor SuperFamily

Chromosomal Location mRNA Accession NO. Uniprot ID
Gene Name/alias Human Human Human Ligand Symbol
TNFR-1, p55–60 12p13.2 NM_001065 P19438 TNFRSF1A
TNFR2, p75–80 1p36.3-36.2 NM_001066 P20333 TNFRSF1B
LTβR 12p13 NM_002342 P36941 TNFRSF3
OX40 1p36 NM_003327 P43489 TNFRSF4
CD40 20q12–q13.2 NM_001250 P25942 TNFRSF5
FAS, CD95 10q24.1 NM_000043 P25445 TNFRSF6
DcR3 20q13 NM_003823 O95407 TNFRSF6B
CD27 12p13 NM_001242 P26842 TNFRSF7
CD30 1p36 NM_001243 P28908 TNFRSF8
4-1BB 1p36 NM_001561 Q07011 TNFRSF9
TRAILR-1, DR4 8p21 NM_003844 O00220 TNFRSF10A
TRAIL-R2, DR5 8p22-p21 NM_003842 O14763 TNFRSF10B
TRAILR3, DcR1 8p22-p21 NM_003841 O14798 TNFRSF10C
TRAILR4, DcR2 8p21 NM_003840 Q9UBN6 TNFRSF10D
RANK, TRANCE-R 18q22.1 NM_003839 Q9Y6Q6 TNFRSF11A
OPG, TR1 8q24 NM_002546 O00300 TNFRSF11B
FN14 16p13.3 NM_016639 Q9NP84 TNFRSF12A
TRAMP, DR3, LARD 1p36.3 NM_003790 Q93038 TNFRSF25
TACI 17p11.2 NM_012452 O14836 TNFRSF13B
BAFFR 22q13.1–q13.31 NM_052945 Q96RJ3 TNFRSF13C
HVEM, HveA, ATAR 1p36.3–p36.2 NM_003820 Q92956 TNFRSF14
p75NTR, NGFR 17q12–q22 NM_002507 P08138 TNFRSF16
BCMA 16p13.1 NM_001192 Q02223 TNFRSF17
AITR, GITR 1p36.3 NM_004195 Q9Y5U5 TNFRSF18
RELT 11q13.2 NM_152222 Q969Z4 TNFRSF19L
TROY, TAJ 13q12.11–q12.3 NM_018647 Q9NS68 TNFRSF19
EDAR 2q11–q13 NM_022336 Q9UNE0 unknown
DR6 6P12.2–21.1 NM_014452 O75509 TNFRSF21
EDA2R Xq11.1 NM_021783 Q9HAV5 TNFRSF27

3. Tumor Necrosis Factor Inhibitors

A tumor necrosis factor (TNF)-alpha inhibitor is a pharmaceutical drug that suppresses the physiologic response to tumor necrosis factor (TNF), which is part of the inflammatory response. TNF is involved in autoimmune and immune-mediated disorders such as rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, psoriasis, hidradenitis suppurativa and refractory asthma, so TNF inhibitors may be used in their treatment. The inhibitor, including etanercept, infliximab, adalimumab, certolizumab pegol, and golimumab, all bind to the cytokine TNF and inhibit its interaction with the TNF receptors[2].

As a cytokine, TNF is involved with the inflammatory and immune response and can bind to TNF receptor 1 (TNFR1) or TNF receptor 2 (TNFR2). It occurs in numerous forms, both monomeric and trimeric, as well as soluble and transmembrane[3]. Etanercept is a fusion protein of two TNFR2 receptor extracellular domains and the Fc fragment of human IgG1. It inhibits the binding of both TNF-alpha and TNF-beta to cell surface TNFRs. Infliximab is a chimeric monoclonal antibody that includes a murine variable region and constant human region. It binds to the soluble and transmembrane forms of TNF-alpha and inhibits the binding of TNF-alpha to TNFR[4].

The important side effects of TNF inhibitors include lymphomas, infections, congestive heart failure, demyelinating disease, a lupus-like syndrome, induction of auto-antibodies, injection site reactions, and systemic side effects[5].

4. Tumor Necrosis Factor Signaling Pathway

TNF can bind two receptors, TNFR1 (TNF receptor type 1) and TNFR2 (TNF receptor type 2) [6]. TNFR1 is expressed in most tissues, and can be fully activated by both the membrane-bound and soluble trimeric forms of TNF, whereas TNFR2 is found typically in cells of the immune system, and respond to the membrane-bound form of the TNF homotrimer. As most information regarding TNF signaling is derived from TNFR1, the role of TNFR2 is likely underestimated. Upon binding, TNF triggers the activation of numerous pathways including the NFκB and MAPK signaling pathway.

The picture of TNF signaling pathway

5. Tumor Necrosis Factor and Diseases

Accumulating evidences have revealed that dysregulation of TNF production was implicated in a variety of human diseases including Alzheimer’s disease[7], cancer[8], major depression[9], psoriasis[10] and inflammatory bowel disease (IBD). Its complex functions in the immune system include the stimulation of inflammation, cytotoxicity, the regulation of cell adhesion, and the induction of cachexia.

Tumor Necrosis Factor and Cancer

TNF-α is frequently detected in biopsies from human cancer, produced either by epithelial tumor cells, as for instance in ovarian and renal cancer; or stromal cells, as in breast cancer[11]. Cancer cell or stromal cell production of TNF-α is involved in the development of a range of experimental tumors, is partially responsible for NF-κB activation in initiated tumor cells and for the cytokine network in found in human cancer[12].

There are several known consequences of TNF-α production by cancer cells that begin to explain its role in cancer progression. As stated above ovarian cancer cell lines, but not normal ovarian surface epithelial cells, produce pg quantities of TNF-α protein and that there were differences in TNF-α mRNA stability between normal and malignant cells[13]. This endogenous TNF-α correlates with increased cancer cell expression of the chemokine receptor CXCR4 and its ligand CXCL12, in both cell lines and biopsies of disease[14]. TNF-α up-regulated CXCR4 expression, cancer cell migration and production of other inflammatory cytokines and chemokines by the ovarian epithelial cells. CXCR4 and its ligand CXCL12 are implicated in metastases and tumor cell survival in a wide range of cancers[15].

Anti-TNF therapy has shown only modest effects in cancer therapy. Treatment of renal cell carcinoma with infliximab resulted in prolonged disease stabilization in certain patients. Etanercept was tested for treating patients with breast cancer and ovarian cancer showing prolonged disease stabilization in certain patients via downregulation of IL-6 and CCL2. On the other hand, adding infliximab or etanercept to gemcitabine for treating patients with advanced pancreatic cancer was not associated with differences in efficacy when compared with placebo[16].

Tumor Necrosis Factor and Inflammation

As TNF plays a key role in the pathogenesis of chronic inflammatory diseases such as Crohn’s disease (CD) and rheumatoid arthritis (RA), a new class of drugs has been developed in an attempt to neutralise its biological activities.

Tumor Necrosis Factor and rheumatoid arthritis

The primary cellular elements in the RA inflammatory process that cause synovitis and other systemic manifestations are the CD4+ lymphocyte, macrophage, and synovial fibroblasts. The cells produce numerous cytokines, of which interleukin (IL)–1, IL-6, and TNF are arguably the most important in the RA inflammatory cascade. The important role of TNF-α has also been verified in clinical trials of TNF inhibitors. TNF-α, a homodimer produced primarily by macrophages/monocytes, is an excellent promoter of RA inflammation. Acting through a p55 or p75 receptor, it stimulates other cells to produce various inflammatory cytokines, for example, IL-2, IL-6, IL-8, IL-12, IL-18, and interferon (IFN)–γ[17].

Tumor Necrosis Factor and Crohn’s disease

Crohn’s disease (CD) is chronic inflammatory conditions characterized by episodes of remission and flare-ups that have a major impact on the patient’s physical, emotional and social well-being. Similar to its role in rheumatoid arthritis, TNFα has also been shown to be crucial in the pathogenesis of Crohn’s disease.

TNF is a crucial mediator in driving inflammatory processes in the gut. It is produced by a variety of mucosal cells, mainly macrophages and T cells, as a preform on the plasma membrane. In addition, Paneth cells in CD affected segments of the terminal ileum were shown to strongly express TNF RNA in contrast to Paneth cells in normal tissue, indicating an induction under pathogenic conditions. The transmembrane precursor form (mTNF), a homotrimer of 26 kDa subunits, is cleaved by the matrixmetalloproteinase TNF alpha converting enzyme (TACE/Adam17) into a soluble form. The expression of mTNF by CD14+ macrophages has been reported to be relevant in CD)[18].

Anti-tumor necrosis factor α (anti-TNFα) antibodies have been used as a potent therapy for CD. These particular agents are effective not only for CD patients who have never undergone surgery but also for those who have received surgery. In fact, fewer endoscopic recurrences were observed in patients who received anti-TNF agents after surgery than in those who did not.6 In the meanwhile, a report suggested that no significant difference in the endoscopic recurrence rate was observed between biological and conventional therapy after ileocecal resections in CD patients. In this context, the efficacy of anti-TNF agents for postoperative CD patients have been evaluated in patients who had no history of undergoing anti-TNFα antibody treatment prior to surgery. Because primary nonresponses or secondary loss of responses can frequently occur in CD patients who are administered anti-TNF agents, a substantial portion of patients who require anti-TNF agents after surgery receive the agents also prior to surgery in clinical practice[19][20].

References

[1] Carl F. Ware. TNF Superfamily 2008[J]. Cytokine Growth Factor Rev, 2008 (3-4): 183–186

[2] Valerie Gerriets1; Steve S. Bhimji2. Tumor Necrosis Factor (TNF), Inhibitors[J]. StatPearls Publishing, 2018 Jan

[3] Meroni PL, Valentini G, et al. New strategies to address the pharmacodynamics and pharmacokinetics of tumor necrosis factor (TNF) inhibitors: A systematic analysis[J]. Autoimmun Rev. 2015 (9): 812-29

[4] Komaki Y, Yamada A, et al. Efficacy, safety and pharmacokinetics of biosimilars of anti-tumor necrosis factor-α agents in rheumatic diseases; A systematic review and meta-analysis[J]. Autoimmun. 2017 (79): 4-16

[5] N Scheinfeld. A comprehensive review and evaluation of the side effects of the tumor necrosis factor alpha blockers etanercept, infliximab and adalimumab[J]. Journal of Dermatological Treatment, 2004 (15): 280–294

[6] Arianne L. Theiss, James G. Simmons, et al. Tumor Necrosis Factor (TNF) Increases Collagen Accumulation and Proliferation in Intestinal Myofibroblasts via TNF Receptor 2[J]. The journal of biological chemistry, 2005 (43): 36099 -36109

[7] Swardfager W, Lanctôt K, et al. A meta-analysis of cytokines in Alzheimer’s disease[J]. Biol Psychiatry, 2010 (68): 930–941

[8] Locksley RM, Killeen N, et al. “The TNF and TNF receptor superfamilies: integrating mammalian biology[J]. Cell, 2001 (104): 487–501

[9] Dowlati Y, Herrmann N, et al. A meta-analysis of cytokines in major depression[J]. Biol Psychiatry, 2010 (5): 446–457

[10] Victor FC, Gottlieb AB. TNF-alpha and apoptosis: implications for the pathogenesis and treatment of psoriasis[J]. Drugs Dermatol, 2002 (3): 264–75

[11] Balkwill, F. (2002). Tumor necrosis factor or tumor promoting factor[J]. Cytokine & Growth Factor Reviews, 2002 (13): 135–141

[12] Galban, S., Fan, J., et al. von Hippel-Lindau protein-mediatedrepression of tumor necrosis factor alpha translation revealed through use of cDNA arrays[J]. Molecular & Cellular Biology, 2003 (23): 2316–2328

[13] Tsan, M.-F. Toll-like receptors, inflammation and cancer[J]. Seminars in Cancer Biology, 2005 (16): 32–37

[14] Kulbe, H., Hagermann T, et al. The inflammatory cytokine TNF-a upregulates chemokine receptor expression on ovarian cancer cells[J]. Cancer Research, 2005 (65): 10355–10362

[15] Balkwill, F. The significance of cancer cell expression of CXCR4[J]. Seminars in Cancer Biology, 2004 (14): 171–179

[16] Korneev KV, Atretkhany KN, et al. TLR-signaling and proinflammatory cytokines as drivers of tumorigenesis[J]. Cytokine, 2017 (89): 127–135

[17] Ma X, Xu S. TNF inhibitor therapy for rheumatoid arthritis[J]. Biomed Rep, 2012 (2): 177–184.

[18] Narayanan Parameswaran, Sonika Patial. Tumor Necrosis Factor-α Signaling in Macrophages[J]. Crit Rev Eukaryot Gene Expr, 2010 (2): 87–103.

[19] Ulrike Billmeier, Walburga Dieterich, et al. Molecular mechanism of action of anti-tumor necrosis factor antibodies in inflammatory bowel diseases[J]. World J Gastroenterol, 2016 (42): 9300–9313

[20] Konstantinos Papamichael, Adam S Cheifetz. Defining and predicting deep remission in patients with perianal fistulizing Crohn’s disease on anti-tumor necrosis factor therapy[J]. World J Gastroenterol. 2017 (34): 6197–6200

The Overview of Interleukin

Interleukin is a kind of cytokines, which plays a critical role in immunological regulation and homeostasis. It is originally discovered from leukocytes. Currently, it is found to be produced by a lot of cells including macrophages, lymphocytic cells with a solid structure and function. In this article, we introduce interleukin briefly from the following aspects, involving family and receptor, signaling pathways, function and that role in inflammation.

1. Interleukin Family and Interleukin Receptors

The members of interleukin are wealthy which are named IL-1~IL-38.

The interleukin receptors can be classified as type I, type II and other type. The type II interleukin receptors include interleukin-10, 20, 22, 28 receptors, the other type include interleukin-1, 8 receptors, the rest of them are type I interleukin receptors.

Table 1. Interleukin Family and Receptors

Gene Name/Alias Uniprot ID Protein Name Receptors
IL-1 α P01583 Interleukin-1 alpha IL1R1, IL1R2
IL-1 β P01584 Interleukin-1 beta IL1R1IL1R2
IL-2 P60568 Interleukin-2 IL2RA, IL2RB, IL2RG
IL-3 P08700 Interleukin-3 IL3RA, IL3RB
IL-4 P05112 Interleukin-4 IL4R
IL-5 P05113 Interleukin-5 IL5RA, IL3RB
IL-6 P05231 Interleukin-6 IL6R
IL-7 P13232 Interleukin-7 IL7R
IL-8/CXCL8 P10145 Interleukin-8 IL-8, IL8RB
IL-9 P15248 Interleukin-9 IL9R
IL-10 P22301 Interleukin-10 IL10RA
IL-11 P20809 Interleukin-11 IL11RA
IL-12 α P29459 Interleukin-12 subunit alpha IL12RB1
IL-13 P35225 Interleukin-13 IL13RA1IL13RA2
IL-14/TXLNA P40222 Alpha-taxilin Unkown
IL-15 P40933 Interleukin-15 IL15RA
IL-16 Q14005 Pro-interleukin-16 CD4
IL-17 α Q16552 Interleukin-17A IL17RA
IL-18 Q14116 Interleukin-18 IL18R1
IL-19 Q9UHD0 Interleukin-19 IL20R
IL-20 Q9NYY1 Interleukin-20 IL20R
IL-21 Q9HBE4 Interleukin-21 IL21R
IL-22 Q9GZX6 Interleukin-22 IL22RA1
IL-23 Q9NPF7 Interleukin-23 subunit alpha IL23R
IL-24 Q13007 Interleukin-24 IL20R
IL-25 Q9H293 Interleukin-25 LY6E
IL-26 Q9NHP9 Interleukin-26 IL20R1
IL-27 α Q8NEV9 Interleukin-27 subunit alpha IL27RA
IL-27 β Q14213 Interleukin-27 subunit beta IL27RA
IL-28 Q8IU57 Interferon lambda receptor 1 IL28R
IL-29/IFNL1 Q8IU54 Interferon lambda-1 Unknown
IL-30 Q8NEV9 Interleukin-27 subunit alpha Unknown
IL-31 Q6EBC2 Interleukin-31 IL31RA
IL-32 P24001 Interleukin-32 Unknown
IL-33 O95760 Interleukin-33 Unknown
IL-35 Q14213 Consist of IL-12α and IL-27β chains Unknown
IL-36 α Q9UHA7 Interleukin-36 alpha Unknown
IL-36 β Q9NZH7 Interleukin-36 beta Unknown
IL-36 γ Q9NZH8 Interleukin-36 gamma Unknown

2. Common Signaling Pathway

In this part, we display several interleukin pathways, including IL-1, IL-10, IL-12, IL-17 and IL-7 signaling pathway.

IL-1 Signaling Pathway

There are 11 members in this family. They (IL-1, 18, 33, 36, 37, 38) binds to IL1, 18 primary receptors. IL-1α, IL-1β, IL-18, IL-33, IL-36α, IL-36β, IL-36γ triggers MPKK and NF-κB leading to inflammatory response. While other members of IL-1 family have anti-inflammatory effects. IL-1 is one hallmark cytokine in this family which can excrete as co-stimulation of T helper cells, maturation and proliferation of B cells, activation of NK cells and is relation to inflammation.

The image of IL-1 signaling pathway

Fig.1. The image of IL-1 signaling pathway

IL-10 Pathway

IL-10 is an important anti-inflammatory cytokine which is produced by activated T cells, B cells, macrophages and monocytes. It involves in cytokine production of macrophages, activation of B cells, stimulated Th2 cells, meanwhile, it inhibits cytokine production of Th1 cells. It can form a homodimer that binds to the tetrameric heterodimer IL-10 receptor and inhibit the IL-1, IL-6 and TNF signaling pathway. It is related with non-small cell lung cancers.

The image of IL-10 signaling pathway

Fig.2. The image of IL-10 signaling pathway

IL-12 Pathway

There are 4 members in this family. It (IL-12, 25, 27, 35) belonging to IL-6 superfamily is a special family as it is formed by heterodimers. It mediates phosphorylation of SAT1, 3, 4 by the JAK/STAT family. IL-12 involves in the stimulation and maintenance of Th1 cellular immune responses, including the normal host defend against various intracellular pathogens.

The image of IL-12 signaling pathway

Fig.3. The image of IL-12 signaling pathway

IL-17 Pathway

There are 6 members in the IL-17 family, and 5 members in its receptor family. It plays critical roles in host immunology. IL-17A is the hallmark in this family that it protects the host against extracellular pathogens, but also promotes inflammatory pathology in autoimmune disease, similar to IL-17C. While IL-17F involves in the mucosal host defense, IL-17E amplifies the Th2 immune response. The IL-17 family activates antibacterial cytokines and chemokines in MAPK, NF-κB and C/EBPs pathway. Act1 is considered as the master mediator in this pathway.

The image of IL-17 signaling pathway

Fig.4. The image of IL-17 signaling pathway

IL-7 Pathway

IL-7 is a kind of glycoprotein which is produced by bone marrows and weighs 25 kDa. It is important for the immunological development, but the mechanism is not clear. A recent research showed that: IL-7 downregulates the Scos3 (the inhibitor of cytokine signaling), thus much cytokines are stimulated and the T cells effectors are increased resulting the clearance of virus[1]. The article conducted by Marc Pellegrini is published in Cell in 2011.

IL-7 can increase the T effector numbers such as CD4 T cells, CD8 T cells, naive T cells and B cells, and then infiltrate organs like liver, kidney and brain. According to the assay in this research, it is T cells rather than B cells to exert the function of virus clearance. This result is consistent with the previous result that B cells contribute just a little to modulate T cells’ response. It also enlightens us to receive IL-7 therapy.

IL-7’s function depends on IL-6, meanwhile IL-7 augments many pro-inflammatory factors, particularly IL-17, IL-6 and IFNγ. But it limits the liver injury and cytotoxicity as it increases the IL-22, a cyto-protective cytokine.

Socs3 is one prominent repressor of IL-6 signaling pathway while IL-6 is increased with IL-7 treatment. It seems to be produced by T cells, and it is interfered by IL-7. Mice with socs3 deficiency can mimic the effect of virus elimination.

3. Interleukin Function

Interleukin is important for transmitting information, activating and regulating immune cells, mediates the activation, proliferation and differentiation of T cells and B cells.

Interleukin-1 contains IL-1α and IL-1β. While the former is produced by diverse cells, the later one is produced by some specific tissues. IL-1β is cleaved by caspase-1 which is formed by proteins termed as “the inflammasome”. It can lead to pain and short-time sleep, so that they study the relationship between fatigue and IL-1[2]. IL-1 also can simulate the nitric oxides, chemokines, cytokines and adhesion molecules that destroy the cartilage, while the IL-1 receptor antagonist can inhibit the destruction of IL-1 through the completion of the same receptor. The study helps us to understand the pathology of these diseases[3].

Interleukin-2 is popular object in the past 36 years as it is important for the immunotherapy of many diseases including cancers. But the adverse of taking it is fearful[4].Thus, timing of IL-2 administration and different T cells status are crucial to IL-2 therapies[5].

Interleukin-10 is an anti-inflammatory cytokine. In the meanwhile, IL-10 suppresses the immune responses by modulating the T cells and antigen-presenting cells. By controlling the receptor of IL-10, we can resolve the chronic viral infection[6]. The research was published in The Journal of Experimental Medicine in 2006.

Interleukin-18 is a regulator of cancer and autoimmune diseases. As a member of IL-1 family, it plays essential roles in inflammation process. It can cooperate with IL-12 to activate cytotoxic T cells (CTLs) and natural killer (NK) cells to produce IFNγ which may contribute to tumor immune. In addition, it can work with IL-23 to induce the secretion of IL-17. It has pros and cons effects in the treatment of many diseases[7].

4. Interleukin and Inflammation

Inflammation is a productive conduct to stimuli such as pathogens and damage cells. Its characters are heat, redness, swelling, pain and loss of function, sometimes accompanied with fever. Inflammasome activation leads to activation of caspase-1, resulting in the induction of apoptosis and the secretion of pro-inflammatory cytokines including IL-1β and IL-18[8]. Without inflammation, we can’t prevent harm from stimuli, but it can lead to chronic infection such as rheumatoid arthritis. Inflammation plays a key role in chronic inflammatory systemic diseases (CISD). There are overlaps between different CISD.

Interleukin-17 and Psoriasis

Psoriasis is a common, infammatory and chronic disease with the character of erythematous, scaly plaques. It is related to cardiovascular disease (CVD) such as artherosclerosis. As a result of immune dysregulation, its pathology refers to infammatory cytokines like tumor necrosis factor (TNF), interferon (IFN) and IL-1β, IL-6, IL-12, IL-17, IL-22, IL-23 produced from dendritic cells, T-helper cells and keratinocytes. Patients with psoriasis have more Th17 cells and higher level of IL-17A mRNA and protein. The recent study demonstrates over-expressing IL-17 causing increased inflammatory cells and levels of nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nitric oxide (NO) makes more severe psoriasis, and endothelial dysfunction. In the contrast, blocking of IL-7 or the genes acting downstream of IL7 improves the severity of psoriasis[8][9].

Interleukin and Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a severe autoimmune disease accompanied with cartilage degradation, joint destruction and poor prognosis [8]. The study indicates that the polymorphism of inflammation genes leads to the susceptibility of RA[10][11][12]. Caspase-1 is a critical factor of RA, we can observe the reduction of RA in the caspase-1-/- mice mode[13]. Another member is NLRP1 which is related to the secretion of IL-1β and IL-18. Inhibiting the NLRP1 can ameliorate the symptom of RA[14].

This coordination starts with the homeostatic prepositioning of innate immune cells throughout the periphery, where they act as local sensors of infection and inflammation through the activation of pattern recognition receptors (PRRs), the inflammasome, and/or RNA and DNA sensors. Neutrophils, monocytes, and basophils, almost all innate immune cells are present to some extent in the periphery under homeostatic conditions. There they lie in wait as sensors of pathogen invasion, via PRRs, or tissue damage, via the interleukin (IL)-33 pathway as one example. MCs and macrophages are classically described as essential immune sensors, based on their expression of a wide variety of PRRs and their broad localization throughout all vascularized tissues. MCs are uniquely capable of responding immediately to infectious or inflammatory stimuli. Lipopolysaccharide (LPS) stimulation of murine peritoneal MCs leads to immediate release of CXCL1 and CXCL2-containing granules, but not histamine-containing granules, as well as transcriptional activation of CXCL1 and CXCL2[13].

Interleukin and Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE), accompanied with inflammatory joints, nephritis, mouth ulcer, swollen lymph nodes and butterfly-shaped red rash on the face, is a rare inflammatory rheumatic disease that attacks normal healthy tissues in the body. The major representation is lupus nephritis (LN) with severe kidney destruction. The study explains the relationship between the expression of inflammasome and LN[15] Tsai et al. reported inhibiting the expression of mRNA and production of IL-1β, IL-18, caspase-1 relieves the symptom of LN[16]. Ka et al. further reported that a main active ingredient in the herbal medicine Litsea cubeca, significantly inhibited activation of NLRP3 inflammasome and caspase-1 and the secretion of IL-1. Moreover, it effectively ameliorated LN symptoms in accelerated and severe LN mice[17].

Interleukin and Crohn’s Disease

Crohn’s disease (CD) is a chronic inflammatory condition of the GI tract with no known cure. It is demonstrated efficient to take antibody-based therapies directed against TNF or interleukin-12/interleukin-23 p40 subunit antibody or integrins in moderate-to-severe CD. However, many patients experience primary non-response or lose response over time to anti-TNF therapy, so that we require dose adjustment, or switch to a non-anti-TNF therapy. Interleukin-6 has multiple pro-inflammatory effects such as inhibition of apoptosis in T-cells and is a target for curing CD. A recent study of the IL-6 receptor inhibitor, tocilizumab, manifests a clinical benefit in moderate-to-severe CD[18].

References

[1]Pellegrini M, Calzascia T, et al. IL-7 Engages Multiple Mechanisms to Overcome Chronic Viral Infection and Limit Organ Pathology[J]. Cell, 2011(144): 601-603

[2]Megan E. Roerink, Marieke E. van der Schaaf, et al. Interleukin-1 as a mediator of fatigue in diseases: a narrative review[J]. Journal of Neuroinflammation, 2017(14): 16

[3]Claire J, Marjolaine G, et al. The role of IL-1 and IL-1Ra in joint inflammation and cartilage degradation[J]. Vitamins and Hormones, 2006(74): 371-403

[4]Dhupkar P, Gordon N. Interleukin-2: old and new approaches to enhance immune-therapeutic efficacy[J]. Adv Exp Med Biol, 2017(995): 33-51

[5]Blattman JN, Grayson JM, et al. Therapeutic use of IL2 to enhance antiviral T-cell responses in vivo[J]. Nat Med, 2003(9): 540-547

[6]Eirnaes M, Filippi CM, et al. Resolution of a chronic viral infection after interleukin-10 receptor blockade[J].J Exp Med, 2006(203): 2461-2472

[7]Esmailbeig M, Ghaderi A. Interleukin-18: a regulator of cancer and autoimmune diseases[J]. Eur Cytokine Netw, 2017(28): 127-140

[8]Yi YS. Role of inflammasomes in inflammatory autoimmune rheumatic diseases[J]. Korean J Physiol Pharmacol, 2018(1): 1-15

[9]Lockshin B, Balaqula Y, et al. Interleukin-17, inflammation, and cardiovascular risk in patients with psoriasis[J]. J Am Acad Dermatol, 2018, accepted

[10]Mathews RJ, Robinson JI, et al. Evidence of NLRP3-inflammasome activation in rheumatoid arthritis (RA); genetic variants within the NLRP3-inflammasome complex in relation to susceptibility to RA and response to anti-TNF treatment)[J]. Ann Rheum Dis, 2014(73): 1202-1210

[11]Jenko B, Praprotnik S, et al. NLRP3 and CARD8 polymorphisms influence higher disease activity in rheumatoid arthritis)[J]. J Med Biochem, 2016(35): 319-323

[12]Sui J, Li H. NLRP1 gene polymorphism influences gene transcription and is a risk factor for rheumatoid arthritis in han chinese. Arthritis Rheum, 2012(64): 647-654

[13]Joosten LA, Netea MG, et al. Inflammatory arthritis in caspase 1 gene-deficient mice: contribution of proteinase 3 to caspase 1-independent production of bioactive interleukin-1)[J]. Arthritis Rheum, 2009(60): 3651-3662

[14]Zhang L, Dong Y, et al. Hydroxysteroid dehydrogenase 1 inhibition attenuates collagen-induced arthritis)[J]. Int Immunopharmacol, 2013(17): 489-494

[15]Roberts TL, Idris A, et al. HIN-200 proteins regulate caspase activation in response to foreign cytoplasmic DNA)[J]. Science, 2009(323): 1057-1060

[16]Tsai PY, Ka SM, et al. Epigallocatechin-3-gallate prevents lupus nephritis development in mice via enhancing the Nrf2 antioxidant pathway and inhibiting NLRP3 inflammasome activation)[J]. Free Radic Biol Med, 2011(51): 744-754

[17]Ka SM, Lin JC, et al. Citral alleviates an accelerated and severe lupus nephritis model by inhibiting the activation signal of NLRP3 inflammasome and enhancing Nrf2 activation)[J]. Arthritis Res Ther. 2015(17): 331

[18]Danese S, Vermeire S, et al. Randomised trial and open-label extensive study of an anti-interleuki8n-6 antibody in crohn’s disease(ANDANTW I and II)[J]. Gut, 2017, doi:10.1136

The Overview of Colony-Stimulating Factor

Colony stimulating factors (CSFs) are glycoproteins that bind to receptor proteins on the surfaces of hemopoietic stem cells, activating intracellular signaling pathways, then promoting production of white blood cells (mainly granulocytes such as neutrophils), in response to infection. Administration of exogenous colony stimulating factors stimulates the stem cells in the bone marrow to produce more of the particular white blood cells. The new white blood cells migrate into the blood and fight the infection. In this article, we introduce the colony stimulating factors from several aspects briefly, including function, members, the relationship with inflammation and cancer, and the latest researches about that.

1. Colony-Stimulating Factors (CSFs) Function

Colony-stimulating factors (CSFs) activate intracellular signaling pathways that can cause the cells to proliferate and differentiate into a specific kind of blood cell (usually white blood cells. For red blood cell formation, see erythropoietin). CSFs circulate in the blood, acting as hormones, and are also secreted locally. General speaking, CSFs include macrophage colony-stimulating factor (CSF1), Granulocyte–macrophage colony-stimulating factor (CSF2), granulocyte colony-stimulating factor (CSF3) and interleukin-3 (IL-3; also known as multi-CSF). But in some extent, CSFs also involve erythropoictin (Epo) and thrombopoietin (Thpo) for their ability of stimulating the formation of red blood.

2. Members

In this section, we list the common colony-stimulating factors and corresponding receptors in the below Table 1.

Table 1. CSFs and receptors

Name Uniprot ID Species Receptor
(macrophage colony-stimulating factor(CSF1) P09603 Human CSF1R
macrophage colony-stimulating factor(CSF1) P07141 Mouse Csf1r
Granulocyte-macrophage colony-stimulating factor protein(GM-CSF) Q9GL44 Rhesus macaque CSF1R
Granulocyte-macrophage colony-stimulating factor protein(CSF2) P04141 Human CSF2RA
Granulocyte-macrophage colony-stimulating factor protein(CSF2) P01587 Mouse CSF2RA
Granulocyte colony-stimulating factor protein(CSF3) P09919 Human CSF3R
Granulocyte colony-stimulating factor protein(CSF3) P09920 Mouse Csf3r
Colony stimulating factor 3 F7H1Q6 Rhesus Macaque CSF3R
Erythropoietin(EPO) P01588 Human EpoR
Thrombopoietin(THPO) P40225 Human CD110

The Member of Colony-Stimulating Factors

CSF1, CSF2, CSF3 and multi-CSF were originally defined by their respective abilities to generate different types of myeloid populations from precursor bone marrow cells in vitro[1], M-CSF stimulated macrophages, G-CSF stimulated granulocytes, GM-CSF stimulated both granulocytes and macrophages, and multi-CSF induced the growth of all hematopoietic different cell types, respectively.

Unlike the other CSFs, CSF1 has the high levels in the blood and is ubiquitously and constitutively expressed in many tissues and by many cell types; the other CSFs are usually produced only after stimulation. For instance, GM-CSF and G-CSF are produced by stimulated haemopoietic and non-haemopoietic cells, and IL-3 is emerged by stimulated T cells and mast cells. The diverse receptor distribution and potential sources of the CSFs are key to the delineation of their separate biological functions and their potential roles in pathology.

Colony-Stimulating Factor Receptors

The receptors for the diverse CSFs (as shown in the Fig.1) are quite different and are expressed on different myeloid populations. General speaking, each receptor is stimulated by a specific CSF, except for CSF1R, which binds to both CSF1 and IL-34.

The CSF1 receptor, also known as CSF1R, is expressed on monocytes and macrophages, and is the only receptor tyrosine kinase that is activated by two ligands of unrelated sequence – CSF1 and IL-34. The biologically active regions of CSF1 and IL-34 have similar cytokine folds in spite of sharing low sequence similarity. However, although existed similarities, the IL-34–CSF1R complex differs from the CSF1–CSF1R complex in many structural ways.

The structures of the CSF receptors

Fig.1. The structures of the CSF receptors

The G-CSF receptor, also called G-CSFR, is a transmembrane protein that has the largest expression in neutrophils, but G-CSFR is also present in other types of cell. Thereby, we cannot affirm that direct interactions with G-CSF only occur in granulocyte lineage populations. Besides that, ligand-induced dimerization of G-CSFR rapidly triggers numerous downstream signal transduction pathways, such as MAPK and PI3K-AKT signaling pathway[2].

The GM-CSF receptor (GM-CSFR) is expressed on monocytes, macrophages, eosinophils and neutrophils. The fundamental GM-CSFR subunit, expressed mainly on myeloid populations, comprises of a unique ligand-binding α-chain that contains three extracellular domains and a signaling β-chain. And this β-common (βc) chain is also a component of the IL-3R. Emerging evidence revealed that GM-CSFR engagement can active JAK-STAT, MAPK, NF-κB and PI3K–AKT signaling pathway[3][4] .

Like GM-CSFR, IL-3 receptor (IL-3R) is a dodecamer, highly produced by many cell types, involving monocytes, macrophages, eosinophils, basophils, plasmacytoid dendritic cells (pDCs) and mast cells.

3. Colony Stimulating Factors (CSFs) and Inflammation

CSFs later became apparent that they could also affect more mature populations in these lineages, promoting their survival and/or proliferation, activation and differentiation, all of which could be relevant to inflammation. The effects of Csf gene deficiency in mice and of specific neutralizing monoclonal antibodies (mAbs) have spurred a reassessment of the roles that these CSFs have in steady-state haematopoiesis. Each of these CSFs can play a part in the host response to tissue injury and infection, which has potential implications for inflammatory and autoimmune diseases[5][6]. Roles for the different CSFs and their targeting, particularly GM-CSF and CSF1, are increasingly being investigated in preclinical models and clinical trials of inflammatory and autoimmune diseases. In this part, we will introduce the primary CSFs and inflammation.

Macrophage colony-stimulating factor (CSF1) and Inflammation

CSF1, also known as Macrophage colony-stimulating factor (M-CSF), unlike the other CSFs, is present at high levels in the blood and is ubiquitously and constitutively expressed in many tissues and by many cell types. CSF1 is one of the most important substances known to affect macrophage physiology. The binding of CSF1 to its sole specific receptor, CSF-1R, stimulates the survival, proliferation, and differentiation of mononuclear phagocytes[7][8]. Among the various candidates, CSF1 is considered an important cytokine. The up-regulation of CSF1 and its receptor CSF-1R has been reported in brain disease, as well as in diabetic complications. However, the mechanism is unclear. An elevated level of glycated albumin (GA) is a characteristic of diabetes, thus, it may be involved in monocyte/macrophage-associated diabetic complications[9].

Inflammation involving vessels and neural tissue occurs early in diabetic retinopathy, while excessive and persistent microglial activation is believed a major contributor to the inflammatory responses. Microglial activation occurs via a complex regulatory system involving multiple signals. Accumulating evidences showed M-CSF is a key cytokine in the regulation of the microglial activation, proliferation and migration in CNS[10][11]. Moreover, the high-affinity binding of M-CSF to CSF-1R plays a role in mononuclear/macrophage-associated diabetic complications, including diabetic retinopathy. Wei Liu previous study provided the evidence that the vigorous expression of M-CSF/CSF-1R occurred in the early diabetic retina and a robust induction of CSF-1R was observed on the activated microglia[12][13][14].

Granulocyte-macrophage colony-stimulating factor protein (CSF2) and Inflammation

Granulocyte–macrophage colony-stimulating factor(GM-CSF; also known as CSF2), particularly during inflammatory responses, can be produced by a number of both haemopoietic and non-haemopoietic cell types upon their stimulation. Moreover, the ligand can activate myeloid populations to produce inflammatory mediators. Therefore, GM-CSF is a multifunctional cytokine that acts at the interface between innate and adaptive immunity[15]. Adrian Achuthan et.al. have identified a new GM-CSF-driven pathway in monocytes/macrophages leading to CCL17 formation and with upstream involvement of JMJD3-regulated IRF4. This pathway was identified in both human and murine cells in vitro, and also in vivo, in the steady state and also during inflammatory responses. This pathway appears to be separate from the GM-CSF-driven pathway(s) in monocytes/macrophages, leading to expression of other key proinflammatory cytokines[16]. Moreover, Andrew D. Cook, et.al. previously identified a new GM-CSF→JMJD3→IRF4→CCL17 pathway that is active in monocytes/macrophages in vitro and important for the development in mice of inflammatory pain, as well as of arthritic pain and disease and suggested previously that CCL17 may be a therapeutic target in inflammatory conditions where GM-CSF is important[17].

Granulocyte colony-stimulating factor and Inflammation

Granulocyte colony-stimulating factor(G-CSF; also known as CSF3), is a glycoprotein that stimulates the bone marrow to produce granulocytes and stem cells and release them into the bloodstream. Like GM-CSF, G-CSF circulates at low concentrations, but its levels are elevated as part of the host response to infection or injury. In vitro, G-CSF can be produced by many cell types upon addition of pro-inflammatory stimuli such as TNF, IL-1 or lipopolysaccharide (LPS). G-CSF is considered to be a key regulator of granulopoiesis by inducing the development of neutrophils from progenitors and by promoting neutrophil release from the bone marrow. The role of neutrophils in inflammation, even in chronic situations, is becoming widely recognized. Given that G-CSF is a key ligand that controls neutrophil numbers (through its pro-survival and trafficking regulation functions) and activation, it is likely to be crucial for many aspects of neutrophil function, thereby providing clues as to potential therapeutic indications. An important role for an IL-17–G-CSF pathway in the regulation of neutrophil homeostasis has been proposed, as IL-17 can regulate G-CSF levels, which has potential implications for anti-IL-17 therapies in development[18][19][20][21][22] .

4. The latest researches about Colony Stimulating Factors

Colony stimulating factors are used in patients who are undergoing cancer treatment that causes low white blood cell counts (neutropenia) and puts the patient at risk of infection. Colony stimulating factors tend to reduce the time where patients are neutropenic. In this part, we numerate several latest researches about colony stimulating factors.

  • Several days ago, Baig H’s team have revealed that prophylactic granulocyte colony-stimulating factor use is appropriately highest for high-risk regimens and lowest for low-risk regimens yet still potentially underused in high risk regimens, overused in low-risk regimens, and not appropriately targeted in intermediate-risk regimens, indicating a need for further education on febrile neutropenia risk evaluation and appropriate granulocyte colony-stimulating factor use.
  • George DM, et al. have published one paper that named “Prodrugs for colon-restricted delivery: Design, synthesis, and in vivo evaluation of colony stimulating factor 1 receptor (CSF1R) inhibitors” in the journal of PLoS One, on 7 September 2018. The paper suggests that a suitable therapeutic index cannot be achieved with CSF1R inhibition by using GI-restricted delivery in mice. At the same time, these efforts provide a comprehensive frame-work in which to pursue additional gut-restricted delivery strategies for future GI targets.
  • Ashrafi F1, a researcher from department of internal medicine of Isfahan University of Medical Sciences in Isfahan, has demonstrated that G-CSF and biosimilar pegylated G-CSF are effective in reducing cytopenia in breast cancer patients treated with dose-dense chemotherapy, but side effects induced by pegylated G-CSF (Pegagen) are higher.

References

1] Burgess, A. W. & Metcalf, D. The nature and action of granulocyte-macrophage colony stimulating factors[J]. Blood. 1980(56)947–958

[2] Metcalf, D. Hematopoietic cytokines[J]. Blood. 2008, 111, 485–491

[3] Masek-Hammerman, K. et al. Monoclonal antibody against macrophage colony-stimulating factor suppresses circulating monocytes and tissue macrophage function but does not alter cell infiltration/activation in cutaneous lesions or clinical outcomes in patients with cutaneous lupus erythematosus[J]. Clin. Exp. Immunol. 2016, 183, 258–270

[4] Michaelson MD, Bieri PL, et al. CSF-1 deficiency in mice results in abnormal brain development[J]. Development. 1996, 122:2661-2672

[5] Théry C, Hétier E, et al. Expression of macrophage colonystimulating factor gene in the mouse brain during development[J]. J Neurosci Res. 1990, 26:129-133

[6] Ahmed N. Advanced glycation endproducts–role in pathology of diabetic complications[J]. Diabetes Res Clin Pract. 2005, 67:3-21

[7] Michaelson MD, Bieri PL, et al. CSF-1 deficiency in mice results in abnormal brain development[J]. Development. 1996, 122:2661-2672

[8] Chitu V, Stanley ER. Colony-stimulating factor-1 in immunity and inflammation[J]. Curr Opin Immunol. 2006, 18:39-48

[9] Chow F, Ozols E, et al. Macrophages in mouse type 2 diabetic nephropathy: correlation with diabetic state and progressive renal injury[J]. Kidney Int. 2004, 65:116-128

[10] Wautier MP, Boulanger E, et al. AGEs, macrophage colony stimulating factor and vascular adhesion molecule blood levels are increased in patients with diabetic microangiopathy[J]. Thromb Haemost. 2004, 91:879-885

[11] Wei Liu1, Ge Z Xu1, et al. Macrophage colony-stimulating factor and its receptor signaling augment glycated albumininduced retinal microglial inflammation in vitro[J]. BMC Cell Biology. 2011, 12:5

[12] John A. Hamilton, Andrew D. Cook, et al. Anti-colony-stimulating factor therapies for inflammatory and autoimmune diseases[J]. Nature. 2016;12(16):53-70

[13] Adrian Achuthan, Andrew D. Cook,, et al. Granulocyte macrophage colony-stimulating factor induces CCL17 production via IRF4 to mediate inflammation[J]. The Journal of Clinical Investigation. 2016;126(9):3453–3466

[14] Achuthan A. Granulocyte macrophage colony-stimulating factor induces CCL17 production via IRF4 to mediate inflammation[J]. J Clin Invest. 2016;126(9):3453–3466.

[15] Cornish, A. L., Campbell, I. K., et al. G-CSF and GM-CSF as therapeutic targets in rheumatoid arthritis[J]. Nat. Rev. Rheumatol. 2009, 5, 554–559.

[16] Eyles, J. L., Roberts, A. W., et al. Granulocyte colony-stimulating factor and neutrophils — forgotten mediators of inflammatory disease[J]. Nat. Clin. Pract. Rheumatol. 2006, 2, 500–510.

[17] Wright, H. L., Moots, R. J, et al. The multifactorial role of neutrophils in rheumatoid arthritis[J]. Nat. Rev. Rheumatol. 2014, 10, 593–601.

[18] Stark, M. A. Phagocytosis of apoptotic neutrophils regulates granulopoiesis via IL-23 and IL-17[J]. Immunity 2005, 22, 285–294.

[19] Joshi, A. Transcription factor, promoter, and enhancer utilization in human myeloid cells[J]. J. Leukoc. Biol. 2015, 97, 985–995.

The Overview of Interferons

Interferons are named for their ability to “interfere” with viral replication by protecting cells from virus infections. As an important class of CUSABIO cytokine proteins collection, we’ve got some questions from researchers doing the related research. Combining their questions and our exploration, we write this article.

In this article, we’ll cover these topics:

1. What is Interferon

Interferon, also known as IFN, is a kind of cytokines which plays important roles in viral defense, tumor inhibition and disease treatment through cytotoxic T cells, NK cells and DC cells, etc. Interferon, produced mainly by monocytes and macrophages and positioned at different cells’surface, regulates cell growth, cell differentiation, immunoediting. CUSABIO has produced various interferon related products, including proteins, antibodies and Elisa kits.

interferon-cytokines

2. Classification of Interferon

The IFN family is consist of three main classes of cytokines, type I IFNs, type II IFN and type III IFN. Among of them, type I IFN and type II IFN are well-studied.

Type I interferon

Type I interferon includes interferon α(which can be further divided into 13 different subtypes(IFN-α1, -α2, -α4, -α5, -α6, -α7, -α8, -α10, -α13, -α14, -α16, -α17 and -α21), β, ε, к, and ω in human. All type I IFNs bind a identical common cell-surface receptor, which is known as the type I IFN receptor. The receptor for type I interferons has multichain structures, which is composed of at least two different submits, IFNAR1 and IFNAR2. Amounting research results demonstrate that type I IFNs plays a key role in microbial infection. However, each member of type I IFNs also has its unique biologic functions. For the instance, although both IFN-α and IFN-β are elicited by Cl-13 infection, losing of IFN-β signaling is the primary factor that initiates early clearance of LCMV persistent infection by blocking IFNAR. in the stage of early viral clearance, the result of blocking IFN-β similar to that observed by blocking the IFNAR despite the presence of high levels of IFN-α; The study of Ng, C.T et al. reports that blockade of at least six forms of IFN-α can not accelerate viral clearance[1]. However, IFN-α was key to controlling viral spread, as only IFN-α blockade altered early viral dissemination, manifesting that the roles played by IFN-β as compared to IFN-α in controlling viral infection are different[2].

Type II Interferon

Type II interferon, only including interferon gamma, also known as IFN γ, is a cytokine that is critical for innate and adaptive immunity against viral, some protozoal and bacterial infections. Comparing with type I interferon, the protein does not exist marked structural homology. The receptor for type II interferons also has multichain structures, which is composed of two different submits, IFNGR1 and IFNGR2. IFN γ is Produced by lymphocytes, activated by specific antigens or mitogens, and has an antiviral activity and important immunoregulatory functions. It is a potent activator of macrophages, and has antiproliferative effects on transformed cells. IFN γ is an important mediator of immunity and inflammation that utilizes the JAK-STAT signaling pathway to activate the STAT1 transcription factor. In addition, emerging evidence shows that it can enforce the antiviral and antitumor effects of the type I interferons.

Type III Interferon

Type III interferon includes interferon λ, which can be further divided into 4 distinct subtypes, IFNλ1, IFNλ2, IFNλ3 and IFNλ4 in human. However, IFNλ1-λ4 are pseudogenes in mice, which prevents the function study of these cytokines in this animal model [3][4].

The members of interferon family are shown in the table 1.

Table 1. The member of IFNs family

Gene members Uniprot ID Protein Name Receptor&Description
IFNα1 P01562 Interferon alpha-1

IFNAR1: Interferon alpha/beta receptor 1 is a component of the receptor for type I interferons. Its function in general as heterodimer with IFNAR2. Type I interferon binding activates the JAK-STAT signaling cascade, and triggers tyrosine phosphorylation of a number of proteins including JAKs, TYK2, STAT proteins and the IFNR alpha- and beta-subunits themselves. Can form an active IFNB1 receptor by itself and activate a signaling cascade that does not involve activation of the JAK-STAT pathway.

IFNAR2: Interferon alpha/beta receptor 2, associated with IFNAR1 to form the type I interferon receptor, is receptor for interferons alpha and beta. It is Involved in IFN-mediated STAT1, STAT2 and STAT3 activation. Isoform 1 and isoform 2 are directly involved in signal transduction due to their association with the TYR kinase, JAK1. Isoform 3 is a potent inhibitor of type I IFN receptor activity.

IFNα2 P01563 Interferon alpha-2
IFNα4 P05014 Interferon alpha-4
IFNα5 P01569 Interferon alpha-5
IFNα6 P05013 Interferon alpha-6
IFNα7 P01567 Interferon alpha-7
IFNα8 P32881 Interferon alpha-8
IFNα10 P01566 Interferon alpha-10
IFNα13 P01562 Interferons alpha-13
IFNα14 P01570 Interferon alpha-14
IFNα16 P05015 Interferon alpha-16
IFNα17 P01571 Interferon alpha-17
IFNα21 P01568 Interferon alpha-21
IFNβ P01574 Interferon beta
IFNε Q86WN2 Interferon epsilon
IFNκ Q9P0W0 Interferon kappa
IFNω P05000 Interferon omega
IFNγ P01579 Interferon gamma

IFNGR1: Interferon gamma receptor 1 associates with IFNGR2 to form a receptor for the cytokine interferon gamma.

IFNGR2: Interferon gamma receptor 2 associates with IFNGR1 to form a receptor for the cytokine interferon gamma. Ligand binding stimulates activation of the JAK/STAT signaling pathway.

IFNλ1 Q8IU54

IFNLR1: Interferon lambda receptor 1 is also known as IFNLR1. The IFNLR1/IL10RB dimer is a receptor for the cytokine ligands IFNL2 and IFNL3 and mediates their antiviral activity.

IL10RB: Interleukin-10 receptor subunit beta is shared cell surface receptor required for the activation of five class 2 cytokines: IL10, IL22, IL26, IL28, and IFNL1. The IFNLR1/IL10RB dimer is a receptor for the cytokine ligands IFNL2 and IFNL3 and mediates their antiviral activity.

IFNλ2 Q8IZJ0 Interferon lambda-2
IFNλ3 Q8IZI9 Interferon lambda-3
IFNλ4 K9M1U5 Interferon lambda-4

3. The Interferon Signaling Pathway

In the past two decades, accumulating evidences have revealed the mechanism of the interferon signaling pathway. Since the original discovery of the classical JAK-STAT signaling pathway, it has become clear that the connection and cooperation of multiple distinct signalling cascades are required for the generation of responses to interferons, including the mitogen-activated protein kinase p38 cascade and the phosphatidylinositol 3-kinase cascade. In this part, we focus on the most fundamental classical signaling pathway[5]. According to different type of interferon and corresponding receptors, we introduce the relevant signaling pathway, respectively.

Type I IFN Signaling Pathway

Almost all cell types particularly plasmacytoid dendritric cells(pDC) upon virus recognition can produce type I interferon. The receptors of type I interferon make up of IFNAR1 and IFNAR2. They stimulate the JAK-STAT pathway, resulting in the expression of IFN-stimulated genes(ISG), which are related to the antiviral host defense. An important transcriptional complex, induced by type I IFNs, is the ISG factor 3 (ISGF3) complex. The mature ISGF3 complex is consist of the phosphorylated STAT1 and STAT2, and combine with IRF9, which does not suffer tyrosine phosphorylation. This complex is the only complex that binds specific elements (known as IFN-stimulated response elements(ISREs)) that are present in the promoters of certain ISGs, then initiating their transcription. Overall, IFNα can be used to treat hepatitis B and C infections, while IFNβ can be used to treat multiple sclerosis. The receptors of type III interferon differ from the former one, but they have the common signaling pathway. Type III interferon plays critical roles in the antiviral host defense, predominantly in the epithelial tissues.

Type I IFN Signaling Pathway

Figure 1 Type I IFN Signaling Pathway

Type II IFN Signaling Pathway

Type II interferon(interferon gamma) is produced by activating T cells, natural killer cells and macrophages et al. upon the stimuli of cytokines like interleukin 12. The receptors of type II interferon make up of IFNGR1 and IFNGR2. The transcription of type II IFN (IFN γ)-dependent genes is regulated by GAS elements, and STAT1 is the most important IFN γ-activated transcription factor for the regulation of these transcriptional responses. After binding to the type II IFN receptor by IFN γ, JAK1 and JAK2 are activated and then phosphorylate STAT1 on the tyrosine residue. Then phosphorylated STAT1 combines with another and forms STAT1–STAT1 homodimers , which translocate to the nucleus and bind GAS elements to initiate transcription. Comparing with type I IFNs, IFN γ does not induce to form ISGF3 complexes, and thereby cannot induce the transcription of genes which have only ISREs in their promoter. In addition to having antiviral activity, type II interferon has important immunoregulatory functions as it is a potent activator of macrophages and T helper 1 cells, at the same time, it has antiproliferative, antiviral and antitumor effects.

Type II IFN Signaling Pathway

Figure 2 Type II IFN Signaling Pathway

4. The Interferon and Diseases

Interferon is so important that it is related to many diseases and the application of it should be highlighted.

Interferon gamma and Tumor

The phases of tumor immunoediting are tumor elimination, tumor dormancy and tumor escape. IFNγ takes part in every phase and the pro-infammation. IFNγ helps the induction to the apoptosis or relapse and progression of tumor.

IFNγ can induce apoptosis and nonapoptosis directly and indirectly. IFNγ can activate the expression of IRF1, a tumor suppressor, in turn, it activates the expression of Bak and reduces the expression of BCL2. These materials stimulate cytochrome c and activate caspase leading to apoptosis of tumor cells. IFNγ simulates amounts of chemicals like ROS and RNI tending to undergo apoptosis. IFNγ can also induce autophagy in human cells. IFNγ can enhance p53-mediated apoptosis and TRAIL or FAS-mediated apoptosis by STAT signaling pathway.

IFNγ can induce dormancy leading to the arrest of cancer growth depend on STAT signaling pathway directly or indirectly. It is manifested that some breast cancer genes like HER2 are dormant in some patients for a long time.

IFNγ facilitates tumor progression and relapse due to its inflammatory characteristic. Melanomas associates with macrophages which produce IFNγ. In turn, inhibiting IFNγ by UV exposure can abolish melanomas. High concentration of IFNγ may lead to NAFLD, subsequent NASH and HCC[6].

Interferon alpha and HIV

IFNα family has 13 members positioned on chromosome 9 in human. Different subtypes have high similarity in their sequence length identity as they have the same ancestor. While the affinity with their receptor, expression level and downstream signaling cascade are different from each subtype in different microenvironment. It is widely acknowledged that IFN has antiviral function. When it is induced by virus, the JAK-STAT signaling pathway is activated, the ISGs(IFN-stimulated genes) are upregulated to resist virus. However, some virus can evade from the IFN immunoregulation and the mechanism is not very clear, it is valuable to explore it deeply for the therapy.

So far, all reports on HIV or SIV infection showed different results in IFNα subtype gene expression, which strongly depended on the analyzed type of tissue, the cell or stimulus. Different IFNα subtypes induce different ISG expression patterns. Some IFNα subtypes(IFNα1, IFNα2, IFNα6, IFNα14, IFNα17 and IFNα21) strongly enhanced the mRNA expression of HIV restriction factors(Mx2, SAMHD1, Tetherin and Trim22), whereas all other IFNα subtypes only slightly increased the ISG expression compared to untreated controls in vitro. They observed that some IFNα subtypes(IFNα14, IFNα6, IFNα17 and IFNα21) potently decreased viral replication shown by cellular p24 levels and infectivity of cell culture supernatants. Interestingly, the clinically used subtype IFNα2 (for HBV therapy) only modestly suppressed HIV replication in vivo. What’s more, structural improvements of IFN might be a considerable option for future immunotherapy regimens in viral infections. It is well established that type I interferon efficiently induces antiviral restriction factors. Accumulating evidence suggests that other types of IFN, specific cytokines and other activators of the cell are also able to upregulate the expression of restriction factors and hence to establish an antiviral cellular state[7].

It was shown that the typical response to IFNα therapy for HCV-infected patients characterized by two phases of viral loads: a rapid decrease due to antiviral ISG expression and a slower decrease mediated by immune cells. Thus, the immunoregulatory activity of IFN may be required for a successful therapy of a chronic virus infection. However, type I interferon inducing immune activation can be either beneficial or harmful in HIV infection as IFNγ rather than IFNα mediates the persistent LCVM disease[2].

Interferon gamma and Tuberculosis

Tuberculosis is a serious infectious disease in our world. The defense depends on the cellular immune response mediated by T cells. IFNγ is produced by T cells, NK cells and macrophages with antiproliferation of transformed cell, antitumor and potentiating the antiviral effects of type I interferon. We obverved that mice with gko deficient could not produce IFNγ and survive well without the pathogen. After the infection of tuberculosis, mice with gko deficient live just 15±1d and have 10× to100× virus compared with the control. There are necrosis of spleen, liver and lung in the gko-knockout mice. After the injection of exogenous IFNγ can heighten the defense and prolong their survival without recovery absolutely. Macrophages activation by IFNγ is proved a resolution of tuberculosis. They have previously reported that NO, and its related gene RNI, are responsible for destruction of virulent tubercle bacilli by murine macrophages, a response that requires treatment in vitro with both IFNγ and TNFα. So that production of RNI, at least in the murine model, may be a necessary mechanism for the control of tuberculosis infection. What’s more, findings in the gko model may have relevance to tuberculosis in AIDS[8].

IFN gamma and Tolerance

IFNγ is one of the most important proinflammatory factor as it can induce the production of Th1 which initiates and maintains the inflammatory process in affected organs. To day, there are amounts of reports which associate IFNγ with immune tolerance induction, both in vitro and in vivo. It seems that these effects, either pro-inflammatory or tolerogenic, are largely dependent on the specific immunological setting and the timeline of the immune response. Dendritric cells(DCs) exerts atigen sampling and messages delivering to responding T cells originally. IFNγ can be produced by DCs and IFNγ can induce DCs activation and tolerance in some scenarios. Treatment of DCs with high doses IFNγ induces the expression of IDO which has an immunorepressive function leading to inhibiting effector T cells, and its long-term maintenance is shown to be supported by kynurenine-aryl hydrocarbon (AhR) pathway. IFNγ seems to be paradoxical that IFNγ sometimes aggravates the severity of autoimmune disease and attenuates it in others[9].

Interferon and Antiretroviraling Restriction Factors

Antiviral restriction factors is the vanguard in the defense line but it is constitutively expressed low in many cell types which should be enhanced encountering pathogens. IFN and some interleukin do this job and establish the antiviral state. The definition of restriction factors is fuzzy as it is diverse with solid function. Restriction factors like SERINC3 and SERINC5 has antiviral function without general inflammation and side effects. Restriction factors like PRRs and TLRs are receptors to restrict the pattern recognition of pathogen. High levels of IFN transiently suppresses viral replication during the chronic phase of HIV-1 infection and the induction of restriction factors contributes to this effect[4].

Interferon and Multiple Sclerosis

Multiple sclerosis(MS) is a chronic and dysregulatory disease of the central nervous system. IFNβ is the first approved and still the most widely used to treat MS. When produced in high amounts, as typically seen in acute viral infections, IFNβ up-regulates anti-inflammatory cytokines, and downregulates the pro-inflammatory ones. IFNα has similar effects of IFNβ. On the contrary, IFNγ has the opposite effects that it further induces Th1 immune response leading to the development and relapse of MS[10].

Interferon and Premature Birth

Pretern birth causes many severe health problems in children under 5 years old due to the infection and inflammation. The inflammation mediates by additional interleukin, tumor necrosis factor and IFNγ will probably cause fetal membrane damage, uterine contraction and biochemical and structural changes in the cervix. What’s more, newborns have weak and damaged innate and adaptive immune system with less IgG[11].

While IFNβ administration during early pregnancy seems to be pharmacologically safe and accumulating real-life evidence suggests that IFNβ therapies are not related to severe pregnancy problems. In consideration of these issues, IFNβ therapy might be continued in women with high risk of disease activity while trying to become pregnant. Additionally, IFNβ is not absorbed through the gastrointestinal tract, and available data suggests that the IFNβ milk levels attainable at usual doses are very low, hence, IFNβ administration seems to be safe for the baby[12][13][14].

Interferon and hepatitis C

Chronic hepatitis, caused by infection with hepatitis C virus C (HCV), also known as chronic hepatitis C (CHC), is parenterally transmitted and primarily through unsafe blood transfusions, the use of injected drugs and therapeutic injections. In humans, the only natural host for HCV is hepatocytes where the virus infects and replicates[15].

The type-1 IFNs include interferon α, β, ε, к, and ω in human. All type I IFNs have antiviral, antiproliferative and immunomodulatory activities, but their relative potencies are not different. Most forms of type I IFN have activity against HCV, yet few have been evaluated clinically[16]. Currently, the commercially available forms of IFNα used for hepatitis C (α2a, α2b and consensus IFN) have somewhat different potent in vitro but appear to yield similar response rates in treated patients. The type-1 IFNs might have similar clinical activities because they share the same, at least in part, cell-surface receptors and intracellular pathways of action. As a crucial mediator of the innate antiviral immune response, interferon alpha(IFNα) was a natural choice for treatment[17].

5. The latest research of Interferon

In this part, we are listing some latest researches about interferon.

#1 The research of Elitza S. Theel et al. suggested that the necessary transition to the QFT-Plus assay would be associated with a minimal difference in assay performance characteristics though comparison of the QuantiFERON-TB Gold Plus and QuantiFERON-TB Gold In-Tube Interferon-γ eelease assays in Patients at Risk for Tuberculosis and in healthcare workers. Please click here to obtain the article.

#2 Li F et al. demonstrated that mice deficient in E3 ligase gene Hectd3 remarkably increased host defense against infection by intracellular bacteria F. novicida, Mycobacterium, and Listeria by limiting bacterial dissemination. In the absence of HECTD3, type I IFN response was impaired during bacterial infection both in vivo and in vitro. These results indicated that HECTD3 mediated TRAF3 polyubiquitination and type I interferon induction during bacterial infection.

#3 Pulmonary, a researcher from critical care & sleep medicine of department of medicine in state university of New York, found that macrophages could be effectively immune-stimulated by aerosol therapy by repurposing IFN γ as an inhaled aerosol and targeting directly to the lung to treat a host of diseases affected by dysregulated immunity.

References

[1] Ng, C.T., Sullivan, B.M., et al. Blockade of Interferon Beta, but Not Interferon Alpha, Signaling Controls Persistent Viral Infection[J]. Cell Host Microbe.2015, 17, 653-661.

[2] Cherie T. Ng,1 Juan L. Mendoza, et al. Alpha and Beta Type 1 Interferon Signaling: Passage for Diverse Biologic Outcomes[J]. Cell. 2016, 164, 349-352.

[3] Nan Y, Wu C, et al. Interferon independent non-canonical STAT activation and virus induced inflammation[J]. Viruses, 2018(4): Apr.

[4] Kathrin S, Julia D, et al. Interferon α subtypes in HIV infection[J]. Cytokines Growth Factor Rev, 2018 Feb.

[5] Leonidas C. Platanias. Mechanisms of type I and type II interferon mediated signaling[J]. Nat Rev Immunol.2005 5(5):375-86.

[6] Aqbi HF, Wallace M, et al. IFN-γ orchestrates tumor elimination, tumor dormancy, tumor escape, and progression[J]. J Leukoc Biol, 2018 Feb.

[7] Hotter D, Kirchhoff F. Interferons and beyond: Induction of antiretroviral restriction factors[J]. J Leukoc Biol, 2018(3): 465-477.

[8] Flynn JL, Chan J, et al. An essential role for interferon γ in resistance to mycobacterium tuberculosis infection[J]. J Exp Med, 1993(6): 2249-2254.

[9] Rozman P, Svajger U. The tolerogenic role of IFN-γ[J]. Cytokines Growth Factor Rev, 2018 Apr

[10] Dumitrescu L, Constantinescu CS, et al. Recent developments in interferon-based therapies for multiple sclerosis[J]. Expert Opin Biol Ther, 2018 Apr.

[11] Helmo FR, Alves EAR, et al. Intrauterine infection, immune system and premature birth[J]. J Matern Fetal Neonatal Med, 2018(9): 1227-1233.

[12] Amato MP, Portaccio E. Fertility, pregnancy and childbirth in patients with multiple sclerosis: impact of disease-modifying drugs[J]. CNS Drugs, 2015(3): 207-220.

[13] Almas S, Vance J, et al. Management of multiple sclerosis in the breastfeeding Mother[J]. Mul Scler Int, 2016: 6527458.

[14] Hale TW, Siddiqui AA, et al.Transfer of interferon beta-1a into human breastmilk[J]. Breastfeed Med, 2012 (2):123-125.

[15] Shepard, C. W., et al. Global epidemiology of hepatitis C virus infection[J]. Lancet Infect. 2005, 5, 558-567.

[16] Robek, M. D., Boyd, et al. Lambda interferon inhibits hepatitis B and C virus replication[J]. J. Virol. 2005, 79, 3851-3854.

[17] Jordan J. Feld and Jay H. Hoofnagle. Mechanism of action of interferon and ribavirin in treatment of hepatitis C[J]. Nature.2005, 436(7053):967-72.

The Overview of Growth Factors

A growth factor, which generally considered as a series of cytokines, is a naturally occurring substance that stimulate cell growth, differentiation, survival, inflammation, and tissue repair. Usually it is a protein or a steroid hormone. Growth factors are important to regulate a variety of cellular processes, which can be secreted by neighboring cells, distant tissues and glands, or even tumor cells themselves. Normal cells show a demand for several growth factors to maintain proliferation and viability. Growth factors can exert their stimulation though endocrine, paracrine or autocrine mechanisms.

1. Growth Factors Classification

According to the database from Wikipedia, we conclude the classification of growth factors in the Table 1, which includes gene name, Uniprot ID and corresponding receptors.

Table 1. The Classification of Growth Factors

Uniprot ID Receptors
Epidermal growth factor (EGF) P01133 EGFR
Fibroblast growth factor (FGF) FGF1 P05230 FGFR1FGFR2[1]FGFR3[2]FGFR4[3]
FGF2 P09038 FGFR1FGFR2
FGF3 P11487 FGFR1FGFR2
FGF4 P08620 FGFR1FGFR2
FGF5 P12034 FGFR1
FGF6 P10767 FGFR1FGFR2
FGF7 P21781 FGFR2[4]
FGF8 P55075 FGFR1FGFR2
FGF9 P31371 FGFR2FGFR3[5]
FGF10 O15520 FGFR1FGFR2
FGF11 Q92914 None[6]
FGF12 P61328 None[6]
FGF13 Q92913 None[6]
FGF14 Q92915 None[6]
FGF15 O35622 To be supplemented
FGF16 O43320 To be supplemented
FGF17 O60258 FGFR1FGFR2
FGF18 O76093 FGFR3[7]
FGF19 O95750 FGFR1
FGF20 Q9NP95 To be supplemented
FGF21 Q9NSA1 FGFR1
FGF22 Q9HCT0 FGFR2
FGF23 FGFR1
Insulin P01308 insulin receptor (IR)
Insulin-like growth factors(IGF) IGF1 P05019 insulin receptor (IR)IGF1R
IGF2 P01344 insulin receptor (IR), GF1R, IGF2R[8]
Transforming growth factors TGF-α P01135 EGFR[9]
TGF-β1 P01137 TGFBR1
TGF-β2 P61812 TGFBR2
TGF-β3 P10600 TGFBR3
Vascular endothelial growth factor(VEGF) VEGF-A P15692 VEGFR-1, VEGFR-2
VEGF-B P49765 VEGFR-1
VEGF-C P49767 VEGFR-2VEGFR-3
VEGF-D O43915 VEGFR-3
PlGF P49763 VEGFR-1
Platelet-derived growth factor (PDGF) PDGFA P04085 PDGFRAPDGFRB
PDGFB P01127 PDGFRAPDGFRB
PDGFC Q9NRA1 PDGFRAPDGFRB
PDGFD Q9GZP0 PDGFRAPDGFRB
Neurotrophins Brain-derived neurotrophic factor (BDNF) P23560 TrkB, LNGFR
Nerve growth factor (NGF) P01138 TrkA
Neurotrophin-3 (NT-3) P20783 TrkC
Neurotrophin-4 (NT-4) P34130 TrkB
Growth differentiation factor-9 (GDF9) O60383 BMPRII, TGFBR1[9][10]
Hepatocyte growth factor (HGF) HGFR(MET)
Hepatoma-derived growth factor (HDGF) P51858 To be supplemented
Migration-stimulating factor (MSF) Q92954 CD44

2. Featured Growth Factors & Receptors

Fibroblast Growth Factors (FGFs) and Receptors

a. Fibroblast growth factors

The fibroblast growth factors are a family of cell signaling proteins, also known as potent regulators of cell proliferation, differentiation and function, which are critically important in normal development, tissue maintenance, wound repair and angiogenesis. FGFs are also associated with several pathological conditions. Mutations in FGF genes are associated with various diseases such as cardiovascular disease, osteoarthritis, hepatocellular carcinoma, intervertebral disc homeostasis and hypophosphatemia[11][12][13].

FGFs bind heparan sulfate glycosaminoglycans (HSGAGs), which facilitates dimerization (activation) of FGF receptors (FGFRs). There are 22 members of the FGF family in humans from FGF-1 to FGF-23 except for FGF-15 which exists in the mouse. All FGFs except for four members (FGF11-FGF14) bind to FGF Receptors. Because FGF11-FGF14, also known as fibroblast growth factor-homologous factors or FHF1-FHF4, share significant sequence and structural homology with FGFs, and the manner of binding HS is similar to the FGFs. In contrast, Olsen et al. And Mohammadi et al. Who analysed FHF-mediated FGFR activation showed that FHFs are incapable of activating any of the four FGFRs, likely as a result of the structural incompatibility of the FGFR interacting region[14][15]. According to the present stage of knowledge, FHFs act as intracellular signaling molecules that function independently of FGFRs, via interaction with islet brain-2 scaffold protein and voltage-gated sodium channels, as discussed in detail later[16]. Based on phylogenetic analysis, the human FGF family can be further divided into seven subfamilies; FGF1-FGF2, FGF4-FGF6, FGF 3/7/10/22, FGF 8/17/18, FGF 9/16/20, FGF 11-FGF14, and FGF 19/21/23. Some other research discoveries showed that FGF24 and 25 are exist in zebra fish, but no data is available about their mammalian counterparts[17][18].

b. Fibroblast growth factors receptors

The fibroblast growth factor receptors, also known as FGFRs, are receptors that bind to members of the fibroblast growth factor family of proteins. FGFRs are single-pass transmembrane receptors with extracellular ligand-binding domains and an intracellular tyrosine kinase domain that have intracellular tyrosine kinase activity, and belong to the family of receptor tyrosine kinases (RTK)[19]. Activation of RTKs by their respective ligands induces kinase activation that in turn initiates intracellular signaling networks that ultimately orchestrate key cellular processes, such as cell proliferation, growth, differentiation, migration, and survival. In this way, RTKs play pivotal biological roles during the development and adult life of multicellular organisms. FGFRs are associated with several pathological conditions, such as cancer cell migrations[20], tumor initiation and progression[21], carcinogenesis[22], congenital skeletal dysplasias[23], et al. Mutations in FGFR genes are associated with various diseases such as breast cancer[24], bladder cancer[25], gastric cancer[26], clear-cell renal cell carcinoma[27], developmental corruption and malignant disease[28]et al.

The FGFRs includes four genes encoding closely related transmembrane, tyrosine kinase receptors (termed FGFR1 to FGFR4). A typical FGFR consists of a signal peptide that is cleaved off, three immunoglobulin (Ig)–like domains, an acidic box, a transmembrane domain, and a split tyrosine kinase domain.

Transforming growth factors & receptors

a. Transforming growth factors

Transforming growth factor, also known as Tumor growth factor, or TGF, is used to refer to two classes of polypeptide growth factors, Transforming growth factor alpha (TGFα) and transforming growth factor beta (TGFβ). TGFα and TGFβ are autocrine/paracrine growth factors that are classically thought of as potent promoters and inhibitors of cell growth, respectively, in normal tissues[29][30][31].

TGFα is upregulated in some human cancers and acts through the EGF receptor. It is produced in macrophages, keratinocytes and brain cells, and induces epithelial development. TGFα is also thought to be invovlved in the pathogenesis process of hepatocarcinogenesis. TGFβ acts through the TGFβ receptor (TGFβR) and exists in three known isoforms in humans, TGFβ1, TGFβ2, and TGFβ3[32], which are upregulated in colorectal adenomas and cancer, and directly associated with more advanced tumor characteristics[33][34]. Moreover, they also play crucial roles in tissue regeneration, cell differentiation, embryonic development, and regulation of the immune system. Isoforms of transforming growth factor-beta (TGF-β1) are also involved in the pathogenesis of epithelial-mesenchymal transition via the NF-κB pathway[35]. TGFβ receptors are single pass serine/threonine kinase receptors[36].

b. Transforming growth factors receptors

In the last paragraph, we have introduced that the receptor of TGFα is epidermal growth factor receptor ( also known as EGFR), which is a transmembrane protein that is a receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligands, and the receptor of TGFβ also has three isoforms in humans, TGFRI, TGFRII and TGFRIII.

EGFR is a transmembrane protein that is activated by binding of its specific growth factor ligands, including TGFα and epidermal growth factor. Upon activation by its specific ligands, EGFR turns to be a transition from an inactive monomeric form to an active homodimer. Mutations that EGFR overexpression, also known as upregulation or amplification, have been associated with several cancers, including squamous-cell carcinoma of the lung, anal cancers, glioblastoma and epithelian tumors of the head and neck[37]. Aberrant EGFR signaling has been implicated in inflammatory disease and monogenic disease. Furthermore, EGFR also has been reported to play a critical role in TGFβ1 dependent fibroblast to myofibroblast differentiation[38].

The Transforming Growth Factor beta (TGFβ) receptors are a superfamily of serine/threonine kinase receptors. There are three isoforms receptors bind members of the TGFβ superfamily of growth factor, TGFRβ1, TGFRβ2, TGFRβ3, can be distinguished by their structural and functional properties. TGFβR1 (also known as ALK5) and TGFβR2 have similar ligand-binding affinities and can be differentiated from each other just by peptide mapping. Both TGFβR1 and TGFβR2 have a high affinity for TGFβ1 and low affinity for TGFβ2. TGFβR3 (also known as β-glycan) has a high affinity for both homodimeric TGFβ1 and TGFβ2 and the heterodimer TGF-β1.2. The TGFβ receptors also bind TGFβ3.

Vascular endothelial growths factor and Receptors

a. Vascular endothelial growth factors

Vascular endothelial growth factors, also known as vascular permeability factor (VPF), or VEGF, constitute a sub-family of growth factors produced by cells that stimulate the formation of blood vessels and a mitogen for vascular endothelial cells. VEGFs are important signaling proteins involved in both vasculogenesis, the de novo formation of the embryonic circulatory system, and angiogenesis, the growth of blood vessels from pre-existing vasculature. There are five members in the vascular growth factor family, include VEGF-A, VEGF-B, VEGF-C, VEGF-D and placenta growth factor (PlGF). VEGF-A is the first discovery member of the vascular endothelial growth factor family. Vascular endothelial growth factors are key mediators of angiogenesis that is crucial for development and metastasis of tumors. Overexpression of VEGF can contribute to disease. Solid cancers cannot grow beyond a limited size without an adequate blood supply; cancers that can express VEGF are able to grow and metastasize. When VEGF is overexpressed, it can cause vascular disease in the retina of the eye and other parts of the body. Drugs can inhibit VEGF and control or slow those diseases, such as aflibercept, bevacizumab, ranibizumab and pegaptanib sodium (Macugen).

b. Vascular endothelial growth factor Receptors

All members of the VEGF family stimulate cellular responses by binding to tyrosine kinase receptors (the VEGFRs) on the cell surface, causing them to be dimer and become activated through transphosphorylation. The VEGFRs have an extracellular portion, which is consist of 7 immunoglobulin-like domains, a single transmembrane spanning region and an intracellular portion containing a split tyrosine-kinase domain. There are three main subtypes of VEGFR, numbered 1, 2 and 3, also known as Flt-1, KDR/Flk-1 and Flt-4, respectively.

VEGF-A binds to VEGFR-1 (Flt-1) and VEGFR-2 (KDR/Flk-1). VEGFR-2 appears to mediate almost all of the known cellular responses to VEGF, which can combines with VEGF-A, VEGF-C, VEGF-D and VEGF-E[39]. Although VEGFR-1 is thought to modulate VEGFR-2 signaling, the function of VEGFR-1 is less well defined. Another function of VEGFR-1 is to act as a dummy/decoy receptor, sequestering VEGF from VEGFR-2 binding. In fact, an alternatively spliced form of VEGFR-1 (sFlt1) is not a membrane bound protein but is secreted and functions primarily as a decoy[40]. A third receptor has been discovered (VEGFR-3), however, VEGF-A is not a ligand for this receptor. VEGFR-3 mediates lymphangiogenesis by binding to VEGF-C and VEGF-D.

3. The Signaling Pathways, Most Popular with Researchers

TGF-β Signaling Pathway

In TGF-β signaling pathway, the family members of TGF-βs include TGF-betas, activins and bone morphogenetic proteins (BMPs), which are structurally related secreted cytokines found in various species ranging from insects to mammals. TGF-β signaling pathway is involved in many cellular processes, including cell growth, cell differentiation, apoptosis, cellular homeostasis, et al.

The image of TGF-β signaling pathway

Fig. 1. The image of TGF-β signaling pathway

The mechanism includes four parts, Ligand binding, Receptor recruitment and phosphorylation, CoSMAD binding, and Transcription. TGF-beta family ligands binds to the type II receptor and recruits Type I, whereby type I receptor is phosphorylated and activated by type II receptor. Then, the type I receptor phosphorylates receptor-activated Smads(R-Smads: Smad1, Smad2, Smad3, Smad5, and Smad8). Once phosphorylated, R-Smads combine with the co-mediator Smad, Smad4, and the heteromeric complex then translocates into the nucleus. In the nucleus, Smad complexes activate specific genes through cooperative interactions with other DNA-binding and coactivator (or co-repressor) proteins.

VEGF Signaling Pathway

When a VEGF binds to its receptor, the receptor can transiently exert its kinase activity and form a complex with an intracellular tyrosine or serine/threonine kinase. Then, the activated receptors result in the activation of other proteins in the signaling pathway and the production of various second messengers. Finally, these signals are transmitted into the nucleus and induce the expression of specific genes.

The image of VEGF signaling pathway

Fig. 2. The image of VEGF signaling pathway

Now, although the evidence that VEGFR-2 is the major mediator of VEGF-driven responses in endothelial cells also is not very much, it is considered to be a crucial signal transducer in both physiologic and pathologic angiogenesis. The binding of VEGF to VEGFR-2 leads to form receptor dimer, then, followed by intracellular activation of the PLCγ; Subsequently, PKC-Raf kinase-MEK-mitogen-activated protein kinase (MAPK) pathway and initiation of DNA synthesis and cell growth, whereas activation of the phosphatidylinositol 3′ -kinase (PI3K)-Akt pathway leads to increased endothelial-cell survival. Activation of PI3K, FAK, and p38 MAPK is implicated in cell migration signaling.

Wnt Signaling Pathway

The Wnt signaling pathway is a group of signal transduction pathway made of proteins that pass signals into a cell through cell surface receptors.

The image of Wnt signaling pathway

Fig. 3. The image of Wnt signaling pathway

Wnt signaling diversifies into three main branches: 1. The canonical Wnt pathway, also known as classical, activates target genes through stabilization of β-catenin in the nucleus. The function of this pathway during embryonic development has been originally elucidated by experimental analysis of axis development in the frog Xenopus laevis and of segment polarity and wing development in the fly Drosophila melanogaster. 2. The planar cell polarity pathway involves RhoA and Jun Kinase (JNK) and controls cytoskeletal rearrangements. Its main role is the temporal and spatial control of embryonic development, as exemplified in the polar arrangement of cuticular hairs in Drosophila or the convergent-extension movements in Xenopus embryos. 3. The Wnt/Ca2+ pathway is stimulated by Wnt 5a and Wnt 11 and involves an increase in intracellular Ca2+ and activation of Ca2+-sensitive signalling components, such as calmodulin-dependent kinase, the phosphatase calcineurin, and the transcription factor NF-AT.

4. The Latest Researches of Growth Factor

  • Komaki Y’s team have revealed that hepatocyte growth factor facilitates esophageal mucosal repair and inhibits the submucosal fibrosis in a rat model of esophageal ulcer. If you want to know more information, please click here to view the article.
  • Regeenes R1, Silva PN, et al. have demonstrated that fibroblast growth factor receptor 5 (FGFR5) is a co-receptor for FGFR1 that is up-regulated in beta-cells by cytokine-induced inflammation. If you want to know more information, please click here to view the article.
  • Breit A1, Miek L, et al. have found that insulin-like growth factor-1 acts as a zeitgeber on hypothalamic circadian clock gene expression via glycogen synthase kinase-3β signaling. If you want to know more information, please click here to view the article.

References

[1] Stauber DJ, DiGabriele AD, et al. Structural interactions of fibroblast growth factor receptor with its ligands[J]. Proceedings of the National Academy of Sciences of the United States of America. 2000, 97 (1): 49–54

[2] Santos-Ocampo S, Colvin JS, et al. Expression and biological activity of mouse fibroblast growth factor-9[J]. The Journal of Biological Chemistry. 1996, 271 (3): 1726–31

[3] Ornitz DM, Xu J, et al. Receptor specificity of the fibroblast growth factor family [J]. The Journal of Biological Chemistry. 1996, 271(25):15292-15297

[4] Duchesne L, Tissot B, et al. N-glycosylation of fibroblast growth factor receptor 1 regulates ligand and heparan sulfate co-receptor binding [J]. The Journal of Biological Chemistry. 2006, 281(37):27178-27189

[5] Davidson D, Blanc A, et al. Fibroblast growth factor (FGF) 18 signals through FGF receptor 3 to promote chondrogenesis[J]. The Journal of Biological Chemistry. 2005, 280(21):20509-20515

[6] Chellaiah A, Yuan W, et al. Mapping ligand binding domains in chimeric fibroblast growth factor receptor molecules. Multiple regions determine ligand binding specificity[J]. The Journal of Biological Chemistry. 1999, 274 (49): 34785–94

[7] Pavel Krejci, Jirina Prochazkoval, et al. Molecular pathology of the fibroblast growth factor family[J]. Hum Mutat. 2009, 30(9): 1245–1255

[8] Laureys G, Barton DE, et al. Chromosomal mapping of the gene for the type II insulin-like growth factor receptor/cation-independent mannose 6-phosphate receptor in man and mouse[J]. Genomics.1988, 3 (3): 224–9

[9] Ojeda, S. R.; Ma, Y. J., et al. The transforming growth factor alpha gene family is involved in the neuroendocrine control of mammalian puberty[J]. Molecular Psychiatry. 1997, 2 (5): 355–358

[10] Gilchrist, R., Lane, M., et al. Oocyte-secreted factors: regulators of cumulus cell function and oocyte quality[J]. Human Reproduction Update. 2008, 14(2), pp.159-177

[11] Yun, Y.-R., Won, J. E., et al. Fibroblast growth factors: biology, function, and application for tissue regeneration[J]. Tissue Eng. 2010, 218142

[12] Coleman SJ, Grose RP, et al. Fibroblast growth factor family as a potential target in the treatment of hepatocellular carcinoma[J]. J Hepatocell Carcinoma. 2014, 29;1:43-54

[13] Ellman MB, An HS, et al. Biological impact of the fibroblast growth factor family on articular cartilage and intervertebral disc homeostasis[J]. Gene. 2008, 15;420(1):82-9

[14] Olsen SK, Garbi M, et al. Fibroblast growth factor (FGF) homologous factors share structural but not functional homology with FGFs[J]. J Biol Chem. 2003, 278:34226–34236

[15] Mohammadi M, Dikic I, et al. Identification of six novel autophosphorylation sites on fibroblast growth factor receptor 1 and elucidation of their importance in receptor activation and signal transduction[J]. Mol Cell Biol. 1996; 16:977–989

[16] Goldfarb M. Fibroblast growth factor homologous factors: evolution, structure, and function[J]. Cytokine Growth Factor Rev. 2005; 16:215–220

[17] Roy NM, Sagerstrom GG. An early Fgf signal required for gene expression in the zebrafish hindbrain primordium[J]. Brain Res Dev Brain Res. 2004; 148(1): 27-42

[18] Katoh Y, Katoh M. Comparative genomics on FGF7, FGF10, FGF22, orthologs, and identification of fgf25[J]. Int J Mol Med. 2005; 16(4): 767-70

[19] Schlessinger J. Cell signaling by receptor tyrosine kinases[J]. Cell. 2000, 103:211–25

[20] Nguyen T, Mège RM. N-Cadherin and Fibroblast Growth Factor Receptors crosstalk in the control of developmental and cancer cell migrations[J]. Eur J Cell Biol. 2016, 95(11):415-426

[21] Feng S, Zhou L, et al. Fibroblast growth factor receptors: multifactorial-contributors to tumor initiation and progression[J]. Histol Histopathol. 2015, 30(1):13-31

[22] Haugsten EM, Wiedlocha A, et al. Roles of fibroblast growth factor receptors in carcinogenesis[J]. Mol Cancer Res. 2010, 8(11):1439-52

[23] Sanak M. Molecular genetics of congenital skeletal dysplasias related to mutations of fibroblast growth factor receptors[J]. Med Wieku Rozwoj. 1999, 3(1):67-82

[24] Wang S, Ding Z. Fibroblast growth factor receptors in breast cancer[J]. Tumour Biol. 2017, 39(5):1010428317698370

[25] Morales-Barrera R, Suárez C, et al. Targeting fibroblast growth factor receptors and immune checkpoint inhibitors for the treatment of advanced bladder cancer: New direction and New Hope[J]. Cancer Treat Rev. 2016, 50:208-216

[26] Inokuchi M, Fujimori Y, et al Therapeutic targeting of fibroblast growth factor receptors in gastric cancer[J]. Gastroenterol Res Pract. 2015, 2015:796380

[27] Sonpavde G, Willey CD, et al. Fibroblast growth factor receptors as therapeutic targets in clear-cell renal cell carcinoma[J]. Expert Opin Investig Drugs. 2014, 23(3):305-15

[28] Kelleher FC, O’Sullivan H, et al. Fibroblast growth factor receptors, developmental corruption and malignant disease[J]. Carcinogenesis. 2013, 34(10):2198-205

[29] Lemmon MA, Schlessinger J. Cell signaling by receptor tyrosine kinases[J]. Cell. 2010, 141:1117–1134

[30] Potter JD. Colorectal cancer: molecules and populations[J]. J Natl. Cancer Inst. 1999, 91:916–932

[31] Ikushima H, Miyazono K. TGFbeta signalling: a complex web in cancer progression[J]. Nat Rev Cancer 2010, 10:415-424

[32] Huakang Tu, Thomas U. Ahearn, et al. Transforming Growth Factors and Receptor as Potential Modifiable Pre-Neoplastic Biomarkers of Risk for Colorectal Neoplasms[J]. MOLECULAR CARCINOGENESIS. 2015, 54:821-830

[33] Bellone G, Gramigni C, et al. Abnormal expression of Endoglin and its receptor complex (TGF-beta1 and TGF-beta receptor II) as early angiogenic switch indicator in premalignant lesions of the colon mucosa[J]. Int J Oncol. 2010, 37:1153–1165

[34] Hawinkels LJ, Verspaget HW, et al. Active TGF-beta1 correlates with myofibroblasts and malignancy in the colorectal adenoma-carcinoma sequence[J]. Cancer Sci. 2009, 100:663–670

[35] Li Y, Zhu G, et al. Simultaneous stimulation with tumor necrosis factor-α and transforming growth factor-β1 induces epithelial-mesenchymal transition in colon cancer cells via the NF-κB pathway[J]. Oncol Lett. 2018, 15(5):6873-6880

[36] Badawy AA, El-Hindawi A, et al. Impact of epidermal growth factor receptor and transforming growth factor-α on hepatitis C virus-induced hepatocarcinogenesis[J]. APMIS. 2015, 123(10):823-31

[37] Walker F, Abramowitz L, et al. Growth factor receptor expression in anal squamous lesions: modifications associated with oncogenic human papillomavirus and human immunodeficiency virus[J]. Human Pathology. 2009, 40 (11): 1517–27

[38] Midgley AC, Rogers M, et al. Transforming growth factor-β1 (TGF-β1)-stimulated fibroblast to myofibroblast differentiation is mediated by hyaluronan (HA)-facilitated epidermal growth factor receptor (EGFR) and CD44 co-localization in lipid rafts[J]. The Journal of Biological Chemistry[J]. 2013, 288 (21): 14824–38

[39] Holmes K, Roberts OL, et al. Vascular endothelial growth factor receptor-2: structure, function, intracellular signalling and therapeutic inhibition[J]. Cell Signal. 2007, 19 (10): 2003–2012

[40] Zygmunt T, Gay CM, et al. Semaphorin-PlexinD1 Signaling Limits Angiogenic Potential via the VEGF Decoy Receptor sFlt1[J]. Dev Cell. 2011, 21 (2): 301–314

CANCER

Cancer is a group of diseases that involve abnormal cell growth with the potential to invade or spread to other parts of the body. They form a subset of neoplasms. Comparing with benign tumors, which do not spread to other parts of the body. A neoplasm or tumor is a group of cells that have undergone unregulated growth and will often form a mass or lump, but may be distributed diffusely.

Melanoma, the Most Serious Type of Skin Cancer

1. What is Melanoma?

Melanoma, usually referred to as malignant melanoma, is a highly malignant tumor derived from melanocytes which control the pigment in your skin. The figure 1 shows melanoma cells extending from the surface of the skin into the deeper skin layers. Melanoma occurs mostly in the skin, but also in the mucous membrane and viscera, accounting for about 3% of all tumors. Melanoma is the deadliest form of skin cancer and strikes tens of thousands of people around the world each year. The number of cases is rising faster than any other type of solid cancer.

a diagram of melanoma
Figure 1. a diagram of melanoma

In 2020, the American Cancer Society’s estimates that there will have approximately 100,350 new melanomas diagnosed (about 60,190 in men and 40,160 in women), and 6,850 deaths from melanoma (about 4,610 men and 2,240 women). The rates of melanoma have been rising rapidly over the past few decades, but this has varied by age. So how does melanoma develop?

 

2. How does Melanoma Develop?

Melanoma occurs when something goes wrong in melanocytes, the cells producing the pigment melanin. Normally, skin cells develop in a controlled and orderly way — healthy new cells push older cells toward to the surface of skin, where they die and eventually fall off. But when some cells undergo DNA damage, new cells may start to grow out of control and can eventually form a mass of cancerous cells. So what damages DNA in skin cells?

In fact, it isn’t still clear. It may be a combination of factors, including environmental and genetic factors, causes melanoma. Currently, doctors believe exposure to ultraviolet (UV) radiation from the sun and from tanning lamps and beds is the leading cause of melanoma. UV light doesn’t cause all melanomas, especially those that occur in places on your body that don’t receive exposure to sunlight. This suggests that other factors may contribute to your risk of melanoma.

 

3. What are the Risk Factors of Melanoma?

As mentioned previously, exposure to ultraviolet (UV) radiation and other sources of ultraviolet light, like tanning beds, is a very important risk factor. In addition to the ultraviolet light, factors that may increase risk of melanoma include:

  • Race. The American Cancer Society states that the lifetime risk of developing melanoma is about 2.6% for white people, 0.1% for Black people and 0.6% for Hispanic people. Accumulating evidence has revealed that melanoma in white people is 20 times more common than black people.
  • A family history of melanoma. If a close relative (such as a parent, child or sibling) has had melanoma, you may have a greater chance of developing melanoma.
  • Weakened immune system. People with weakened immune systems also have an increased risk of melanoma and other skin cancers. Your immune system may be impaired if you take medicine to suppress the immune system, such as after an organ transplant, or if you have a disease that impairs the immune system, such as AIDS.
  • Age. The risk of melanoma grows as you age. The average age at diagnosis is 65, even though it’s one of the most common cancers among young adults.

 

4. What are the Symptoms of Melanoma?

Studies reported that the origin of melanocytes is associated with the fetal period and the melanocyte precursors. The melanocyte precursors are produced in the neural ridge which migrate to various localizations in the body during fetal development, including the skin, meningeal coverings, mucous membrane, the upper part of esophagus, and the eyes. So melanoma can develop by malignant transformation of melanocytes anywhere on your body [2] [3]. The most likely areas, though, are chest and back for men, legs for women, neck and face, because these areas have more exposure to the sun than other parts of the body.

The first symptoms of melanoma often are changes in an existing mole and the development of a new pigmented or unusual growth on your skin. Clues that a mole might be melanoma are: irregular shape, irregular border, multicolored or uneven coloring, larger than a quarter of an inch, changes in size, shape, or color, itchiness or bleeding. Sometimes, the skin will appear normal even though melanoma has begun to develop.

As well as sun exposure, distinct genetic alterations have been identified as associated with melanoma [4]. In the next section, we illustrate the mechanisms of melanoma as brief.

 

5. What are the Mechanisms of Melanoma?

Melanoma caused by transformation of melanocytes requires a complex interaction of exogenous and endogenous events. There are tremendous progress has been reported to make in unravelling the genetic basis of melanoma [5] [6] [7]. As the figure 2a shows, under normal conditions, mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3‑kinase (PI3K)–AKT signaling permit balanced control of basic cellular functions, including cell cycle regulation, survival, motility and metabolism.

However, in melanoma, several genetic alterations depicted in the figure 2b are frequently observed, leading to constitutive pathway activation (indicated by thick arrows) and loss of cellular homeostasis. Malignant transformation can require combinations of genetic defects. The functional consequences of genetic events determine whether mutations can coexist or remain mutually exclusive. For example, mutations in NRAS and BRAF occur very rarely in the same melanoma cell, whereas combined genetic alterations of BRAF and PTEN are common.

signaling pathways in melanoma
Figure 2. signaling pathways in melanoma
*this diagram is derived from publication on Nature Reviews.

 

6. How to Diagnose Melanoma?

There are a series of tests and procedures used to diagnose melanoma, including:

  • Physical examination. Your doctor will ask questions about your health history and examine your skin carefully to look for signs (as mentioned on section 4) that may indicate melanoma.
  • Blood chemistry studies. As the levels of lactate dehydrogenase (LDH) can be higher than normal when you have melanoma, you will be informed to check this enzyme in your blood. But note that LDH levels may not be checked for early stage disease.
  • Skin biopsy. It usually refers to removing a sample of tissue for testing, and is the only way to confirm melanoma. The sample removed from your skin is sent to a lab for examination. If at all possible, the entire suspected area should be removed.
  • Lymph node biopsy. If melanoma is diagnosed, your doctor may need to find out if cancer cells have spread, though they won’t do this for melanoma in situ. The first step is to perform a sentinel node biopsy.
  • Imaging tests. Imaging tests are used to see if cancer has spread beyond the skin to other parts of the body. These tests include CT scan, MRI and PET scan.

 

7. What are the Treatment of Melanoma?

If there’s a diagnosis of melanoma, it’s important to determine the stage. This will provide information on your overall outlook and help guide treatment. Treatment depends on the stage of melanoma. Melanoma is staged based on the size of the tumor and the extent to which the cancer has spread. The stages of melanoma are divided into five stages. We collect the stages and treatments of melanoma on the following table.

Description Treatments
Stage 0 The tumor is in the epidermis and has not spread elsewhere. The suspicious tissue of melanoma in stage 0 is possible to be completely removed during a biopsy. You may not need further treatment.
Stage 1 The tumor is less than 2 mm thick, is developing slowly and hasn’t spread to other organs. Very thin melanomas can be completely removed during biopsy. If not, they can be surgically removed later. This involves removing the cancer along with a margin of healthy skin and a layer of tissue underneath the skin. Early-stage melanoma doesn’t necessarily require additional treatment.
Stage 2 The tumor is from 1-4+ mm thick, may be ulcerated, and hasn’t spread to other organs.
Stage 3 The cancer has spread to nearby skin or lymph nodes, lymph nodes may be enlarged, and the developing tumor may be ulcerated. In stage 3, wide-excision surgery is used to remove the tumor and affected lymph nodes. In stage 4, The skin tumors and some enlarged lymph nodes can be removed by surgery. Moreover, you also need to have surgery to remove tumors on internal organs based on the number, size, and location of tumors.
Stage 4 The cancer has spread to distant organs or lymph nodes. At this stage the cancer may be referred to as a metastatic melanoma.

Besides, stages 3 and 4 generally require some additional treatments, involving:

  • Immunotherapy drugs. Currently, the immunotherapy drugs usually include interferon or interleukin-2 (IL-2) or checkpoint inhibitors, such as ipilimumab, nivolumab, and pembrolizumab.
  • Targeted therapy for those cancers related to mutations in the BRAF gene. These may include cobimetinib, dabrafenib, trametinib, and vemurafenib.
  • Targeted therapy for melanoma related to mutations in the C-KIT gene. These may include imatinib and nilotinib.
  • Vaccines. These may include Bacille Calmette-Guerin (BCG) and T-VEC (Imlygic).
  • Radiation therapy. This is used to shrink tumors and to kill cancer cells that may have been missed during surgery. Radiation can also help relieve symptoms of cancer that has metastasized.
  • Isolated limb perfusion. This involves infusing only the affected arm or leg with a heated solution of chemotherapy.
  • Systemic chemotherapy. This may include dacarbazine (DTIC) and temozolomide (Temodar), which may be used to kill cancer cells throughout your body.

 

 

References

[1] Karl Smart, Ian Pope, Robert Sullivan. MELANOMA [J]. Nature. 2014, 515: S109.

[2] Ribas A, Slingluff CL, Rosenberg SA. Cutaneous Melanoma [J]. Principles and Practice of Oncology. 2015. pp. 1346-94.

[3] Coricovac D, Dehelean C, Moaca EA, et al. Cutaneous melanoma long road from experimental models to clinical outcome: a review [J]. Int J Mol Sci. 2018, 19:1566.

[4] Dirk Schadendorf, David E. Fisher, Claus Garbe, et al. Melanoma [J]. NATURE REVIEWS. 2015.

[5] Bastian, B. C. The molecular pathology of melanoma: an integrated taxonomy of melanocytic neoplasia [J]. Annu. Rev. Pathol. 2014, 9, 239–271.

[6] Sheppard, K. E. & McArthur, G. A. The cell-cycle regulator CDK4: an emerging therapeutic target in melanoma [J]. Clin. Cancer Res. 2013, 19, 5320–5328.

[7] Shi, J. et al. Rare missense variants in POT1 predispose to familial cutaneous malignant melanoma [J]. Nat. Genet. 2014, 46, 482–486.

 

Leukemia, Why is it So Common?

Upon mentioned leukemia, marrow transplantation and anemia as keywords of leukemia come to your mind. Leukemia is the most common cancer in children and teens, accounting for almost 1 out of 3 cancers. Usually, the number of new cases of leukemia diagnosed in the United States each year is about 14 per 100,000 men and women. It is the tenth most common cancer according to new cases diagnosed each year. Leukemia accounts for 3.5% of all new cancer cases in the United States. So what is the leukemia? And what are the types of leukemia? This article collect several FAQ of leukemia, including:

1. What is Leukemia?

Leukemia is a malignant clonal disease of hematopoietic stem cells. Leukemia cells in the clone will stop at different stages of cell development due to uncontrolled proliferation, differentiation failure, and obstructed apoptosis. In bone marrow and other hematopoietic tissues, leukemia cells proliferate and accumulate in large numbers, and infiltrate other tissues and organs, causing normal hematopoietic function to be inhibited. As the figure 1 shows, normal blood contains red blood cells (RBCs), white blood cells (WBCs), and platelets. Leukemia cells outnumber normal cells in leukemia.

a diagram of components of normal blood and leukemia
Figure 1. a diagram of components of normal blood and leukemia

Generally speaking, leukemia refers to cancers of the WBCs. WBCs play a vital role in protecting body from invasion by bacteria, viruses, and fungi. In leukemia, the WBCs have an abnormal unlike normal WBCs. They divide too quickly and eventually crowd out normal cells. Most of WBCs are produced in the bone marrow, but certain types of WBCs are also made in the lymph nodes, spleen, and thymus gland.

2. What are The Types of Leukemia?

In fact, there are many types of leukemia in clinic. Based on different speed of disease development, leukemia is divided into two types, including acute leukemia and chronic leukemia. In acute leukemia, leukemia cells multiply rapidly and the disease progresses quickly. In chronic leukemia, the disease progresses slowly and early symptoms may be very mild.

Most often, leukemia is a cancer of the white blood cells, but some leukemias start in other blood cell types. According to different cell types, leukemia is classified into two types. One is myelogenous leukemia developing from the myeloid cell line. Another is lymphocytic leukemia developing from the lymphoid cell line.

Hence, there are four major types of leukemia in clinic. As the following table shows, acute myelogenous leukemia is the most common form of leukemia. The five-year survival rate of chronic lymphocytic leukemia is the highest. Most childhood leukemias are acute lymphocytic leukemia (ALL). Most of the remaining cases are acute myeloid leukemia (AML). Chronic leukemias are rare in children.

Acute myeloid leukemia Acute lymphocytic leukemia Chronic myelogenous leukemia Chronic lymphocytic leukemia
Abbreviation AML ALL CML CLL
Prone group Children and adults Children Adults Adults
annual new cases in the United States 21,000 6,000 9,000 20,000
Five-year survival rate 26.9% 68.2% 66.9% 83.2%

In addition to these four main types of leukemia, there also are various subtypes of leukemia. Subtypes of lymphocytic leukemia include hairy cell, Waldenstrom’s macroglobulinemia, prolymphocytic, and lymphoma cell leukemia.

3. How does Leukemia Develop?

What causes leukemia? This question is frequently asked by patients and parents alike. As mentioned previously, blood has three types of cells, involving red blood cells, white blood cells, and platelets. White blood cells fight infection, red blood cells carry oxygen, and platelets help blood clot. Every day, your bone marrow produces billions of new blood cells, and most of them are red cells. When you have leukemia, your body produces more white cells than it needs.

These leukemia cells can’t fight infection as well as white blood cells do. And because there are so many of them, they start to affect the function of your organs. Over time, you may not have enough red blood cells to carry oxygen, enough platelets to clot your blood, and enough normal white blood cells to fight infection.

Generally, leukemia develops when the DNA of some blood cells (mainly white cells) mutates or damages, disabling their ability to guide the action of cells. Certain abnormalities cause the cell to grow and divide more rapidly and to continue living when normal cells would die. Over time, these mutated cells replace the healthy blood cells and crowd out healthy blood cells in the bone marrow, leading to fewer healthy white blood cells, red blood cells and platelets, causing the signs and symptoms of leukemia.

4. What are the Symptoms of Leukemia?

Different types of leukemia can cause different problems. You might not notice any signs in the early stages. Although the signs and symptoms aren’t enough to diagnose the disease, they can be clues for you and your doctor so that you can find the problem as soon as possible. When you do have symptoms, they may include:

Poor blood clotting: This can cause a person to bruise or bleed easily and heal slowly.

Red spots on the skin: These red spots, also called petechiae develop when immature white blood cells crowd out platelets, which are crucial for blood clotting.

Frequent infections: The white blood cells are crucial for fighting infection. If white blood cells don’t function correctly, a person may develop frequent infections.

Anemia: As fewer effective red blood cells become available, a person may become anemic. This means that they do not have enough hemoglobin in their blood.

Additionally, the symptoms of leukemia also include weakness or fatigue, fever or chills, pain in your bones or joints, weight loss, night sweats, shortness of breath and swollen lymph nodes or organs like your spleen. Leukemia can also cause symptoms in organs that have been infiltrated by the cancer cells. For example, if the cancer spreads to the central nervous system, it can cause headaches, nausea and vomiting, confusion, loss of muscle control, and seizures. Furthermore, leukemia can also spread to other parts of your body, including: the lungs, gastrointestinal tract, heart and kidneys.

5. What are the Causes and Risk Factors of Leukemia?

What causes leukemia? This question is frequently asked by patients and parents alike [1]. Currently, scientists don’t understand the exact causes of leukemia. It seems to develop from a combination of genetic and environmental factors. Most subtypes of childhood leukemia have their initial genetic mutation before birth [2] and only a fraction of these preleukemic clones will progress to the development of leukemia.

You can’t prevent leukemia, but certain things (called risk factors) may trigger it. A risk factor is anything that affects your chance of getting a disease. But having one or more risk factors does not mean that you will get the disease. However, it’s still important to know about the risk factors for leukemia because there may be things you can do that might lower your risk of getting it. The risks of leukemia include:

  • Exposure to high levels of radiation or chemotherapy: This could include having received radiation therapy or chemotherapy for a previous cancer, although this is a more significant risk factor for some types than others.
  • Certain viruses: The human T-lymphotropic virus (HTLV-1) has links to leukemia.
  • Exposure to benzene: This is a solvent that manufacturers use in some cleaning chemicals and hair dyes.
  • Have a family history of leukemia: Having siblings with leukemia can lead to a low but significant risk of leukemia. If a person has an identical twin with leukemia, they have a 1 in 5 chance of having the cancer themselves.
  • Have a genetic disorder like Down syndrome: Children with Down syndrome have a third copy of chromosome 21. This increases their risk of acute myeloid or acute lymphocytic leukemia to 2–3%, which is higher than in children without this syndrome.
  • Smoking, which increases your risk of developing acute myeloid leukemia (AML).
  • Immune suppression: Childhood leukemia may develop because of the deliberate suppression of the immune system. This might occur after an organ transplant when a child takes medications to prevent their body from rejecting the organ.

6. How to Diagnose Leukemia?

Leukemia may be suspected if you have concerning symptoms. Your doctor will begin with

Blood tests: a complete physical examination, but leukemia can’t be fully diagnosed by a physical exam. So doctors will further to use blood tests, biopsies, and imaging tests to make a diagnosis.

Blood tests: A complete blood count is usually used to determine the numbers of RBCs, WBCs, and platelets in the blood.

 

Biopsies: Tissue biopsies can be obtained from the bone marrow or lymph nodes to look for evidence of leukemia. The type of leukemia and its growth rate can be identified by these small samples. Moreover, biopsies of other organs, like the liver and spleen, can suggest if the cancer has spread.

Once leukemia is diagnosed, it’ll be staged. Staging helps your doctor determine your outlook. And a number of other tests can be used to assess the progression of the disease, including flow cytometry (determining their growth rate), liver function tests (whether leukemia cells are affecting or invading the liver), lumbar puncture (whether the cancer has spread to the central nervous system) and Imaging tests (such as X-rays, ultrasounds, and CT scans, help doctors look for any damage to other organs that’s caused by the leukemia).

7. What are the Treatment of Leukemia?

The treatment of Leukemia usually depends on the type of the cancer a person has, their age, and their overall state of health. Some types of leukemia grow slowly and don’t need immediate treatment. However, if treatment starts early, the chance of a person achieving remission is higher. Types of treatment for leukemia usually involves one or more of the following:

Watchful waiting: A doctor may not actively treat slower growing leukemias, such as chronic lymphocytic leukemia (CLL).

Chemotherapy, a primary treatment for AML, uses drugs to target and kill leukemia cells through a drip or a needle. According to different types of leukemia, you may take a single drug or a combination of different drugs. However, besides killing cancer cells, they can also damage noncancerous cells and cause severe side effects, including hair loss, weight loss, and nausea.

Radiation therapy uses high-energy radiation to destroy bone marrow tissue before a transplant. Radiation can be applied to a specific area or to your entire body.

Stem cell transplantation replaces diseased bone marrow with healthy bone marrow to create noncancerous blood cells, either your own or from a donor. This procedure is also called a bone marrow transplant. Before transplantation, your doctor will destroy the existing bone marrow with chemotherapy, radiation therapy, or both.

Immune therapy uses treatments that help your immune system recognize and attack cancer cells [3].

Targeted therapy uses tyrosine kinase inhibitors that target cancer cells without affecting other cells, reducing the risk of side effects. For example, imatinib (Gleevec) is a targeted drug that’s commonly used against CML.

References

[1] Gary Dahl and Joseph Wiemels. What Causes Leukemia [J]? Pediatr Blood Cancer. 2015, 62:1123–1124.

[2] Greaves MF, Wiemels J. Origins of chromosome translocations in childhood leukaemia [J]. Nat Rev Cancer. 2003, 3:639–649.

[3] Evan M. Hersh, Jordan U. Gutterman, and Giora M. Immunotherapy of leukemia [J]. Medical Clinics of North America. 1976.

Endometrial Cancer, a Female Killer That is Easily Ignored

1. What is Endometrial Cancer?

Endometrial cancer, sometimes also called uterine cancer, starts in the layer of cells that form the lining (endometrium) of the uterus (Figure 1). Most uterine cancers start as endometrial cancer. Other types of cancer can form in the uterus, including uterine sarcoma, but all of them are much less common than endometrial cancer. Endometrial cancer affects mainly post-menopausal women. The mean age of women diagnosed with endometrial cancer is 61 years, with most cases diagnosed in women between the ages of 50 and 60 years [1] [2]. It’s uncommon in women under the age of 45.

a diagram of endometrial cancer
Figure 1. a diagram of endometrial cancer

According to the National Cancer Institute, approximately 3 in 100 women will be diagnosed with endometrial cancer at some point in their lives. More than 80 percent of people with endometrial cancer survive for five years or longer after receiving the diagnosis.

2. What are The Types of Endometrial Cancer?

Endometrial cancer commonly has been classified into two types. Type I commonly is estrogen-related and accounts for about 80% of endometrial cancers. It usually occurs in younger, obese, or perimenopausal women. These tumors are usually low-grade and mainly secondary to endometrial hyperplasia. The degree of malignancy is not high, and it is closely related to estrogen exposure without progesterone resistance. The risk factors for type I endometrial cancer are relatively clear, including exposure to more endogenous estrogen or exogenous estrogen. These tumors may show microsatellite instability and mutations in PTEN, PIK3CA, K-ras, and CTNNBI [3].

Type II is relatively rare. It was originally called non-estrogen-dependent. It occurs in an older cohort of women than type I, and is mainly high-grade serous cell carcinoma and clear cell carcinoma. These tumors may exhibit p53 mutations in approximately 10–30% of cases. Type II disease represents up to 10% of cases. The epidemiologic profile of women with type II disease is not certain. In this article, we focus on the type I endometrial cancer.

3. What Are The Symptoms of Endometrial Cancer?

Unlike most other cancers in the U.S, endometrial cancer is rising in both incidence and associated mortality [4]. The patient with endometrial cancer usually has some symptoms as follows:

  • Vaginal bleeding: A small number of early endometrial cancers may have no symptoms and are difficult to detect clinically. But 90% of the main symptoms of endometrial cancer are various vaginal bleeding, including after menopause and between periods. Among of them, Postmenopausal vaginal bleeding is the main symptom of endometrial cancer patients, and more than 90% of postmenopausal patients see a doctor with vaginal bleeding symptoms.
  • Menstrual disorders: About 20% of endometrial cancer patients are perimenopausal women, and only 5%-10% of young women under 40 years old. Patients may present with changes in the length or heaviness of menstrual periods.
  • Abnormal vaginal discharge: a small amount of serous or bloody discharge can be seen in the early stage. In the late stage, local infection and necrosis occurred due to the increase in tumor volume, and foul-smelling pus and blood-like fluid was discharged.
  • Pain: It is mostly low abdominal pain and discomfort, which can be caused by empyema or effusion in the uterus. In the late stage, the disease spreads to the parauterine tissue ligaments or compresses nerves and organs, and lower limbs or lumbosacral pain may also occur.
  • Others: The enlarged uterus in the lower abdomen can be palpable in advanced patients, and systemic failure such as anemia, weight loss, fever, and cachexia can occur.

4. How is Endometrial Cancer Diagnosed?

Endometrial cancer is most often diagnosed after a woman see a doctor. The doctor will ask about the woman’s symptoms, risk factors, and medical history. Moreover, the doctor will also do a pelvic exam and a physical exam. Procedures used to diagnose endometrial cancer usually include:

  • Examining the pelvis. During a pelvic exam, your doctor carefully inspects the outer portion of your genitals, and then inserts two fingers of one hand into your vagina and simultaneously presses the other hand on your abdomen to feel your uterus and ovaries. Additionally, He or she also inserts a device called a speculum into your vagina. The speculum opens your vagina so that your doctor can view your vagina and cervix for abnormalities.
  • Using sound waves to take pictures of the inside of the body. A transducer or probe gives off sound waves and picks up the echoes as they bounce off the organs. A computer translates the echoes into pictures. Your doctor may recommend a transvaginal ultrasound to look at the thickness and texture of the endometrium and help rule out other conditions.

To find out exactly what kind of endometrial change is present, the doctor usually does the following procedures.

  • Using a scope to examine your endometrium. During a hysteroscopy, your doctor inserts a very thin, flexible, lighted tube via your vagina and cervix into your uterus.
  • Removing a sample of tissue for testing. To get a sample of cells from inside your uterus, you’ll likely undergo an endometrial biopsy. This involves removing tissue from your uterine lining for laboratory analysis.
  • Dilation and curettage (D&C). If biopsy sample doesn’t provide enough tissue or if the biopsy results are unclear, a D&C must be done. During D&C, tissue is scraped from the lining of your uterus and examined under a microscope for cancer cells.

5. What are The Stages of Endometrial Cancer?

Over time, endometrial cancer can potentially spread from the uterus to other parts of the body. Once you have been diagnosed as endometrial cancer, doctor works to determine the stage of your cancer. Tests used to determine your cancer’s stage may include a chest X-ray, a computerized tomography (CT) scan, positron emission tomography (PET) scan and blood tests (including complete blood count and CA-125 blood test). The final determination of your cancer’s stage may not be made until after you undergo surgery. Generally, the cancer is classified into five stages based on how much it has grown or spread:

Stages Description
Stage 0 Cancerous cells remain where they started, on the surface of the inner lining of the uterus.
Stage 1 The cancer has spread through the inner lining of the uterus to the endometrium and possibly to the myometrium — the middle layer of the uterine wall.
Stage 2 The cancer is present in the uterus and cervix.
Stage 3 The cancer has spread outside the uterus, but not as far as the rectum or bladder. It might be present in the fallopian tubes, ovaries, vagina, and/or nearby lymph nodes.
Stage 4 The cancer has spread beyond the pelvic area. It might be present in the bladder, rectum, and/or distant tissues and organs.

6. What are The Risk Factors for Endometrial Cancer?

A risk factor is anything that increases your chance of getting a disease. Different cancers have different risk factors. Some risk factors, such as smoking or sun exposure, can be changed. But, others, like a person’s age or family history, can’t be changed. The epidemiology of endometrial cancer includes women with genotypic and phenotypic risk, including:

  • Obesity – raises oestrogen levels. Obesity is one of the most important risk factors for this disease, and as rates of obesity have risen, rates of endometrial cancer have also increased. Obesity and conditions associated with metabolic syndrome, including diabetes and polycystic ovary syndrome, are risk factors for the development of endometrial cancer [5] [6] [7]. In the U.S, 57% of all endometrial cancers are attributable to obesity.
  • Reproductive, menstrual, and medical risk comorbidities can increase or decrease the risk of a woman having development of endometrial cancer [8]. Continuous estrogen stimulation, albeit it exogenous or endogenous, like taking estrogen after menopause, birth control pills, or tamoxifen, can alter the normal endometrial cycle.
  • Using an intrauterine device (IUD) for birth control seem to have a lower risk of getting endometrial cancer. Information about this protective effect is limited to IUDs that do not contain hormones.
  • Age. The risk of endometrial cancer increases as a woman gets older.
  • Family history. Endometrial cancer tends to run in some families with the history of endometrial, colorectal, or breast cancer.

7. What are The Treatments for Endometrial Cancer?

The stage of endometrial cancer is the most important factor in choosing treatment. In another word, Treatment depends upon the stage. Generally speaking, surgery is the first treatment for almost all women diagnosed as endometrial cancer. The operation includes removing the uterus, fallopian tubes, and ovaries. Lymph nodes from the pelvis and around the aorta may also be removed and tested for cancer spread. And pelvic washings may be done, too. The tissues removed at surgery are tested to see how far the cancer has spread (the stage, please see the section 5). Depending on the stage of the cancer, other treatments, such as radiation and/or chemotherapy may be recommended.

For some women who still want to be able to get pregnant, surgery may be put off for a time and other treatments tried instead. If a woman isn’t well enough to have surgery, other treatments, like radiation, will be used.

References

[1] Sorosky JI. Endometrial cancer [J]. Obstet Gynecol. 2008, 111: 436–47.

[2] Joel I. Sorosky. Endometrial cancer [J]. OBSTETRICS & GYNECOLOGY. 2012, 120 (2): 383-397.

[3] Prat J, Gallardo A, Cuatrecasas M, et al. Endometrial carcinoma: pathology and genetics [J]. Pathology. 2007, 39: 1–7.

[4] Henley SJ, Ward EM, Scott S, et al. Annual report to the nation on the status of cancer. I. National cancer statistics [J]. Cancer. 2020, 126: 2225-49.

[5] Lauby-Secretan B, Scoccianti C, Loomis D, et al. Body fatness and cancer — viewpoint of the IARC Working Group [J]. N Engl J Med. 2016, 375: 794-8.

[6] Saed L, Varse F, Baradaran HR, et al. The effect of diabetes on the risk of endometrial cancer: an updated a systematic review and meta-analysis [J]. BMC Cancer. 2019, 19: 527.

[7] Karen H. Lu, and Russell R. Broaddus. Endometrial Cancer [J]. N Engl J Med. 2020, 383: 2053-64.

[8] Brinton LA, Berman ML, Mortel R, et al. Reproductive, menstrual, and medical risk factors for endometrial cancer: results from a case-control study [J]. Am J Obstet Gynecol 1992, 167: 1317–25.

Bladder Cancer, A Malignancy that Favors Men

Bladder cancer is a common malignancy in women and is the fourth most common malignancy in men [1]. Men’s risk is 3-4 times that of women. In 2020, the American Cancer Society estimates that there will have been approximately 81,400 new cases of bladder cancer (about 62,100 in men and 19,300 in women) and 17,980 deaths from bladder cancer (about 13,050 in men and 4,930 in women) in the U.S. The rates of new bladder cancers and deaths linked to bladder cancer and have been dropping slightly in women in recent years. In men, incidence rates have been decreasing, but death rates have been stable. So what is bladder cancer? And how to prevent yourself from it? Continuing to read this article…

1. What is Bladder Cancer?

Bladder cancer refers to a malignant tumor that occurs on the cells of bladder. The bladder is a hollow muscular organ in your lower abdomen that stores urine (Figure 1). Bladder cancer most often begins in the cells (also called urothelial cells) that line the inside of your bladder. It is the most common malignant tumor of the urinary system and one of the ten most common tumors throughout the body. Its incidence is second only to prostate cancer in the West. Bladder cancer can occur at any age, even in children. The incidence rate increases with age, with a high incidence age of 50 to 70 years.

Male urinary system
Figure 1. Male urinary system

In 2004, the pathological types of bladder cancer in the histological classification of urinary system tumors in the WHO “Urinary System and Male Reproductive Organ Tumor Pathology and Genetics” include bladder urothelial carcinoma, bladder squamous cell carcinoma, bladder adenocarcinoma, and other rare (including bladder clear cell carcinoma, bladder small cell carcinoma and bladder carcinoid). The most common one is bladder urothelial cancer, which accounts for more than 90% of the total number of bladder cancer patients. The commonly referred to as bladder cancer refers to bladder urothelial cancer (formerly called bladder transitional cell carcinoma).

2. What are The Symptoms of Bladder Cancer?

No matter what’s your age, it’s good to know the possible symptoms of bladder cancer. Although they aren’t enough to diagnose the disease, they can be clues for you and your doctor so that you can find the problem as soon as possible. Treatment works best early on, when a tumor is small and hasn’t spread. These symptoms are important to see your doctor so they can take a closer look at your health and take action. Bladder cancer symptoms may include blood in urine (hematuria), frequent urination, painful urination and back pain.

Among of them, blood in urine is the main symptom of bladder cancer. About 90% of patients with bladder cancer have hematuria in the initial clinical manifestations, usually painless, intermittent, gross hematuria, and sometimes microscopic hematuria. Hematuria may only occur once or last for 1 day to several days, and can be relieved or stopped by itself. It often gives the patient with the hematuria the illusion of healing after taking the medicine.

3. What are The Stages of Bladder Cancer?

Before learning the stages of bladder cancer, we need to know the structure of bladder. The bladder consists of three layers of tissue (Figure 2). The innermost layer of the bladder (called mucosa or urothelium), which comes in contact with the urine stored inside the bladder. The middle layer is a thin lining (known as the “lamina propria”) and forms the boundary between the inner “mucosa” and the outer muscular layer. This layer has a network of blood vessels and nerves and is an important landmark of the staging of bladder cancer. The outer layer of the bladder (the “muscularis”) comprises of the “detrusor” muscle. This is the thickest layer of the bladder wall.

Types and stages of bladder cancer.
Figure 2. Types and stages of bladder cancer.
*This figure is derived from the publication on Nat Rev Dis Primers[2]

As the Figure 2 shows, bladder cancer generally originates from the urothelium of the bladder and is referred to as urothelial carcinoma, which is the most common type of bladder cancer. Papillary tumors that are limited to mucosa or have invaded the lamina propria are classified as Ta and T1, respectively. Carcinoma in situ (Tis) is a flat, poorly differentiated tumor confined to mucosa. Stage 2 is that tumors have invaded the muscle layer either superficially (T2a) or deeply (T2b). T3 tumors have invaded beyond the muscularis propria into perivesical fat (T3a invasion is microscopic, T3b is macroscopic). T4a tumours have invaded the prostate, uterus, vagina and/or bowel, whereas T4b tumours have invaded the pelvic or abdominal walls [3].

4. Mechanisms of Bladder Cancer?

Current studies have shown that bladder cancer, like many other cancers, is due to a variety of carcinogenic factors acting on normal cells for a long time, leading to the activation of proto-oncogenes, and failure to repair damaged DNA in time during the replication and transcription process, affecting the cell cycle and causing unlimited replication and proliferation of cancer cells.

In terms of mechanisms of bladder cancer, metabolism of bladder cancer represents a key issue for cancer research [4]. Several metabolic altered pathways are involved in bladder tumorigenesis. In this section, we list the main metabolic pathways involved in the pathogenesis of bladder cancer.

Tumor cells, including urothelial cancer cells, rely on a peculiar shift to aerobic glycolysis-dependent metabolism (the Warburg-effect) as the main energy source to sustain their uncontrolled growth and proliferation. And the high glycolytic flux usually depends on the overexpression of glycolysis-related genes, including SRC-3, GLUT1, GLUT3, LDHA, LDHB, HK1, HK2, PKM, and HIF-1a, leading to an overproduction of pyruvate, alanine and lactate.

Concurrently, bladder cancer metabolism also displays an increased expression of genes G6PD and FASN, and companies with a decrease of AMPK and Krebs cycle activities. G6PD is favored in the pentose phosphate pathway, and FASN is favored in the fatty-acid synthesis. Moreover, the PTEN/PI3K/AKT/mTOR pathway, as central regulator of aerobic glycolysis, is hyper-activated in bladder cancer, contributing to cancer metabolic switch and tumor cell proliferation. Besides glycolysis, glycogen metabolism pathway also plays a robust role in bladder cancer development.

5. What are The Risk Factors for Bladder Cancer?

The etiology of bladder cancer is currently unclear. There are both internal factors and external environmental factors. The two more clear risk factors for disease are smoking and occupational exposure to aromatic amine chemicals.

Smoking is currently the most certain risk factor for bladder cancer. 30% to 50% of bladder cancer is caused by smoking. Comparing to people without smoking, smoking can increase the risk of bladder cancer by 2 to 6 times. With the prolongation of smoking, the incidence of bladder cancer also significantly increased.

Another important disease risk factor is related to a series of occupations or occupational exposure. It has been confirmed that aniline, diaminobiphenyl, 2-naphthylamine, and 1-naphthylamine are all carcinogens of bladder cancer. People with long-term exposure to these chemicals are more likely to develop bladder cancer. Patients with bladder cancer caused by occupational factors account for 25% of the total number of bladder cancer patients. Industries related to bladder cancer include aluminum products, coal tar, asphalt, dyes, rubber, and coal gasification.

In addition, according to a report issued by the International Agency for Research on Cancer (IARC) on October 17, 2013, air pollution is also one of the human carcinogens, and its carcinogenic risk is classified as the first category. The report pointed out that there is sufficient evidence that air pollution not only has a causal relationship with lung cancer, but also increases the risk of bladder cancer. So far, haze is also one of the clear carcinogenic factors.

6. What are The Treatments for Bladder Cancer?

Urothelial carcinoma of the bladder is divided into non-muscle invasive urothelial carcinoma and muscle invasive urothelial carcinoma. Patients with non-muscular invasive urothelial carcinoma usually use transurethral resection of the bladder tumor, followed by bladder perfusion to prevent recurrence.

Patients with muscular invasive urothelial carcinoma, bladder squamous cell carcinoma, and adenocarcinoma are mostly treated with total cystectomy, and some patients can be treated with partial cystectomy. Patients with muscular invasive urothelial carcinoma can also be treated with neoadjuvant chemotherapy and surgery first. Metastatic bladder cancer is dominated by chemotherapy. Commonly used chemotherapy regimens include M-VAP (methotrexate + vinblastine + adriamycin + cisplatin), GC (gemcitabine + cisplatin) and MVP (methotrexate + The vinblastine + cisplatin) regimen, the effective rate of chemotherapy is 40% to 65%.

7. What Treatments are needed to Better Prevent Recurrence after Surgery?

Bladder cancer has the characteristics of multifocality and implantation, so the recurrence rate after surgery is high. Therefore, after bladder cancer surgery, adjuvant treatment is usually needed. So, what treatments are needed after bladder cancer surgery?

As mentioned previously, patients with non-muscular invasive urothelial carcinoma will be treated with bladder perfusion therapy. Bladder perfusion therapy is to inject anticancer drugs into the bladder to kill tumor cells remaining after surgery. There are two main types of drugs for bladder perfusion therapy, one is chemotherapeutics and the other is immunotherapy, and chemotherapy drugs are currently more commonly used. The chemotherapeutics used for bladder cancer include birubicin, epirubicin, adriamycin and mitomycin. For most bladder cancers, bladder infusion chemotherapy can significantly reduce the risk of tumor recurrence after surgery.

In addition to bladder perfusion therapy, regular cystoscopy is also very important. In low-risk patients, there was no recurrence after the cystoscopy was rechecked 3 months after the operation. The next cystoscopy can be checked 1 year after the operation. Then once a year for 5 years. But, high-risk patients need to review the cystoscopy every 3 months for 2 years after the operation, and every 6 months from the 3rd year, and once a year after the 5th year.

8. How to prevent yourself from Bladder Cancer?

Although there’s no guaranteed way to prevent bladder cancer, you can take the following steps to help reduce your risk.

Increase drinking water: Researchers from Harvard University in the United States conducted a 10 year follow-up study on nearly 50,000 American men between the ages of 40 and 75, and found that men who drink 6 large glasses of plain water a day have a lower risk of bladder cancer than those who drink only 1 cup. It may be that the liquid will excrete carcinogens from the body before they can affect the bladder. Thereby reducing the chance of attaching to the bladder wall. Note that, in order to minimize the intake of the chemical components in the water, the water must be boiled.

Quit smoking and alcohol: Studies have shown that cigarettes contain nicotine, tar, tobacco-specific nitrosamines and other toxic carcinogens. People who smoke a lot have a higher concentration of carcinogens in the urine. If the daily smoking index reaches 600 (number of cigarettes smoked per day × number of years of smoking), it has reached the risk of bladder cancer. Therefore, early quitting smoking and drinking can minimize the risk of bladder cancer.

Adhere to scientific eating habits and eat more fresh vegetables and fruits: Eat as little meat as possible, because meat can produce substances similar to aniline and benzidine during the process of metabolism in the body. An investigation found that workers exposed to chemical raw materials such as aniline and benzidine suffer more from bladder cancer.

References

 

Cervical Cancer, One of the Most Common Killers of Women

1. What is the Cervical Cancer?

Cervical cancer is a type of cancer that occurs in the cells of the cervix-the lower part of the uterus that connects to the vagina (Figure 1). It is the most common gynecological malignancy. This cancer can affect the deeper tissues of their cervix and may spread to other parts of their body, often the lungs, liver, bladder, vagina, and rectum.

a diagram of cervical cancer
Figure 1. a diagram of cervical cancer

Cervical cancer is mainly divided into two types, including squamous cell carcinoma and adenocarcinoma. Among of them, squamous cell carcinoma begins in the thin, flat cells (squamous cells) lining the outer part of the cervix, which projects into the vagina. It is the main type of cervical cancers. Adenocarcinoma begins in the column-shaped glandular cells that line the cervical canal. Actually, less commonly, cervical cancer have features of both squamous cell carcinomas and adenocarcinomas. This type of cervical cancer is also called adenosquamous carcinomas or mixed carcinomas.

2. What is the Cause of Cervical Cancer?

Generally, cervical cancer begins when healthy cells in the cervix develop changes or mutations in their DNA. The mutations tell the cells to grow and multiply out of control, and they don’t die. And the accumulating abnormal cells form a tumor. Cancer cells invade nearby tissues and can break off from a tumor to metastasize elsewhere in the body.

Currently, accumulating evidence has revealed that most cervical cancer are caused by the sexually transmitted human papillomavirus (HPV), which is a group of about 100 related virus. Some of them cause a type of growth called papillomas, which are more commonly known as warts. In addition to HPV infection, there are also several other things that can increase your risk of cervical cancer, including having HIV (the virus that causes AIDS), smoking, taking birth control pills for a long time (five or more years), having given birth to three or more children and having several sexual partners. So what is HPV? And how does HPV infection cause cervical cancer?

3. What is HPV?

HPV encompass more than 120 different types that may infect human skin and mucosa. HPV is a relatively small, non-enveloped virus, 55 nm in diameter. The HPV gene consists of a single molecule of double-stranded, circular DNA containing approximately 7,900 bp associated with histones. All open reading frame (ORF) protein-coding sequences are restricted to one strand. The gene is functionally divided into three regions. The first is a noncoding upstream regulatory region of 400 to 1,000 bp, which has been referred to as the noncoding region, the long control region (LCR), or the upper regulatory region. The second is an early region, consisting of ORFs E1, E2, E4, E5, E6, and E7, which are involved in viral replication and oncogenesis. The third is a late region, which encodes the L1 and L2 structural proteins for the viral capsid (Figure 2) [3] [4].

Schematic representation of the circular HPV DNA gene
Figure 2. Schematic representation of the circular HPV DNA gene
*This figure is derived from the publication on Clin. Microbiol[4]

Among of these HPVs, Only 13–15 are found in cervical cancers and other malignancies and are called ‘high risk’ HPV (HPV-HR) [5]. HPV 16 is the most important HPV-HR-type, and HPV 18 is the second. HPV 16 and 18 are associated with two thirds of all cervical cancers. HPV-HR differs from other HPV types by oncogenic properties of two proteins E6 and E7 that may interfere with cell regulation and differentiation. In fact, uterine cervix infected with HPV is very common, especially in women in their early 20s. Most infections will clear spontaneously and only a minority will finally persist for many years and decades.

4. How does HPV Infection Cause Cervical Cancer?

As mentioned before, being infected with a cancer-causing strain of HPV doesn’t mean you’ll get cervical cancer. As the figure 3 shows, your immune system eliminates the vast majority of HPV infections and prevents the virus from doing serious harm within two years. But sometimes, the virus survives for years (generally 10-30 years). The virus can lead to the conversion of normal cells on the surface of the cervix into cancerous cells.

How HPV damages cells
Figure 3. How HPV damages cells
*This figure is derived from The Nobel Committee for Physiology or Medicine 2008 illustration: Annika Rohl

Regarding of pathogenesis of oncogenic HPV, as HPVs encode only 8 to 10 proteins, they must employ host cell factors to regulate viral transcription and replication. The replication of HPV begins with host cell factors which interact with the LCR region of the HPV gene and begin transcription of the viral E6 and E7 genes. The proteins encoded by E6 and E7 gene deregulate the host cell growth cycle via binding and inactivating tumor suppressor proteins, cell cyclins, and cyclin-dependent kinases (Fig. 2) [6]. The function of the proteins encoded by E6 and E7 gene during a productive HPV infection is to bind to cellular p53 and pRB proteins, disrupt their functions, and alter cell cycle regulatory pathways, leading to cellular transformation.

Pathogenesis of oncogenic HPV
Figure 4. Pathogenesis of oncogenic HPV
*This figure is derived from the publication on Clin. Microbiol[4]

5. How is Cervical Cancer Diagnosed?

In terms of diagnosis, doctors usually use many tests to find, or diagnose, cancer. Here, we describe the most common examination and tests for cervical cancer diagnosis. If you are suspected with cervical cancer, your doctor may do a colposcopy to check the cervix for abnormal cells. During the colposcopic examination, your doctor will take a sample of cervical cells for laboratory testing. There are two ways to obtain tissue. One is using punch biopsy, which involves using a sharp tool to pinch off small samples of cervical tissue. Another is using endocervical curettage, which uses a small, spoon-shaped instrument (curet) or a thin brush to scrape a tissue sample from the cervix.

If the biopsy indicates that cervical cancer is really present, the doctor will recommend the woman to a gynecologic oncologist, which is a doctor who specializes in treating cervical cancer. The specialist may suggest additional tests to see whether the cancer has spread beyond the cervix, such as pelvic examination under anesthesia, X-ray, computed tomography (CT or CAT) scan, magnetic resonance imaging (MRI) and positron emission tomography (PET) or PET-CT scan.

6. What are the Treatments for Cervical Cancer?

Treatment for cervical cancer depends on the kind of cervical cancer and how far it has spread. Treatments include surgery, chemotherapy, radiation therapy and a combination of the three.

First, surgery is the typical treatment in the early-stage cervical cancer. According to different size of your cancer, its stage and whether you would like to consider becoming pregnant in the future, there are three options of surgery, including cutting away the cancer only, removing the cervix and hysterectomy.

Second, chemotherapy is a drug treatment that uses special medicines to shrink or kill the cancer. The drugs can be pills you take or medicines given through your veins, or sometimes both. For locally advanced cervical cancer, low doses of chemotherapy are often combined with radiation therapy, since chemotherapy may enhance the effects of the radiation. Higher doses of chemotherapy might be recommended to help control symptoms of very advanced cancer.

Third, Radiation therapy uses high-energy rays to kill the cancer. Radiation therapy is often combined with chemotherapy as the primary treatment for locally advanced cervical cancers. It can also be used after surgery if there’s an increased risk that the cancer will come back.

7. How to Prevent Yourself from Cervical Cancer?

Actually, cervical cancer is one of the few cancers that’s almost totally preventable. It comes down to avoiding HPV, which is sexually transmitted. As mentioned before, HPV is the primary cause of cervical cancer. But it doesn’t always cause the disease. Many people have HPV and don’t develop cervical cancer.

If you’re sexually active, you will be informed to have Pap or HPV tests, which can find abnormal cells in your cervix before the cancer starts. In addition, there’s also an HPV vaccine that you might want to get. It targets some of the strains of HPV that are the riskiest. And HPV vaccine is usually the most common way to prevent yourself from cervical cancer.

Regarding to HPV vaccine, there are three kind of HPV vaccine now, including 2-valent, 4-valent and 9-valent HPV vaccine. The 2-valent vaccine, suitable for women aged 9-45, has a protective effect on two high-risk types (HPV-16 and HPV-18). The 4-valent HPV vaccine is suitable for women aged 20-45. Two low-risk types HPV-6 and HPV-11 are added to the bivalent HPV vaccine, which can prevent the four types of HPV6, 11, 16, 18 infections. The 9-valent HPV vaccine, suitable for women aged 16-26, is a non-infectious recombinant vaccine prepared from the purified virus-like particles (VLPs) of the major capsid (L1) protein of HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. It is an upgraded version of the 4-valent vaccine. The WHO pointed out: From the perspective of public health, there is no significant difference in the immunogenicity of the 2-valent, 4-valent, and 9-valent vaccines in terms of effectiveness in preventing HPV-related types 16 and 18.

References

[1] Campos NG, Sharma M, Clark A, et al. The health and economic impact of scaling cervical cancer prevention in 50 low- and lower-middle-income countries [J]. Int J Gynaecol Obstet. 2017;138 (suppl 1): 47-56.

[2] Carla J. Chibwesha, Jeffrey S. A. Cervical Cancer as a Global Concern Contributions of the Dual Epidemics of HPV and HIV [J]. JAMA. 2019, 332 (16):1558-1560.

[3] Apt, D., R. M. Watts, G. Suske, et al. High Sp1/Sp3 ratios in epithelial cells during epithelial differentiation and cellular transcription correlate with the activation of the HPV-16 promoter [J]. Virology. 1996, 224:281–291.

[4] Eileen M. Burd. Human Papillomavirus and Cervical Cancer [J]. Clin. Microbiol. Rev. 2003, 16(1):1.

[5] KARL ULRICH PETRY. HPV and cervical cancer [J]. Scandinavian Journal of Clinical & Laboratory Investigation. 2014, 74(Suppl 244): 59–62.

[6] Syrja¨nen, S. M., and K. J. Syrja¨nen. New concepts on the role of human papillomavirus in cell cycle regulation [J]. Ann. Med. 1999, 31:175–187.

Ovarian Cancer – The Silent Killer

1. Histological Classification of Ovarian Cancer

According to the origin of tumor cells, ovarian cancer can be divided into three types: epithelial tumor, stromal tumor and germ cell tumor.

1.1 Epithelial Tumor

Epithelial tumors are derived from the germinal epithelium of the ovary, which is the predominant form of ovarian cancer. About 90% of ovarian cancers are epithelial tumors. These tumors may be benign or malignant.

1.2 Stromal Tumor

This ovarian cancer is derived from the specific sex stroma of the ovary and is therefore also called sex stromal tumor. About 7% of ovarian cancers are stromal tumor. It includes granulosa cell tumor, theca cell tumor, fibroma, androblastoma, gynandroblastoma and the like. In general, theca cell tumor and fibroma are benign tumors, others are low-grade malignant tumors.

1.3 Germ Cell Tumor

Germ cell tumors are derived from germ cells of the ovary. It usually happens to young people. In addition, there are metastatic tumors, which refer to malignant tumors originating from other organs, including the digestive tract and other organs of the gynecology.

Among ovarian cancer, 90% to 95% are primary ovarian cancers, and only 5% to 10% are metastatic ovarian cancer.

2. Symptoms of Ovarian Cancer

There are almost no symptoms in the early stage of ovarian cancer, and even if there are symptoms, it is not specific. It’s difficult to diagnosis it in the early stage of ovarian cancer. When receiving treatment, 60% to 70% of patients are in advanced stages.

This seriously affects the survival of patients with ovarian cancer. Therefore, ovarian cancer is also known as the “silent killer”.

Symptoms in the early stages of ovarian cancer are often vague and can easily be attributed to other causes. So if these symptoms appear, you should be alert to whether it is related to ovarian cancer.

Early signs of ovarian cancer include bloating, abdominal and/or pelvic pain, fatigue and shortness of breath [2], lower body pain, lower abdominal pain, back pain, indigestion or heartburn, rapid satiety when eating, frequent and urgent urination, painful intercourse, and changing bowel habits, such as constipation. As ovarian cancer progresses, it can also cause nausea, weight loss and loss of appetite.

If these symptoms occur frequently, you need to see a doctor as soon as possible.

Sign and symptom of ovarian cancer

Figure 2 Sign and symptom of ovarian cancer

3. Risk Factors for Ovarian Cancer

The cause of ovarian cancer is unclear. However, genetic factors, reproductive factors, environmental factors and lifestyle factors may all play a role.

3.1 Genetic Factors

In ovarian cancer studies, BRCA1 and BRCA2 mutations are the most important known genetic risk factors for ovarian cancer, with up to 17% of patients having these two mutations [3]. The risk of ovarian cancer in ordinary women is only about 1%, while the risk of ovarian cancer in BRCA1 and BRCA2 germline carriers is 54% and 23%, respectively, which is a high-risk group for ovarian cancer. Besides BRCA1 and BRCA2, many genes increase the risk of ovarian cancer. For example, RAD51C, RAD51D, BRIP1, BARD1 and PALB2 [4] [5]. In addition, CHEK2, MRE11A, RAD50, ATM and TP53 may also increase the risk of ovarian cancer.

3.2 Family History

Compared with other women, the incidence of ovarian cancer increased significantly in women with a family history of ovarian cancer, breast cancer, endometrial cancer, and colorectal cancer. For these people, genetic screening can be used to determine whether someone carries a gene associated with an increased risk.

3.3 Breast Cancer

Women diagnosed with breast cancer are at higher risk for ovarian cancer.

3.4 Reproductive Factors

Compared with women who did not give birth, women who gave birth had a reduced risk of all subtypes of ovarian cancer, with the most significant reduction in the risk of clear cell carcinoma.

Multiple pregnancies, breastfeeding and oral contraceptives may reduce the risk of ovarian cancer. Women who took oral contraceptives for 5-9 years reduced their risk by about 35 percent. Oral contraceptives have been shown to reduce the risk of ovarian cancer in individuals with germline BRCA1 mutations and those without genetic predisposition [6].

3.4.1 Fertility Treatment

People with a history of infertility have an increased risk of ovarian cancer, and infertility treatment may also increase the risk.

3.4.2 Continuous Ovulation

Continuous ovulation causes continuous damage and repair of the ovarian surface epithelium, which may lead to ovarian cancer. There is a correlation between the total number of ovulations in women’s lifetime and the risk of ovarian cancer. The use of ovulation drugs can increase the risk of ovarian tumors.

3.5 Surgery

Some studies have shown that tubal ligation can significantly reduce the risk of ovarian cancer by up to 70%.

3.6 Hormone Replacement Therapy (HRT)

HRT increases the risk of ovarian cancer in postmenopausal women [7]. The longer the HRT lasts, the greater the risk, and once the treatment is stopped, the risk returns to normal.

3.7 Endometriosis

Endometriosis is a disease in which endometrial tissue-like tissue grows outside the uterus. Women with endometriosis have a 30% higher risk of ovarian cancer than other women.

3.8 Age

Although ovarian cancer can occur at any stage of a woman’s life, most ovarian cancer occurs in women over the age of 65. In about 90 percent of cases, ovarian cancer occurs after age 40, and most cases after age 60.

3.9 Obesity

People who are obese or overweight have a higher risk of cancer. Studies have shown that obesity is also a possible risk factor for ovarian cancer after menopause [8].

3.10 Environment and Other Factors

Epidemiological data suggest that various physical or chemical products of the industry may be associated with the onset of ovarian cancer.

In addition, studies have investigated the relationship between dietary factors and the risk of ovarian cancer in the general population. Whether the incidence of ovarian cancer is related to eating habits or ingredients (high cholesterol levels) is still inconclusive. Other lifestyle factors that may affect the risk of ovarian cancer include the use of talcum powder and non-steroidal anti-inflammatory drugs, and smoking.

Risk factors for ovarian cancer

Figure 3 Risk factors for ovarian

4. Diagnosis of Ovarian Cancer

The typical symptoms of ovarian cancer are not obvious in the early stage, and there is still no proper screening method, which leads to its high mortality rate, making it the third most malignant tumor in the female reproductive system. Finding effective methods for early diagnosis and improving the specificity of diagnosis are the focus of ovarian cancer diagnostic research.

The following tests are used to diagnose ovarian cancer:

Blood test: Tumor marker CA125 and human epididymis protein 4 (HE4) are the most valuable tumor markers in ovarian epithelial cancer.

However, CA125 level is also increased in some non-ovarian cancer diseases, such as breast cancer, lung cancer, endometrial cancer and some benign ovarian tumors [9]. This indicates that serum CA125 has poor sensitivity and specificity in the diagnosis of ovarian cancer, and the false positive rate is high. Therefore, in the diagnosis of ovarian cancer, the detection of CA125 level has certain limitations. The combination of human epididymis protein 4 and CA125 can provide a higher diagnostic rate for ovarian cancer. HE4 is a glycoprotein expressed in epithelial carcinoma of ovary, which is specific for the diagnosis of ovarian cancer. Ferraro et al[10] found that human epididymis protein 4 was more advantageous than CA125.

In addition to these two tumor markers, there are several other markers:

Carcinoembryonic antigen (CEA);

Alpha fetoprotein (AFP);

Carbohydrate antigen 199 (CA199)

Many new tumor markers are still being studied, such as serum macrophage colony-stimulating factor (M-CSF) and lysophosphatidic acid (LPA). The positive rate in serum of LPA ovarian cancer patients was high [11].

Ultrasonography: Ultrasonography is the first choice for ovarian cancer screening to determine the benign and malignant tumors. At present, transvaginal ultrasound, transabdominal ultrasound are widely used.

Laparoscopy: a laparoscope (a thin observation tube with a camera at the end) is inserted into the patient through a small incision in the lower abdomen.

Colonoscopy: If the patient has symptoms of rectal bleeding or constipation, the doctor may ask for a colonoscopy of the large intestine (colon).

CT Scan: CT scan is used to detect ovarian lesions, which can clearly show the location, size and relationship of the tumor to adjacent organs and tissues. It is also used for tumor location, characterization, and staging.

Magnetic Resonance Imaging: MRI provides fine pelvic anatomy , which plays an important role in the detection of ovarian diseases.

Genomics and Proteomics Assays: most of these techniques are currently in the laboratory. In addition, the doctor will also perform a vaginal examination to confirm whether the uterus or ovary is abnormal. It is also necessary to inquire about the patient’s history and family history. For women with confirmed ovarian cancer, doctors need to determine the stage and grade.

5. Treatment of Ovarian Cancer

Treatments for ovarian cancer include surgery, chemotherapy, surgery and chemotherapy, and sometimes radiotherapy. The type of treatment depends on the type, stage and grade of ovarian cancer, as well as the patient’s overall health. At present, cytoreductive surgery and platinum-based chemotherapy are the gold standard for the treatment of ovarian cancer.

5.1 Surgery

Surgery for ovarian cancer includes total hysterectomy, bilateral ovariosalpingectomy, tumor reduction, omentectomy [12]. If patients want to preserve their reproductive function, they can have the accessory resection of the affected side, but this also provides more opportunities and risks for the further deterioration of the tumor.

5.2 Chemotherapy

In addition to surgery, chemotherapy is also an important way to treat ovarian cancer patients. Chemotherapy can be used for cancer cells that cannot be removed surgically. At present, paclitaxel combined with platinum drugs is still the first-line chemotherapy drugs for ovarian cancer.

5.3 Targeted Therapy

Compared with traditional chemotherapy, targeted therapy has less damage to normal cells and has fewer side effects.

5.3.1 Targeted Drugs for Ovarian Cancer

Poly(ADP-ribose) polymerase, PARP inhibitor: Olapani is the most widely used PARP inhibitor. As a PARP inhibitor, olaparib has achieved good tumor inhibition compared with liposomal doxorubicin in phase I clinical trials and randomized trials [13]. A large number of clinical trial data confirmed that it was well tolerated and could significantly prolong the progression-free survival of ovarian cancer patients [14]. PARP inhibitors such as Veliparib, Niraparib and Talazoparib can prolong the progression-free survival of ovarian cancer patients [15].

Angiogenesis Inhibitor: Tumors require blood vessels to meet growth and metastasis requirements, and angiogenesis inhibitors can control tumor growth. Bevacizumab, a monoclonal anti-VEGF antibody, inhibits tumor angiogenesis and slows tumor growth and metastasis by inhibiting the binding of VEGF to its receptors VEGFR1 and VEGFR2.

PI3K/AKT/mTOR Signaling Pathway Inhibitor: PI3K/AKT/mTOR signaling pathway inhibitors can be divided into PI3K inhibitors, mTOR inhibitors, mTOR/PI3K inhibitors, and AKT inhibitors.

Signaling pathways and new therapeutic targets for ovarian cancer

Figure 4 Signaling pathways and new therapeutic targets for ovarian cancer [16]

In the targeted therapy of ovarian cancer, the use of antibody drug conjugates (ADCs) greatly increases the specificity of the coupled drug.

3C12 is a monoclonal antibody of Sp17, which is coupled with doxorubicin (DOX) to form an antibody drug conjugate 3C12-DOX. The 3C12-DOX conjugate has obvious tumor suppressing effects in vitro and in vivo, and its safety is superior to that of the chemotherapy drug DOX [17].

The immunotoxin MOC31PE formed by the coupling of EpCAM monoclonal antibody MOC31 and pseudomonas exotoxin A (PE) can inhibit protein synthesis of ovarian cancer cells, weaken cell viability and reduce cancer cell metastasis.

With the deepening of research on ovarian cancer, there will be more ovarian cancer drugs in the future.

References

[1] Gubbels J A, Claussen N, Kapur A K, et al. The detection, treatment, and biology of epithelial ovarian cancer [J]. Journal of Ovarian Research, 2010, 3(1): 8.

[2] Goff B A, Mandel L, Muntz H G, et al. Ovarian carcinoma diagnosis [J]. Cancer, 2015, 89(10): 2068-2075.

[3] Zhang S, Royer R, Li S, et al. Frequencies of BRCA1 and BRCA2 mutations among 1,342 unselected patients with invasive ovarian cancer [J]. Gynecologic Oncology, 2011, 121(2): 353-357.

[4] Pennington K P, Swisher E M. Hereditary ovarian cancer: Beyond the usual suspects [J]. Gynecologic Oncology, 2012, 124(2): 347-353.

[5] Norquist B M, Harrell M I, Brady M F, et al. Inherited Mutations in Women With Ovarian Carcinoma [J]. Jama Oncol, 2015, 2(4): 482-490.

[6] Moorman P G, Havrilesky L J, Gierisch J M, et al. Oral Contraceptives and Risk of Ovarian Cancer and Breast Cancer Among High-Risk Women: A Systematic Review and Meta-Analysis [J]. Journal of Clinical Oncology, 2013, 31(33): 4188-4198.

[7] Ellen L?kkegaard, Susanne KrügerKjaer, Ellen L?kkegaard. Hormone therapy and ovarian cancer [J]. Lancet, 2015, 386(9998): 298.

[8] Keum N N, Greenwood D C, Lee D H, et al. Adult Weight Gain and Adiposity-Related Cancers: A Dose-Response Meta-Analysis of Prospective Observational Studies [J]. JNCI Journal of the National Cancer Institute, 2015, 107(3).

[9] Moss E L, Hollingworth J, Reynolds T M. The role of CA125 in clinical practice [J]. Journal of Clinical Pathology, 2005, 58(3): 308-312.

[10] Ferraro S, Braga F, Lanzoni M, et al. Serum human epididymis protein 4 vs carbohydrate antigen 125 for ovarian cancer diagnosis: a systematic review [J]. Journal of Clinical Pathology, 2013, 66(4): 273-281.

[11] Jacobs I. Discussion: Ovarian Cancer Screening [J]. Gynecologic Oncology, 2003, 88(1-supp-S): 0-0.

[12] King M C. Breast and Ovarian Cancer Risks Due to Inherited Mutations in BRCA1 and BRCA2 [J]. Science, 2003, 302(5645): 643-646.

[13] Kaye S B, Lubinski J, Matulonis U, et al. Phase II, open-label, randomized, multicenter study comparing the efficacy and safety of olaparib, a poly (ADP-ribose) polymerase inhibitor, and pegylated liposomal doxorubicin in patients with BRCA1 or BRCA2 mutations and recurrent ovarian cancer [J]. Journal of Clinical Oncology, 2012, 30(4): 372-379.

[14] Ledermann J A, El-Khouly F. PARP inhibitors in ovarian cancer: Clinical evidence for informed treatment decisions [J]. British Journal of Cancer, 2015, 113: S10-S16.

[15] Jones P, Wilcoxen K, Rowley M, et al. Niraparib: A Poly (ADP-ribose) Polymerase (PARP) Inhibitor for the Treatment of Tumors with Defective Homologous Recombination [J]. Journal of Medicinal Chemistry, 2015, 58(8): 3302-3314.

[16] Gianpiero D L, Croce C M. The Role of microRNAs in the Tumorigenesis of Ovarian Cancer [J]. Frontiers in Oncology, 2013, 3.

[17] Song J X, Li F Q, Cao W L, et al. Anti-Sp17 monoclonal antibody-doxorubicin conjugates as molecularly targeted chemotherapy for ovarian carcinoma [J]. Targeted Oncology, 2013, 9(3): 263-272.

Tumor markers

Oncogenes and Cancer

In fact, everyone has genes that possess the ability to cause cancer. These genes are known as proto-oncogenes, which are expressed to control normal cell processes such as proliferation, differentiation, and apoptosis. Although all people carry proto-oncogenes, it does not mean that everyone will necessarily develop cancer. Accumulating mutations in the normal cells activate proto-oncogenes transform into oncogenes, leading to the uncontrolled and continuous proliferation of normal cells ultimately resulting in tumorigenesis.

In this article, we will introduce oncogenes from the definition, activation mode, category, and their relationship with cancer.

1. What Are Oncogenes?

Oncogenes, also called cancer-causing genes, were first discovered in certain retroviruses and were identified as carcinogenic agents in many animals. They are aberrantly expressed or mutated versions of their corresponding proto-oncogenes.

2. Proto-oncogenes to Oncogenes Conversion Mechanisms

Proto-oncogenes are normal growth-regulatory genes and codes for proteins including growth factors and transmembrane signal transducers, that promote cell growth, proliferation, and differentiation. Normal cells usually do not express a large number of proto-oncogenes, but alteration of sequence and expression amount of proto-oncogenes can activate them to covert into oncogenes. Upon activation by gain-of-function mutations, oncogenes anarchically continue to express, allowing cells to proliferate spontaneously to form tumors.

In humans, proto-oncogenes can be coverted to oncogenes in three ways. Although they perform differently in mechanism, all of them lead to a lack or decrease in cell regulation.

2.1 Point Mutations

Spontaneous occurring or environmental factor-causing point mutations can change, insert, or delete a single nucleotide base pair, probably producing an altered protein, thus activating proto-oncogenes and promoting their conversion into oncogenes. Point mutations are common detected in the RAS family of proto-oncogenes [1].

2.2 Chromosomal Translocations

Chromosomal translocations are frequently found in human cancer and have become guideposts for the discovery of many new oncogenes [2] [3]. The production of oncogenic fusion proteins or oncogene activation by a novel promoter or enhancer during the process of translocation leads to alteration of protein or expression level, ultimately resulting in oncogenesis [4]. The Philadelphia chromosome [t(9;22)] is the first identified specific chromosomal translocation in myeloid leukemia.

2.3 Gene Amplifications

Gene amplification refers to increased copies for a restricted region of a chromosome arm and is one of the most important chromosomal abnormalities [5]. Additional copies of amplified genes lead to more production of protein, enhancing the transformative activity of proto-oncogenes.

The mechanisms of proto-oncogenes conversion into oncogenes
Figure: The mechanisms of proto-oncogenes conversion into oncogenes

3. Lists of Oncogenes

Oncogenes can be divided into five categories: growth factors, growth factor receptors, signal transducers, transcription factors, and others including programmed cell death regulators.

Oncogenes Oncoproteins Neoplasm Mechanism of Activation
Growth Factors v-sis V-SIS Glioma/fibrosarcoma Constitutive production
int2 FGF3 Mammary carcinoma Constitutive production
KS3 FGF4 Kaposi sarcoma Constitutive production
HST FGF4 Kaposi sarcoma Constitutive production
Growth Factor Receptors EGFR EGFR Squamous cell carcinoma Gene amplification/increased protein
v-fms V-FMS Sarcoma Constitutive activation
v-kit V-KIT Sarcoma Constitutive activation
v-ros V-ROS Sarcoma Constitutive activation
MET MET MNNG-treated human osteocarcinoma cell line DNA rearrangement/ligand-independent constitutive activation (fusion proteins)
TRK NTRK1 Colon/thyroid carcinomas DNA rearrangement/ligand-independent constitutive activation (fusion proteins)
NEU ERBB2 Neuroblastoma/breast carcinoma Gene amplification
RET RET Carcinomas of thyroid; MEN2A, MEN2B DNA rearrangement/point mutation (ligand-independent constitutive activation/fusion proteins)
mas MAS Epidermoid carcinoma Rearrangement of 5′ noncoding region
Trancription Factors SRC Colon carcinoma Constitutive activation
v-yes V-YES Sarcoma Constitutive activation
v-fgr V-FGR Sarcoma Constitutive activation
v-fes V-FES Sarcoma Constitutive activation
ABL ABL1 CML DNA rearrangement translocation (constitutive activation/fusion proteins)
H-RAS H-RAS Colon, lung, pancreas carcinmoas Point mutation
RAS RAS AML, thyroid carcinoma, melanoma Point mutation
N-RAS N-RAS Carcinoma, melanoma Point mutation
gsp GSP Adenomas of thyroid Point mutation
gip GIP Ovary, adrenal carcinoma Point mutation
Dbl MCF2 Diffuse B-cell lymphoma DNA rearrangement
Vav VAV Hematopoietic cells DNA rearrangement
v-mos V-MOS Sarcoma Constitutive activation
v-raf V-RAF Sarcoma Constitutive activation
pim-1 PIM1 T-cell lymphoma Constitutive activation
v-crk V-CRK Constitutive tyrosine phosphorilation of cellular substrates (eg, paxillin)
Others BCL2 BCL2 B-cell lymphomas Constitutive activity
MDM2 MDM2 Sarcomas Gene amplification/increased protein

4. Oncogenes and Cancer

Cancer is a molecule-based genetic disease. It specifically manifests as the deregulation of normal cellular processes involved in cell growth, differentiation, and apoptosis. The discovery that human tumors harbor activated oncogenes has inspired scientists to understand their causal role in the development of cancer. Cancer-associated oncogenes induce anarchic proliferation as well as genomic and chromosomal instability. Therefore, scientists have tried hard to target oncogenes to research cancer therapy and related drugs.

In fact, cancer is induced by multiple genetic and epigenetic aberrations. Although the carcinogenesis is complex, tumorous cells’ growth and survival can often be impaired by the inactivation of a single or a few oncogenes [6] [7]. In other words, some cancers depend on one or a few oncogenes for the maintenance of their malignant phenotypes, a phenomenon known as “oncogene addiction,” which provides a potent rationale for molecular targeted therapy [8]. It has remained a challenge for targeting these addicted oncogenes with specific small molecule inhibitors in human malignancies (e.g. RAS and MYC). However, successful therapeutic targeting of oncogene addiction has been achieved in some relatively uncommon types of cancer with a defined molecular pathology.

References

[1] Mark Steven Miller and Lance D Miller. RAS Mutations and Oncogenesis: Not all RAS Mutations are Created Equally [J]. Front Genet. 2012 Jan 3;2:100.

[2] Falini B and Mason DY. Proteins encoded by genes involved in chromosomal alterations in lymphoma and leukemia: clinical value of their detection by immunocytochemistry [J]. Blood. 2002;99:409–26.

[3] Tomescu O and Barr FG. Chromosomal translocations in sarcomas: prospects for therapy [J]. Trends Mol Med. 2001;7:554–9.

[4] Jie Zheng. Oncogenic chromosomal translocations and human cancer (review) [J]. Oncol Rep. 2013 Nov;30(5):2011-9.

[5] Albertson DG. Gene amplification in cancer [J]. Trends Genet. 2006;22(8):447–55.

[6] Weinstein, IB. Addiction to oncogenes—the Achilles heal of cancer [J]. Science 2002; 297: 63–4.

[7] Weinstein IB, Joe AK. Mechanisms of disease: oncogene addiction—a rationale for molecular targeting in cancer therapy [J]. Nat Clin Pract Oncol 2006; 3: 448–57.

[8] Weinstein IB, Begemann M, et al. Disorders in cell circuitry associated with multistage carcinogenesis: exploitable targets for cancer prevention and therapy [J]. Clin Cancer Res 1997; 3: 2696–702.

FAP may be a drug target for pancreatic cancer

Novel drug target for pancreatic cancer

Fibroblast activation protein (FAP) may be a novel drug target for pancreatic cancer, according to a study (Fibroblast activation protein augments progression and metastasis of pancreatic ductal adenocarcinoma) published in the Journal of Clinical Investigation Insight on October 5, 2017[1].

Pancreatic cancer, which forms in the pancreas, is very hard to control. One problem is that pancreatic cancer is rarely detectable in its early stages. Pancreatic cancer generally spreads rapidly, and symptoms don’t appear until it’s too late. The prognosis of pancreatic cancer patients remains dismal, with a 5-year survival rate of only about 5%.

FAP, which is a transmembrane cell surface proteinase, belongs to the serine protease family. Expression of FAP has been detected in cancer-associated fibroblasts of many human cancers, such as pancreatic cancer, breast cancer, colorectal cancer, and cervical cancer. Some studies uncovered that FAP depletion suppresses cancer cell proliferation and metastasis in experimental animals.

For the current study, a team consisting of researchers from the University of Pennsylvania in the USA, National Yang-Ming University School of Medicine, and Academia Sinica in Taiwan further explored the role of FAP in pancreatic cancer. Using immunofluorescent staining method, the team examined FAP expression in clinical specimens collected from patients with pancreatic cancer and discovered that the level of FAP was much higher in stromal cells in pancreatic tumors than that in adjacent normal pancreatic tissues. Similar results were found in FAP luciferase reporter knockin mice. Investigating the association between FAP level and patient outcome, the team found that high FAP level could predict shorter survival.

Next, the team carried out experiments in mouse models of pancreatic cancer. The results suggested that FAP is not essential for the initiation of pancreatic cancer but is critical for promoting the progression of pancreatic cancer. Deletion of FAP prolonged the animals’ survival. Furthermore, the study indicated that FAP expression by stromal and/or tumor cells could contribute to the resistance of pancreatic cancer to necrotic cell death and could drive the spread of cancer cells to multiple visceral organs.

To conclude, the data support a role of FAP in augmenting progression and metastasis of pancreatic cancer. Therefore, FAP might be a new target for drug therapy in this deadly disease.

Dr. Ellen Puré, a professor at the University of Pennsylvania School of Veterinary Medicine and the corresponding author of this study, noted that their study is the first to demonstrate that FAP contributes to metastasis.

The laboratory of Dr. Puré is focusing on the cellular and molecular basis of inflammation and fibrosis. Their recent studies explore the function of FAP and other molecules in human disease.

Cause and risk factors of pancreatic cancer

The exact cause of pancreatic cancer is not known. Doctors are usually unable to tell why a specific patient developed pancreatic cancer. It’s well established that cancer is characterized by uncontrolled cell growth driven by DNA damage. Only 5%-10% of all cases of pancreatic cancer report a family history. While the genetic basis for the majority of the familial clustering of pancreatic cancer remains unclear, several pancreatic cancer susceptibility genes have been established or suggested, such as BRCA2, STK11/LKB1, PALB2, PRSS1, SPINK1, CDKN2A, BRCA1, CFTR, and the ABO blood group locus[2].

In addition to genetic factors, there are many other risk factors for the disease. Here is a list of confirmed and suspected risk factors for pancreatic cancer[3][4].

1. A family history
2. Older age
3. Smoking
4. High alcohol intake
5. Dietary factors
6. Diabetes
7. Chronic pancreatitis
8. Exposure to toxic substances
9. Previous peptic ulcer
10. Organ transplant
11. Overweight or obesity
12. Sedentary lifestyle
13. Hepatitis
14. Breast and ovarian cancer syndrome
15. Other serious diseases

Pancreatic tumors have profoundly oncogenic alterations, which occur in high frequencies. These alterations drive growth and cell survival and alter the metabolism of pancreatic cancer. There are also rare alterations, that are found in effectively unique combinations in each patient. All these genetic alterations may imply an ability to rapidly develop acquired resistance to therapies[5].

Invasive nature of pancreatic cancer

During the past several decades, there has been an overall reduction in cancer-related death in developed countries, in particular for lung, breast, colorectal and prostate cancer. However, for pancreatic cancer, the mortality rates are increased. Pancreatic cancer is a highly aggressive cancer that kills more than half of all its victims within 6 months after diagnosis. Nearly all diagnosed patients ultimately succumb to the disease. Why is pancreatic cancer so lethal? There are several reasons:

1. Rapid progress
2. Lack of early signs
3. Late diagnosis
4. Low resection rate
5. Lack of efficacious therapies
6. Incomplete knowledge of etiology

Pancreatic cancer often grows fast and spreads microscopically early in the disease course. When diagnosed, only 7% of pancreatic cancers are considered localized disease, which is alarmingly low compared to other cancers[6]. This means that most patients with pancreatic cancer are not suitable to undergo a surgery because their cancer has spread from its primary site to distant organs and complete resection of tumors by surgery is usually impossible.

Our understanding of what drives the development and metastasis of pancreatic cancer is far from complete. There is a lack of markers of early detection as well as a lack of targets for treatment. At the early stage of pancreatic cancer, symptoms such as weight loss, abdominal pain, the onset of diabetes, unexplained jaundice, and unprovoked thrombosis may occur. However, these symptoms are non-specific and may also appear in other diseases.

For breast, prostate, melanoma, and testicular cancers, simple examinations can evaluate the condition. In contrast, the pancreas is buried deep in the abdomen behind the stomach, making it hard to access.

Fig 1. The Pancreas
(By Cancer Research UK – Original email from CRUK, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34334263)

For these reasons, pancreatic cancer often goes unnoticed until it is too late. Once metastasis occurs, it’s hard to treat. For advanced pancreatic cancer, there are still treatment options, but the most efficacious are also the most burdensome.

 

Recurrence of pancreatic cancer after treatment is another factor that contributes to the dismal prognosis. Despite treatment at early stages, there is a 40% chance of recurrence.

For these reasons, the 5-year survival rate of pancreatic cancer remains quite low. In fact, pancreatic cancer is one of the leading cause of cancer-related death worldwide. According to estimates, pancreatic cancer accounts for about 3% of all cancers in the US and 7% of all cancer deaths.

Type of cancer Percentage of localized disease at diagnosis 5-year survival rate
Pancreatic cancer 7% 5%
Breast cancer 61% 17%
Colon cancer 40% 60%
Lung cancer 16% 10%
Ovarian cancer 19% 45%
Prostate cancer 91% 99%
Fig. 2 Metastasis and prognosis of pancreatic cancer compared with other cancers
Reference:
[1] Albert Lo et al, Fibroblast activation protein augments progression and metastasis of pancreatic ductal adenocarcinoma, Journal of Clinical Investigation Insight (2017).
[2] Alison P. Klein, Genetic susceptibility to pancreatic cancer, Molecular Carcinogenesis (2011).
[3] Marco Del Chiaro et al, Early detection and prevention of pancreatic cancer: Is it really possible today? World Journal of Gastroenterology (2014).
[4] Ramesh Khadka et al, Risk factor, early diagnosis and overall survival on the outcome of association between pancreatic cancer and diabetes mellitus: Changes and advances, a review, International Journal of Surgery (2018).
[5] Paul E. Oberstein et al, Pancreatic cancer: why is it so hard to treat? Therapeutic Advances in Gastroenterology (2013).
[6] Chengfei Zhao et al, Pancreatic cancer and associated exosomes, Cancer Biomarkers (2017).

Role of non-coding RNA in prostate cancer progression

Novel approach to combat prostate cancer

Dr. Arul Chinnaiyan, professor of urology and director of the Michigan Center for Translational Pathology, and his team have recently discovered that a non-coding RNA called ARLNC1 could play a role in the progression of prostate cancer. This discovery suggests ARLNC1 as a new potential drug target [1].

The Chinnaiyan lab is committed to dissecting cancer biology, using multiple methods such as genomic, proteomic, metabolomic and bioinformatics. Their research interests include prostate cancer.

Long noncoding RNAs (lncRNAs) are emerging as important regulators of tissue physiology and disease processes including cancer. But little is known about the underlying mechanisms. For this, lncRNAs are also referred to as the dark matter of the genome.

In 2015, Dr. Chinnaiyan’s team delineated genome-wide lncRNA expression by using RNA sequencing libraries from tumors, normal tissues and cell lines comprising sequence information from many studies. They identified more than 46,000 lncRNAs that were previously unannotated[2].

Dr. Chinnaiyan’s team continued their research to find that ARLNC1 (androgen receptor (AR)-regulated long noncoding RNA 1) is increased in prostate cancer compared with that in normal tissue. Additionally, this lncRNA is associated with AR signaling in prostate cancer progression. On one hand, the AR induces the expression of ARLNC1. On the other hand, ARLNC1 stabilizes the AR transcript via RNA-RNA interaction. Both in vitro and in vivo experiments revealed that blocking ARLNC1 could inhibit AR expression, global AR signaling, and prostate cancer growth. By contrast, increasing ARLNC1 could result in the formation of large tumors.

These data, collectively, suggest that the lncRNA ARLNC1 may play a role in prostate cancer progression and represent a new therapeutic target.

The AR is a nuclear receptor that functions as a transcription factor and regulates the normal development and growth of the prostate. It is activated by binding either of the androgenic hormones, testosterone, or dihydrotestosterone. However, the AR is also involved in the development of prostate cancer. Many studies have shown that the AR helps prostate cancer cells to survive. Thus, the AR has been suggested as a drug target. But inhibiting the AR has only proven to be effective in animal studies.

According to Dr. Chinnaiyan, it’s important to better elucidate the AR. Their latest study reveals a mechanism involving ARLNC1 that potentiates AR signaling during prostate cancer progression and provides a novel approach to inhibit the AR.

Finally, Dr. Chinnaiyan pointed out that they’ll further explore the dark matter of the genome. Except for ARLNC1, there are many other lncRNAs that remain poorly understood. A deeper understanding of these molecules would provide new insights into cancer, other diseases, as well as normal physiological processes.

Causative mechanisms in prostate cancer

Prostate cancer is the most common malignancy in men and the cause of 1-2% of deaths in men. The exact causes of prostate cancer remain unclear. Several risk factors for developing prostate cancer have been identified. However, which of these risk factors cause a prostate cell to become cancerous is not fully understood.

1. Age

Approximately 90% of patients with prostate cancer are over 50 years old. Old age is a major risk factor of prostate cancer.

2. Race

Epidemiology studies have suggested that prostate cancer occurs most frequently in African Americans while having lower rates in Asian males[3].

Fig. 1 Incidence of prostate cancer

3. A family history

Men who have a first-degree relative with prostate cancer have twice the risk of developing the disease compared to those in the general population. Genetic linkage studies in multiple-case families have identified the homeobox gene HOXB13 as a definite prostate cancer predisposition gene[4].

4. Obesity

Obesity is linked to aggressive prostate cancer. Avoiding obesity may prevent the risk of developing high-grade prostate cancer[5].

5. Nutrition and dietary factors

Accumulating evidence suggests that many dietary components may play a role in the pathogenesis of prostate cancer. For instance, excessive intake of animal fats appears to contribute to the onset of prostate cancer, and plant foods that provide a multitude of antioxidants and phytochemicals have a demonstrable beneficial effect on prostate cancer. However, the results of previous studies in this field have yielded inconsistent results, with individual antioxidants having been shown to have positive, negative, or no association with prostate cancer risk[6][7].

6. Environmental exposure disruptors

Several studies have suggested a link between exposure to certain chemicals and risk of prostate cancer. These chemicals include The bisphenol A (BPA), which is a synthetic estrogen, chlordecone, and Pesticides.

Screening of prostate cancer

Measurement of prostate specific antigen (PSA) is useful in screening of prostate cancer.

PSA is a protein produced by normal, as well as malignant, cells of the prostate gland. The PSA test measures the level of PSA in a man’s blood. When a man has prostate cancer, his PSA level often increases. This is why the PSA test is usually the first step in any prostate cancer diagnosis.

However, the PSA screening by itself cannot tell you if cancer is present. It is often done along other examinations such as a digital rectal exam (DRE). In addition, PSA levels can be affected by many factors, such as age, race, certain medical procedures, certain medications, an enlarged prostate, and a prostate infection.

Many countries recommend offering the PSA test and DRE yearly to men 50 years or older who have a life expectancy of at least 10 years. But in some countries, the coverage of PSA test is relatively low, which is not good for early detection of prostate cancer.

Signs of prostate cancer

In its early stages, prostate cancer usually causes no symptoms. When it progresses to more advanced stages, it may cause signs and symptoms such as frequent urination, nocturia, difficulty starting and maintaining a steady stream of urine, blood in the urine, and painful urination. These symptoms can also occur in other diseases and conditions. If you have one or more of these symptoms, you’d better go to your doctor.

Prognosis of prostate cancer

The prognosis of prostate cancer is associated with disease stage. For men with localized prostate cancer, the prognosis is quite excellent that the 5-year survival rate is nearly 100%. Once prostate cancer has spread beyond the prostate, survival rates fall. In most cases, prostate cancer spreads to bones, such as the hip, spine, and pelvis bones. Patients with prostate cancer metastases have limited treatment options, prognosis, and outlook, compared with those with localized disease.

Reference:

[1] Yajia Zhang et al. Analysis of the androgen receptor-regulated lncRNA landscape identifies a role for ARLNC1 in prostate cancer progression. Nature Genetics (2018).
[2] Matthew K Iyer et al. The landscape of long noncoding RNAs in the human transcriptome. Nature Genetics (2015).
[3] Zeigler-Johnson M. Charnita et al, Evaluation of prostate cancer characteristics in four populations worldwide, The Canadian journal of urology (2008).
[4] Gerhardt Attard et al, Prostate cancer, The Lancet (2015).
[5] Adriana C. Vidal et al, Obesity Increases the Risk for High-Grade Prostate Cancer: Results from the REDUCE Study, Cancer Epidemiology, Biomarkers & Prevention (2014).
[6] Venita H Patel, Nutrition and prostate cancer: an overview, Expert Review of Anticancer Therapy (2014).
[7] Terrence M. Vance et al, Dietary Antioxidants and Prostate Cancer: A Review, Nutrition and Cancer (2013).

Breast Cancer Pathway Map

Breast Cancer Pathway Map

Breast cancer is the leading cause of cancer death among women worldwide. The vast majority of breast cancers are carcinomas that originate from cells lining the milk-forming ducts of the mammary gland. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, fluid coming from the nipple, or a red scaly patch of skin. Risk factors for developing breast cancer include being female, obesity, lack of physical exercise, drinking alcohol, hormone replacement therapy during menopause, ionizing radiation, early age at first menstruation, having children late or not at all, older age, and family history. About 5–10% of cases are due to genes inherited from a person’s parents, including BRCA1 and BRCA2 among others.
As the following figure shows, we summarize the breast cancer pathway and aim to help us in the research of breast cancer, including causes identification and the development of strategies for prevention, diagnosis, treatments and cure. Cusabio has a sound platform for the development of ELISA kit, mature antigen-antibody research and development system. Now we offer 178 ELISA kits in high specificity, high sensitivity, high stability and different species for your breast cancer research. Some of our products has cited by publications, such as HER2, HES1, WNT10B, and so on. We also have other products such as gene, protein and antibody for breast cancer research. If you are in need of other products such as gene, protein and antibody for breast cancer research, please feel free to contact us.

Breast Cancer Pathway

Product Name Code Sample Type Detect Range Sensitivity
Human AKT1 ELISA Kit CSB-EL001553HU serum, plasma, cell lysates 0.312 ng/ml-20 ng/ml 0.078 ng/ml
Human APC ELISA Kit CSB-E09909h serum, plasma, tissue homogenates 1.56 pg/ml-100 pg/ml 0.39 pg/ml
Mouse APC ELISA Kit CSB-E09914m serum, plasma and tissue homogenates 62.5 pg/ml-4000 pg/ml 15.6 pg/ml
Human BRAF ELISA Kit CSB-EL002791HU serum, plasma, cell lysates 31.25 pg/ml-2000 pg/ml 7.8pg/ml
Human CDK4 ELISA Kit CSB-E09174h serum, plasma 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Human CTNNB1 ELISA Kit CSB-E08963h serum, plasma, cell culture supernates, tissue homogenates and cell lysates 15.6 pg/ml-1000 pg/ml 3.9 pg/ml
Mouse CTNNB1 ELISA Kit CSB-E11307m serum, plasma, tissue homogenates, cell lysates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Human DLL1 ELISA Kit CSB-EL006947HU serum, plasma, tissue homogenates 18.75 pg/ml-1200 pg/ml 4.68 pg/ml
Human DLL3 ELISA Kit CSB-EL006948HU serum, plasma, tissue homogenates 18.75 pg/ml-1200 pg/ml 4.68pg/ml
Human DLL4 ELISA Kit CSB-EL006949HU serum, plasma, tissue homogenates 23.5 pg/ml-1500 pg/ml 5.8 pg/ml
Mouse DLL4 ELISA Kit CSB-EL006949MO serum, plasma, tissue homogenates 10 ng/ml-0.16 ng/ml 0.04 ng/ml
Human EGF ELISA Kit CSB-E08027h serum, plasma, cell culture supernates, tissue homogenates 1.56 pg/ml-100 pg/ml 0.39 pg/ml
Mouse EGF ELISA Kit CSB-E08028m serum, plasma, tissue homogenates 7.8 pg/ml-500pg/ml 1.95 pg/ml
Rat EGF ELISA Kit CSB-E08029r serum, plasma, tissue homogenates 3.12 pg/ml-200 pg/ml 0.78 pg/ml
Human EGFR ELISA Kit CSB-E12124h serum, plasma, tissue homogenates 0.312 ng/ml-20 ng/ml 0.019 ng/ml
Human ERBB2 ELISA Kit CSB-E11161h serum, plasma, tissue homogenates, cell lysates 0.156 ng/ml-10 ng/ml 0.04 ng/ml
Human ESR1 ELISA Kit CSB-E08652h serum, plasma, tissue homogenates, cell lysates 3.12 pg/ml-200 pg/ml 0.78 pg/ml
Rat ESR1 ELISA Kit CSB-E06848r serum, plasma, tissue homogenates, cell lysates 31.25 pg/ml-2000 pg/ml 7.81 pg/ml
Human FGF1 ELISA Kit CSB-E04546h serum, plasma, tissue homogenates 15.6 pg/ml-1000 pg/ml 3.9 pg/ml.
Mouse FGF1 ELISA Kit CSB-E07327m serum, plasma, tissue homogenates 6.25 pg/ml-400 pg/ml 1.56 pg/ml
Human FGF10 ELISA Kit CSB-E14965h serum, plasma and tissue homogenates 3.12 pg/ml-200 pg/ml 0.78pg/ml
Mouse FGF10 ELISA Kit CSB-E13045m serum, plasma, cell culture supernates, tissue homogenates 1.56 pg/ml-100 pg/ml 0.39 pg/ml
Human FGF13 ELISA Kit CSB-E13849h serum, plasma, cell culture supernates 12.5 pg/ml-800 pg/ml 3.12 pg/ml
Human FGF17 ELISA Kit CSB-EL008622HU serum, plasma, cell culture supernates and tissue homogenates 3.12 pg/ml -200 pg/ml 0.78 pg/ml
Human FGF18 ELISA Kit CSB-EL008623HU serum, plasma, cell culture supernates and tissue homogenates 31.25 pg/ml-2000 pg/ml 7.81 pg/ml
Human FGF19 ELISA Kit CSB-EL008624HU 0 Request Information Request Information
Human FGF2 ELISA Kit CSB-E08000h serum, plasma, cell culture supernates, tissue homogenates 1.56 pg/ml-100 pg/ml 0.39 pg/ml
Mouse FGF2 ELISA Kit CSB-E08001m serum, plasma, cell culture supernates, tissue homogenates 3.12 pg/ml-200 pg/ml 0.78 pg/ml
Rat FGF2 ELISA Kit CSB-E08002r serum, plasma, tissue homogenates 0.9 pg/ml-60 pg/ml 0.22 pg/ml
Human FGF20 ELISA Kit CSB-EL008626HU serum, plasma, tissue homogenates, cell lysates 12.5 pg/ml-800 pg/ml 3.12 pg/ml
Rat FGF20 ELISA Kit CSB-EL008626RA serum, plasma, tissue homogenates 1000 pg/ml-15.63 pg/ml 3.91 pg/ml
Human FGF21 ELISA Kit CSB-E16844h serum, plasma, cell culture supernates, tissue homogenates 15.6 pg/ml-1000 pg/ml 3.9 pg/ml
Mouse FGF21 ELISA Kit CSB-EL008627MO serum, plasma, tissue homogenates, cell lysates 31.25 pg/ml-2000 pg/ml 7.8 pg/ml
Rat FGF21 ELISA Kit CSB-EL008627RA serum, plasma, tissue homogenates 23.5 pg/ml-1500 pg/ml 5.8pg/ml
Human FGF23 ELISA Kit CSB-E10113h serum, cell culture supernates, urine, tissue homogenates 3.12 pg/ml-200 pg/ml 0.78 pg/ml
Mouse FGF23 ELISA Kit CSB-EL008629MO serum, plasma, tissue homogenates 23.44 pg/ml-1500 pg/ml 5.86 pg/ml
Rat FGF23 ELISA Kit CSB-E12170r serum, plasma, cell culture supernates and tissue homogenates 1.56 pg/ml-100 pg/ml 0.39pg/ml
Human FGF4 ELISA Kit CSB-E04548h serum, plasma 6.25 pg/ml-400 pg/ml 1.56pg/ml
Human FGF5 ELISA Kit CSB-EL008632HU serum, plasma, tissue homogenates 15.6 pg/ml-1000 pg/ml 3.9pg/ml
Mouse FGF5 ELISA Kit CSB-EL008632MO serum, plasma, tissue homogenates 31.25 pg/ml-2000 pg/ml 7.8 pg/ml
Human FGF6 ELISA Kit CSB-E04549h serum, plasma, tissue homogenates 500 pg/ml-7.81 pg/ml 1.95 pg/ml
Human FGF7 ELISA Kit CSB-E08939h serum, plasma, tissue homogenates 31.25 pg/ml -2000 pg/ml 7.8 pg/ml
Mouse FGF7 ELISA Kit CSB-E13046m serum, plasma, cell culture supernates and tissue homogenates 1.56 pg/ml-100 pg/ml 0.39 pg/ml
Rat FGF7 ELISA Kit CSB-E12905r serum, plasma 31.25 pg/ml-2000 pg/ml 7.81 pg/ml
Human FGF8 ELISA Kit CSB-E15861h serum, plasma, tissue homogenates, cell lysates 15.6 pg/ml-1000 pg/ml 3.9 pg/ml
Human FGF9 ELISA Kit CSB-E04550h serum, plasma, cell culture supernates and tissue homogenates 6.25 pg/ml-400 pg/ml 1.56 pg/ml
Human FLT4 ELISA Kit CSB-E04765h serum, plasma, tissue homogenates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Mouse FLT4 ELISA Kit CSB-E04766m serum, plasma, tissue homogenates 9.38 pg/ml-600 pg/ml 2.34 pg/ml
Human IGF1 ELISA Kit CSB-E04580h serum, plasma and tissue homogenates 7.8 ng/ml-500 ng/ml 1.95 ng/ml
Mouse IGF1 ELISA Kit CSB-E04581m serum, plasma, tissue homogenates 0.156 ng/ml-10 ng/ml 0.151 ng/ml
Rat IGF1 ELISA Kit CSB-E04582r serum, plasma, cell culture supernates and tissue homogenates 0.156 ng/ml-10 ng/ml 0.151 ng/ml
Human IGF1R ELISA Kit CSB-E13766h serum, plasma, tissue homogenates 0.312 ng/ml-20 ng/ml 0.078 ng/ml
Rat IGF1R ELISA Kit CSB-E13873r serum, plasma, tissue homogenates 3.12 pg/ml-200 pg/ml 0.78 pg/ml.
Human JAG1 ELISA Kit CSB-EL011927HU serum, plasma, tissue homogenates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Human KRAS ELISA Kit CSB-EL012493HU serum, plasma, tissue homogenates 23.5 pg/ml-1500 pg/ml 5.8 pg/ml
Human LRP6 ELISA Kit CSB-E08952h serum, tissue homogenates, cell lysates 0.312 ng/ml-20 ng/ml 0.078 ng/ml
Human mTOR ELISA Kit CSB-E09038h serum, plasma, tissue homogenates 1.56 pg/ml-100 pg/ml 0.39pg/ml
Human MYC ELISA Kit CSB-E09260h serum, plasma, tissue homogenates, cell lysates 0.312 ng/ml-20 ng/ml 0.078ng/ml
Human NOTCH1 ELISA Kit CSB-EL015949HU serum, plasma, tissue homogenates, cell lysates 78 pg/ml-5000 pg/ml 19.5 pg/ml
Human NOTCH3 ELISA Kit CSB-EL015952HU serum, plasma, tissue homogenates and cell lysates 125 pg/ml-8000 pg/ml 31.25 pg/ml
Human PGR ELISA Kit CSB-E09214h 0 0.357 ng/ml-10 ng/ml 0.14 ng/ml
Mouse PIK3CA ELISA Kit CSB-E08419m serum, plasma, tissue homogenates 23.5 pg/ml-1500 pg/ml 5.8 pg/ml
Human TNFSF11 ELISA Kit CSB-E05125h serum, plasma, cell culture supeernates, tissue homogenates 7.8 pg/ml-500 pg/ml 1.95pg/ml
Mouse TNFSF11 ELISA Kit CSB-E05127m serum, plasma, cell culture supernates, tissue homogenates 15.6 pg/ml-1000 pg/ml 3.9 pg/ml
Rat TNFSF11 ELISA Kit CSB-E05126r serum, plasma, cell culture supernates 62.5 pg/ml-4000 pg/ml 15.6 pg/ml
Human TP53 ELISA Kit CSB-E08334h serum, cell culture supernates, urine, cerebrospinal fluid (CSF), tissue homogenates, cell lysates 9.38 pg/ml-600 pg/ml 2.34 pg/ml
Rat TP53 ELISA Kit CSB-E08336r serum, plasma, tissue homogenates 12.5 pg/ml-800 pg/ml 3.12pg/ml
Human WNT1 ELISA Kit CSB-EL026128HU serum, plasma, tissue homogenates 0.312 ng/ml-20 ng/ml 0.078 ng/ml
Mouse WNT1 ELISA Kit CSB-EL026128MO serum, plasma, tissue homogenates 18.75 pg/ml-1200 pg/ml 4.68pg/ml
Mouse WNT10B ELISA Kit CSB-EL026130MO serum, plasma, tissue homogenates 9.4 pg/ml-600 pg/ml 2.35 pg/ml
Human WNT16 ELISA Kit CSB-EL026132HU serum, plasma and tissue homogenates 31.25 pg/ml-2000 pg/ml 7.81 pg/ml.
Mouse WNT16 ELISA Kit CSB-EL026132MO serum, plasma, tissue homogenates, cell lysates 62.5 pg/ml-4000 pg/ml 15.6 pg/ml
Human WNT2 ELISA Kit CSB-EL026133HU serum, plasma, tissue homogenates 0.45 ng/ml-30 ng/ml 0.11 ng/ml
Mouse WNT2 ELISA Kit CSB-EL026133MO serum, plasma, tissue homogenates 15.6 pg/ml-1000 pg/ml 3.9 pg/ml
Human WNT2B ELISA Kit CSB-EL026134HU serum, plasma, tissue homogenates, cell lysates 62.5pg/ml-4000pg/ml 15.6pg/ml
Human WNT3 ELISA Kit CSB-EL026135HU serum, plasma, tissue homogenates, cell lysates 0.156 ng/ml-10 ng/ml 0.039ng/ml
Mouse WNT3 ELISA Kit CSB-EL026135MO serum, plasma, tissue homogenates and cell lysates 39.07 pg/ml-2500 pg/ml 9.77 pg/ml
Human WNT3A ELISA Kit CSB-EL026136HU serum, plasma 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Mouse WNT3A ELISA Kit CSB-EL026136MO serum, plasma, tissue homogenates 23.5 pg/ml-1500 pg/ml 5.8 pg/ml
Human WNT4 ELISA Kit CSB-EL026137HU serum, plasma and tissue homogenates 23.5 pg/ml-1500 pg/ml 5.8pg/ml
Mouse WNT4 ELISA Kit CSB-EL026137MO serum, plasma, tissue homogenates 500 pg/ml-7.813 pg/ml 1.953 pg/ml
Human WNT5A ELISA Kit CSB-EL026138HU serum, plasma, tissue homogenates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Mouse WNT5A ELISA Kit CSB-EL026138MO serum, plasma, cell culture supernates, tissue homogenates 3.12 pg/ml-200 pg/ml 0.78 pg/ml
Human WNT5B ELISA Kit CSB-EL026139HU serum, plasma, cell culture supernates, tissue homogenates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Mouse WNT7A ELISA Kit CSB-EL026141MO serum, plasma, tissue homogenates, cell lysates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Human WNT7B ELISA Kit CSB-EL026142HU serum, plasma, tissue homogenates 0.156 ng/ml-10 ng/ml 0.039 ng/ml
Mouse WNT7B ELISA Kit CSB-EL026142MO serum, plasma, tissue homogenates 0.312 ng/ml-20 ng/ml 0.078ng/ml

The Overview of Breast Cancer: Related Signaling Pathways, Therapeutic Targets

Breast cancer is a cancer that develops in the tissues of breasts. Symptoms of breast cancer usually include a lump in the breast, a change in breast shape, dimpling of the skin, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. Among them, the first sign of breast cancer often is a breast lump or an abnormal mammogram in breast. Breast cancer starts when cells in the breast begin to grow out of control. These cells usually form a tumor that can often be seen on an x-ray or felt as a lump. If the cells can invade surrounding tissues or spread to distant areas of the body, the tumor is malignant. Breast cancer occurs almost entirely in women, but men can get breast cancer, too. In the recent decades years, breast cancer prevalence and mortality are still on the rise, meanwhile, the studies of breast cancer is hot in Clinical research and basic research. In this review, we summarize breast cancer-related signaling pathways and hotspot therapeutic targets, and hope that can give your research a hand.

1. The Common Types of The Breast Cancer

Breast cancers can start from different parts of the breast. Based on the different parts of the breast, breast cancer is divided into several types. Among them, the more common types are ductal cancers (breast cancers begin in the ducts that carry milk to the nipple) and lobular cancers (some start in the glands that make breast milk). There are also other types of breast cancer which based on Histochemistry, including inflammatory breast cancer, invasive breast cancer, et al. Besides that, therapeutically, it is sub classified into three groups: estrogen receptor (ER) positive, HER2 positive (amplified for the ERBB2 gene), and ER negative or triple negative.

2. Related Signaling Pathways in Breast Cancer

General speaking, signal transduction is critical in the development and treatment of cancer. Together with recent research, we have summarized the signaling pathways associated with breast cancer.

NF-κB Signaling Pathway and Breast Cancer

Nuclear factor kappa-light-chain-enhancer of activated B cells, also known as nuclear factor-kappa B (NF-kB), is a heterodimeric DNA-binding protein that consists of two major subunits, p50 and p65. NF-κB is widely used by eukaryotic cells as a regulator of genes that control cell proliferation and cell survival. In cancer, the crucial regulator proteins of NF-κB signaling pathway are mutated or aberrantly expressed, leading to defective coordination between the malignant cell and the rest of the organism. This is evident both in metastasis, as well as in the inefficient eradication of the tumor by the immune system[1]. Activated NF-kB can bind to DNA and lead to the expression of diverse genes that promote cell proliferation, regulate apoptosis, facilitate angiogenesis and stimulate invasion and metastasis[2][3][4]. Accumulating evidence show that NF-κB activity is commonly elevated in breast cancer. For instance, H Nakshatri, et al. reported that NF-kappaB was constitutively active in ER-negative breast cancer cell lines in 1997[5]. Furthermore, NF-κB recently becomes a key target to breast cance treatment. Jisheng Xiao, et al. demonstrated that blocking the NF-kB signaling pathway can inhibit metastasis and growth of breast cancer via using bioreducible PEI-based/p65 shRNA complex nanoparticles[6]. Besides that, several studies also suggest that the NF-κB signaling pathway can become a treatment target of breast cancer[7][8].

TGF-beta Signaling Pathway and Breast Cancer

The transforming growth factor beta (TGFβ) signaling pathway, also known as TGFβ signaling pathway, is involved in many cellular processes including cell growth, cell differentiation, apoptosis, cellular homeostasis and other cellular functions. The TGF-β ligands have three described isoforms; TGF-β1, TGF-β2, and TGF-β3. TGF-β plays a dual role in cancer development as it displays both tumorigenic and tumor-suppressive effects. TGF-β has been reported to act as a tumor suppressor by inhibiting the cell proliferation of breast cancer cell lines[9]. In the research of E. M. de Kruijf, et al., they have demonstrated that the combination of TGF-β pathway biomarkers can provide valuable prognostic value for breast cancer patients. Stratifying tumors according to the low or high expression of TGF-β biomarkers had strong prognostic implications in our patient population. Additionally, their results highlight the importance of accounting for protein expression levels and the complex interactions taking place between components with the TGF-β pathway[10].

PI3/AKT/mTOR Signaling Pathway and Breast Cancer

The PI3K/AKT/mTOR pathway is an intracellular signaling pathway important in regulating the cell cycle and is directly related to cellular quiescence, proliferation, cancer, and longevity. PI3K activation phosphorylates and activates AKT, localizing it in the plasma membrane[11]. The signaling pathway is activated by stimulation of receptor tyrosine kinases, which in turn trigger PI3K activation, followed by phosphorylation of AKT and mTOR complex 1 (mTORC1). In various subtypes of breast cancer, aberrations in the PI3K/AKT/mTOR pathway are the most common genomic abnormalities, including the PIK3CA gene mutation, the loss-of-function mutations or epigenetic silencing of phosphatase, tensin homologue (PTEN), et al[12][13]. Triple-negative breast cancer (TNBC) is defned by the absence of targetable aberrations, such as hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2). In TNBC, oncogenic activation of the PI3K/AKT/mTOR pathway can happen as a function of overexpression of upstream regulators (e.g., epidermal growth factor receptor [EGFR]), activating mutations of PI3K catalytic subunit α (PIK3CA), loss of function or expression of phosphatase and tensin homolog (PTEN), and the proline-rich inositol polyphosphatase, which are downregulators of PI3K[14][15][16]. Recently, emerging preclinical data support the notion that aberrations in the PI3K/AKT/mTOR pathway predict TNBC inhibition by targeted agents[17].

Notch Signaling Pathway and Breast Cancer

The Notch signaling pathway is a highly conserved, intercellular signaling mechanism essential for proper embryonic development in all metazoan organisms. Mammals possess four different notch receptors (NOTCH1, NOTCH2, NOTCH3, and NOTCH4). Accumulating studies in primary human breast cancer have shown that high-level expression of Jag1 (Jag1High) or Notch1 (Notch1High) mRNA in tumors correlates with poor outcome and is an independent prognostic indicator[18][19]. Emerging evidence has demonstrated that the oncogenic role of Notch in breast cancer is mediated in part via its crosstalk with other signaling pathways, such as the estrogen pathway. Approximately 80% of breast cancers express the estrogen receptor and are treated with anti-estrogens, but resistance to anti-estrogens often develops. One mechanism of resistance may be via the Notch pathway[20]. From a therapeutic standpoint, concurrently targeting both the estrogen receptor and the notch pathway may help to overcome or at least in part delay this resistance.

Several Studies of Other Signaling Pathway in Breast Cancer

In 2011, Mamiko Shimizu, et al. reported that Notch knockdown reduced transcription of uPA and phenocopied uPA knockdown in breast cancer cells. Moreover, the data of their research suggested that JAG1-induced Notch activation results in breast cancer progression by upregulation of the plasminogen activator system, directly linking these 2 important pathways of poor prognosis.

In addition, Lauren L.C. Marotta, et al. found that the IL-6/JAK2/Stat3 pathway was preferentially active in CD44+CD24- breast cancer cells compared with other tumor cell types, and inhibition of JAK2 decreased their number and blocked growth of xenografts. Furthermore, their results highlight the differences between distinct breast cancer cell types and identify targets such as JAK2 and Stat3 that may lead to more specific and effective breast cancer therapies.

Furthermore, Perrin F. Windham from University of Montevallo found that the cGMP signaling pathway may be aberrantly regulated in breast cancer and can be a target for the prevention and treatment of breast cancer.

This year, Chien-Wei Tseng, from China Medical University, demonstrated that transketolase regulates the metabolic switch to control breast cancer cell metastasis via the alpha-ketoglutarate signaling pathway and can be exploited as a modality for improving therapy.

3. The Most Popular Targets in Breast Cancer Treatment

As you known, breast cancer is the most common female cancer in the world, the second leading cause of cancer death after lung cancer, and the main cause of death in women aged 20 to 59. With the further study of breast cancer mechanism, the target of breast cancer treatment has been gradually found.

HER2 for The Treatment of Breast Cancer

HER2 (also known as ERBB2), a member of the HER family of tyrosine kinase receptors (HER1–4), is an essential breast cancer oncogene. Emerging evidence founded that a significant correlation exists between ERBB2 overexpression and reduced survival of breast cancer patients, and amplification of ERBB2 occurs in 30% of early-stage breast cancers[21]. Treatment with the anti-HER2 monoclonal antibody trastuzumab has revolutionized the outcome of patients with this aggressive breast cancer subtype, but intrinsic and acquired resistance is common. With the further study of breast cancer mechanism, growing understanding of the biology and complexity of the HER2 signaling network and of potential resistance mechanisms has guided the development of new HER2-targeted agents. Combinations of these drugs to more completely inhibit the HER receptor layer, or combining HER2-targeted agents with agents that target downstream signaling, alternative pathways, or components of the host immune system, are being vigorously investigated in the preclinical and clinical settings[22]. As shown in the figure 1, the HER2 network and HER2-targeted therapy for HER2+ breast cancer.

Androgen Receptor for The Treatment of Breast Cancer

Androgen receptor (AR) is a steroid hormonal receptor that belongs to the nuclear receptors family together with estrogen (ER), progesterone (PR), glucocorticoid and mineralcorticoid receptor. Recent data suggest that triple negative breast cancer (TNBC) is not a single disease, but it is rather an umbrella for different ontology-profiles such as mesenchymal, basal like 1 and 2, and the luminal androgen receptor (LAR). The LAR subtype is characterized by the expression of the Androgen Receptor (AR) and its downstream effects. Notwithstanding the role of the AR in several signaling pathways, its impact on a biological and clinical standpoint is still controversial. The LAR subtype has been associated with better prognosis, less chemotherapy responsiveness and lower pathologic complete response after neoadjuvant treatment. Clinical evidence suggests a role for anti-androgen therapies such as bicalutamide, enzalutamide and abiraterone, offering an interesting chemo-free alternative for chemo-unresponsive patients, and therefore potentially shifting current treatment strategies[23].

Beside the two targets, there are still several targets for treatment of breast cancer, such as The CXCL12-CXCR4 chemotactic pathway, Adipose tissue, EP4, et al. These targets not only are genes, but also are tissue or signaling pathway. Despite our remarkable success in breast cancer research, there is still a long way to go to study the mechanism of breast cancer.

References

[1] Vlahopoulos, SA. Aberrant control of NF-κB in cancer permits transcriptional and phenotypic plasticity, to curtail dependence on host tissue: molecular mode [J]. Cancer biology & medicine. 2017, 14: 254-270.
[2] Wu Y, Deng J, et al. Stabilization of snail by NF-kB is required for inflammation-induced cell migration and invasion [J]. Cancer Cell. 2009, 15:416-28.>
[3] Park BK, Zhang H, et al. NF-kB in breast cancer cells promotes osteolytic bone metastasis by inducing osteoclastogenesis via GM-CSF [J]. Nat Med. 2007, 13:62-9.
[4] Huang S, DeGuzman A, et al. Nuclear factor-kB activity correlates with growth, angiogenesis, and metastasis of human melanoma cells in nude mice [J]. Clin Cancer Res. 2000, 6:2573-81.
[5] Nakshatri H, Bhat-Nakshatri P, et al. Constitutive activation of NF-kappaB during progression of breast cancer to hormone-independent growth [J]. Molecular and cellular biology. 1997, 17:3629-39.
[6] Xiao J,Duan X,et al. The inhibition of metastasis and growth of breast cancer by blocking the NF-κB signaling pathway using bioreducible PEI-based/p65 shRNA complex nanoparticles [J]. Biomaterials. 2013, 34(21):5381-90.
[7] Yanjie Kong, Fubin Li, et al. KHF16 is a Leading Structure from Cimicifuga foetida that Suppresses Breast Cancer Partially by Inhibiting the NF-κB Signaling Pathway [J]. Theranostics. 2016, 6(6):875-86.
[8] Federica Fusella, Laura Seclì, et al. The IKK/NF-κB signaling pathway requires Morgana to drive breast cancer metastasis [J]. Nat Commun. 2017, 8(1):1636.
[9] Zugmaier G, Ennis BW, Deschauer B et al. Transforming growth factors type beta 1 and beta 2 are equipotent growth inhibitors of human breast cancer cell lines [J]. J Cell Physiol. 1989, 141(2): 353–361.
[10] E. M. de Kruijf, T. J. A. Dekker, et al. The prognostic role of TGF-b signaling pathway in breast cancer patients [J]. Ann Oncol. 2013, 24(2):384-90.
[11] King. D, Yeomanson. D, et al. PI3King the Lock: Targeting the PI3K/Akt/mTOR Pathway as a Novel Therapeutic Strategy in Neuroblastoma [J]. Journal of pediatric hematology/oncology. 2015, 37 (4): 245–51.
[12] Atlas N. Comprehensive molecular portraits of human breast tumours[J]. Nature. 2012, 490(7418):61–70.
[13] Raphael, Jacques; Desautels, Danielle. Phosphoinositide 3-kinase inhibitors in advanced breast cancer: A systematic review and meta-analysis [J]. European Journal of Cancer. 2018, 91: 38–46.
[14] Liu T, Yacoub R, et al. Combinatorial efects of lapatinib and rapamycin in triplenegative breast cancer cells [J]. Mol Cancer Ther. 2011, 10(8):1460–1469.
[15] Cossu-Rocca P, Orru S, et al. Analysis of PIK3CA mutations and activation pathways in triple negative breast cancer [J]. PLoS ONE 2015, 10(11):e0141763.
[16] Ooms LM, Binge LC, et al. The inositol polyphosphate 5-phosphatase PIPP regulates AKT1-dependent breast cancer growth and metastasis [J]. Cancer Cell. 2015, 28(2):155–169.
[17] Ricardo L. B. Costa, Hyo Sook Han, et al. Targeting the PI3K/AKT/mTOR pathway in triple‑negative breast cancer: a review [J]. Breast Cancer Res Treat. 2018, 169(3):397-406.
[18] Reedijk M, Odorcic S, et al. High-level coexpression of JAG1 and NOTCH1 is observed in human breast cancer and is associated with poor overall survival [J]. Cancer Res. 2005, 65:8530–7.
[19] Reedijk M, Pinnaduwage D, et al. JAG1 expression is associated with a basal phenotype and recurrence in lymph nodenegative breast cancer [J]. Breast Cancer Res Treat. 2008, 111:439–48.
[20] Hamed Al-Hussaini, Deepa Subramanyam, et al. Notch Signaling Pathway as a Therapeutic Target in Breast Cancer [J]. Mol Cancer Ther. 2011, 10(1):9-15.
[21] Slamon, D.J. et al. Human breast cancer: correlation of relapse and survival with amplification of the HER-2/neu oncogene [J]. Science. 1987, 235, 177–182.
[22] Mothaffar F. Rimawi, et al. Targeting HER2 for the Treatment of Breast Cancer [J]. Annu. Rev. Med. 2015, 66:111-28.
[23] L. Gerratanaa, D. Basilea, et al. Androgen receptor in triple negative breast cancer: A potential target for the targetless subtype [J]. Cancer Treat Rev. 2018, 68():102-110.

TASIN represents a promising approach for prevention of colorectal cancer

Colorectal cancer attracts the attention of the scientific community as well as the general population because of its relatively high incidence compared with other types of cancer. According to estimates, colorectal cancer is the third most common cancer in the world that approximately 700,000 people die from it each year.

The cause of cancer is a complex question that has not been fully understood. What is clear is that an error in the genes plays a key role in this process.

Recently, a new study has found a method to fight against the most common genetic mutation in colorectal cancer. The method uses a small molecule, named TASIN-1, to target and destroy cancer cells carrying mutations in a gene called APC. Considering the high prevalence of APC mutations in patients with colorectal cancer, the method should be a very effective strategy for the treatment and prevention of the lethal disease.

The study is a collaboration of several institutions in the USA and an institution in Korea. Jerry Shay, Ph.D., Distinguished Teaching Professor at the University of Texas (UT) Southwestern Medical Center, is the lead researcher, and his major research interests include cell biology of the cancer genome.

Shay noted that “Even though such mutations are common in colorectal cancer, there are currently not any therapeutics that directly target these types of mutations, so this represents fresh avenues to approach.”

You can read the full paper, entitled Selective targeting of mutant adenomatous polyposis coli (APC) in colorectal cancer, in the journal Science Translational Medicine (2016).

The gene APC, short for adenomatous polyposis coli, is classified as a tumor suppressor gene, meaning that it acts to prevent the development and progression of cancer. This gene codes for a protein that has a role in many fundamental cellular processes, such as the regulation of canonical WNT signaling pathway, cell proliferation, migration, differentiation, and apoptosis.

Mutation of APC is found in more than 80% of all colorectal tumors, and it’s thought that APC mutations contribute to the initiation of colorectal cancer. The vast majority of APC mutations generate stable truncated gene products, referred to as APC truncations. These truncated proteins not only lead to the loss of APC tumor-suppressing functions but also may exert functions that contribute to colorectal tumorigenesis. Although APC is frequently mutated in colorectal cancer, currently there is no known drug that could directly target this type of mutation.

To find drugs that target APC mutations, Shay and co-workers from UT Southwestern Medical Center, along with researchers from Inha University College of Medicine, screened more than 200,000 small molecules to see which of them could selectively inhibit cell growth of human colorectal cancer cell lines with truncated APC. A compound named TASIN-1 (truncated APC selective inhibitor–1) stood out. It effectively killed cancer cells with truncated APC in vitro but did not exhibit potent toxicity toward cancer cells with normal APC.

Next, the researchers examined the anti-tumor activity of TASIN-1 in vivo. Mice transplanted with human cancer cells were treated with TASIN-1. Results showed that TASIN-1 treatment reduced the tumor-forming ability of human cancer cells with truncated APC in mice, but did not affect cancer cells that had normal APC.

The researchers also tested TASIN-1 in mice genetically engineered to develop colorectal cancer that carried truncated APC and found that TASIN-1 treatment greatly reduced tumor burden in the colons of these animals, without causing detectable toxicity in other tissues of them such as livers, kidneys, and spleens.

Finally, the researchers explored the mechanisms underlying the anti-tumor effects of TASIN-1. They identified that the compound interferes with cholesterol biosynthesis and pinpointed EBP (emopamil-binding protein) as a potential target of TASIN-1. “TASIN-1 exerts its killing effects primarily by depleting cholesterol through inhibition of EBP activity,” the researchers concluded.

Taken together, these data suggest that the compound TASIN-1 could selectively target and destroy cancer cells carrying APC truncations while sparing cancer cells with wild-type APC as well as healthy cells. An advantage of the compound is that it triggers no apparent toxicity. This is significant because side effects or safety is an important factor that must be taken into consideration during drug development.

Targeting the APC gene is believed to be a potential therapeutic strategy for colorectal cancer, given that most colorectal tumors carrying APC mutations. TASIN-1 and similar small molecules might be a potential drug to target APC mutations since the current study demonstrates the potent cancer-killing effect of TASIN-1 both in vitro and in vivo.

“Our latest finding confirms that targeting TASINs is a viable approach,” said Shay.

The current study would facilitate the development of a novel anti-cancer drug for the treatment and prevention of colorectal cancer, but more investigation is required to validate the results.

Colorectal cancer (which is often used interchangeably with the term ‘colon cancer’) originates from the out-of-control growth of cells in our colon and/or rectum, which form the lower part of our digestive system, as shown in Fig. 1 below. Cancer is thought to result from the complex interactions between genetic and environmental factors. To date, a variety of environmental factors and lifestyle choices have been associated with colorectal cancer, such as an unbalanced diet, overweight or obesity, a sedentary lifestyle, alcohol use, smoking, etc.

Fig. 1 The colon and rectum
(By Indolences created it on the English Wikipedia. This SVG image was created by Medium69. Cette image SVG a été créée par Medium69.Please credit this : William Crochot – US PD picture., Public Domain, https://commons.wikimedia.org/w/index.php?curid=1521879)

Shay’s study and studies by many other groups deepen our understanding of the genetic aspect of colorectal cancer and key molecular mechanisms involved in it and might also open doors for research into the complex interactions between genetic and environmental factors implicated in colorectal cancer and therefore help develop preventive strategies.

If there was a choice, no one wanted to develop cancer. Individuals with genetic risk factors are more prone to a specific disease compared with the general population. Even though we know this, there is often a lack of drugs that can target these genetic factors, such as in the case of APC mutations in colorectal cancer. Development of drugs that target disease-causing mutations might offer opportunities for prevention of disease, and of course, requires a great deal of work, and may face a lot of failures.

Hepatocellular carcinoma (HCC) refers to cancer that originates in the liver, which is distinguished from “secondary” liver cancer that spreads from other organs to the liver. Hepatocellular carcinoma, which accounts for 90% of all primary liver cancers, is the sixth most common cancer in the world and the second leading cause of cancer death [1]. It has the highest incidence in East Asia and other regions where HBV is prevalent.

1. Epidemiology

Asia and sub-Saharan Africa are the areas with the highest incidence of HCC and are also high-risk areas of HBV infection. HBV and aflatoxin together influence the occurrence of HCC in Africa. It is estimated that aflatoxin B1 is a cofactor in 60% of liver cancer cases in Sudan.

In North America, Europe, and Japan, hepatitis C is the leading cause of liver cancer.

The situation in some countries is as follows:

Figure 1 The global burden of HCC

This image is from the literature Hepatitis B and Hepatocellular Carcinoma [2]
Figure 1 The global burden of HCC

2. About the Liver

The liver is the largest internal organ in the human body. It is of great significance to human health. It has several important features:

  • Storage and Decomposition of Substances. Some nutrients must be altered in the liver. It also breaks down alcohol, drugs and toxic waste in the blood.
  • Production of Coagulation Factors. When you’re injured, it produces most of the coagulation factors that prevent you from bleeding too much.
  • It secretes bile into the intestines and helps absorb nutrients (especially fat).

3. What Affects Hepatocellular Carcinoma?

Hepatocellular carcinoma is the most common type of liver cancer in adults. It is usually diagnosed in people aged 50 or older.

The etiology of liver diseases is diverse, including chronic viral infection of hepatitis b or hepatitis c virus, alcohol toxicity, autoimmune and cholestasis liver diseases, and metabolic factors [3].

3.1 TNF-TNFR2 Signaling in Allergy

Hepatocellular carcinoma is more common in men than in women [4]. But one of the subtypes, the fibroblast, which is very rare and accounts for less than 1% of HCC, is more common in women.

3.2 Chronic Viral Hepatitis

Liver cancer often occurs in the context of chronic hepatitis. Chronic (long-term) infection with either hepatitis b virus (HBV) or hepatitis C virus (HCV) is the most common risk factor for liver cancer [5] [6].These infections cause cirrhosis of the liver. Hepatitis C-induced progressive hepatic fibrosis and aging are recognized as high-risk conditions for liver cancer development [7].

3.3 Cirrhosis

Cirrhosis [8] is a disease in which liver cells are damaged and replaced by scar tissue. Most liver cancer patients have signs of cirrhosis.

3.4 Alcohol Abuse

Alcoholism [9] is one of the main causes of liver cirrhosis, which in turn increases the risk of liver cancer.

3.5 Obesity and Diabetes

Obesity can lead to nonalcoholic fatty liver disease, and people with nonalcoholic fatty hepatitis (NASH) can develop cirrhosis of the liver. Studies have shown that there is a close relationship between neuromodulation, endocrinology and liver cancer in obese patients [10].

The high risk of diabetes may be due to high insulin levels in diabetics or liver damage caused by diabetes. The choice of antidiabetic treatment may affect the development of liver cancer. Insulin therapy has been reported to increase the risk of liver cancer, while metformin seems to reduce the risk of liver cancer [11].

3.6 Iron Storage Related Diseases

Hemochromatosis, which causes the liver and other organs to store excess iron. People with the disease can develop hepatocellular carcinoma.

3.7 Exposure to Certain Hazardous Substances

Aflatoxin: Long-term exposure to aflatoxin is a major risk factor for liver cancer.

Vinyl chloride and cerium oxide: Exposure to these chemicals increases the risk of hepatic angiosarcoma.

Arsenic: Long-term consumption of arsenic-contaminated water increases the risk of certain types of liver cancer.

3.8 Some Rare Diseases

Diseases that increase the risk of liver cancer include:

Porphyria cutanea tarda.

Wilson disease.

Alpha1-antitrypsin deficiency.

Tyrosinemia.

Glycogen storage diseases.

3.9 Other Factors

Smoking [12] increases the risk of liver cancer

Recent findings suggest that adeno-associated virus 2 (AAV2) infection is a new cause of this disease, especially in people without cirrhosis [13].

The impact factors and processes of HCC

Figure 2 The impact factors and processes of HCC

4. Symptoms of Hepatocellular Carcinoma

In the early stages of hepatocellular carcinoma, there may be no symptoms. As cancer progresses, the following symptoms may occur:

A lump or pain on the right side of the abdomen.

Abdominal swelling or effusion.

Loss of appetite.

Unexplained weight loss.

Nausea and vomiting.

Weakness or extreme fatigue.

Yellowing of the skin and eyes (jaundice).

Fever.

Abnormal bruises or bleeding.

Abdominal vein dilatation.

5. Diagnosis and Detection

Early diagnosis of hepatocellular carcinoma is of great value for the treatment and prognosis of patients with hepatocellular carcinoma.

5.1 Detection Method

People who have (or may have) liver cancer need more tests.

  • Medical history and physical examination.
  • Imaging tests.
  • UltrasonicThe test can show that tumors are growing in the liver and can be tested for cancer if needed.
  • Computed tomography (CT)Abdominal CT scans can help identify many types of liver tumors. CT scans can also be used to direct a biopsy needle to precisely enter a suspected tumor.
  • Magnetic resonance imaging (MRI)MRI scans can sometimes distinguish between benign and malignant tumors. They can also be used to look at blood vessels inside and outside the liver and to see if liver cancer has spread.
  • AngiographyAngiography can be used to show the arteries that supply blood to liver cancer. It can also be used to guide nonsurgical treatments, such as embolization.
  • Bone scanBone scans can see if cancer has spread to the bone.
  • Laparoscopy
  • BiopsyA biopsy is a sample taken from a tissue to see if it is cancer.
  • Alpha-fetoprotein blood (AFP) test

    Adult AFP levels can often rise due to liver disease, liver cancer or other cancers.

    AFP levels can help identify possible treatment options and evaluate treatment outcomes.

5.2 Liver function test (LFTs)

Clotting test: prothrombin time (PT) is used to test the ability of the liver to produce clotting factors.

Viral hepatitis test: check for hepatitis b and c in the blood.

Kidney function tests: include blood urea nitrogen (BUN) and creatinine levels.

Whole blood cell count (CBC): measures red, white, and platelet levels.

5.3 Biomarker

Sensitive biomarkers may help early detection of chronic hepatitis patients.

AFP (> 400 ng / mL) is the most commonly used biomarker for liver cancer, but its sensitivity and accuracy are not high, and half of the patients have not detected liver cancer. Another marker is des-gamma-carboxyprothrombin (DCP), however, elevated DCP may be due to other reasons, and normal DCP does not exclude HCC.

Recent studies have shown that serum microRNA is a promising method for monitoring liver function [14].

6. Preventive Measures

Targeted prevention according to risk factors for hepatocellular carcinoma.

6.1 Avoid and treat hepatitis infections

Hepatitis B virus (HBV) and hepatitis C virus (HCV) can spread from person to person by sharing contaminated needles and non-protective sex. Therefore, not sharing needles and using safer sexual practices (such as continuous condom use) can prevent some cancers.

Vaccination and antiviral therapy will have a positive impact [15].Vaccination can reduce the risk of hepatitis and liver cancer. Interferon-based regimen has been the mainstay of anti-hepatitis c therapy [16].

Blood transfusions are also a source of hepatitis infection. Rigorous testing of blood Banks is needed to reduce the risk of transmission through this route.

6.2 Limit alcohol and tobacco use

Drinking and smoking both increase the risk of liver cancer.

6.3 Healthy weight

Avoiding obesity is another way to help prevent liver cancer. Obese people are more likely to develop fatty liver and diabetes, both of which are associated with liver cancer.

6.4 Reduce exposure to carcinogenic chemicals

6.5 Treat diseases that increase the risk of liver cancer

Hemochromatosis screening and timely treatment should be carried out for hemochromatosis family members.

7. Treatment

Treatment depends on the extent of cancer progression.

The most commonly used liver cancer comprehensive staging tool in the world is the Barcelona Clinical Liver Cancer (BCLC) system.

  • (BCLC A): Patients with single tumours or up to three nodules that are 3 cm or smaller and preserved liver function are classified as having very early or early-stage hepatocellular carcinoma. The treatments available to patients at this stage are surgical resection, liver transplantation or local ablation.
  • (BCLC B): In the mid-term, patients with compensatory cirrhosis have no tumor-related symptoms or vascular invasion. Transarterial chemoembolization (TACE) can be considered.
  • (BCLC C): In advanced stages, the patient’s symptoms at this stage are characterized by tumors or invasive tumors (extra-hepatic spread or vascular invasion), or both. This stage can be treated with the multi-kinase inhibitor sorafenib.
  • (BCLC D): At the end of the period, there are serious cancer-related symptoms or severe liver damage, or both, and are not suitable for transplantation. Symptomatic treatment is recommended at this stage.

7.1 Surgery

The best treatment opportunity for hepatocellular carcinoma is resection. When the tumor is single and less than 2 cm, the survival rate after resection is close to 70%. However, only 10% of patients met the criteria at the time of discovery. Therefore, early diagnosis is essential to improve prognosis.

7.2 Liver transplantation

The criteria for determining whether a liver cancer patient is eligible for a liver transplant are very different worldwide. However, MC remains the benchmark for patient selection [17].

During liver transplant surgery, the entire liver is removed and replaced with a healthy liver. After the transplant, you need to continue taking the drug to prevent the body from rejecting the new liver.

However, the current status is that the number of patients waiting for liver transplantation each year exceeds the number of patients undergoing liver transplantation.

7.3 Ablation therapy

Ablation therapy removes or destroys tissue.

Radiofrequency ablation (RFA) [18]: the first line of ablation technique, which involves the use of a special needle to insert directly into the skin or through the abdominal incision to reach the tumor. High-energy radio waves heat needles and tumors that kill cancer cells.

Microwave therapy: A therapy that exposes a tumor to high temperatures generated by microwaves. This can destroy and kill cancer cells.

Percutaneous injection of ethanol: using ethanol kill cancer cells. The local control effect of ethanol injection is poor [19].

Cryoablation: A therapy that uses instruments to freeze and destroy cancer cells.

Electroporation treatment: An electrical pulse is sent through an electrode placed in a tumor to kill cancer cells. Electroporation therapy is being studied in clinical trials.

Embolization therapy: Embolization treatment is to block or reduce the flow of blood through the hepatic artery to the tumor. Thereby inhibiting the growth of the tumor.

7.4 Targeted therapy

Targeted therapy is a method that uses drugs or other substances to specifically recognize and attack specific cancer cells without harming normal cells.

Hepatocellular carcinoma is associated with abnormal activation of multiple cellular signaling pathways [20], which leads to the complexity of its etiology. The current therapeutic targets for hepatocellular carcinoma include:

The targets involved in hepatocellular carcinoma

Figure 3 The targets involved in hepatocellular carcinoma

Cell membrane receptors: such as tyrosine kinase receptor, vascular endothelial growth factor receptor.

Growth factors: Wnt/beta-catenin, Ras /Raf /MEK /ERK and PI3K /Akt /mTOR.

Cell cycle regulatory proteins: p53, p16 /INK4, cyclin /CDK complex.

Unfortunately, currently there are so few clinically effective HCC targeted therapies that multiple kinase inhibitors are the only HCC therapy drugs approved by FDA.

Sorafenib

Sorafenib is currently approved as a first-line systemic therapy for unresectable liver cancer [21]. It is a multi-kinase inhibitor and is the only advanced HCC-targeted drug currently marketed in the United States and the European Union.

Sorafenib inhibits kinases such as RAF kinase, VEGFR-2, VEGFR-3, PDGFR-β, KIT and FLT-3. It can also directly inhibit tumor growth through the RAF / MEK / ERK signaling pathway; it also inhibits tumor cell growth indirectly by inhibiting VEGFR and PDGFR.

7.5 Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill or prevent cancer cells from growing.

7.6 New therapy

Studies on microflora and HCC have found that in the mouse model of liver cancer induced in the laboratory, intestinal microorganisms influence the development of tumors and induce the occurrence of tumors [22].One study found that a specific probiotics (inulin type fructan) can reduce the proliferation of hepatocellular carcinoma cells in mice by stimulating the production of short-chain fatty acid propionate [23].

 

8. Prognosis

Even after liver cancer treatment is completed, you still need some tests, such as alphafetoprotein (AFP) level, liver function test (LFTs) and so on.

Patients after liver transplantation need to take medication to prevent rejection.

References

[1] Jemal A, Bray F, Center M M, et al. Global cancer statistics [J]. Ca Cancer J Clin, 2011, 61(2): 69-90.

[2] Hemming A W, Berumen J, Mekeel K. Hepatitis B and Hepatocellular Carcinoma [J]. Gastroenterologist, 2016, 20(4): 703-720.

[3] Ibrahim G A, Khan S A, Toledano M B, et al. Hepatocellular carcinoma: Epidemiology, risk factors and pathogenesis [J]. World Journal of Gastroenterology, 2008, 14(27): 4300-.

[4] Yang D, Hanna D L, Usher J, et al. Impact of sex on the survival of patients with hepatocellular carcinoma: A Surveillance, Epidemiology, and End Results analysis [J]. Cancer, 2015, 120(23): 3707-3716.

[5] Bosetti C, Turati F, La Vecchia C. Hepatocellular carcinoma epidemiology [J]. Best Practice & Research Clinical Gastroenterology, 2014, 28(5): 753-770.

[6] Stanaway J D, Flaxman A D, Naghavi M, et al. The global burden of viral hepatitis from 1990 to 2013: findings from the Global Burden of Disease Study 2013 [J]. The Lancet, 2016: 1081-1088.

[7] Hoshida Y, Fuchs B C, Bardeesy N, et al. Pathogenesis and prevention of hepatitis C virus-induced hepatocellular carcinoma [J]. Journal of Hepatology, 2014, 61(1): S79-S90.

[8] Bolondi L. Surveillance programme of cirrhotic patients for early diagnosis and treatment of hepatocellular carcinoma: a cost effectiveness analysis [J]. Gut, 2001, 48(2): 251-259.

[9] Turati F, Galeone C, Rota M, et al. Alcohol and liver cancer: a systematic review and meta-analysis of prospective studies [J]. Annals of Oncology, 2014, 25(8): 1526-1535.

[10] Gan L, Liu Z, Sun C. Obesity linking to hepatocellular carcinoma: A global view [J]. Biochimica et Biophysica Acta (BBA) – Reviews on Cancer, 2018, 1869(2): 97-102.

[11] Chen H P, Shieh J J, Chang C C, et al. Metformin decreases hepatocellular carcinoma risk in a dose-dependent manner: population-based and in vitro studies [J]. Gut, 2013, 62(4): 606-615.

[12] Chuang S C, Vecchia C L, Boffetta P. Liver cancer: Descriptive epidemiology and risk factors other than HBV and HCV infection [J]. Cancer Letters, 2009, 286(1): 0-14.

[13] Nault J C, Datta S, Imbeaud S, et al. Recurrent AAV2-related insertional mutagenesis in human hepatocellular carcinomas [J]. Nature Genetics, 2015.

[14] Hayes C, Kazuaki C. MicroRNAs as Biomarkers for Liver Disease and Hepatocellular Carcinoma [J]. International Journal of Molecular Sciences, 2016, 17(3): 280-.

[15] Lai C L, Yuen M F. Prevention of hepatitis B virus-related hepatocellular carcinoma with antiviral therapy [J]. Hepatology, 2013, 57(1): 399-408.

[16] Webster D P, Klenerman P, Dusheiko G M. Hepatitis C [J]. Lancet, 2015, 385(9973): 1124-1135.

[17] Clavien P A, Lesurtel M, Bossuyt P M, et al. Recommendations for liver transplantation for hepatocellular carcinoma: an international consensus conference report [J]. Lancet Oncology, 2012, 13(1): e11-e22.

[18] Lencioni R, Crocetti L. Local-Regional Treatment of Hepatocellular Carcinoma [J]. Radiology, 2012, 262(1): 43-58.

[19] Lin S M. Randomised controlled trial comparing percutaneous radiofrequency thermal ablation, percutaneous ethanol injection, and percutaneous acetic acid injection to treat hepatocellular carcinoma of 3 cm or less [J]. Gut, 2005, 54(8): 1151-1156.

[20] Cervello M, Mccubrey J A, Cusimano A, et al. Targeted therapy for hepatocellular carcinoma: novel agents on the horizon [J]. Oncotarget, 2012, 3(3).

Hepatocellular carcinoma (HCC) is the third most common death-related cancer in the world and the sixth most common tumor. The major risk factors for liver cancer include chronic viral hepatitis, alcoholism, carcinogens or genetic diseases. Advances in cancer biology have shown that HCC development is associated with changes in several important cellular signaling pathways. Targeting these pathways can help prevent, delay or even reverse tumor development, which is of great significance for the treatment of hepatocellular carcinoma.

1. Current Status of Hepatocellular Carcinoma Therapy

The present situation is that most patients (approximately 80%) diagnosed with hepatocellular carcinoma are at advanced stage and cannot be surgically resected due to the absence of early HCC symptoms, coupled with a lack of awareness of screening and unclear definition of screening strategies [1] [2]. Sorafenib, a first-line systemic therapy for advanced HCC, is a multikinase inhibitor. As the first effective drug to target liver cancer, it significantly prolongs patient survival and progression time, but its overall survival benefit is limited [3]. The lack of effective treatment options is one of the main reasons for the high mortality of HCC patients, which highlights the need for new treatments.

2. Signaling Pathways Associated With Hepatocellular Carcinoma

Several major molecular signaling pathways involved in the pathogenesis of liver cancer:

2.1 The Receptor Tyrosine Kinase Pathways

Receptors for the receptor tyrosine kinase pathway include the EGF receptor, the FGF receptor, the HGF receptor c-MET, the stem cell growth factor receptor c-KIT, the PDGF receptor, and the vascular endothelial growth factor (VEGF) receptor. These receptors activate multiple downstream signals. The Ras/MAPK and PI3K/Akt kinase signaling pathways are activated by ligand binding and phosphorylation of several growth factor tyrosine kinase receptors, including activation of the Grb2/Shc/SOS adaptor complex and downstream activation of Ras/Raf/Erk1/2 MAPK pathway, thereby activating AP-1 transcriptional activator.

The receptor tyrosine kinase signaling pathway

Figure 1 The receptor tyrosine kinase signaling pathway

In hepatocellular carcinoma, many growth factors, including VEGF receptor, EGFR, IGF and HGF/c-MET, have significant effects on the occurrence and pathogenesis of tumors.

VEGF receptor

Tumor growth and invasion of liver cancer are dependent on angiogenesis disorders. VEGF is a key angiogenic factor. Therefore, VEGF plays an important regulatory role in liver cancer. Studies have shown that both VEGF and VEGFR expression are increased in HCC patients (including VEGFR-1, VEGFR-2, and VEGFR-3). Hepatitis b x antigen is associated with the up-regulation of VEGFR-3 [4]. VEGF expression is induced by hypoxic tumor environment (HIF-2), EGFR activation and COX-2 signaling [5] [6].

High expression of VEGF was associated with HCC tumor grade [7], poor prognosis after resection, disease recurrence, vascular invasion and portal vein embolism Therefore, VEGF growth factor can be used as a therapeutic target for HCC.

Sorafenib, a drug currently used to treat hepatocellular carcinoma, has major molecular targets including vascular endothelial factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and Raf [8].This indicates that targeted growth factor is an effective treatment.

2.1 EGFR and HGF/c-MET signals

  • EGFEGF is a ligand that binds to EGFR and plays an important role in tumor angiogenesis and proliferation. These effects are mainly achieved by activating the RAF/MEK/ERK and PI3K/AKT/mTOR pathways. Studies have shown that EGFR signaling plays a role in early liver cancer. In HCC, EGF and related growth factors are generally up-regulated.
  • IGFThe IGF signaling pathway regulates a variety of cellular processes, including proliferation, motility, and apoptosis inhibition. The IGF signaling pathway is activated by binding of ligands (IGF-1 and IGF-2) to membrane-bound receptors (IGF-1R).Major processes in the IGF signaling pathway: ligand binding to IGF-1R initiates autophosphorylation of the receptor, followed by phosphorylation of intracellular targets, which in turn activates downstream cellular effector factors and ultimately activates the PI3K, protein kinase B, and RAF/MEK/ERK pathways.In hepatocellular carcinoma, the insulin-like growth factor (IGF) signaling pathway is frequently dysregulated. The imbalance of IGF signal is mainly manifested in the level of IGF-2 bioavailability. IGF-2R is overexpressed in most hepatocellular carcinomas, and this excess ligand availability leads to increased binding to the receptor and further action on the MAPK and PI3K/AKT/mTOR pathways.
  • HGFHGF is a cytokine involved in the invasion of malignant tumors. It works primarily by binding to the tyrosine kinase receptor c-MET. Major functions of c-MET include tissue regeneration, cell proliferation, migration, survival, branch morphogenesis, and angiogenesis. Binding of HGF results in homodimerization and self-phosphorylation of the c-MET receptor and further phosphorylation of adaptor proteins (including GRB2) and GAB1 (GRB2-associated -binding protein 1), which then activate downstream effector molecules (including phospholipase C, PI3K, and ERK). C-MET phosphorylation can also be activated by the epidermal growth factor receptor (EGFR), cell adhesion, or replacement ligand des-γ-carboxythrombin.

    Signaling pathways involved in the pathogenesis of hepatocellular carcinoma

    Figure 2 Signaling pathways involved in the pathogenesis of hepatocellular carcinoma

2.2 RAF/ERK/MAPK Pathway

RAF/MEK/ERK pathway is a ubiquitous signal transduction pathway whose main role is to regulate cell proliferation, differentiation, angiogenesis and survival. Activation of this pathway contributes to tumor development, progression and metastasis.

The ERK/MAPK pathway is regulated by various growth factors, and the binding of growth factors leads to the phosphorylation of receptors and the activation of an adaptive molecular complex. This in turn activates the RAF/MEK/ERK pathway, triggering a series of specific phosphorylation events [5]. The intermediate signaling pathway is regulated by mitogen/extracellular protein kinases MEK1 and MEK2, which are responsible for phosphorylation of downstream signaling molecules ERK1 and ERK2. ERK1/2 regulates cellular activity through a variety of substrates that act on the cytoplasm and nucleus.

In hepatocellular carcinoma, RAF/MEK/ERK pathway is usually activated by two main mechanisms:

  • Oncogenic mutation in RAS gene leads to constitutive CRAF activation.
  • A disorder in the overexpression of growth factors and their receptors leads to constitutive CRAF activation.

It is reported that RAF/MEK/ERK pathway also can be activated by HBV infection in HCC.

The role of RAF/ERK/MAPK pathway in tumorigenesis indicates that this pathway is also an effective therapeutic target for HCC.

2.3 PI3K/Akt/mTOR Signal Pathway

Activation of the PI3K/AKT/mTOR signaling pathway is a major determinant of tumor cell growth and survival in multiple solid tumors. mTOR pathway plays an important role in the pathogenesis of liver cancer, with 15% ~ 41% of liver cancer patients suffering from mTOR pathway aberration.

In the PI3K/AKT/mTOR signaling pathway, the binding of growth factors (IGF and EGF) to receptors activates PI3K. PI3K then produces a second lipid messenger, PIP3b (phosphoinositol triphosphate), which in turn activates the serine/threonine kinase AKT. Activated AKT regulates various transcription factors and phosphorylates several cytoplasmic proteins, including BAD and mTOR. The mTOR protein in turn regulates phosphorylation of the p70-S6 kinase, the serine threonine kinase, and the translational inhibitory protein PHAS-1/4E-BP. These proteins regulate the translation of cell cycle regulatory proteins and promote cell cycle progression.

mTORC1 and mTORC2 are important components in this signaling pathway. mTORC1 is a downstream signal of AKT, which activates S6 kinase to regulate protein synthesis and induces cell cycle progression from G1 phase to S phase [9].

In hepatocellular carcinoma, the overactive EGF and IGF signaling pathways are responsible for inducing the PI3K/AKT/mTOR pathway and promoting tumor progression. In addition, PTEN dysfunction is also the cause of excessive activation of PI3K/AKT/ mTOR pathway [10]. PTEN inhibits this pathway by reversing the PI3K response and blocking Akt activation. In hepatocellular carcinoma, PTEN gene expression is down-regulated, and its down-regulation is regulated by HBX protein. The interaction between GPC3 and FGF-2 is frequently observed in liver cancer cells and is responsible for phosphorylation of ERK and AKT [11].

There is also some evidence that the PI3K/AKT/mTOR signal may be activated by somatic mutations in the PI3K-catalyzed gene PIK3CA.

The PI3K/ AKT/mTOR pathway plays a key role in the pathogenesis of HCC. As a key role in mTOR signaling pathway, mTOR activity is often increased in HCC. Inhibition of mTOR activity can reduce cell proliferation in vitro and tumor growth in xenograft mouse models [12]. Blocking mTOR with everolimus slows tumor growth and improves survival. HSP90 is involved in the folding and activity of many oncoprotein proteins. Therefore, blocking HSP90 blocks the rapamycin-induced AKT signaling pathway, thereby enhancing the anti-tumor effect of mTOR inhibitor rapamycin [13].

The PI3Kinase/AKT/mTOR pathway

Figure 3 The PI3Kinase/AKT/mTOR pathway

2.4 Wnt/β-catenin Pathway

β-catenin in the Wnt signaling pathway is an important factor in the development of early and early carcinogenic events in HCC.

Wnt is a glycoprotein ligand that acts as a ligand for the Frizzled cell surface receptor family and activates a receptor-mediated signaling pathway [14].

In the absence of Wnt ligands, β-catenin binds to E-cadherin in most cells. Cytosol β-catenin forms complexes with adenomatous polyposis coli (APC) and AXIN1 or AXIN2, which mediates casein kinase 1 and glycogen synthase kinase 3b (GSK3b), resulting in continuous β-catenin Phosphorylation and degradation.

In the presence of Wnt ligand, extracellular Wnt ligand binds to the cell surface Frizzled family receptor, resulting in phosphorylation and inhibition of GSK3b, leading to accumulation of cytosolic β-catenin. Then β-catenin is translocated to the nucleus, interacts with TCF and LEF transcription factors, and activates transcription of target genes, including cyclin D1, c-Myc, c-MET, FGF4, metalloproteinases, and VEGF. Accumulation of β-catenin provides growth advantages for tumor cells by promoting proliferation and inhibiting differentiation.

In hepatocellular carcinoma, aberrant activation of the Wnt pathway is primarily a mutation in β-catenin. Studies have shown that treatment of HCC cell lines with TGF-β results in activation of β-catenin, suggesting that this pathway may also be mediated by TGF-β.

Glypican-3 (GPC3) is a cell surface protein. The expression level of GPC3 is higher in HCC cell lines. GPC3 exerts its carcinogenic effect by activating Wnt/β-catenin signaling.

Cadherin 17 (CDH17) is an up-regulated adhesion molecule in HCC, which is related to tumorigenesis in various regions of the gastrointestinal tract [15]. Inhibition of CDH17 leads to the relocation of nuclear β-catenin to the cytoplasm, thereby weakening the Wnt/β-catentin signaling pathway [16]. Targeting CDH17 simultaneously inactivates the Wnt/β-catenin signal pathway.

The role of Wnt in the regulation of liver regeneration and the maintenance and self-renewal of pluripotent stem and progenitor cells suggests that it may be an ideal target for cancer therapy.

Different targeting targets can be proposed for the different activation of the Wnt channel:

  • Targeting the interaction of Wnt ligands with Fzd receptors.
  • Targeting the destruction of the complex.
  • Targeting-catenin/LEF-TCF transcription complex.

Several drugs currently in clinical use have been shown to have anti-Wnt pathway activity. These drugs include non-selective cyclooxygenase (COX) [17], inhibitors indomethacin, sulinic acid, aspirin, and nitric oxide releasing aspirin, and selective inhibitors celecoxib and rofekoxib.

Wnt/β-catenin Pathway

Figure 4 Wnt/β-catenin Pathway

2.5 Ubiquitin-Proteasome Pathway

The ubiquitin-proteasome system is a highly conserved cellular protein degradation system in eukaryotic systems. The ubiquitin-proteasome system plays an important role in maintaining cell homeostasis such as cell cycle regulation, apoptosis, receptor signal transduction and endocytosis.

The ubiquitin-labeled protein is degraded by the proteasome or absorbed by endocytosis and degraded in the lysosome. Ubiquitin-proteasome-mediated protein degradation is accomplished through a series of steps including ubiquitin-activating enzyme (E1), polyubiquitin-coupled enzyme (E2s), and ubiquitin ligase (E3s).

Deregulation of NF-κB in HCC is one of the carcinogenic events induced by ubiquitin-proteasome system defects. Furthermore, HBV-expressed proteins [18] and HCV-expressed proteins [19] cause changes in the ubiquitin-proteasome system, leading to viral replication, liver tumorigenesis and host immune damage. This further illustrates the importance of the ubiquitin-proteasome system in the development of HCC.

A variety of cancer-associated proteins are regulated by the ubiquitin-proteasome system, including:

  • Tumor suppressor p53, p27, PTEN.
  • Cell surface tyrosine kinase growth factor receptor EGFR and transforming growth factor β (TGF-β) receptor.
  • Other cell cycle regulators and oncogenic molecules.

Some cancer-related proteins are also involved in the ubiquitin conjugation mechanism: FRA6E fragile locus protein Parkin, an E3 ligase targeting cyclin E and P38, have been shown to act as tumor suppressors in HCC.

2.6 Hedgehog Signaling Pathway

Hedgehog (Hh) signaling pathway is a highly conserved system that plays a crucial role in tissue pattern, cell differentiation and proliferation [20]. Abnormal activation of Hh signaling pathway leads to the occurrence and development of tumorigenesis in pancreas, colon, stomach [21], lung [22], prostate [23], breast, skin and other cancers.

Recent studies have shown that the Hh pathway is abnormally activated in human HCC. GPC3 interacts with the hedgehog signaling pathway in regulating developmental growth [24]. And the GPC3-hedgehog signaling pathway is thought to contribute to the development of HCC. The Hh pathway plays an important role in the development and invasion of HCC. Blocking the Hh signaling pathway may be a potential target for new HCC treatment strategies [25]. Downregulation of Gli2 with a ligand blocking antibody or KAAD-cyclopamine (selective Smo antagonist) or inhibition of this pathway has been shown to delay tumor growth and reduce tumor size.

2.7 Ras and Jak/Stat Pathways

Ras and Jak/Stat pathways are generally activated in HCC, and Ras pathway is the main signal network promoting cell proliferation and survival. The binding of different growth factors (eg EGF and IGF-1) to the receptor (eg EGFR, IGF-1R) induces the activation of Ras, which in turn activates c-RAF, MEK and ERK.

Ras and Jak/Stat inhibitors and demethylating agents can be used as a treatment for human liver cancer.

References

[1] Bruix J, Sherman M. Management of hepatocellular carcinoma: An update [J]. Hepatology, 2011, 53(3): 1020-1022.

[2] X-P. Chen, F-Z. Qiu, Z-D. Wu, et al. Long-term outcome of resection of large hepatocellular carcinoma [J]. Br J Surg, 2010, 93(5): 600-606.

[3] Schwartz J D. Sorafenib in Advanced Hepatocellular Carcinoma [J]. N Engl J Med, 2008, 359(23): 378-390.

[4] Lian Z, Liu J, Wu M, et al. Hepatitis B x antigen up-regulates vascular endothelial growth factor receptor 3 in hepatocarcinogenesis [J]. Hepatology, 2007, 45: 1390–1399.

[5] Avila MA, Berasain C, Sangro B, et al. New therapies for hepatocellular carcinoma [J]. Oncogene, 2006, 25: 3866–3884.

[6] Bangoura G, Liu ZS, Qian Q, et al. Prognostic significance of HIF-2 alpha/EPAS1 expression in hepatocellular carcinoma [J]. World J Gastroenterol, 2007, 13: 3176–3182.

[7] Yamaguchi R, Yano H, Iemura A, et al. Expression of vascular endothelial growth factor in human hepatocellular carcinoma [J]. Hepatology, 1998, 28: 68–77.

[8] Wilhelm S M, Carter C, Tang L Y, et al. BAY 43-9006 Exhibits Broad Spectrum Oral Antitumor Activity and Targets the RAF/MEK/ERK Pathway and Receptor Tyrosine Kinases Involved in Tumor Progression and Angiogenesis [J]. Cancer Research, 2004, 64(19): 7099-7109.

[9] Bjornsti M A, Houghton P J. The TOR pathway: a target for cancer therapy [J]. Nature Reviews Cancer, 2004, 4(5): 335-48.

[10] Hu T H, Huang C C, Lin P R, et al. Expression and prognostic role of tumor suppressor gene PTEN/MMAC1/TEP1 in hepatocellular carcinoma [J]. Cancer, 2010, 97(8): 1929-1940.

[11] Midorikawa Y, Ishikawa S, Iwanari H, et al. Glypican-3, overexpressed in hepatocellular carcinoma, modulates FGF2 and BMP-7 signaling [J]. International Journal of Cancer, 2003, 103(4): 455-465.

[12] Villanueva A, Chiang D Y, Newell P, et al. Pivotal Role of mTOR Signaling in Hepatocellular Carcinoma [J]. Gastroenterology, 2008, 135(6): 1972-1983.e11.

[13] Lang S A, Moser C, Fichnterfeigl S, et al. Targeting heat-shock protein 90 improves efficacy of rapamycin in a model of hepatocellular carcinoma in mice [J]. Hepatology, 2010, 49(2): 523-532.

[14] Laurent-Puig P, Zucman-Rossi J. Genetics of hepatocellular tumors [J]. ONCOGENE, 2006, 25(27): 3778-3786.

[15] Wang X Q, Luk J M, Leung P P, et al. Alternative mRNA splicing of liver intestine-cadherin in hepatocellular carcinoma [J]. Clinical Cancer Research, 2005, 11(1): 483-489.

[16] Liu L X, Lee N P, Chan V W, et al. Targeting cadherin-17 inactivates Wnt signaling and inhibits tumor growth in liver carcinoma [J]. Hepatology, 2009, 50(5): 1453-63.

[17] Lucrecia Márquez-Rosado, María Cristina Trejo-Solís, Claudia María García-Cuéllar, et al. Celecoxib, a cyclooxygenase-2 inhibitor, prevents induction of liver preneoplastic lesions in rats [J]. Journal of Hepatology, 2005, 43(4): 0-660.

[18] Hu Z, Zhang Z, Doo E, et al. Hepatitis B Virus X Protein Is both a Substrate and a Potential Inhibitor of the Proteasome Complex [J]. Journal of Virology, 1999, 73(9): 7231-7240.

[19] Munakata T, Nakamura M, Liang Y, et al. Down-regulation of the retinoblastoma tumor suppressor by the hepatitis C virus NS5B RNA-dependent RNA polymerase [J]. Proc Natl Acad Sci USA, 2005, 102(50): 18159-18164.

[20] Altaba A R I, Pilar Sánchez, Dahmane N. Gli and hedgehog in cancer: tumours, embryos and stem cells [J]. Nature Reviews Cancer, 2002, 2(5): 361-72.

[21] Katoh Y, Katoh M. Hedgehog signaling pathway and gastric cancer [J]. Cancer Biology & Therapy, 2005, 4(10): 1050-1054.

[22] Velcheti V, Govindan R. Hedgehog Signaling Pathway and Lung Cancer [J]. Journal of Thoracic Oncology, 2007, 2(1): 7-10.

[23] Thiyagarajan S, Bhatia N, Reaganshaw S, et al. Role of GLI2 transcription factor in growth and tumorigenicity of prostate cells [J]. Cancer Research, 2007, 67(22): 10642-10646.

[24] Capurro M I, Xu P, Shi W, et al. Glypican-3 Inhibits Hedgehog Signaling during Development by Competing with Patched for Hedgehog Binding [J]. Developmental Cell, 2008, 14(5): 0-711.

[25] Tian. Role of Hedgehog signaling pathway in proliferation and invasiveness of hepatocellular carcinoma cells [J]. International Journal of Oncology, 2009, 34(3): 829-836.

The Overview of Gastric Cancer

1. What is Gastric Cancer?

Gastric cancer, also known as stomach cancer, begins when cancer cells form in the inner lining of your stomach. As the figure 1 shows, these cells can grow into a tumor. The disease usually grows slowly over many years.

Gastric cancer begins in the cells of your stomach

Figure 1 Gastric cancer begins in the cells of your stomach

2. What are The High-risk Groups of Gastric Cancer?

In general, cancer begins when an error (mutation) occurs in a cell’s DNA. The mutation causes the cell to grow and divide at a rapid rate and to continue living when a normal cell would die. The accumulating cancerous cells form a tumor that can invade nearby structures. And cancer cells can break off from the tumor to spread throughout the body.

In this section, we summarize six types of people who have gastric cancer with high-risk.

The Six High-risk Groups of Gastric Cancer

Figure 3 The Six High-risk Groups of Gastric Cancer

2.1 Long-term Alcoholism and Smoking

The damage that alcohol causes to people’s bodies is very serious. This is because alcohol can cause changes in mucosal cells and cause cancer. In addition, smoking is also an important factor leading to the emergence of gastric cancer diseases. If you smoke all the year round, the chances of getting sick will be very great.

2.2 Bad Eating Habits

If the diet is not regular enough, then the health of the body will be directly affected. And the usual eating speed is too fast, like high salt or hot food, and smoked foods or a diet with low fruits and vegetables, often eat mildew food, etc. These bad habits will increase the chance of gastric cancer, I hope everyone can pay attention.

2.3 Family History of Disease

Experts examined some patients in the clinic and found that patients with a history of disease in their family members were 2-3 times more likely to develop the disease than others.

2.4 Patients with Atrophic Gastritis

The final outcome of most patients with atrophic gastritis is gastric cancer. Some people even think that atrophic gastritis is the early stage of gastric cancer. Therefore, patients with atrophic gastritis should have a gastroscopy every two years to find gastric cancer earlier.

2.5 Patients with Large Stomach Ulcers

Large stomach ulcers actually refer to ulcers larger than two centimeters in diameter. Once a large ulcer is found, it should be treated immediately, and it should be treated for at least six weeks. After the ulcer is cured, it should be reviewed regularly. The time is half a year or one year.

2.6 Residual Stomach Patient

Because some diseases have removed part of the stomach, it is called residual stomach, and the relationship between residual stomach and stomach cancer is also very close. Some studies have suggested that if there is more than five years of residual stomach, the chance of suffering from gastric cancer will increase, so I have done stomach. Patients with residual stomach surgery should have a gastroscopy every other year.

3. The Symptoms of Gastric Cancer

Generally, gastric cancer may not cause any signs or symptoms or it may cause only nonspecific symptoms in its early stages because the tumor is small. Also, the abdomen and stomach are large structures that are able to expand, so a tumor can grow without causing symptoms.

Once symptoms occur, the cancer has often reached an advanced stage and may have metastasized (tumor grows into surrounding tissues and organs), which is one of the main reasons for its relatively poor prognosis. See your doctor if you have the following signs and symptoms:

3.1 Early Stage of Gastric Cancer

3.1.1 Abdominal Discomfort (May Be Vague or Mild)

There are a lot of patients with stomach cancer who will have a feeling of swell, although this swell is not serious, but repeated occurrences will inevitably bring trouble to life, especially when it is quiet, the symptoms are more obvious.

Because the symptoms are very mild, many people don’t think of stomach cancer, but treat it as a normal stomach.

3.1.2 Upper Abdominal Pain

In the early stage of gastric cancer, patients with gastric cancer usually have upper abdominal pain. Some patients think that this is a stomach disease, and they don’t pay much attention to it.

But as the condition worsens, the pain is getting stronger and stronger, and it lasts for a long time. This pain is not easy to relieve, even after remission. In fact, this is a symptom of early gastric cancer, it is best to go to the hospital for examination.

3.1.3 Loss of Appetite and Indigestion

There are some people with bad stomachs, they often have indigestion, but as patients with gastric cancer, in addition to the phenomenon of indigestion, there will be loss of appetite, many patients with gastric cancer think this is a stomach ulcer or gastritis. The medicine will be good, but in fact, not only will the stomach medicine not relieve the symptoms, but it will appear acid reflux. And over time, the symptoms are getting worse.

3.1.4 Fecal Occult Blood Positive or Black Stool

In patients with gastric cancer, symptoms of fecal occult blood positive or black stool may occur in the early stage. This may be the case that gastric cancer comes to you. Patients with similar conditions need to go to the hospital for examination.

3.1.5 Changes in Pain Orderliness

Some patients have stomach pains and think that they are stomach ailments, but the law of these pains is different from the pain law of stomach diseases, and even if it is eaten, it does not achieve good results.

3.2 Advanced Gastric Cancer

When the gastric cancer has developed to the advanced stage, the patient will present on the following symptoms:

3.2.1 Weight Loss and Anemia

According to relevant experts, about 90% of patients suffer from weight loss, and they tend to lose weight when they lose more than 3 kg. Immediately, sexual weight loss is more obvious, and some can reach more than 5 kg. Experts also found that about half of the patients were accompanied by anemia, limb weakness and other symptoms.

3.2.2 Lasting Upper Abdominal Pain

More patients with advanced gastric cancer have more abdominal pain and longer duration, which is not easy to relieve as the main symptom. Because of the individual differences in the patient’s degree of pain, the severity is also different. In severe cases, there may be pain, edema, dull pain, sharp pain and other manifestations. After eating, it can’t be relieved, and the symptoms are aggravated. Some patients are also accompanied by symptoms such as loss of appetite, nausea and vomiting, fullness, and difficulty swallowing. These symptoms are gradually increasing.

3.2.3 Gastric Metastasis

Advanced gastric cancer has a high probability of metastasis. It can spread directly to the adjacent pancreas, liver, transverse colon, etc. It can also metastasize to lymph nodes and distant lymph nodes, and some can touch hard inactive lymph nodes on the left collarbone. It can also be transferred to the liver, lungs, brain, bones, ovaries, etc. through blood circulation, resulting in symptoms such as ascites, jaundice, and enlarged liver. The enlargement of the cancer itself can also cause complications such as gastric perforation, hemorrhage, necrosis, and obstruction. Symptoms of advanced gastric cancer include hematemesis, melena or occult blood positive.

4. Related Signaling Pathways

As mentioned before, gastric cancer is one of the world’s most common cancers. However, the pathogenesis mechanism of gastric cancer is still not completely clear. Here, we refer to the research data and pathway from KEGG and collect several gastric cancer related signaling pathways.

According to Lauren’s histological classification gastric cancer is divided into two distinct histological groups – the intestinal and diffuse types. Several genetic changes have been identified in intestinal-type GC.

As shown in figure 2, the intestinal metaplasia is characterized by mutations in p53 gene, reduced expression of retinoic acid receptor beta (RAR-beta) and hTERT expression. Gastric adenomas furthermore display mutations in the APC gene, reduced p27 expression and cyclin E amplification. In addition, amplification and overexpression of c-ErbB2, reduced TGF-beta receptor type I (TGFBRI) expression and complete loss of p27 expression are commonly observed in more advanced GC. The main molecular changes observed in diffuse-type GCs include loss of E-cadherin function by mutations in CDH1 and amplification of MET and FGFR2F.

The diagram of gastric cancer signaling pathway

Figure 2 The diagram of gastric cancer signaling pathway

As the figure 2 shows, pathways affected by gastric cancer normally regulate cell growth and differentiation including Wnt, cell cycle, PI3K/AKT and TGFβ signaling pathway [1][2][3][4][5]. Besides, the analysis of gastric cancer data have revealed a fact that gastric cancer affects 3 times as many men than women. This fact suggests a protective effect by estrogen and its signaling pathways.

In addition, a signaling pathway demonstrated via a large amount of studies plays a critical role in gastric cancer. It is hedgehog signaling pathway.

During progression from the inflamed stomach to gastric cancer, the epithelium goes through defined series of morphological transitions. Interestingly high Shh expression in the stomach is lost upon the development of intestinal metaplasia, suggesting that gastric epithelium-specific effects of the morphogen. Indeed Shh controls gastric epithelial cell maturation and differentiation in the adult stomach [6][7][8].

5. The Treatments of Gastric Cancer

Gastric cancer has long been seen as one of the most difficult gastrointestinal malignancies to treat. According to different clinical stages, gastric cancer has different treatment methods. The specific methods are as follows:

Surgical treatment: for early gastric cancer, no distant metastasis and invasion of surrounding organs, surgery can be performed, after surgery with radiotherapy, chemotherapy, the majority of patients with good prognosis.

Actually, surgical resection is the only effective treatment for this cancer, although current surgical therapeutic strategies are far from optimal and most patients are diagnosed with late-stage disease when surgical intervention is of limited use.

Targeted therapy: for patients who have lost the opportunity for the first diagnosis, targeted drug therapy, some patients can obtain long-term tumor-bearing state.

General treatment: maintain a good attitude, courageously face the reality, and actively adjust the lifestyle and diet structure.

However, the prognosis, is still unsatisfactory, with an overall five-year survival rate of 24%. Hence, there is an urgent need for new therapeutic strategies.

References

[1] Melucci E, Casini B, et al. Expression of the Hippo transducer TAZ in association with WNT pathway mutations impacts survival outcomes in advanced gastric cancer patients treated with first-line chemotherapy [J]. J Transl Med. 2018, Feb, 16,1,22.

[2] Clements WM, Wang J, et al. beta-Catenin mutation is a frequent cause of Wnt pathway activation in gastric cancer [J]. Cancer Res. 2002, Jun, 62, 12, 3503-6.

[3] Yin J, Ji Z, et al. Sh-MARCH8 Inhibits Tumorigenesis via PI3K Pathway in Gastric Cancer [J]. Cell Physiol Biochem. 2018, Aug, 49, 1, 306-321.

[4] Chen ZL, Qin L, et al. INHBA gene silencing inhibits gastric cancer cell migration and invasion by impeding activation of the TGF-β signaling pathway [J]. J Cell Physiol. 2019, Apr.

[5] Almasi S, Sterea AM, et al. TRPM2 ion channel promotes gastric cancer migration, invasion and tumor growth through the AKT signaling pathway [J]. Sci Rep. 2019, Mar, 9, 1, 4182.

[6] Merchant JL, Ding L. Hedgehog Signaling Links Chronic Inflammation to Gastric Cancer Precursor Lesions [J]. Cell Mol Gastroenterol Hepatol. 2017, 3:201-10.

[7] Adamu Ishaku Akyala and Maikel P. Peppelenbosch. Gastric cancer and Hedgehog signaling pathway: emerging new paradigms [J]. Genes & Cancer. 2018, January, 9 (1-2).

[8] van den Brink GR, Hardwick JC, et al . Sonic hedgehog regulates gastric gland morphogenesis in man and mouse [J]. Gastroenterology. 2001, 121:317-28.

What you have to know about Lung Cancer

Lung cancer is the leading cause of cancer deaths in both men and women in the U.S. and worldwide. It claims more lives each year than do colon, prostate, ovarian and breast cancers combined, and the cause of lung cancer is still not completely clear. For this reason, the pathogenesis and treatment of lung cancer has always been the focus of research by researchers. Here, combining with the latest research data, we discuss the lung cancer from six aspects as follows:

1. What is Lung Cancer?

Lung cancer is a malignant tumor that begins in the lungs. Our lungs are two spongy organs in your chest that take in oxygen when you inhale and release carbon dioxide when you exhale. Clinically, lung cancer, also called primary bronchogenic carcinoma, is a type of cancer that originates in the bronchi and alveoli. As the figure 1 shows:

Lung cancer begins in the cells of your lungs

Figure 1. Lung cancer begins in the cells of your lungs

2. Symptoms

The clinical symptoms of lung cancer are very complex. Actually, lung cancer typically doesn’t cause signs and symptoms in its earliest stages. Signs and symptoms of lung cancer typically occur only when the disease is advanced.

Generally speaking, the symptoms of lung cancer include cough, blood in the sputum, chest pain, hoarseness, shortness of breath and fever.

2.1 Cough

Cough is the most common symptom, which accounts for 35% to 75% in the lung cancer patients as the first symptom. Cough mainly manifests as repeated irritating cough, dry cough without sputum or only a small amount of white foamy sputum, and general cough medicine is difficult to control.

If the tumor grows in the thin bronchial mucosa below the segment, the cough is not obvious. But for patients with smoking or chronic bronchitis, if the degree of cough is aggravated, the frequency is changed, and the cough properties change, such as high-pitched metal tones, especially in the elderly, the possibility of lung cancer is highly alert.

2.2 Blood in The Sputum

Blood or hemoptysis in the sputum is also a common symptom of lung cancer, which accounts for about 30% of the first symptoms. Due to the rich blood supply of the tumor tissue, the blood vessels rupture and cause bleeding during the cough. Moreover, the hemoptysis may also be caused by local necrosis or vasculitis. The hemoptysis of lung cancer is characterized by discontinuity or persistence.

2.3 Chest Pain

About 25% of patients with lung cancer who have chest pain as the first symptom. Chest pain often manifests as irregular pain or dull pain in the chest. In most cases, chest pain is caused by infection or tumor invasion of the chest wall.

2.4 Hoarseness

Hoarseness is the most important and dangerous signs of the lung cancer. It indicates that cancer is advanced.

5% to 18% of lung cancer patients who have hoarseness as the first complaint. They usually accompany by cough. Vocal sputum generally suggests a direct mediastinal invasion or lymph node enlargement involving the ipsilateral recurrent laryngeal nerve leading to left vocal cord paralysis. Vocal cord paralysis can also cause upper airway obstruction.

2.5 Shortness of Breath

Shortness of breath is usually caused by pleural effusion caused by tumor obstruction of the trachea or tumor.

2.6 Fever

The fever is usually around 38℃, mostly in the afternoon and evening. If anti-infective treatment is used, the body temperature will drop, but it may have a fever again soon.

3. The Types of Lung Cancer

Lung cancer can occur in any lung of both lungs, but the right lung is more than the left lung, the upper lobe is more than the lower lobe, the middle lobe is the least, and the upper lobe is the most.

Clinically, lung cancer is mainly divided into non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). And non-small cell lung cancer accounts for about 85% of lung cancer.

The proliferation and expansion of NSCLC and SCLC are completely different, and the treatment measures are different.

3.1 The Feature of NSCLC

Based on different cell morphology, NSCLC can be divided into three subtypes, including adenocarcinoma, squamous cell carcinoma and large cell carcinoma.

3.1.1 Adenocarcinoma

Adenocarcinoma, among the three subtypes, accounts for 40% of all lung cancer types, accounting for about 55% of non-small cell lung cancer. The tumors often occupy a place in the surrounding area of the lungs.

In this subtype of NSCLC, the more common mutant genes are EGFR, ALK, c-Met, ROS1, HER2, KRAS, etc., and are currently the most targeted cancer drugs. The drugs that can be used for EGFR gene mutation include gefitinib, erlotinib, and ectinib; the target drugs for ALK mutation include crizotinib, ceritinib, and erlotinib.

3.1.2 Squamous Cell Carcinoma

Squamous cell carcinoma is a common subtype of smoking. It is more common in male patients, often originates from a larger airway. Therefore it tends to occupy a central position in the lungs.

In the United States, squamous cell carcinoma accounts for about 25% to 30% of the total number of lung cancers, including papillary squamous cell carcinoma, clear cell squamous cell carcinoma, small cell squamous cell carcinoma, and basal squamous cell carcinoma.

In this subtype of NSCLC, common gene mutations include FGFR1, STK11, SOX, PIK3CA, DDR2, PDGFRA, MDM2, etc. Targeted drugs for squamous cell carcinoma are still in clinical stage.

3.1.3 Large cell Carcinoma

Large cell carcinoma accounts for about 10%-15% of NSCLC, including four subtypes, clear cell large cell carcinoma, basal cell-like large cell carcinoma, pulmonary lymphoepithelial neoplasia, and lung large cell neuroendocrine carcinoma.

It appears as a highly undifferentiated or immature large cell through the microscope, and can occupy any part of the lungs without the tendency to be surrounded or centered. Currently, there is no particularly effective targeted drug for large cell lung cancer.

3.2 The Feature of SCLC

SCLC can observe very small cells under the microscope, and the shape of the cells is spindle-shaped or polygonal. It accounts for about 15% of the total number of lung cancers and has a high degree of malignancy and limited treatment.

Currently, there are no approved targeted drugs, and it has a good response to chemotherapy and radiotherapy. The occurrence of small cell lung cancer is closely related to smoking, and only 1% of small cell lung cancer has nothing to do with smoking.

It grows and spreads faster than non-small lung cancer, and tends to metastasize early in the disease. Most patients have already metastasized at the time of diagnosis. In addition, small cell lung cancer tends to occupy a large airway, so it is generally located in the center of the lung.

4. Related Signaling Pathways

Although the pathogenesis mechanism of lung cancer is still not completely clear, we refer to the research data and pathway from KEGG and summarize several lung cancer related signaling pathways.

4.1 Non-small Cell Lung Cancer Signaling Pathway

As mentioned before, Non-small-cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer and represents a heterogeneous group of cancers, consisting mainly of squamous cell (SCC), adeno (AC) and large-cell carcinoma.

Molecular mechanisms altered in NSCLC include activation of oncogenes, such as K-RAS, EGFR and EML4-ALK, and inactivation of tumor-suppressor genes, such as p53, p16INK4a, RAR-beta, and RASSF1. Point mutations within the K-RAS gene inactivate GTPase activity and the p21-RAS protein continuously transmits growth signals to the nucleus.

Mutations or overexpression of EGFR leads to a proliferative advantage. EML4-ALK fusion leads to constitutive ALK activation, which causes cell proliferation, invasion, and inhibition of apoptosis. Inactivating mutation of p53 can lead to more rapid proliferation and reduced apoptosis.

The protein encoded by the p16INK4a inhibits formation of CDK-cyclin-D complexes by competitive binding of CDK4 and CDK6. Loss of p16INK4a expression is a common feature of NSCLC. RAR-beta is a nuclear receptor that bears vitamin-A-dependent transcriptional activity. RASSF1A is able to form heterodimers with Nore-1, an RAS effector. Therefore loss of RASSF1A might shift the balance of RAS activity towards a growth-promoting effect. As the figure 2 shows:

the diagram of NSCLC signaling pathway

Figure 2. The diagram of NSCLC signaling pathway

4.2 PI3K-AKT Signaling Pathway

PI3K-Akt signaling pathway is an intracellular signaling pathway important in regulating the cell cycle and is activated by many types of cellular stimuli or toxic insults. It regulates fundamental cellular functions, involving transcription, translation, proliferation, growth, and survival in response to extracellular signals. More information you may be interested in the article named PI3K-Akt Signaling Pathway and Cancer.

Accumulating evidence has indicated that PI3K-Akt signaling pathway is overactive in most NSCLCs, promoting proliferation, migration, invasion and resistance to therapy [1] [2] [3].

In De Marco C’s study, they found that, altogether, aberrant PI3K/AKT signaling in lung epithelial cells regulated the expression of 1,960/20,436 genes (9%), though only 30 differentially expressed genes (DEGs) (15 up-regulated, 12 down-regulated and 3 discordant) out of 20,436 that were common among BEAS-AKT1-E17K, BEAS-PIK3CA-E545K and BEAS-shPTEN cells (0.1%).

4.3 p53 Signaling Pathway

p53 is a tumor suppressor gene that is involved in the development of most cancers in humans. And it is the most frequently altered gene in human cancers. The name is due to its molecular mass. You may be interested in reading the article expounding p53 comprehensively.

The regulation mechanism and function of p53 signaling pathway are mainly characterized by cell cycle regulation, DNA damage repair, apoptosis, cell senescence, regulation of metabolism.

Recent decade years, emerging plentiful studies reveal that p53 signaling pathway plays a critical role in the pathogenesis mechanism of lung cancer. And discover several targets in lung cancer which regulate the p53 signaling pathway, such as YEATS4, TNFAIP8 and WDR79 and so on [4] [5] [6].

4.4 MAPK Signaling Pathway

The MAPK signaling pathway is essential in regulating many cellular processes including inflammation, cell stress response, cell differentiation, cell division, cell proliferation, metabolism, motility and apoptosis. The role of the MAPK pathway in cancer, immune disorders and neurodegenerative diseases has been well recognized [7].

In Bhardwaj V’s study, he revealed the role of epigallocatechin-3-gallate in regulating putative novel and known microRNAs which target the MAPK pathway in non-small-cell lung cancer a549 cells by next-generation sequencing. This study identified signature microRNAs that can be used as novel biomarkers for lung cancer diagnosis [8].

4.5 Wnt Signaling Pathway

The Wnt signaling pathway is a group of signal transduction pathway made of proteins that pass signals into a cell through cell surface receptors. Accumulating studies have demonstrated that abnormal activated Wnt singling pathway is closely related to the development of cardiovascular disease, liver fibrosis and cancer. You may be interested in reading the article expounding Wnt Signaling Pathway comprehensively.

A study, from McDonnell Genome Institute located in Washington University School of Medicine, has demonstrated that recurrent WNT pathway alterations are frequent in relapsed small cell lung cancer. And their results suggest WNT signaling activation as a mechanism of chemo-resistance in relapsed SCLC [9].

References

[1] De Marco C, Laudanna C, et al. Specific gene expression signatures induced by the multiple oncogenic alterations that occur within the PTEN/PI3K/AKT pathway in lung cancer [J]. PLoS One.2017, 12(6).

[2] Fan J, Bao Y, et al. Mechanism of modulation through PI3K-AKT pathway about Nepeta cataria L.’s extract in non-small cell lung cancer [J]. Oncotarget. 2017, 8(19):31395-31405.

[3] Jin X, Luan H, et al. Netrin?1 interference potentiates epithelial?to?mesenchymal transition through the PI3K/AKT pathway under the hypoxic microenvironment conditions of non?small cell lung cancer [J]. Int J Oncol.2019, 54(4):1457-1465.

[4] Pikor LA, Lockwood WW, et al. YEATS4 is a novel oncogene amplified in non-small cell lung cancer that regulates the p53 pathway [J]. Cancer Res.2013, 73(24):7301-12.

[5] Sun Y, Cao L, et al. WDR79 promotes the proliferation of non-small cell lung cancer cells via USP7-mediated regulation of the Mdm2-p53 pathway [J]. Cell Death Dis. 2017, 8(4):e2743.

[6] Xing Y, Liu Y, et al. TNFAIP8 promotes the proliferation and cisplatin chemoresistance of non-small cell lung cancer through MDM2/p53 pathway [J]. Cell Commun Signal. 2018, 16(1):43.

[7] Okimoto RA, Lin L, et al. Preclinical efficacy of a RAF inhibitor that evades paradoxical MAPK pathway activation in protein kinase BRAF-mutant lung cancer [J]. Proc Natl Acad Sci U S A. 2016, 113(47):13456-13461.

[8] Bhardwaj V, Mandal AKA. Next-Generation Sequencing Reveals the Role of Epigallocatechin-3-Gallate in Regulating Putative Novel and Known microRNAs Which Target the MAPK Pathway in Non-Small-Cell Lung Cancer A549 Cells [J]. Molecules. 2019, Jan, 24, 2.

[9] Wagner AH, Devarakonda S, et al. Recurrent WNT pathway alterations are frequent in relapsed small cell lung cancer [J]. Nat Commun. 2018, Sep 17;9(1):3787.

About Thyroid Tumor, This Information you must know!

The thyroid gland is part of the endocrine system and is a hormone-producing gland that regulates the body’s functions. Thyroid cancer (TC), which occurs in thyroid cells, is the most common endocrine – related cancer, accounting for about 1% of systemic malignancies.

Thyroid cancer is more common in females, and the ratio of females to males is 3:1 in most geographical regions and population groups [1], making it the fifth most common cancer among females. Most thyroid cancers are curable by surgery and other means.

1. The Thyroid Gland

The thyroid gland is a butterfly-shaped gland located in front of the neck, under the throat, and above the clavicle. The thyroid gland is part of the endocrine system that controls heart rate, blood pressure, body temperature and metabolism by secreting hormones.

There are two main cell types in the thyroid gland: follicular cells and C cells.

Follicular cells use iodine in the blood to make thyroid hormones, which help regulate the body’s metabolism. The amount of thyroid hormone released by the thyroid gland is regulated by the pituitary gland at the bottom of the brain, which promotes the release of thyroid hormone by producing a substance called thyroid stimulating hormone (TSH).

C cells (also known as parafollicular cells) produce calcitonin, a hormone that helps control how the body uses calcium.

Hormones produced by the thyroid gland

Figure 1 Hormones produced by the thyroid gland

2. Type of Thyroid Tumor

Thyroid cancer can be classified into four types according to the origin of cells and the rate of cancer cell division: papillary thyroid carcinoma, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer.

2.1 Papillary Thyroid Cancer (PTC)

It is the most common type of thyroid cancer, and 70% to 80% of thyroid cancers are papillary thyroid cancer. Although it can occur at any age, most occur between the ages of 30 and 60. The disease is three times more common in women than men, and is usually more aggressive for older patients.

Papillary thyroid cancer may spread, usually involving the neck lymph nodes, and less involving the lungs.

Most people with this type of cancer can be cured if they are diagnosed early.

2.2 Follicular Thyroid Cancer (FTC)

Follicular thyroid cancer accounts for less than 15% of all thyroid cancers. Hürthle cells are variants of FTC. This type of thyroid cancer occurs mostly in adults between the ages of 40 and 60. Women get it more often than men. Cancer cells can invade blood vessels and travel to tissues such as bones or lungs.

PTC and FTC, as well as the less common Hürthle cell carcinoma, are classified as differentiated thyroid carcinoma (DTC) [2] [3], which originated from follicular epithelial thyroid cells. Both PTC and FTC are slow to progress and usually have a good prognosis, especially if diagnosed early.

2.3 Medullary Thyroid Cancer (MTC)

It accounts for about 3% of all thyroid cancers [4]. It is developed by C-cells or parafollicular cells that produce calcitonin (which regulates calcium and phosphate levels in the blood and promotes bone growth) [5], and elevated levels of calcitonin indicate cancer. It is usually diagnosed between the ages of 40 and 50, and women and men are equally affected.

Compared to other types of thyroid cancer, it is more likely to run in the family (familial medullary thyroid carcinoma, FMTC).

2.4 Anaplastic Thyroid Cancer (ATC)

Anaplastic thyroid cancer is a rare thyroid cancer, which accounts for less than 2% of all thyroid cancers (77% of women).

ATC originates from follicular cells, but it does not have its original biological characteristics [6]. Unlike other thyroid tumors, it is characterized by rapid growth and spread and aggressive. Therefore, anaplastic thyroid cancer (ATC) is the most invasive type of thyroid cancer among all thyroid cancers [7]. It usually occurs in patients over the age of 65, and women are slightly more affected than men. ATC is not sensitive to conventional treatment [8]. The prognosis was the worst, with a 5-year survival rate of 5% [9].

There’s also thyroid lymphoma. This is a rare thyroid cancer that starts with immune system cells in the thyroid gland and grows very fast. Thyroid lymphoma usually occurs in the elderly.

Type of thyroid cancer

Figure 2 Type of thyroid cancer

3. Thyroid Tumor Symptoms

In the early stages, thyroid cancer usually shows no signs or symptoms.

As a thyroid tumor grows, it may produce the following symptoms:

Neck mass or node: This is the most common symptom of thyroid cancer. A hard, fixed mass with an uneven surface was found in the thyroid gland. The glands are less mobile up and down during swallowing.

Persistent hoarseness or changes in voice, and frequent coughs unrelated to a cold may occur.

Difficulty swallowing or breathing.

Swollen lymph nodes in the neck.

Pain in the ear, pillow, shoulder, etc. may occur in the late stage.

4. Risk Factors for Thyroid Tumors

Risk factors for thyroid cancer include ionizing radiation, family history, gender, obesity, alcohol consumption, and smoking. Recent studies have also demonstrated the relationship between exposure to flame retardants and PTC [10].

4.1 Gender and Race

Thyroid cancer is more common in women than men. White or Asian people are more likely to develop thyroid cancer.

4.2 Age

Most thyroid cancer patients are between 20 and 55 years old.

4.3 Radiation Exposure

Exposure to high levels of radiation may increase the risk of thyroid cancer.

4.4 Genetic Factors

Most TC cases are sporadic, only 5% of DTC is characterized as familial (mainly PTC), and about 25% of MTC is inherited as an autosomal trait [11].

Certain genetic syndromes increase the risk of thyroid cancer. These include familial myeloid thyroid cancers and multiple endocrine neoplasms (type 2A and type 2B). Multiple endocrine neoplasms (MEN2A and MEN2B) affect glands of the endocrine system such as the thyroid, parathyroid, and adrenal glands.

Mutations in certain genes are also important causes of thyroid cancer. Mutations in BRAF [12] and RAS family [4] also occur frequently in thyroid cancer. Chromosomal translocations also occur in thyroid cancer, such as peroxisome proliferation-activated receptor (PPAR gamma) translocations in about 30% of follicular thyroid cancer cases [13].

Key molecular signaling pathways involved in thyroid cancer include mitogen activated protein kinase (MAPK) pathway, PI3K / mTOR pathway, p53 tumor suppressor factor, etc.

Risk factors of thyroid cancer

Figure 3 Risk factors of thyroid cancer

5. Diagnosis of Thyroid Tumor

First, the doctor needs to understand the basic condition of the patient and whether there are common clinical symptoms of thyroid tumor. For patients with a family history of medullary thyroid cancer, your doctor will test your blood for calcitonin and calcium levels. Elevated levels of calcitonin suggest cancer.

The main methods of diagnosis of thyroid tumors are as follows:

5.1 Thyroid Scan

Thyroid scans are used to test the function of the glands. Test results may be reported as normal function, cold (insufficient activity), or hot (excessive activity). Suspected cold nodules can be further evaluated by fine needle aspiration (needle biopsy).

5.2 Ultrasound Guided Fine Needle Aspiration Biopsy (FNA)

Fine needle aspiration (FNA) is a diagnostic method for thyroid cancer. Cancer cells usually look different from normal cells, so the type of thyroid cancer is determined by microscopic examination of thyroid cells found in nodules (neck masses) or growth.

5.3 Molecular Detection

Many genetic changes are thought to play an important role in thyroid cancer formation. The frequent occurrence of RAS mutations in follicular adenoma suggests that the activated RAS may play a role in the early stage of tumorigenesis. Molecular tests (classification of gene expression) can be used to help make a diagnosis when the result of a fine needle biopsy is uncertain.

6. Treatment of Thyroid Tumor

Cancer treatment strategies need to be developed according to the stage of the tumor.

6.1 Tumor Staging

Thyroid cancer staging is a classification by doctors based on the characteristics of malignant thyroid tumors. Tumor staging can help doctors determine the best treatment for thyroid cancer. The TNM staging system was developed by the American joint cancer commission (AJCC). “T” represent tumor, “N” represent lymph node, and “M” represent metastasis. The following table shows the staging of thyroid cancer using the TNM staging system.

Table 1 TNM staging system for thyroid cancer

T N M
X=Tumor can’t be evaluated NX=Local lymph nodes cannot be evaluated MX=Unable to assess distant transfer (and diffusion)
T0=No primary tumor N0=Non-diffusion to regional lymph nodes M0=No distant transfer
T1=Tumor size is 2 cm wide or smaller N1=Tumor has spread to local lymph nodes M1=Distant metastasis involves distant lymph nodes, internal organs, etc
T2=Tumor size 2 – 4cm wide N1a= The tumor has spread to the lymph nodes around the thyroid
T3=The tumor is larger than 4 cm or has begun to grow outside the thyroid gland N1b= The tumor has spread to the lymph nodes in the neck or upper chest
T4a=Tumors (any size) have been extensively grown into local neck tissue other than the thyroid
T4b=The tumor has grown to the spine or local large blood vessels

6.2 Treatment

6.2.1 Surgical Treatment

Surgery is the basic method for treating various types of thyroid cancer except for anaplastic thyroid cancer. Other auxiliary treatment methods such as nuclide, thyroid hormone and external radiation are usually used.

Surgical treatment of thyroid cancer includes partial thyroidectomy or lobectomy and total thyroidectomy.

Partial thyroidectomy or lobectomy is the surgical removal of part of the thyroid gland, such as the left or right lobe of the tumor. Lobectomy is generally used to remove single-focal tumors less than 4 cm without evidence of external thyroid expansion or lymph node metastasis. Total thyroidectomy is a complete surgical removal of the thyroid gland.

6.2.2 Endocrine Therapy

TSH can stimulate the proliferation of thyroid cancer cells through its receptor [14].

Therefore, thyroid hormone therapy such as TSH inhibitors is used after surgery. This method can significantly reduce recurrence and cancer-related mortality in patients with different types of thyroid cancer [15].

6.2.3 Radionuclide Therapy

Some patients with papillary or follicular carcinoma may require systemic radioactive iodine (RAI) after thyroidectomy [16]. When radioactive iodine enters the bloodstream, it selectively destroys the remaining thyroid tissue and cancer cells without affecting any other cells. The adjuvant therapy is applicable to patients over 45 years old, multiple cancerous foci, locally invasive tumors, and distant metastases.

6.2.4 Chemotherapy

Chemotherapy is rarely used to treat thyroid cancer, except for malignant tumors such as undifferentiated thyroid cancer.

6.2.5 External Radiation Therapy

Mainly used for anaplastic thyroid cancer.

6.2.6 Targeted Therapy

Routine treatment for thyroid cancer includes thyroidectomy, radioactive iodide therapy, and thyroid stimulating hormone (TSH) suppression therapy. Although the overall prognosis is good, there are still a small number of patients with lymph node metastasis, tumor recurrence, drug resistance and other conditions.

Therefore, it is extremely important to develop new therapeutic strategies for thyroid cancer.

Mutations in the MAPK pathway are believed to initiate the development of thyroid cancer and lead to changes in gene expression, which can promote cell proliferation, cell growth, and angiogenesis. Changes in PI3K/mTOR pathway and p53 tumor suppressor factor are believed to promote tumor progression. In thyroid cancer, anti-tumor effects have been widely used by blocking the MAPK pathway.

Thyroid cancer-related pathways

Figure 4 Thyroid cancer-related pathways

FDA has approved four different drugs targeting the mitogen activated protein kinase (MAPK) signaling pathway for the treatment of advanced thyroid cancer [17] [18].

Among them, Lenvatinib and Sorafenib are mainly used for the treatment of advanced, recurrent and drug resistant DTC, while Cabozantinib and Vandetanib target MTC.

In addition, BRAF mutations play an important role in the progression of thyroid cancer and account for 29-83% of all gene mutations [19]. A class of targeted drugs called kinase inhibitors may help treat certain genetically mutated thyroid cancer cells, such as BRAF and RET/PTC. Drugs that target the BRAF gene are vemurafenib, dabrafenib, and selumetinib.

References

[1] Kilfoy B, Zheng T, Holford T, et al. International patterns and trends in thyroid cancer incidence, 1973-2002 [J]. CANCER CAUSES & CONTROL, 2009, 20(5): 525-531.

[2] Arribas J, Castellvi J, Marcos R, et al. Expression of YY1 in Differentiated Thyroid Cancer [J]. Endocrine Pathology, 2015, 26(2): 111-118.

[3] Nagy R, Ringel M D. Genetic Predisposition for Nonmedullary Thyroid Cancer [J]. Hormones and Cancer, 2015, 6(1): 13-20.

[4] Nikiforov Y E, Nikiforova M N. Molecular genetics and diagnosis of thyroid cancer [J]. NATURE REVIEWS ENDOCRINOLOGY, 2011, 7(10): 569-580.

[5] Carneiro R M, Carneiro B A, Agulnik M, et al. Targeted therapies in advanced differentiated thyroid cancer [J]. Cancer Treatment Reviews, 2015, 41(8): S0305737215001243.

[6] Chiacchio S, Lorenzoni A, Boni G, et al. Anaplastic thyroid cancer: Prevalence, diagnosis and treatment [J]. Minerva endocrinologica, 2009, 33(4): 341-357.

[7] Xu B, Ghossein R. Genomic Landscape of poorly Differentiated and Anaplastic Thyroid Carcinoma [J]. Endocrine Pathology, 2016, 27(3): 205-212.

[8] Chiappetta G, Valentino T, Vitiello M, et al. PATZ1 acts as a tumor suppressor in thyroid cancer via targeting p53-dependent genes involved in EMT and cell migration [J]. Oncotarget, 2014, 6(7): 5310-23.

[9] Hoang J K, Nguyen X V, Davies L. Overdiagnosis of Thyroid Cancer: Answers to Five Key Questions [J]. Academic Radiology, 2015, 22(8): 1024-1029.

[10] Hoffman K, Lorenzo A, Butt C M, et al. Exposure to flame retardant chemicals and occurrence and severity of papillary thyroid cancer: A case-control study [J]. Environment International, 2017, 107: 235-242.

[11] Lodish M B, Stratakis C A. RET oncogene in MEN2, MEN2B, MTC and other forms of thyroid cancer [J]. Expert Review of Anticancer Therapy, 2008, 8(4): 625-632.

[12] None. Integrated Genomic Characterization of Papillary Thyroid Carcinoma [J]. Cell, 2014, 159(3): 676-690.

[13] Raman P, Koenig R J. Pax-8–PPAR-γ fusion protein in thyroid carcinoma [J]. Nature Reviews Endocrinology, 2014, 10(10): 616-623.

[14] Biondi B, Filetti S, Schlumberger M. Thyroid-hormone therapy and thyroid cancer: a reassessment [J]. Nature Clinical Practice Endocrinology & Metabolism, 2005, 1(1): 32-40.

[15] Mazzaferri E L. Current Approaches to Primary Therapy for Papillary and Follicular Thyroid Cancer [J]. Journal of Clinical Endocrinology & Metabolism, 2001, 86(4): 1447-1463.

[16] Spitzweg C, Bible K C, Hofbauer L C, et al. Advanced radioiodine-refractory differentiated thyroid cancer: the sodium iodide symporter and other emerging therapeutic targets [J]. The Lancet Diabetes & Endocrinology, 2014, 2(10): 830-842.

[17] Cooper D S, Doherty G M, Haugen B R, et al. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer [J] .Thyroid, 2009, 19: 1167-214.

[18] Haugen Bryan R, Alexander Erik K, Bible Keith C, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer [J] .Thyroid, 2016, 26: 1-133.

[19] Xing M. BRAF mutation in thyroid cancer[J]. Endocrine Related Cancer, 2005, 12(2): 245-262.

TRANSMEMBRANE PROTEINS

Transmembrane proteins are a group of integral membrane proteins that attach the biological membrane permanently. Many transmembrane proteins function as gateways to permit specific substances to across the biological membrane. They frequently undergo significant conformational changes to move a substance through the membrane.

The Nature of Detergent and Its Application in Membrane Proteins

In recent years, membrane protein research has made significant progress, which is inseparable from the development of membrane-related tools and reagents [1]. Among them, the detergent plays an important role in the membrane protein extraction, purification and operation. Their amphiphilic nature allows them to interact with hydrophobic membrane proteins, extract and dissolve membrane proteins from natural lipid bilayers. But dissolution does not mean that the natural structure and stability of the protein can be completely restored; The detergent that can effectively extract the membrane protein at the same time may also not be suitable for purification and further biochemical studies; And the detergent that is suitable for a certain membrane protein may not be suitable for another membrane protein. In a word, there is no set of criteria that can estimate if a certain detergent is appropriate in the membrane protein study. This article describes the physical and chemical properties of detergents, as well as the application of detergent in membrane protein process, hope our introduction can help you to choose the right detergent.

1. Structure of Detergent

Detergent is a kind of surfactant, which has widely applications, including: polyacrylamide gel electrophoresis (PAGE), dissolution of inclusion bodies, preparation of liposomes, membrane protein solubilization and activity structure studies. Moreover, detergent can also be used as membrane model for in vitro studies.

The function of the detergent is related to its structure: The polar hydrophilic portion of the detergent molecule is used as a hydrophilic head group, while the non-polar hydrophobic portion is used as the tail (Figure 1A). Some detergents also have lenticular shapes (Figure 1B), which have polar and non-polar faces, including bile acid derivatives, such as CHAPS and CHAPSO.

Figure 1.Detergent monomer

2. Classification of Detergents

The detergents can be divided into ionic (cationic or anionic), nonionic and zwitterionic according to different hydrophilic groups.

The ionic detergents include sodium dodecyl sulfate (SDS), N-lauryl sarcosine, CTAB, etc., which are effective in extracting proteins from the membrane. These detergents can effectively disrupt the interaction between intramolecular and intermolecular proteins, but are harsh and tend to denature protein. Among them, bile acid salts are also ionic detergents, such as sodium cholate and deoxycholic acid, but their skeletons are composed of rigid steroids, which are milder than the linear ionic detergents.

Nonionic detergents include maltosides, glucosides and polyoxyethylene glycols. The feature of this type of detergent is that the hydrophilic head groups are not charged. These detergents are mild, non-denatured, and can disrupt interactions between protein-lipid and lipid-lipid.

The zwitterionic detergents include Zwittergents, Fos-Cholines, and CHAPS / CHAPSO, etc. Their hydrophilic head groups contain positive and negative charges. These detergents are electrically neutral like nonionic detergents, but they are usually able to disrupt the interaction between proteins like ionic detergents, so intermedium mild. Most successful NMR membrane proteins studies use the zwitterionic detergents, for example Fos-Choline 12.

3. Several Concepts about Detergents

3.1 The Critical Micelle ConcentrationCMC

Micellization is a key phenomenon when considering the application of detergents. Each kind of detergents has a CMC value, when the detergent concentration is higher than CMC, the monomer is self-assembled into non-covalent aggregate, also called micelles. The micellization does not actually occur at a single concentration, but occurs within a narrow concentration range.

When applying detergents to membrane proteins, one rule of thumb is that the working concentration of the detergent should be at least 2xCMC and the weight ratio of detergent to protein is at least 4: 1. When the membrane protein is dissolved from the original membrane, the working concentration of the detergent is much higher than that of CMC, and the molar ratio of detergent to lipid is 10: 1. Therefore CMC determines the amount of detergent to be added to various proteins and membrane products [2].

The CMC value of the detergent is not fixed, it will change with the pH, ionic strength and temperature of the solution [3]. For example, the CMC value of the ionic detergent will decrease as the ionic strength increases.

3.2 Micellization

Micelles are aggregates of the detergent monomer in the solution, and the micelles forming process is called micellization[4]. Detergent interacts with the membrane protein and membrane in the form of micelles, and the dissolution of the protein depends on the formation of micelles in the solution. Micelles are usually considered to have a “rough” surface, which is a dynamic structure. The detergent monomer in the micelles rapidly exchange with the free detergent monomer in the solution. Once the membrane protein is dissolved, we usually think that the detergent molecules form a torus around the hydrophobic transmembrane domain.

4. The Application of Detergents in Membrane Proteins

4.1 Replacement or Removal of Detergents

Detergents that can effectively solubilize membrane proteins may be unsuitable for further biochemical studies, which require transferring membrane proteins to a more suitable detergent solution. When assembling liposomes or nanodiscs, we need to remove the detergent. The CMC can be used to determine the available method to replace or remove unwanted detergents. The detergents with high CMC are easily removed through dialysis, and the detergent solution can be diluted to a value below CMC through dialysis, then the micelles will break down into monomers and the monomers can easily pass through the dialysis membrane. In general, the detergent solution is dialyzed by detergent-free buffer with more than 200 times volumes, and change the buffer for several times in the middle period, for example Fos-Choline 12. The detergents with low CMC are typically removed by adsorption of hydrophobic beads, such as DDM. It can also be purified by nickel column. After the membrane protein binds to the column material, change the buffer with another detergent solution.

4.2 The Identification of Membrane Proteins

If the membrane protein is identified by SDS-PAGE, the boiling treatment may result in aggregation of membrane proteins. So we can incubate the membrane protein at room temperature for 10min, and then conduct gel electrophoresis. Membrane proteins usually do not migrate at the predicted molecular weight in SDS-PAGE. They generally migrate faster, that means their molecular weight will look smaller, probably because the fold is not complete or each molecular weight unit combine with more SDS than the water-soluble protein [5].

5. The Expression of Membrane Proteins

We just introduced the basic properties of detergents, but in fact the preparation of membrane protein is very difficult. For most of the membrane proteins, it’s difficult to obtain sufficient quantity from the natural environment, therefore they need to be overexpressed. Unfortunately, it is difficult to obtain a sufficient amount of functional and stable membrane protein through E.coli or other expression systems. In general, the more transmembrane domains they have, the more difficult it is to express membrane proteins, such as aquaporins containing 6 transmembrane domains.

5.1 Aquaporins

Aquaporin that is located at the cell membrane is a transmembrane protein with 6 transmembrane domains, and they form a “channel” on the cell membrane that can control the water in and out of the cell. The water molecules will form a single column when going through the aquaporin, when entering into the curved narrow channel, the internal dipolar force and polarity will help the water molecules to rotate at an appropriate angle through the narrow channel.

Aquaporins predominantly exist in mammalian kidneys and also exist in plants. Aquaporins play an important role in kidney urine concentration, digestive physiology, neurophysiology, respiratory physiology, eye physiology and skin physiology.

5.2 Active Aquaporins

Cusabio adopts E.coli cell free expression technology. The technology is not limited by cell structure and is suitable for the expression of membrane proteins and toxic proteins that are toxic to cells, with yield up to mg/ml level. According to the traditional cell-based expression, conventional treatment of membrane proteins requires destruction of the cell membrane, which tends to cause the therein inserted membrane conformation change or even denaturation. But the open E.coli cell free expression system can optimize expression yield in vitro in multiple ways, and the expressed membrane proteins can be immediately enveloped by the detergents after translation during the expression, to maximum avoid exposure to aqueous solution. Now we have already successfully developed the following active aquaporins.

5.2.1 Recombinant Escherichia coli Aquaporin Z (aqpZ)

Function: Channel that permits osmotically driven movement of water in both directions. It is involved in the osmoregulation and in the maintenance of cell turgor during volume expansion in rapidly growing cells. It mediates rapid entry or exit of water in response to abrupt changes in osmolarity.

Fig 2.aqpZ in detergent micelles

Figure 3.  The binding activity of aqpZ with ytfE.

Activity: Measured by its binding ability in a functional ELISA. Immobilized aqpZ at 5 μg/ml can bind human ytfE. The EC50 of human ytfE protein is 197.90-259.70 μg/ml.

References

[1] R.M. Garavito, S. Ferguson-Miller, Detergents as tools in membrane biochemistry, J. Biol. Chem. 276 (2001) 32403–32406.

[2] Anatrace, Detergents and Their Uses in Membrane Protein Science.

[3] M. le Maire, P. Champeil, J.V. Mbller, Interaction of membrane proteins and lipids with solubilizing detergents, Biochim. Biophys.Acta 1508 (2000) 86–111.

[4] From Wikipedia, the free encyclopedia.

[5] Purifying Challenging Proteins Principles and Methods, 28-9095-31.

The Application of Nanodiscs in Membrane Proteins

In the previous chapter, we briefly introduced the basic properties of detergents and their use in membrane proteins. In detergent-containing buffers, most membrane proteins can maintain stability and activity. However, a few detergent-sensitive membrane proteins are not suitable for buffer containing detergents and have features including inability to be purified (eg, the purified membrane proteins with very poor purity and low yields), poor stability (susceptible to degradation or significant precipitation) and no activity (probably the membrane protein is sensitive to detergents or its activity requires the structure of the phospholipid bilayer). For this type of membrane protein, we suggest to use nanodiscs technology. Currently, Nanodiscs technology shows important advantages in membrane protein isolation, purification, structure studies and functional characterization. This article describes the composition and structure of nanodiscs, the comparison of nanodiscs with liposomes, and the application of nanodiscs in membrane proteins. Hope it can help you learn more about membrane proteins through our introduction.

1. Composition and Structure of Nanodiscs

The main components of Nanodiscs are synthetic phospholipids and amphipathic helical proteins, also known as membrane scaffold proteins (MSPs). Membrane-scaffold proteins are associated with serum apolipoproteins, whereas serum apolipoproteins are the major component of high-density lipoproteins. The two membrane scaffold proteins are ribbon-shaped and surround the phospholipids, as shown in Fig 1 [1], ie, the discoid phospholipid bilayers Nanodiscs.

Fig 1. Model of Nanodiscs structure viewed (a) perpendicular to the bilayer and (b) in the plane of the bilayer, based on the molecular belt model of discoidal HDL. Two monomers of the membrane scaffold protein (blue and cyan) form an amphipathic helical belt around a segment of phospholipid bilayer (in white)~10 nm in diameter. The model is courtesy of S. C. Harvey[1].

2. Model Membrane

We mainly compare two models of liposomes and nanodiscs.

2.1 Liposomes

Liposomes are amphipathic lipid bilayer vesicles. There are many ways to prepare liposomes. The best-known and easiest one is the Bangham method [2]. The target lipid is dissolved in a volatile organic solvent and dried under a stream of inert gas. The obtained thin-layer lipid is vortexed with water-soluble buffer and then finally transformed into a monolayer bubble by various methods such as sonication, homogenization and extrusion through a filter of known size (typically 100-200 nm pore size). However, this also results in some obvious disadvantages of liposomes, including instability, inhomogeneity, and difficulty of reproduction.

Liposomes is easy to aggregate and fuse, and is often unstable under operation of long period of time or under certain physical manipulations, such as stopping the flow or mixing vigorously. The size of liposomes prepared by the extruder is not homogeneous, there may be significant differences in the preparation of different batches [3]. Membrane proteins assembled into liposomes often result in cloudy and viscous samples, which may limit the use of some biochemical analytical techniques.

2.2 Nanodiscs

The preparation of nanodiscs involves preparation of master mix containing phospholipid, membrane scaffold protein and detergent, and the remaining components are assembled as a discoid phospholipid bilayer 8-16 nm in diameter, namely nanodiscs [4], upon removal of the detergent. The diameter of Nanodiscs is determined by the length of the MSP band and when the phospholipid is in the optimum molar ratio to MSP, uniform nanodiscs are formed.

Nanodiscs are more homogeneous (in one preparation) and consistent (in different batches of preparation) than liposomes; nanodiscs have more precise particle size and can be sized by adjusting the length of MSP sequences; nanodiscs is more stable.

3. Application of Nanodiscs in Membrane Proteins

For the application of Nanodiscs, there is an outstanding review [5]. The structural studies can be found in the following table, which can be applied to structural biology and various technologies such as electron microscopy, NMR, EPR and spectroscopy detection.

Table 1. Methods and tools used with MPs incorporated into nanodiscs

SPR: Surface plasmon resonance; LSPR: localized SPR; CPR: NADPH–cytochrome P450 reductase[5].

4. AQPs are Expressed UsingIn Vitro E.coli Protein Expression and Nanodiscs Technology

Cusabio incorporates both in vitro E.coli protein expression and nanodiscs technology, adding pre-assembled nanodiscs to in vitro E.coli protein expression systems. The membrane proteins are assembled into nanodiscs while they are translated, forming membrane protein-nanodiscs complexes (Fig. 2). This simulated artificial lipid environment provides new avenues for analyzing the effects of different lipids on membrane proteins, allowing us to better understand membrane proteins.

Fig. 3. Results of SDS-PAGE after successfully assembly of nanodiscs into Escherichia coli Aquaporin Z (aqpZ). As shown in figure 2, there are two bands, one for MSP and one for the target protein of membrane protein aqpZ.

Fig 2. Schematic illustration of a MSP nanodiscs with a 7-transmembrane protein embedded.

Diameter is about 10.6 nm. Picture from Sligar.

Fig 3.

5. Cusabio’s New Strategy for Membrane Protein Expression

Cusabio provides risk-free services for membrane protein expression (detergent preparation) and nanodics assembly for proteins under 300aa.

References

[1]     Applications of Phospholipid Bilayer Nanodiscs in the Study of Membranes and Membrane Proteins. Abhinav Nath, William M. Atkins, and Stephen G. Sligar. Biochemistry, 2007, 46 (8), 2059-2069

[2]     Large volume liposomes by an ether vaporization method. D Deamer, AD Bangham. Biochimica et Biophysica Acta, 443 (1976) 629-~34

[3]     Applications of Phospholipid Bilayer Nanodiscs in the Study of Membranes and Membrane Proteins. Abhinav Nath, William M. Atkins, and Stephen G. Sligar. Biochemistry, 2007, 46 (8), 2059-2069

[4]     Self-assembly of discoidal phospholipid bilayer nanoparticles with membrane scaffold proteins. Timothy H. Bayburt,Yelena V. Grinkova, and Stephen G. Sligar. Nano Letters, 2002, 2 (8), pp 853–856

[5]     Nanodiscs for structural and functional studies of membrane proteins.Ilia G Denisov   & Stephen G Sligar. Nature Structural & Molecular Biology 23, 481–486 (2016)

Transmembrane protein series one: Aquaporin

What are Aquaporins?

Aquaporin (AQPs) is a kind of membrane protein, which widely exists in prokaryotic and eukaryotic cell membranes and has the characteristics of highly selective transport of water molecules. In addition, AQP is also involved in various physiological and pathological processes of the body, including cell proliferation, apoptosis, migration, phagocytosis and nerve signal transduction.

The Discovery of Aquaporins

In 1985, Benga et al. first discovered the existence of water-permeating channel proteins in erythrocyte membrane. In 1988, Agre et al. discovered a transmembrane protein in the erythrocyte membrane while identifying the human Rh blood group antigen. The protein’s molecular weight is 28 KD, so it named “channel-forming integral membrane protein (CHIP28)”. Subsequently, Agre et al. identified the function of CHIP28 to transfer water and renamed it aquaporin1 (AQP1).

At present, A total of 13 AQP have been found in human bodies, which are AQP0-AQP12, belonging to the major intrinsic protein (MIP) family, composed of 250 ~ 295 amino acids.

Classification of Aquaporins

Aquaporins found in mammals can be divided into three subfamilies based on differences in gene structure and transport function.

The first subfamily is aquaporin, including AQP 0, AQP 1, AQP 2, AQP 4, AQP 5, AQP 6 and AQP 8. They are only permeable to water, except for AQP 6 and AQP 8. AQP 6 is permeable to anions, while AQP 8 is permeable to urea.

The second subfamily is aquaglyceroporin, including AQP 3, AQP 7, AQP 9 and AQP 10. The second subfamily can transport water and other small molecular solutes such as glycerin and urea.

The third subfamily is known as the superaquaporins, including AQP 11 and AQP 12.

Molecular Structure and Biochemical Properties of AQPs

The typical AQP gene structure contains a large exon (exon 1) encoding the amino terminus of AQP and three smaller exons (exons 2 ~ 4) encoding the hydroxy-terminus of AQP.

AQP1 is a glycoprotein. Its primary structure is a single peptide chain that spans the membrane 6 times. The amino and hydroxyl terminals are all located in the cell, and it contains 3 extracellular rings (A, C, E) and 2 intracellular rings (B, D). B ring and E ring are hydrophobic, and any variation will cause the decrease of the activity of aquaporin. The asparagine-valine-alanine (NPA) motifs located on the B and E rings are a common feature of members of the AQP family.

The tertiary structure of aquaporin is the “hourglass” model proposed by Jung et al. The hydrophobic B ring and E ring are located in and outside the cell respectively, and fold into the membrane lipid bilayer. The two NPAs are folded to form a single water channel, each of which is approximately a water molecule in size. The concentrated electrostatic field around the NPA prevents the passage of charged protons and other ions.

The structure of the AQP

Figure 1 The structure of the AQP

Distribution of Aquaporins

Aquaporin is widely distributed in various tissues and organs of the body, including nervous system, cardiovascular system, respiratory system, kidney, digestive system and reproductive system.

Nervous system: Aquaporin is widely expressed in central nervous system and peripheral nervous system. Aquaporin in the brain are mainly AQP1, AQP4 and AQP9.

Cardiovascular system: Human heart expressions include AQP1, AQP3, AQP4, AQP5, AQP7, AQP9, AQP10 and AQP11.

Respiratory system: Four aquaporins, AQP1, AQP3, AQP4 and AQP5, are mainly expressed in the respiratory system.

Kidney: The reabsorption of water by the kidneys is mainly mediated by AQP, which in turn completes the urine concentration process. The AQP types in the kidney are mainly AQP1-4, AQP6-8 and AQP11.

Digestive system: The main functions of the digestive system include digestion and absorption, both of which require liquid transport across the cell membrane. Aquaporins in the digestive system include AQP1, AQP3, AQP4, AQP8, and AQP9.

Reproductive system: Recent studies on the human reproductive system AQP have shown that aquaporins play an important physiological role in the reproductive system. AQP is associated with diseases of the reproductive system, such as polycystic ovary syndrome, ovarian tumors, etc.

In addition, aquaporins are also distributed in the skin system and musculoskeletal system.

The Function of the AQP

With the isolation and identification of a large number of aquaporins, aquaporins have been found to be not only water-selective channel proteins, but also many other physiological and biochemical functions, and are a class of multifunctional proteins. The new functions of different members are mainly related to the cells they are located in.

  • For example, AQP1 is mainly located on vascular endothelial cells and lymphatic vascular endothelial cells, which are mainly involved in the formation of blood vessels and lymphatic vessels.
  • AQP3 located on the surface of keratinocytes and dendritic cells of the skin is associated with skin moisturization, innate immunity, and acquired immunity; mutations in AQP3 localized on renal tubular epithelial cells are associated with the pathogenesis of polycystic kidney disease.
  • AQP4 is mainly located in glial cells and ependymal cells in the central nervous system, which is involved in the occurrence and maintenance of cerebral edema.
  • AQP5 locates on the surface of ovarian epithelial cells, which is related to the occurrence of ovarian epithelial tumors.
  • AQP8 and AQP9 were located in liver cancer cells, and their decreased expression was related to their anti-apoptotic properties.

AQP plays an important role in the pathogenesis of many diseases and can be used as a new target for pharmacological treatment.

CUSABIO provides the products you need for your research. At present, we can produce aquaporin-related proteins, antibodies and kit products.

Hot products

Recombinant Escherichia coli Aquaporin Z (aqpZ)CSB-CF352724ENV)

 

Recombinant Human Aquaporin-1(AQP1) (CSB-CF001957HU(A4)

 

Aquaporin related proteins for your research

Target Product Name Code Expression System
AQP Recombinant Encephalitozoon intestinalis Aquaporin Recombinant Encephalitozoon intestinalis Aquaporin CSB-CF631887EIX
AQP Recombinant Nosema ceranae Aquaporin Recombinant Nosema ceranae Aquaporin CSB-CF505319NHO
Aqp1 Recombinant Mouse Aquaporin-1 Recombinant Mouse Aquaporin-1 CSB-CF586908MO
AQP10 Recombinant Human Aquaporin-10 Recombinant Human Aquaporin-10 CSB-CF853482HU
AQP11 Recombinant Human Aquaporin-11 Recombinant Human Aquaporin-11 CSB-CF847678HU
AQP12A Recombinant Human Aquaporin-12A Recombinant Human Aquaporin-12A CSB-CF816900HU
AQP12B Recombinant Human Aquaporin-12B Recombinant Human Aquaporin-12B CSB-CF001961HU
Aqp2 Recombinant Mouse Aquaporin-2 Recombinant Mouse Aquaporin-2 CSB-CF001962MO
AQP3 Recombinant Human Aquaporin-3 Recombinant Human Aquaporin-3 CSB-CF849752HU
Aqp4 Recombinant Mouse Aquaporin-4 Recombinant Mouse Aquaporin-4 CSB-CF001964MO
AQP5 Recombinant Human Aquaporin-5 Recombinant Human Aquaporin-5 CSB-CF001965HU
Aqp6 Recombinant Mouse Aquaporin-6 Recombinant Mouse Aquaporin-6 CSB-CF806019MO
AQP7 Recombinant Human Aquaporin-7 Recombinant Human Aquaporin-7 CSB-CF001967HU
AQP7P3 Recombinant Human Putative aquaporin-7-like protein 3 Recombinant Human Putative aquaporin-7-like protei CSB-CF001970HU
Aqp8 Recombinant Mouse Aquaporin-8 Recombinant Mouse Aquaporin-8 CSB-CF001972MO
AQP9 Recombinant Human Aquaporin-9 Recombinant Human Aquaporin-9 CSB-CF001973HU
aqpA Recombinant Dictyostelium discoideum Aquaporin A Recombinant Dictyostelium discoideum Aquaporin A CSB-CF866191DKK
aqpB Recombinant Dictyostelium discoideum Aquaporin-B Recombinant Dictyostelium discoideum Aquaporin-B CSB-CF706896DKK
aqpM Recombinant Archaeoglobus fulgidus Probable aquaporin AqpM Recombinant Archaeoglobus fulgidus Probable aquapo CSB-CF521560DOC
aqpZ Recombinant Bordetella parapertussis Aquaporin Z Recombinant Bordetella parapertussis Aquaporin Z CSB-CF767021BIK
AQY1 Recombinant Saccharomyces cerevisiae Aquaporin-1 Recombinant Saccharomyces cerevisiae Aquaporin-1 CSB-CF001957STA
AQY2 Recombinant Saccharomyces cerevisiae Aquaporin-2 Recombinant Saccharomyces cerevisiae Aquaporin-2 CSB-CF001962SAC
DIP Recombinant Antirrhinum majus Probable aquaporin TIP-type Recombinant Antirrhinum majus Probable aquaporin T CSB-CF330266DNE
Drip Recombinant Drosophila melanogaster Aquaporin Recombinant Drosophila melanogaster Aquaporin CSB-CF893235DLU
gla Recombinant Lactococcus lactis subsp. cremoris Glycerol facilitator-aquaporin gla Recombinant Lactococcus lactis subsp. cremoris Gly CSB-CF325214LNF
MCP1 Recombinant Medicago sativa Probable aquaporin TIP-type Recombinant Medicago sativa Probable aquaporin TIP CSB-CF331409MQO
MIP Recombinant Sheep Lens fiber major intrinsic protein Recombinant Sheep Lens fiber major intrinsic prote CSB-CF764270SH
NIP1-4 Recombinant Oryza sativa subsp. japonica Aquaporin NIP1-4 Recombinant Oryza sativa subsp. japonica Aquaporin CSB-CF726469OFG
NIP2-2 Recombinant Oryza sativa subsp. japonica Aquaporin NIP2-2 Recombinant Oryza sativa subsp. japonica Aquaporin CSB-CF714994OFG
NIP2-3 Recombinant Zea mays Aquaporin NIP2-3 Recombinant Zea mays Aquaporin NIP2-3 CSB-CF861006ZAX
NIP3-3 Recombinant Oryza sativa subsp. japonica Aquaporin NIP3-3 Recombinant Oryza sativa subsp. japonica Aquaporin CSB-CF772832OFG
NIP4-2 Recombinant Arabidopsis thaliana Probable aquaporin NIP4-2 Recombinant Arabidopsis thaliana Probable aquapori CSB-CF855405DOA
NIP5-1 Recombinant Arabidopsis thaliana Probable aquaporin NIP5-1 Recombinant Arabidopsis thaliana Probable aquapori CSB-CF890454DOA
NIP6-1 Recombinant Arabidopsis thaliana Aquaporin NIP6-1 Recombinant Arabidopsis thaliana Aquaporin NIP6-1 CSB-CF871020DOA
NIP7-1 Recombinant Arabidopsis thaliana Probable aquaporin NIP7-1 Recombinant Arabidopsis thaliana Probable aquapori CSB-CF817165DOA
PIP1.4 Recombinant Arabidopsis thaliana Probable aquaporin PIP1-4 Recombinant Arabidopsis thaliana Probable aquapori CSB-CF653696DOA
PIP1-6 Recombinant Zea mays Aquaporin PIP1-6 Recombinant Zea mays Aquaporin PIP1-6 CSB-CF861009ZAX
PIP2-8 Recombinant Arabidopsis thaliana Probable aquaporin PIP2-8 Recombinant Arabidopsis thaliana Probable aquapori CSB-CF116052DOA
SIP1-2 Recombinant Zea mays Aquaporin SIP1-2 Recombinant Zea mays Aquaporin SIP1-2 CSB-CF861008ZAX
SIP2-1 Recombinant Oryza sativa subsp. japonica Aquaporin SIP2-1 Recombinant Oryza sativa subsp. japonica Aquaporin CSB-CF607470OFG
TIP1-3 Recombinant Arabidopsis thaliana Aquaporin TIP1-3 Recombinant Arabidopsis thaliana Aquaporin TIP1-3 CSB-CF526874DOA
TIP2-2 Recombinant Zea mays Aquaporin TIP2-2 Recombinant Zea mays Aquaporin TIP2-2 CSB-CF859337ZAX
TIP2-3 Recombinant Arabidopsis thaliana Aquaporin TIP2-3 Recombinant Arabidopsis thaliana Aquaporin TIP2-3 CSB-CF863746DOA
TIP3-2 Recombinant Oryza sativa subsp. japonica Probable aquaporin TIP3-2 Recombinant Oryza sativa subsp. japonica Probable CSB-CF801726OFG
TIP4-4 Recombinant Zea mays Aquaporin TIP4-4 Recombinant Zea mays Aquaporin TIP4-4 CSB-CF857688ZAX
TIP5-1 Recombinant Arabidopsis thaliana Probable aquaporin TIP5-1 Recombinant Arabidopsis thaliana Probable aquapori CSB-CF874520DOA
TIP5-1 Recombinant Zea mays Aquaporin TIP5-1 Recombinant Zea mays Aquaporin TIP5-1 CSB-CF859752ZAX
TRG-31 Recombinant Pisum sativum Probable aquaporin PIP-type 7a Recombinant Pisum sativum Probable aquaporin PIP-t CSB-CF335149EWE
wacA Recombinant Dictyostelium discoideum Aquaporin C Recombinant Dictyostelium discoideum Aquaporin C CSB-CF690723DKK

 

Aquaporin related antibodies for your research

Target Product Name Code Species Reactivity Tested Applications
AQP1 AQP1 Antibody CSB-PA001957GA01HU Human,Mouse,Rat ELISA,WB,IHC
AQP1 AQP1 Antibody CSB-PA16085A0Rb Human,Mouse,Rat ELISA,WB,IF
AQP1 AQP1 Antibody CSB-PA16087A0Rb Human ELISA,IHC,IF
AQP1 AQP1 Antibody,Biotin conjugated CSB-PA16085D0Rb Human ELISA
AQP1 AQP1 Antibody,FITC conjugated CSB-PA16087C0Rb Human ELISA
AQP1 AQP1 Antibody CSB-PA009568 Human,Mouse,Rat ELISA,WB
AQP1 AQP1 Antibody CSB-PA076907 Human,Mouse,Rat ELISA,IHC
AQP1 AQP1 Antibody CSB-PA118586 Human ELISA,WB
AQP1 AQP1 Antibody CSB-PA990867 Human,Mouse,Rat ELISA,WB,IHC
AQP10 AQP10 Antibody CSB-PA853482LA01HU Human ELISA,IF
AQP10 AQP10 Antibody,FITC conjugated CSB-PA853482LC01HU Human ELISA
AQP10 AQP10 Antibody,HRP conjugated CSB-PA853482LB01HU Human ELISA
AQP10 AQP10 Antibody CSB-PA693604 Human ELISA,WB
AQP11 AQP11 Antibody CSB-PA008895 Human,Mouse,Rat ELISA,WB
AQP11 AQP11 Antibody CSB-PA781210 Human ELISA,IHC
AQP12A AQP12A Antibody CSB-PA972136 Human ELISA,WB
AQP12A/AQP12B AQP12A/AQP12B Antibody CSB-PA000912 Human ELISA,WB
AQP2 AQP2 Antibody CSB-PA16069A0Rb Human ELISA,IF
AQP2 AQP2 Antibody,Biotin conjugated CSB-PA16069D0Rb Human ELISA
AQP2 AQP2 Antibody,FITC conjugated CSB-PA16069C0Rb Human ELISA
AQP2 AQP2 Antibody,HRP conjugated CSB-PA16069B0Rb Human ELISA
AQP2 AQP2 Antibody CSB-PA000913 Human,Mouse,Rat,Monkey ELISA,WB,IHC,IF
AQP2 AQP2 Antibody CSB-PA411017 Human,Mouse,Rat ELISA,IHC
AQP2 AQP2 Antibody CSB-PA597642 Human,Mouse,Rat ELISA,IHC
AQP2 Phospho-AQP2 (S256) Antibody CSB-PA009580 Human,Mouse,Rat ELISA,IHC
AQP3 AQP3 Antibody CSB-PA13909A0Rb Human ELISA,IHC,IF
AQP3 AQP3 Antibody,Biotin conjugated CSB-PA13909D0Rb Human ELISA
AQP3 AQP3 Antibody,FITC conjugated CSB-PA13909C0Rb Human ELISA
AQP3 AQP3 Antibody CSB-PA009603 Human,Mouse,Rat ELISA,IHC
AQP3 AQP3 Antibody CSB-PA203676 Human,Mouse,Rat ELISA,IHC
AQP3 AQP3 Antibody CSB-PA531552 Human,Mouse,Rat ELISA,WB,IHC
AQP4 AQP4 Antibody CSB-PA001964GA01HU Human,Mouse,Rat ELISA,WB,IHC
AQP4 AQP4 Antibody CSB-PA000914 Human,Mouse,Rat ELISA,WB,IHC
AQP4 AQP4 Antibody CSB-PA579941 Human,Mouse,Rat ELISA,WB,IHC
AQP4 AQP4 Antibody CSB-PA905782 Human,Mouse,Rat ELISA,WB,IHC
AQP5 AQP5 Antibody CSB-PA000915 Human ELISA,WB,IHC
AQP5 AQP5 Antibody CSB-PA191314 Human ELISA,IHC
AQP5 AQP5 Antibody CSB-PA978373 Human ELISA,IHC
AQP6 AQP6 Antibody CSB-PA16139A0Rb Human ELISA,IHC
AQP6 AQP6 Antibody,FITC conjugated CSB-PA16139C0Rb Human ELISA
AQP6 AQP6 Antibody,HRP conjugated CSB-PA16139B0Rb Human ELISA
AQP7 AQP7 Antibody CSB-PA276755 Human ELISA,IHC
AQP7 AQP7 Antibody CSB-PA390632 Human ELISA,IHC
AQP8 AQP8 Antibody CSB-PA186529 Human ELISA,IHC
AQP8 AQP8 Antibody CSB-PA905788 Human ELISA,IHC
MIP MIP Antibody CSB-PA013834LA01HU Human ELISA,IHC,IF
MIP MIP Antibody,Biotin conjugated CSB-PA013834LD01HU Human ELISA
MIP MIP Antibody,HRP conjugated CSB-PA013834LB01HU Human ELISA
MIP MIP Antibody CSB-PA000910 Human,Mouse,Rat ELISA,WB,IHC

 

Aquaporin related ELISA kits for your research

Target Product Name Code Expression System
AQP1 Human Aquaporin 1,AQP-1 ELISA Kit CSB-E08248h serum, plasma, cell culture supernates, cell lysates 3.9 pg/mL
AQP2 Human Aquaporin 2,AQP-2 ELISA Kit CSB-E08242h serum, plasma, urine, tissue homogenates 0.078 ng/mL
AQP3 Human Aquaporin 3,AQP-3 ELISA Kit CSB-E08251h serum, plasma, tissue homogenates 0.078 ng/mL
AQP4 Human Aquaporin 4,AQP-4 ELISA Kit CSB-E08254h serum, plasma, tissue homogenates 0.039 ng/mL
AQP5 Human Aquaporin 5,AQP-5 ELISA Kit CSB-E08257h serum, plasma, tissue homogenates 0.039 ng/mL
AVP Human antidiuretic hormone/vasopressin/arginine vasopressin,ADH/VP/AVP ELISA Kit CSB-E09080h serum, plasma, tissue homogenates 0.312 pg/mL

A Switch that Controls the Entry and Exit of Ions


Transmembrane protein series two: Ion Channels

What are Ion Channels?

Transmembrane proteins are widely present in organisms and play important physiological functions. Its function differs significantly depending on the type of difference. It constitutes a variety of ion channels, which inputs nutrients and some inorganic electrolytes into cells, and excretes toxic or useless metabolites from cells.

Ion channels are commonly called channel proteins. Some stimuli bind to and interact with the channel proteins on the cell membrane, changing the conformation of ion channles. Conformational alteration of ion channels regulates the opening and closing of ion channels, modulating the ability of corresponding substances to enter and exit cells, thereby regulating various key physiological processes of the living system. Sometimes ion channle gating is controlled by the membrane potential. Almost all cellular processes rely on ion channels.

Ion channel function

  • Substance absorption
  • Osmotic pressure regulation
  • Electrical impulse formation: The various sensory mechanisms of animals, such as vision, taste, smell and temperature perception, are related to changes in potential caused by ion channels.
  • Signal transmission: Certain ions (Ca2+, K+, etc.) in the cytoplasm rapidly increase in concentration to form signal stimulation, further affecting downstream signaling pathways. Ion channels are the primary channel for adjusting ion concentration.

Ion channels and diseases

Ion channel genetic variation and dysfunction are associated with the development and progression of many diseases. The ion channel disease, which is well studied, mainly involves the fields of potassium, sodium, calcium and chloride channels.

Ion channels have a certain relationship with tumors. Ion channels also play a conservative role in development.

To learn more about ion channels, there may be information you want to know in this article: A Switch that Controls the Entry and Exit of Ions.

Ion channels and their correlation with nerves, cardiovasculars, immune diseases, and cancer make ion channels an important target for drug design. Different target drugs can be designed according to different types of channels.

These ion channel related products produced by CUSABIO provide convenience for your research. At present, we have produced more than 1200 ion channel related products: 1106 antibody products, 70 protein products, 37 ELISA kits.

Hot Products

Recombinant human Calmodulin
(CSB-EP004445HU)

Recombinant Human Chitinase domain-containing protein 1(CHID1)
(CSB-MP883614HU)

Recombinant Human Potassium channel subfamily K member 3(KCNK3)
(CSB-CF012071HU)

Recombinant Human Voltage-dependent calcium channel subunit alpha-2/delta-1(CACNA2D1),partial
(CSB-EP004407HU1)

Ion channels related proteins for your research

Target Product Name Code Expression System
KCNJ10 Recombinant Human ATP-sensitive inward rectifier potassium channel 10(KCNJ10) ,partial CSB-EP012048HU E.coli
KCNJ1 Recombinant Human ATP-sensitive inward rectifier potassium channel 1(KCNJ1),partial CSB-YP012047HU Yeast
KCNJ1 Recombinant Human ATP-sensitive inward rectifier potassium channel 1(KCNJ1),partial CSB-EP012047HU E.coli
KCND2 Recombinant Human Potassium voltage-gated channel subfamily D member 2(KCND2),partial CSB-YP012023HU Yeast
KCND1 Recombinant Human Potassium voltage-gated channel subfamily D member 1(KCND1),partial CSB-YP012022HU Yeast
KCND1 Recombinant Human Potassium voltage-gated channel subfamily D member 1 protein(KCND1),partial CSB-EP012022HU E.coli
KCNAB2 Recombinant Human Voltage-gated potassium channel subunit beta-2(KCNAB2) CSB-EP012014HU E.coli
KCNA1 Recombinant Human Potassium voltage-gated channel subfamily A member 1 protein(KCNA1),partial CSB-EP012005HU E.coli
HTR3E Recombinant Human 5-hydroxytryptamine receptor 3E(HTR3E),partial CSB-CF010894HU in vitro E.coli expression system
HTR3D Recombinant Human 5-hydroxytryptamine receptor 3D(HTR3D),partial CSB-CF747864HU in vitro E.coli expression system
GRIN2A Recombinant Human Glutamate receptor ionotropic, NMDA 2A(GRIN2A),partial CSB-EP618634HU1 E.coli
GRIN1 Recombinant Human Glutamate [NMDA] receptor subunit zeta-1(GRIN1),partial CSB-EP009911HU E.coli
GRIA3 Recombinant Human Glutamate receptor 3(GRIA3),partial CSB-YP009900HU Yeast
GRIA3 Recombinant Human Glutamate receptor 3(GRIA3),partial CSB-EP009900HU E.coli
GABRA4 Recombinant Human Gamma-aminobutyric acid receptor subunit alpha-4(GABRA4),partial CSB-EP009143HU E.coli
FXYD3 Recombinant Human FXYD domain-containing ion transport regulator 3(FXYD3),Partial CSB-EP622789HU E.coli
FXYD2 Recombinant Human Sodium/potassium-transporting ATPase subunit gamma(FXYD2) CSB-EP009090HU E.coli
CYBB RecombinantHumanCytochromeb-245heavychain(CYBB),partial CSB-YP006325HU1 Yeast
EGF Recombinant Human Pro-epidermal growth factor(EGF) ,partial CSB-RP062444h E.coli
CYBB Recombinant Human Cytochrome b-245 heavy chain(CYBB),partial CSB-EP006325HU1a2 E.coli
CTNNB1 Recombinant Human Catenin beta-1(CTNNB1) CSB-YP006169HU Yeast
CTNNB1 Recombinant Human Catenin beta-1(CTNNB1) CSB-EP006169HU E.coli
CNGA4 Recombinant Human Cyclic nucleotide-gated cation channel alpha-4(CNGA4) CSB-CF808540HU in vitro E.coli expression system
CLIC4 Recombinant Human Chloride intracellular channel protein 4(CLIC4) CSB-EP005549HU E.coli
CAV3 Recombinant Human Caveolin-3(CAV3) CSB-EP004573HU E.coli
CALM1 Recombinant Human Calmodulin(CALM1) CSB-EP004445HU E.coli
ATP6V1F Recombinant Human V-type proton ATPase subunit F(ATP6V1F) CSB-RP015744h E.coli
ATP6V1G1 Recombinant Human V-type proton ATPase subunit G 1(ATP6V1G1) CSB-RP001344h E.coli
ATP6V0D1 Recombinant Human V-type proton ATPase subunit d 1(ATP6V0D1) CSB-EP002390HU E.coli
ANXA5 Recombinant Human Annexin A5(ANXA5) CSB-YP001846HU Yeast
ANXA5 Recombinant Human Annexin A5(ANXA5) CSB-YP001846HU Yeast
ANXA2 Recombinant Human Annexin A2(ANXA2) CSB-EP001840HUb2 E.coli
ANXA2 Recombinant Human Annexin A2(ANXA2) CSB-EP001840HUa0 E.coli
ANXA2 Recombinant Human Annexin A2(ANXA2) CSB-EP001840HU E.coli
ANXA2 Recombinant Human Annexin A2(ANXA2) CSB-EP001840HUe0 E.coli
YWHAQ Recombinant Human 14-3-3 protein theta(YWHAQ) CSB-EP026290HU E.coli
YWHAH Recombinant Human 14-3-3 protein eta(YWHAH),partial CSB-RP021744h E.coli
UCP1 Recombinant Human Mitochondrial brown fat uncoupling protein 1(UCP1) CSB-YP025554HU Yeast
UCP1 Recombinant Human Mitochondrial brown fat uncoupling protein 1(UCP1) CSB-EP025554HU E.coli
TRPA1 Recombinant Human Transient receptor potential cation channel subfamily A member 1(TRPA1),partial CSB-EP025074HU E.coli
SLC8A1 Recombinant Human Sodium/calcium exchanger 1 (SLC8A1),partial CSB-YP021723HU Yeast
RYR3 Recombinant Human Ryanodine receptor 3(RYR3),partial CSB-EP020621HU E.coli
RYR1 Recombinant Human Ryanodine receptor 1(RYR1),partial CSB-EP020619HU E.coli
PRKCSH Recombinant Human Glucosidase 2 subunit beta(PRKCSH),partial CSB-RP029254h E.coli
NCS1 Recombinant Human Neuronal calcium sensor 1(NCS1) CSB-EP008983HU E.coli
KCNMA1 Recombinant Human Calcium-activated potassium channel subunit alpha-1(KCNMA1),partial CSB-EP614255HU E.coli
KCNK3 Recombinant Human Potassium channel subfamily K member 3(KCNK3) CSB-CF012071HU in vitro E.coli expression system
KCNK2 Recombinant Human Potassium channel subfamily K member 2(KCNK2),partial CSB-YP012070HU Yeast
KCNJ10 Recombinant Human ATP-sensitive inward rectifier potassium channel 10(KCNJ10) CSB-CF012048HU in vitro E.coli expression system

Ion channels related antibodies for your research

Target Product Name Code Expression System Tested Applications
ANO2 ANO2 Antibody CSB-PA001813GA01HU Human, Mouse, Rat ELISA, WB, IF
ANXA2 ANXA2 Antibody CSB-PA001840GA01HU Human, Mouse, Rat ELISA, WB, IHC
ANXA7 ANXA7 Antibody CSB-PA001848GA01HU Human, Mouse, Rat ELISA, WB, IHC
AP2M1 AP2M1 Antibody CSB-PA00627A0Rb Human, Mouse, Rat ELISA, WB, IHC
ARRB1 ARRB1 Antibody CSB-PA002134GA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
ATP1B1 ATP1B1 Antibody CSB-PA002326LA01HU Human, Rat, Mouse ELISA, WB, IHC, IF
CACNA1B CACNA1B Antibody CSB-PA004398GA01HU Human, Mouse, Rat ELISA, WB, IHC
CAMK2D CAMK2D Antibody CSB-PA004467GA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
CASQ2 CASQ2 Antibody CSB-PA004557GA01HU Human, Mouse, Rat ELISA, WB, IHC
CAV1 CAV1 Antibody CSB-PA004571GA01HU Human, Mouse, Rat ELISA, WB, IHC
CHP1 CHP1 Antibody CSB-PA860773LA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
CHRNA3 CHRNA3 Antibody CSB-PA005389GA01HU Human, Mouse, Rat ELISA, WB, IHC
CHRNB1 CHRNB1 Antibody CSB-PA005395GA01HU Human, Mouse, Rat ELISA, WB, IHC
CIB1 CIB1 Antibody CSB-PA005426GA01HU Human, Mouse, Rat ELISA, WB, IHC
CLCNKA CLCNKA Antibody CSB-PA005487GA01HU Human, Mouse, Rat ELISA, WB, IHC
CLIC1 CLIC1 Antibody CSB-PA005545GA01HU Human, Mouse, Rat ELISA, IHC, IF
CTNNB1 CTNNB1 Antibody CSB-PA006169GA01HU Human, Mouse, Rat, Zebrafish ELISA, WB, IHC
CYBB CYBB Antibody CSB-PA006325KA01HU Human, Mouse, Rat ELISA, WB, IHC
DIAPH1 DIAPH1 Antibody CSB-PA006890GA01HU Human, Mouse, Rat ELISA, WB, IF
FXYD2 FXYD2 Antibody CSB-PA009090GA01HU Human, Mouse, Rat ELISA, WB, IHC
FXYD6 FXYD6 Antibody CSB-PA009094GA01HU Human, Mouse, Rat ELISA, WB, IHC
GABRG2 GABRG2 Antibody CSB-PA009152GA01HU Human, Mouse, Rat ELISA, WB, IF
GRIA3 GRIA3 Antibody CSB-PA009900KA01HU Human, Mouse, Rat ELISA, WB, IHC
GRID1 GRID1 Antibody CSB-PA009902GA01HU Human, Mouse, Rat ELISA, WB, IHC
GRIN2A GRIN2A Antibody CSB-PA14129A0Rb Human, Mouse, Rat ELISA, WB, IHC, IF
HTR3A HTR3A Antibody CSB-PA010890GA01HU Human, Mouse, Rat ELISA, WB, IHC
KCNA1 KCNA1 Antibody CSB-PA012005LA01HU Human, Mouse, Rat ELISA, WB, IF
KCNAB1 KCNAB1 Antibody CSB-PA012013GA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
KCNIP1 KCNIP1 Antibody CSB-PA012043GA01HU Human, Mouse, Rat ELISA, WB, IHC
KCNJ11 KCNJ11 Antibody CSB-PA012049GA01HU Human, Mouse, Rat ELISA, WB, IF
KCNS2 KCNS2 Antibody CSB-PA012096GA01HU Human, Mouse, Rat ELISA, WB, IHC
NCS1 NCS1 Antibody CSB-PA008983ESR1HU Human, Mouse, Rat ELISA, WB, IHC
P2RX4 P2RX4 Antibody CSB-PA017322GA01HU Human, Mouse, Rat ELISA, WB, IHC
P2RX4 P2RX4 Antibody CSB-PA859513LA01HU Human, Mouse, Rat ELISA, WB, IHC
PACSIN3 PACSIN3 Antibody CSB-PA017375GA01HU Human, Mouse, Rat ELISA, WB, IHC
PANX2 PANX2 Antibody CSB-PA839405LA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
POMP POMP Antibody CSB-PA018365GA01HU Human, Mouse, Rat ELISA, WB, IF
PRKCSH PRKCSH Antibody CSB-PA018709GA01HU Human, Mouse, Rat ELISA, WB, IHC
SCNN1G SCNN1G Antibody CSB-PA020851GA01HU Human, Mouse, Rat ELISA, WB, IHC
SGK3 SGK3 Antibody CSB-PA021191GA01HU Human, Mouse, Rat ELISA, WB, IHC
SLC39A7 SLC39A7 Antibody CSB-PA021636GA01HU Human, Mouse, Rat ELISA, WB, IHC
STIM1 STIM1 Antibody CSB-PA022829GA01HU Human, Mouse, Rat, Zebrafish ELISA, WB, IHC
VDAC1 VDAC1 Antibody CSB-PA025821GA01HU Human, Mouse, Rat ELISA, WB, IHC
VDAC3 VDAC3 Antibody CSB-PA025827GA01HU Human, Mouse, Rat ELISA, WB, IHC
YES1 YES1 Antibody CSB-PA026253GA01HU Human, Mouse, Rat ELISA, WB, IHC
YWHAE YWHAE Antibody CSB-PA026287GA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
YWHAQ YWHAQ Antibody CSB-PA026290GA01HU Human, Mouse, Rat ELISA, WB, IF

Ion channels related ELISA kits for your research

Target Product Name Code Sample Type Sensitivity
S100A10 Human Protein S100-A10(S100A10) ELISA kit CSB-EL020623HU serum, plasma, tissue homogenates 0.078 ng/mL
S100A1 Human Soluble protein-100,S-100 ELISA Kit CSB-E08067h serum, plasma, tissue homogenates 0.039 ng/mL
P2RX7 Human P2X purinoceptor 7(P2RX7) ELISA kit CSB-EL017325HU serum, plasma, tissue homogenates, cell lysates 6.25 pg/mL
GRIN1 Human Glutamate [NMDA] receptor subunit zeta-1(GRIN1) ELISA kit CSB-EL009911HU serum, plasma, tissue homogenates, cell lysates 31.25 pg/mL
EGF Human Epidermal growth factor,EGF ELISA Kit CSB-E08027h serum, plasma, cell culture supernates, tissue homogenates_x005f_x000D_ 0.39 pg/mL
CTNNB1 Human Catenin beta-1 (CTNNB1/CTNNB/OK/SW-cl.35/PRO2286) ELISA kit CSB-E08963h serum, plasma, cell culture supernates, tissue homogenates, cell lysates 3.9 pg/mL
CLDN4 Human Claudin 4 (CLDN4)ELISA Kit CSB-E17961h serum, plasma, tissue homogenates, cell lysates 1.56 pg/mL
CFTR Human Cystic fibrosis transmembrane conductance regulator(CFTR) ELISA kit CSB-EL005292HU serum, plasma, tissue homogenates, cell lysates 7 pg/mL
CDH5 Human Vascular Endothelial-Cadherin,VE-cad ELISA Kit CSB-E09372h serum, plasma, tissue homogenates 0.98 ng/mL
CAV1 Human Caveolin-1,Cav-1 ELISA KIT CSB-E09682h serum, plasma, tissue homogenates 7.8 pg/mL
ATP6V0A2 Human V-type proton ATPase 116 kDa subunit a isoform 2(ATP6V0A2) ELISA kit CSB-EL002386HU serum, plasma, tissue homogenates 7.81 pg/mL
ATP5MC1 Human ATP synthase lipid-binding protein, mitochondrial(ATP5G1) ELISA kit CSB-EL002359HU serum, plasma, tissue homogenates, cell lysates 5.86 pg/mL
ANXA5 Human Annexin Ⅴ,ANX-Ⅴ ELISA Kit CSB-E04882h serum, plasma, cell culture supernates, cell lysates 0.078 ng/mL
ANXA2 Human Annexin Ⅱ(ANX-Ⅱ) ELISA Kit CSB-E12156h serum, urine, saliva, cell lysates 0.098 ng/mL
ANXA1 Human Annexin Ⅰ(ANX-Ⅰ) ELISA Kit CSB-E12155h serum, plasma, tissue homogenates 0.078 ng/mL
SGK1 Human Serine/threonine-protein kinase Sgk1(SGK1) ELISA kit CSB-EL021189HU serum, plasma, tissue homogenates, cell lysates 5.86 pg/mL
STX1A Human Syntaxin-1A(STX1A) ELISA kit CSB-EL022895HU serum, tissue homogenates 3.9 pg/mL
TRPV1 Human transient receptor potential cation channel subfamily V member 1 (TrpV1)ELISA Kit CSB-E14198h serum, plasma, tissue homogenates, cell lysates 0.078 ng/mL
TRPV4 Human transient receptor potential cation channel subfamily V member 4 (TrpV4)ELISA Kit CSB-E14199h serum, plasma, tissue homogenates, cell lysates 3.9 pg/mL
UCP1 Human Mitochondrial brown fat uncoupling protein 1(UCP1) ELISA kit CSB-EL025554HU serum, plasma, tissue homogenates 7.81 pg/mL
YWHAE Human 14-3-3 protein epsilon(YWHAE) ELISA kit CSB-EL026287HU serum, plasma, tissue homogenates, cell lysates 19.5 pg/mL
YWHAH Human 14-3-3 protein eta(YWHAH) ELISA kit CSB-EL026289HU serum, plasma, tissue homogenates 0.156 ng/mL
YWHAQ Human 14-3-3 protein theta(YWHAQ) ELISA kit CSB-EL026290HU serum, plasma, tissue homogenates, cerebrospinal fluid (CSF) 0.11 ng/mL
YWHAZ Human 14-3-3 protein zeta/delta(YWHAZ) ELISA kit CSB-EL026293HU serum, plasma, tissue homogenates 0.156 ng/mL

A transport machine - ATP-binding cassette

ATP-binding cassette (ABC) transporters are the largest known transmembrane protein superfamily, widely distributed in eukaryotes and prokaryotes. ABC proteins bind and hydrolyze ATP and use energy to drive various molecules across the plasma membrane as well as the endoplasmic reticulum (ER), peroxisome and mitochondrial inner membrane [1][2]. It is involved in the transport of specific molecules on the lipid membrane and the resistance in all organisms.

The Structure of ATP-binding cassette

Figure 1 The Structure of ATP-binding cassette, The picture is from wikipedia

1. The Structure of ABC

Three basic organization forms of ABC transporters

Figure 2 Three basic organization forms of ABC transporters

ABC protein has a typical modular structure, consisting of four protein domains or subunits: two hydrophobic transmembrane domains (TMD) are considered to constitute transmembrane transport pathways or channels (usually composed of six transmembrane alpha helix); two hydrophilic nucleotide binding domains (NBDs) (ATP binding domains, known as nucleotide binding folding (NBF)) provide energy for active transport [2]. NBF contains three conserved domains: Walker A and B domains, and C motif [3]. The C domain is unique to the ABC transporter.

In addition to the complete transporters, there are also half transporters that contain one of each domain.

Figure 3 The structure and transport process of ABC

Figure 3 The structure and transport process of ABC

2. The Substrate

The ATP-binding cassette (ABC) transporter superfamily transfers a variety of substrates, including sugars, amino acids, metal ions, peptides and proteins, as well as a large number of hydrophobic compounds and metabolites across the extracellular and intracellular membranes.

3. ABC Superfamily

ABC transporters are one of the largest known protein superfamily: there are 49 ABC transporters in humans and 80 in gram-negative E. coli bacteria.

The ABC gene in the human genome is divided into 7 subfamilies (ABCA~ABCG) based on amino acid sequence similarity and phylogeny. The following table is a list of human ABC genes.

Table 1 List of human ABC genes and function

Subfamily Member Function
ABCA ABCA1 Cholesterol efflux onto HDL
ABCA2 Drug resistance
ABCA3 Phosphatidyl choline efflux
ABCA4 N-retinylidiene-PE efflux
ABCA5ABCA6; ABCA7;ABCA8ABCA9; ABCA10; ABCA11; ABCA12ABCA13. /
ABCB ABCB1 Multidrug resistance
ABCB3 Peptide transport
ABCB4 PC transport
ABCB5 Iron transport
ABCB6 Fe/S cluster transport
ABCB11 Bile salt transport
ABCB2; ABCB7ABCB8ABCB9ABCB10. /
ABCC ABCC1 Drug resistance
ABCC2 Organic anion efflux
ABCC3 Drug resistance
ABCC4 Nucleoside transport
ABCC5 Nucleoside transport
CFTR (ABCC7) Chloride ion channel
ABCC8 Sulfonylurea receptor
ABCC9 Potassium channel regulation
ABCC6ABCC10ABCC11ABCC12. /
ABCD ABCD1 VLCFA transport regulation
ABCD2ABCD3ABCD4. /
ABCE ABCE1 Elongation factor complex
ABCF ABCF1ABCF2ABCF3. /
ABCG ABCG1 Cholesterol transport
ABCG2 Toxin efflux, drug resistance
ABCG4 Cholesterol transport
ABCG5 Sterol transport
ABCG8 Sterol transport

4. The Function of ABC

The ATP-binding cassette (ABC) superfamily gene plays an important role in transporting compounds between the intestinal tract, the blood-brain barrier, and the placenta. It also plays an important role in the body’s core function of resisting foreign bodies and detoxification [4]. Different subtypes have different functions and can act as drug efflux transporters (ABCB1, ABCC subfamily and ABCG2) or sterol transporters (ABCA1, ABCA7, ABCG1, ABCG5 and ABCG8).

4.1 T Eukaryotic

In eukaryotes, most ABC genes move compounds from the cytoplasm to the extracellular or extracellular compartment (endoplasmic reticulum, mitochondria, peroxisomes). Its importance in eukaryotic systems has been fully demonstrated, characterized by its association with genetic diseases and its role in multidrug resistance to cancer.

4.2 Prokaryote

In bacteria, the ABC gene is mainly involved in the import of essential compounds that cannot pass through cells through diffusion (eg, sugars, vitamins, metal ions, etc.). These genes play a role in nutrient absorption, toxin secretion and antibacterial drugs. The role of ABC transporters is mainly in the pathogenicity and toxicity of bacteria. In pathogenic bacteria, these functions are usually to evade or resist the host’s defense. Therefore, many cell surfaces or secreted factors can be useful targets for antibacterial therapy or vaccine development.

4.3 Plant

ATP-binding cassette (ABC) transporter in plant is an important membrane protein used to transport a variety of compounds, including heavy metals, antibiotics, phytohormones and secondary metabolites [5]. The number of ABC family members in the plant genome has more than doubled compared to animals and insects.

In plants, ATP-binding cassette transporters have important physiological functions such as cell detoxification, cuticle formation, stomatal regulation, seed germination, and resistance to pathogenic bacteria.

In rice, several ATP-binding cassette transporters of the ABCG family are essential for cuticle formation [6].

In tomato, the ATP-binding cassette transporter is involved in the transport of tomato fruit auxin. As a member of the subfamily ABCB, SlABCB4 plays an important role in the transport of auxin during tomato fruit development.

In Arabidopsis, some members of the ABC transporter ABCB subfamily also are involved in auxin transport [7].

ABC transporters also play an important role in the detoxification of pesticides.

The ATP-binding cassette (ABC) transporter [8] was identified as an important detoxifying enzyme in Plutella xylostella.

Epis et al[9] demonstrated the role of ABC transporters in insecticide defense.

5. ABC and Disease

The ATP-binding cassette (ABC) superfamily genes encode membrane proteins that transport different substrates on the cell membrane. The genetic variation of the ATP-binding cassette (ABC) transporter superfamily gene is the cause or contributing factor of various Mendelian diseases and complex genetic diseases in humans. The heterozygous variation in ABC gene mutations is related to the susceptibility of specific complex diseases.

Currently, there are 17 ABC genes related to Mendelian inheritance. These include adrenoleukodystrophy, cystic fibrosis, retinal degeneration, hypercholesterolemia and cholestasis, neurological diseases, anemia and drug reactions. Many of the ABC genes that cause disease lead to many different clinical phenotypes. For example, cystic fibrosis associated with specific CFTR genotypes includes pancreatic sufficiency and pancreatic insufficiency.

5.1 ABCA1

ABCA1 mediates the transport of intracellular free cholesterol and phospholipids through the cell membrane to poor apoA1 to form HDL [10]. It plays a key role in reverse cholesterol transport and cellular lipid efflux, is the initial rate-limiting step of reverted cholesterol transport (RCT) in macrophages [11], and is the most critical determinant of plasma high density lipoprotein (HDL) levels in hepatic cells.

Mutations in the ABCA1 gene may induce Tangier disease [12] and familial hypolipoproteinemia [13] and may also result in loss of cellular cholesterol homeostasis in prostate cancer. In the general population, some common single-nucleotide polymorphisms of ABCA1 also affect blood lipid levels, atherosclerosis generation and the severity of coronary heart disease [14].

In recent years, a large amount of evidence indicates that abnormal cholesterol metabolism may play an important role in the development of Alzheimer’s disease AD (ABCA2/ABCA7), and apoE gene is also closely related to the metabolism of cholesterol in the brain [15].

Regulatory Factors of ABC1

The expression of the ABCA1 gene is mainly regulated by the liver X receptor (LXR)/retinoid X receptor (RXR).In addition, interferon- γ (IFN- γ ) inhibits liver X receptor α (LXR α ) through the JAK/STAT signaling pathway, which can down-regulate ABCA1 expression and intracellular cholesterol outflow [16].

5.2 ABCA4

Mutations in the ABCA4 gene lead to retinitis pigmentosa, recessive pyramidal malnutrition, and Stargardt disease [17]. All of these diseases are characterized by retinal degeneration, the severity of which is roughly related to the predicted severity of ABCA4 mutation. Patients with heterozygous mutation of ABCA4 gene are more likely to suffer from late-onset macular degeneration – age-related macular degeneration (AMD) [18]. Women with heterozygous mutations of liver transporters that lead to cholestasis may have a higher risk of cholestasis during pregnancy [19].

5.3 ABCG

Members of the ABCG subfamily, ABCG5 and G8 are involved in the development of glutathione, a genetic disorder of lipid metabolism. ABCG1 mainly mediates the transport of intracellular free cholesterol to mature HDL. It works synergistically with ABCA1 to promote extracellular lipids out of the cell and complete reverse cholesterol transport in the body [20]. ABCG1 deficiency can also participate in foam cell formation, endothelial cell dysfunction and inflammatory response, and thus affects the formation and development of atherosclerosis.

Table 2 Diseases and phenotyes caused by ABC genes

Gene Mendelian disorder Complex disease Animal model
ABCA1 Tangier disease, FHDLD HDL levels Mouse, chicken
ABCA3 Surfactant deficiency / /
ABCA4 Stargardt/FFM, RP, CRD AMD Mouse
ABCA12 Lamellar ichthyosis / /
ABCB1 Ivermectin sensitivitya Digoxin uptake Mouse, dog
ABCB2 Immune deficiency / Mouse
ABCB3 Immune deficiency / Mouse
ABCB4 PFIC-3 ICP /
ABCB7 XLSA/A / /
ABCB11 PFIC-2 / /
ABCC2 Dubin-Johnson Syndrome / Rat, sheep, monkey
ABCC6 Pseudoxanthoma elasticum / Mouse
ABCC7 Cystic Fibrosis, CBAVD Pancreatitis, bronchiectasis Mouse
ABCC8 FPHHI Mouse
ABCC9 DCVT
ABCD1 ALD Mouse
ABCG5 Sitosterolemia Mouse
ABCG8 Sitosterolemia Mouse

This table derived from literature “Evolution of the ATP-binding cassette (ABC) transporter superfamily in vertebrates” [21]

6. ABC and Drug Resistance

Currently, chemotherapy is one of the approaches to cancer treatment, and multidrug resistance (MDR) is a major obstacle to successful chemotherapy [22]. MDR refers to the phenomenon that tumor cells are cross-resistant to a variety of structurally unrelated chemotherapeutic drugs. Clinically, drug resistance is caused by multiple factors. The efflux of cytotoxic drugs mediated by ATP-binding cassette transporters is the “classical MDR” pathway [23]. ABC transporters pump drugs out of cells and reduce the concentration of intracellular chemotherapy drugs. Overexpression of ABC transporters in tumor cells is the main mechanism of tumor MDR.

6.1 ATP Binding Cassette (ABC) Multidrug Transporter

ATP binding cassette transporters (ABC transporters) can transport chemotherapy drugs to the extracellular environment and reduce intracellular drug concentration. There are four main types ATP binding cassette multidrug transporter: P-glycoprotein (P-gp, MDR1, ABCB1), Multidrug resistance-associated protein (MDR-related protein /MRP, ABCC), lung resistance-related protein (LRP) and breast cancer resistance protein (BCRP, ABCG2) [24].

Breast cancer resistance protein (BCRP, ABCG2) belongs to the ABCG gene family. The gene is located on chromosome 4 and is a recently discovered ABC drug efflux transporter. In structure, BCRP is “half transporter” [25].

6.2 Liver Cancer MDR

Acquired MDR of hepatocellular carcinoma may be related to the expression of MRP1, MRP3 and MRP5 genes, and MRP2 is the main target of endogenous drug resistance, BCRP is a new drug efflux pump related to tumor MDR. Liver cancer MDR mediated by ATP-binding cassette transporter severely limits chemotherapy efficacy and prognosis.

6.3 Pancreatic Cancer

Pancreatic cancer is resistant to a variety of chemotherapeutic drugs, and resistance is associated with the ATP-binding cassette (ABC) transport vector superfamily [26].

7. How to overcome ABC drug efflux transporter-mediated drug resistance?

For MDR induced by ATP-binding cassette transporters, inhibition of ATP-binding cassette transporter-mediated drug efflux is the easiest and direct route.

7.1 ABC Inhibitors

Inhibitors of ABC transporters include competitive and non-competitive inhibitors. Currently, there are 3 generations of chemical reversals, most of which are competitive inhibitors of MDR1.

First-generation drugs: (including verapamil, tamoxifen, cyclosporine A, quinine).Calcium channel blocker verapamil inhibits MDR1 synthesis and its activity at mRNA level while competing for MDR1 binding sites, thereby reversing drug resistance [27].

Second-generation drugs: (including biricodar, elacridar and valspodar) failed to show overall efficacy improvements in multiple randomized clinical trials due to poor efficacy and increased toxicity.

Third-generation drugs: have high transporter affinity and low pharmacokinetics, including Tariquidar, Zosuquidar and Laniquidar.

Strategies for circumvention of MDR also include small interfering RNA (siRNA) [28] and microRNA (miRNA) to down-regulate the expression of ABC transporters.

Plant Anti-Tumor Drugs: Plant anti-tumor drugs provide new ideas for the development of MDR reversal agents due to their small side effects, natural sources and low cost.

It has been found that artemisinin, quercetin, magnolia officinalis phenol, emodin, zhejiang fritillaria alkaloid, osmanthus cnidii, ginsenoside, total saponin of panax notoginseng, root of mahonia mahogany, ganoderma lucidum and other traditional Chinese medicines or their effective components can reverse the drug resistance of tumor cells by down-regulating the expression of MDR1.

Psoralen, tetramethylpyrazine, tetrandrine, and paeonol are calcium antagonists, which can inhibit the function of pumping drugs out of cells by binding to P-gp, increase the concentration of intracellular chemotherapeutic drugs, and then reverse Resistance.

Studies have found that diosgenin can reverse the resistance of leukemia cells by inhibiting NF-κB down-regulation of MDR1 [29].

7.2 Other

In addition, immunotherapy reversion, gene reversion, somatostatin and its analogues reversion and Chinese herbal reversion were also used to reverse MDR.

The increased oxidative stress and the activated NF-κB transcription factor may be involved in the inhibition of ABCG1 expression by high glucose.

References

[1] Momburg F, Roelse J, Howard J C, et al. Selectivity of MHC-encoded peptide transporters from human, mouse and rat [J]. Nature (London), 1994, 367(6464): 648-651.
[2] Higgins C F. ABC transporters: from microorganisms to man [J]. Annu Rev Cell Biol, 1991, 8(1): 67-113.
[3] Hyde S C, Emsley P, Hartshorn M J, et al. Structural model of ATP-binding proteing associated with cystic fibrosis, multidrug resistance and bacterial transport [J]. Nature, 1990, 346(6282): 362-365.
[4] Fletcher J I, Haber M, Henderson M J, et al. ABC transporters in cancer: more than just drug efflux pumps [J]. Nature Reviews Cancer, 2010, 10(2): 147.
[5] Yazaki K, Shitan N, Sugiyama A, et al. Cell and molecular biology of ATP-binding cassette proteins in plants [J]. Int Rev Cell Mol Biol, 2009, 276: 263-299.
[6] Bessire M, Borel S, Fabre G, et al. A Member of the PLEIOTROPIC DRUG RESISTANCE Family of ATP Binding Cassette Transporters Is Required for the Formation of a Functional Cuticle in Arabidopsis [J]. Plant Cell, 2011, 23(5): 1958-1970.
[7] Cho M, Cho H T. The function of ABCB transporters in auxin transport [J]. Plant Signaling & Behavior, 2013, 8(2): e22990.
[8] He W, You M, Vasseur L, et al. Developmental and insecticide-resistant insights from the de novo assembled transcriptome of the diamondback moth, Plutella xylostella [J]. Genomics, 2012, 99(3): 169-177.
[9] Epis S D, Porretta V, Mastrantonio S, et al. Temporal dynamics of the ABC transporter response to insecticide treatment: insights from the malaria vector Anopheles stephensi [J]. Sci Rep, 2014, 4: 7435-7435.
[10] Oram J F, Heinecke J W. ATP-Binding Cassette Transporter A1: A Cell Cholesterol Exporter That Protects Against Cardiovascular Disease [J]. Physiological Reviews, 2005, 85(4): 1343.
[11] Jiang Z, Zhou R, Xu C, et al. Genetic variation of the ATP-binding cassette transporter A1 and susceptibility to coronary heart disease [J]. Molecular Genetics and Metabolism, 2011, 103(1): 0-88.
[12] Santamarina-Fojo S, Remaley A T, Neufeld E B, et al. Regulation and intracellular trafficking of the ABCA1 transporter [J]. Journal of Lipid Research, 2001, 42(9): 1339-1345.
[13] Brookswilson A, Marcil M, Clee S M, et al. Mutations in ABC1 in Tangier disease and familial high-density lipoprotein deficiency [J]. Nature Genetics, 1999, 22(4): 336-345.
[14] Cenarro A, Artieda M, Castillo S, et al. A common variant in the ABCA1 gene is associated with a lower risk for premature coronary heart disease in familial hypercholesterolaemia [J]. Journal of Medical Genetics, 2003, 40(3): 163-168.
[15] Lahiri D. Apolipoprotein e as a target for developing new therapeutics for Alzheimer’s disease based on studies from protein, RNA, and regulatory region of the gene [J]. Journal of Molecular Neuroscience, 2004, 23(3): 225-234.
[16] Hao X, Cao D, Hu Y, et al. IFN-γ down-regulates ABCA1 expression by inhibiting LXRα in a JAK/STAT signaling pathway-dependent manner [J]. Atherosclerosis, 2009, 203(2): 417-428.
[17] Amalia MartínezMir, Paloma E, Allikmets R, et al. Retinitis pigmentosa caused by a homozygous mutation in the Stargardt disease gene ABCR [J]. Nature Genetics, 1998, 18(1): 11.
[18] Allikmets R. Simple and Complex ABCR: Genetic Predisposition to Retinal Disease [J]. American Journal of Human Genetics, 2000, 67(4): 793-799.
[19] Pauli-Magnus C, Lang T, Meier Y, et al. Sequence analysis of bile salt export pump (ABCB11) and multidrug resistance p-glycoprotein 3 (ABCB4, MDR3) in patients with intrahepatic cholestasis of pregnancy [J]. Pharmacogenetics, 2004, 14(2): 91-102.
[20] Gelissen I C, Harris M, Rye K A, et al. ABCA1 and ABCG1 Synergize to Mediate Cholesterol Export to ApoA-I [J]. Arteriosclerosis Thrombosis & Vascular Biology, 2006, 7(3): 541-541.
[21] Dean M, Annilo T. EVOLUTION OF THE ATP-BINDING CASSETTE (ABC) TRANSPORTER SUPERFAMILY IN VERTEBRATES*[J]. Annu Rev Genomics Hum Genet, 2005, 6(1): 123-142.
[22] Binkhathlan Z, Lavasanifar A. P-glycoprotein Inhibition as a Therapeutic Approach for Overcoming Multidrug Resistance in Cancer: Current Status and Future Perspectives [J]. Curr Cancer Drug Targets, 2013, 13(3):-.
[23] Borst P, Elferink R O. Mammalian ABC transporters in health and disease [J]. Ann Rev Biochem, 2003, 71(1): 537.
[24] Igarashi A, Konno H, Tanaka T, et al. Liposomal photofrin enhances therapeutic efficacy of photodynamic therapy against the human gastric cancer [J]. Toxicology Letters, 2003, 145(2): 133-141.
[25] Chang G, Roth C B. Structure of MsbA from E. coli: a homolog of the multidrug resistance ATP binding cassette (ABC) transporters [J]. Science, 2001, 293(5536): 1793-800.
[26] Nieth C, Priebsch A, Stege A, et al. Modulation of the classical multidrug resistance (MDR) phenotype by RNA interference (RNAi) [J]. Febs Letters, 2003, 545(2): 144-150.
[27] Kohno M, Pouyssegur J. Targeting the ERK signaling pathway in cancer therapy [J]. Annals of Medicine, 2006, 38(3): 200-211.
[28] Abbasi M, Lavasanifar A, Uludag H. Recent attempts at RNAi-mediated P-glycoprotein downregulation for reversal of multidrug resistance in cancer [J]. Medicinal Research Reviews, 2013, 33(1): 33-53.
[29] Wang L, Meng Q, Wang C, et al. Dioscin restores the activity of the anticancer agent adriamycin in multidrug-resistant human leukemia K562/adriamycin cells by down-regulating MDR1 via a mechanism involving NF-κB signaling inhibition [J]. Journal of Natural Products, 2013, 76(5): 909-914.

Transmembrane protein series four: ATP-binding cassette transporters

What is ATP-binding cassette transporters?

Transmembrane proteins span the lipid bilayer. According to the number of transmembrane times, it can be divided into one transmembrane protein or multiple transmembrane proteins. Many naturally occurring transmembrane proteins act as channels for specific substances to pass through the biofilm. Some transmembrane proteins can receive or transmit cellular signals. Transmembrane proteins also play an important role in molecular transport.

ATP-binding cassette (ABC) transporters is a transmembrane protein involved in molecular transport.

ATP-binding cassette transporters are the largest known transmembrane protein superfamily. ABC proteins bind and hydrolyze ATP and use energy to drive various molecules across the plasma membrane as well as the endoplasmic reticulum (ER), peroxisome and mitochondrial inner membrane. It is involved in the transport of specific molecules on the lipid membrane and the resistance in all organisms.

ATP-binding cassette (ABC) transporters and disease

ABC gene mutations are associated with the development of certain diseases. These diseases include adrenal white matter dystrophy, cystic fibrosis, retinal degeneration, hypercholesterolemia and cholestasis, neurological diseases, anemia and drug reactions.

Some common single nucleotide polymorphisms in ABCA1 also affect blood lipid levels, atherogenesis, and the severity of coronary heart disease.

ATP-binding cassette (ABC) transporters and drug resistance

MDR refers to the phenomenon that tumor cells have cross-resistance to multiple chemotherapy drugs. This condition is mainly caused by the efflux of cytotoxic drugs mediated by ATP-binding cassette transporter. In the chemotherapy of liver cancer, pancreatic cancer and other tumors, ATP-binding cassette transporter-mediated MDR seriously restricts the efficacy and prognosis of chemotherapy.

ATP-binding cassette (ABC) transporters inhibitors

Evading MDR can inhibit MDR1 synthesis and its activity at the mRNA level, or compete for MDR1 binding sites. In addition, the reversal methods of MDR include immunotherapy reversal, gene reversal, reversal of somatostatin and its analogues, and reversal of Chinese herbal medicine. More information about ABC, you can have a look at this article: A transport machine — ATP-binding cassette.

In many studies of ABC-related diseases, drug resistance, you may need ABC – related products. CUSABIO has a special transmembrane protein expression system. We could produce 36000+ transmembrane proteins and could also provide marker proteins at mg level for NMR and X-ray studies.

At present, we can produce 133 ABC-related products: 124 antibody products, 5 protein products, 4 ELISA products.

Hot Products

Recombinant Human ABCB8, partial
(CSB-CF868325HU)

Recombinant Human ABCC1, partial
(CSB-EP001056HU)

Recombinant Human ABCD1
(CSB-CF001068HU)

Recombinant Human ABCG1, partial
(CSB-YP001080HU)

 

ATP-binding cassette (ABC) transporters related proteins for your research

Target Product Name Code Expression System
ABCB1 Recombinant Human Multidrug resistance protein 1(ABCB1),partial CSB-RP117374h(A6) E.coli
ABCB8 Recombinant Human ATP-binding cassette sub-family B member 8, mitochondrial(ABCB8),partial CSB-CF868325HU in vitro E.coli expression system
ABCC1 Recombinant Human Multidrug resistance-associated protein 1 (ABCC1),partial CSB-EP001056HU E.coli
ABCD1 Recombinant Human ATP-binding cassette sub-family D member 1(ABCD1) CSB-CF001068HU in vitro E.coli expression system
ABCG1 Recombinant Human ATP-binding cassette sub-family G member 1(ABCG1),partial CSB-YP001080HU Yeast

ATP-binding cassette (ABC) transporters related antibodies for your research

Target Product Name Code Species Reactivity Tested Applications
ABCB10 ABCB10 Antibody CSB-PA001047GA01HU Human, Mouse, Rat ELISA, WB
ABCA9 ABCA9 Antibody CSB-PA812864LA01HU Human ELISA, IF
ABCB1 ABCB1 Antibody CSB-PA11737A0Rb Human ELISA, WB, IHC, IF
ABCA3 ABCA3 Antibody CSB-PA859942ESR1HU Human ELISA, IHC
ABCA5 ABCA5 Antibody CSB-PA845163LA01HU Human ELISA, IHC
ABCA2 ABCA2 Antibody CSB-PA887172LA01HU Human ELISA, IHC
ABCA12 ABCA12 Antibody CSB-PA774804LA01HU Human ELISA, IF
ABCA2 ABCA2 Antibody CSB-PA001038GA01HU Human, Mouse, Rat ELISA, WB
ABCB4 ABCB4 Antibody CSB-PA001050LA01HU Human ELISA, IHC, IF
ABCB5 ABCB5 Antibody CSB-PA643574LA01HU Human ELISA, IHC, IF
ABCB6 ABCB6 Antibody CSB-PA001052GA01HU Human, Mouse, Rat ELISA, WB
ABCB7 ABCB7 Antibody CSB-PA001053GA01HU Human, Mouse, Rat ELISA, WB
ABCB7 ABCB7 Antibody CSB-PA001053LA01HU Human ELISA, IHC
ABCB8 ABCB8 Antibody CSB-PA868325ESR1HU Human, Mouse ELISA, WB, IHC
ABCB8 ABCB8 Antibody CSB-PA868325ESR2HU Human ELISA, IHC
ABCB9 ABCB9 Antibody CSB-PA001055GA01HU Human, Mouse, Rat ELISA, WB
ABCB9 ABCB9 Antibody CSB-PA889064LA01HU Human, Mouse ELISA, WB, IF
ABCC11 ABCC11 Antibody CSB-PA846641ESR1HU Human ELISA, IHC
ABCC2 ABCC2 Antibody CSB-PA001061GA01HU Human ELISA, WB
ABCC2 ABCC2 Antibody CSB-PA852918LA01HU Human ELISA, IHC, IF
ABCC3 ABCC3 Antibody CSB-PA001062LA01HU Human ELISA, IF
ABCC4 ABCC4 Antibody CSB-PA001063KA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCC4 ABCC4 Antibody CSB-PA001063LA01HU Human ELISA, IF
ABCC5 ABCC5 Antibody CSB-PA001064LA01HU Human ELISA, IHC, IF
ABCC6 ABCC6 Antibody CSB-PA001065LA01HU Human ELISA, IF
ABCC8 ABCC8 Antibody CSB-PA22439A0Rb Human ELISA, IHC, IF
ABCC9 ABCC9 Antibody CSB-PA001067LA01HU Human ELISA, IHC, IF
ABCD1 ABCD1 Antibody CSB-PA001068GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCD1 ABCD1 Antibody CSB-PA001068LA01HU Human ELISA, IHC
ABCD2 ABCD2 Antibody CSB-PA866202LA01HU Human ELISA, IHC
ABCD4 ABCD4 Antibody CSB-PA001075LA01HU Human ELISA, IHC
ABCE1 ABCE1 Antibody CSB-PA001076GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCE1 ABCE1 Antibody CSB-PA001076ESR2HU Human ELISA, WB, IHC
ABCF1 ABCF1 Antibody CSB-PA001077GA01HU Human, Mouse, Rat ELISA, WB
ABCF2 ABCF2 Antibody CSB-PA001078GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCF2 ABCF2 Antibody CSB-PA871400ESR2HU Human ELISA, WB, IHC
ABCF3 ABCF3 Antibody CSB-PA889115LA01HU Human ELISA, IHC
ABCG1 ABCG1 Antibody CSB-PA001080GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCG1 ABCG1 Antibody CSB-PA001080LA01HU Human ELISA, IHC
ABCG2 ABCG2 Antibody CSB-PA001081GA01HU Human, Mouse, Rat ELISA, WB
ABCG2 ABCG2 Antibody CSB-PA891568LA01HU Human ELISA, IF
ABCG4 ABCG4 Antibody CSB-PA001082GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCG5 ABCG5 Antibody CSB-PA863956LA01HU Human ELISA, WB, IHC, IF
ABCG8 ABCG8 Antibody CSB-PA875651LA01HU Human, Mouse ELISA, WB, IHC, IF
TAP1 TAP1 Antibody CSB-PA023120GA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
TAP1 TAP1 Antibody CSB-PA023120ESR1HU Human ELISA, IHC
TAP2 TAP2 Antibody CSB-PA22539A0Rb Human ELISA, IHC

ATP-binding cassette (ABC) transporters related ELISA kits for your research

Target Product Name Code Sample Type Sensitivity
ABCB1 Human permeability glycoprotein,P-gp/ABCB1 ELISA Kit CSB-E11709h serum, plasma, ascitic fluid, tissue homogenates 0.78 ng/mL
ABCC5 Human Soluble Mesothelin Related Peptide(SMRP)ELISA Kit CSB-E13725h serum, plasma, tissue homogenates, cell lysates 0.078 pmol/mL
ABCG2 Human ATP-binding cassette transporter G2,ABCG2 ELISA Kit CSB-E11251h serum, plasma, cell lysates, cell culture supernates 0.039 ng/mL
CFTR Human Cystic fibrosis transmembrane conductance regulator(CFTR) ELISA kit CSB-EL005292HU serum, plasma, tissue homogenates, cell lysates 7 pg/mL

A Transport Machine -- ATP-binding Cassette

ATP-binding cassette (ABC) transporters are the largest known transmembrane protein superfamily, widely distributed in eukaryotes and prokaryotes. ABC proteins bind and hydrolyze ATP and use energy to drive various molecules across the plasma membrane as well as the endoplasmic reticulum (ER), peroxisome and mitochondrial inner membrane [1][2]. It is involved in the transport of specific molecules on the lipid membrane and the resistance in all organisms.

The Structure of ATP-binding cassette
Figure 1 The Structure of ATP-binding cassette, The picture is from wikipedia.

1. The Structure of ABC

Three basic organization forms of ABC transporters

Figure 2 Three basic organization forms of ABC transporters

ABC protein has a typical modular structure, consisting of four protein domains or subunits: two hydrophobic transmembrane domains (TMD) are considered to constitute transmembrane transport pathways or channels (usually composed of six transmembrane alpha helix); two hydrophilic nucleotide binding domains (NBDs) (ATP binding domains, known as nucleotide binding folding (NBF)) provide energy for active transport [2]. NBF contains three conserved domains: Walker A and B domains, and C motif [3]. The C domain is unique to the ABC transporter.

In addition to the complete transporters, there are also half transporters that contain one of each domain.

Figure 3 The structure and transport process of ABC

Figure 3 The structure and transport process of ABC

2. The Substrate

The ATP-binding cassette (ABC) transporter superfamily transfers a variety of substrates, including sugars, amino acids, metal ions, peptides and proteins, as well as a large number of hydrophobic compounds and metabolites across the extracellular and intracellular membranes.

3. ABC Superfamily

ABC transporters are one of the largest known protein superfamily: there are 49 ABC transporters in humans and 80 in gram-negative E. coli bacteria.

The ABC gene in the human genome is divided into 7 subfamilies (ABCA~ABCG) based on amino acid sequence similarity and phylogeny. The following table is a list of human ABC genes.

Table 1 List of human ABC genes and function

Subfamily Member Function
ABCA ABCA1 Cholesterol efflux onto HDL
ABCA2 Drug resistance
ABCA3 Phosphatidyl choline efflux
ABCA4 N-retinylidiene-PE efflux
ABCA5ABCA6ABCA7;ABCA8ABCA9ABCA10ABCA11ABCA12; ABCA13. /
ABCB ABCB1 Multidrug resistance
ABCB3 Peptide transport
ABCB4 PC transport
ABCB5 Iron transport
ABCB6 Fe/S cluster transport
ABCB11 Bile salt transport
ABCB2ABCB7ABCB8ABCB9; ABCB10. /
ABCC ABCC1 Drug resistance
ABCC2 Organic anion efflux
ABCC3 Drug resistance
ABCC4 Nucleoside transport
ABCC5 Nucleoside transport
CFTR (ABCC7) Chloride ion channel
ABCC8 Sulfonylurea receptor
ABCC9 Potassium channel regulation
ABCC6ABCC10ABCC11ABCC12. /
ABCD ABCD1 VLCFA transport regulation
ABCD2ABCD3ABCD4. /
ABCE ABCE1 Elongation factor complex
ABCF ABCF1ABCF2ABCF3. /
ABCG ABCG1 Cholesterol transport
ABCG2 Toxin efflux, drug resistance
ABCG4 Cholesterol transport
ABCG5 Sterol transport
ABCG8 Sterol transport

4. The Function of ABC

The ATP-binding cassette (ABC) superfamily gene plays an important role in transporting compounds between the intestinal tract, the blood-brain barrier, and the placenta. It also plays an important role in the body’s core function of resisting foreign bodies and detoxification [4]. Different subtypes have different functions and can act as drug efflux transporters (ABCB1, ABCC subfamily and ABCG2) or sterol transporters (ABCA1, ABCA7, ABCG1, ABCG5 and ABCG8).

4.1 T Eukaryotic

In eukaryotes, most ABC genes move compounds from the cytoplasm to the extracellular or extracellular compartment (endoplasmic reticulum, mitochondria, peroxisomes). Its importance in eukaryotic systems has been fully demonstrated, characterized by its association with genetic diseases and its role in multidrug resistance to cancer.

4.2 Prokaryote

In bacteria, the ABC gene is mainly involved in the import of essential compounds that cannot pass through cells through diffusion (eg, sugars, vitamins, metal ions, etc.). These genes play a role in nutrient absorption, toxin secretion and antibacterial drugs. The role of ABC transporters is mainly in the pathogenicity and toxicity of bacteria. In pathogenic bacteria, these functions are usually to evade or resist the host’s defense. Therefore, many cell surfaces or secreted factors can be useful targets for antibacterial therapy or vaccine development.

4.3 Plant

ATP-binding cassette (ABC) transporter in plant is an important membrane protein used to transport a variety of compounds, including heavy metals, antibiotics, phytohormones and secondary metabolites [5]. The number of ABC family members in the plant genome has more than doubled compared to animals and insects.

In plants, ATP-binding cassette transporters have important physiological functions such as cell detoxification, cuticle formation, stomatal regulation, seed germination, and resistance to pathogenic bacteria.

In rice, several ATP-binding cassette transporters of the ABCG family are essential for cuticle formation [6].

In tomato, the ATP-binding cassette transporter is involved in the transport of tomato fruit auxin. As a member of the subfamily ABCB, SlABCB4 plays an important role in the transport of auxin during tomato fruit development.

In Arabidopsis, some members of the ABC transporter ABCB subfamily also are involved in auxin transport [7].

ABC transporters also play an important role in the detoxification of pesticides.

The ATP-binding cassette (ABC) transporter [8] was identified as an important detoxifying enzyme in Plutella xylostella.

Epis et al[9] demonstrated the role of ABC transporters in insecticide defense.

5. ABC and Disease

The ATP-binding cassette (ABC) superfamily genes encode membrane proteins that transport different substrates on the cell membrane. The genetic variation of the ATP-binding cassette (ABC) transporter superfamily gene is the cause or contributing factor of various Mendelian diseases and complex genetic diseases in humans. The heterozygous variation in ABC gene mutations is related to the susceptibility of specific complex diseases.

Currently, there are 17 ABC genes related to Mendelian inheritance. These include adrenoleukodystrophy, cystic fibrosis, retinal degeneration, hypercholesterolemia and cholestasis, neurological diseases, anemia and drug reactions. Many of the ABC genes that cause disease lead to many different clinical phenotypes. For example, cystic fibrosis associated with specific CFTR genotypes includes pancreatic sufficiency and pancreatic insufficiency.

5.1 ABCA1

ABCA1 mediates the transport of intracellular free cholesterol and phospholipids through the cell membrane to poor apoA1 to form HDL [10]. It plays a key role in reverse cholesterol transport and cellular lipid efflux, is the initial rate-limiting step of reverted cholesterol transport (RCT) in macrophages [11], and is the most critical determinant of plasma high density lipoprotein (HDL) levels in hepatic cells.

Mutations in the ABCA1 gene may induce Tangier disease [12] and familial hypolipoproteinemia [13] and may also result in loss of cellular cholesterol homeostasis in prostate cancer. In the general population, some common single-nucleotide polymorphisms of ABCA1 also affect blood lipid levels, atherosclerosis generation and the severity of coronary heart disease [14].

In recent years, a large amount of evidence indicates that abnormal cholesterol metabolism may play an important role in the development of Alzheimer’s disease AD (ABCA2/ABCA7), and apoE gene is also closely related to the metabolism of cholesterol in the brain [15].

Regulatory Factors of ABC1

The expression of the ABCA1 gene is mainly regulated by the liver X receptor (LXR)/retinoid X receptor (RXR).In addition, interferon- γ (IFN- γ ) inhibits liver X receptor α (LXR α ) through the JAK/STAT signaling pathway, which can down-regulate ABCA1 expression and intracellular cholesterol outflow [16].

5.2 ABCA4

Mutations in the ABCA4 gene lead to retinitis pigmentosa, recessive pyramidal malnutrition, and Stargardt disease [17]. All of these diseases are characterized by retinal degeneration, the severity of which is roughly related to the predicted severity of ABCA4 mutation. Patients with heterozygous mutation of ABCA4 gene are more likely to suffer from late-onset macular degeneration – age-related macular degeneration (AMD) [18]. Women with heterozygous mutations of liver transporters that lead to cholestasis may have a higher risk of cholestasis during pregnancy [19].

5.3 ABCG

Members of the ABCG subfamily, ABCG5 and G8 are involved in the development of glutathione, a genetic disorder of lipid metabolism. ABCG1 mainly mediates the transport of intracellular free cholesterol to mature HDL. It works synergistically with ABCA1 to promote extracellular lipids out of the cell and complete reverse cholesterol transport in the body [20]. ABCG1 deficiency can also participate in foam cell formation, endothelial cell dysfunction and inflammatory response, and thus affects the formation and development of atherosclerosis.

Table 2 Diseases and phenotyes caused by ABC genes

Gene Mendelian disorder Complex disease Animal model
ABCA1 Tangier disease, FHDLD HDL levels Mouse, chicken
ABCA3 Surfactant deficiency / /
ABCA4 Stargardt/FFM, RP, CRD AMD Mouse
ABCA12 Lamellar ichthyosis / /
ABCB1 Ivermectin sensitivitya Digoxin uptake Mouse, dog
ABCB2 Immune deficiency / Mouse
ABCB3 Immune deficiency / Mouse
ABCB4 PFIC-3 ICP /
ABCB7 XLSA/A / /
ABCB11 PFIC-2 / /
ABCC2 Dubin-Johnson Syndrome / Rat, sheep, monkey
ABCC6 Pseudoxanthoma elasticum / Mouse
ABCC7 Cystic Fibrosis, CBAVD Pancreatitis, bronchiectasis Mouse
ABCC8 FPHHI Mouse
ABCC9 DCVT
ABCD1 ALD Mouse
ABCG5 Sitosterolemia Mouse
ABCG8 Sitosterolemia Mouse

This table derived from literature “Evolution of the ATP-binding cassette (ABC) transporter superfamily in vertebrates” [21]

6. ABC and Drug Resistance

Currently, chemotherapy is one of the approaches to cancer treatment, and multidrug resistance (MDR) is a major obstacle to successful chemotherapy [22]. MDR refers to the phenomenon that tumor cells are cross-resistant to a variety of structurally unrelated chemotherapeutic drugs. Clinically, drug resistance is caused by multiple factors. The efflux of cytotoxic drugs mediated by ATP-binding cassette transporters is the “classical MDR” pathway [23]. ABC transporters pump drugs out of cells and reduce the concentration of intracellular chemotherapy drugs. Overexpression of ABC transporters in tumor cells is the main mechanism of tumor MDR.

6.1 ATP Binding Cassette (ABC) Multidrug Transporter

ATP binding cassette transporters (ABC transporters) can transport chemotherapy drugs to the extracellular environment and reduce intracellular drug concentration. There are four main types ATP binding cassette multidrug transporter: P-glycoprotein (P-gp, MDR1, ABCB1), Multidrug resistance-associated protein (MDR-related protein /MRP, ABCC), lung resistance-related protein (LRP) and breast cancer resistance protein (BCRP, ABCG2) [24].

Breast cancer resistance protein (BCRP, ABCG2) belongs to the ABCG gene family. The gene is located on chromosome 4 and is a recently discovered ABC drug efflux transporter. In structure, BCRP is “half transporter” [25].

6.2 Liver Cancer MDR

Acquired MDR of hepatocellular carcinoma may be related to the expression of MRP1, MRP3 and MRP5 genes, and MRP2 is the main target of endogenous drug resistance, BCRP is a new drug efflux pump related to tumor MDR. Liver cancer MDR mediated by ATP-binding cassette transporter severely limits chemotherapy efficacy and prognosis.

6.3 Pancreatic Cancer

Pancreatic cancer is resistant to a variety of chemotherapeutic drugs, and resistance is associated with the ATP-binding cassette (ABC) transport vector superfamily [26].

7. How to overcome ABC drug efflux transporter-mediated drug resistance?

For MDR induced by ATP-binding cassette transporters, inhibition of ATP-binding cassette transporter-mediated drug efflux is the easiest and direct route.

7.1 ABC Inhibitors

Inhibitors of ABC transporters include competitive and non-competitive inhibitors. Currently, there are 3 generations of chemical reversals, most of which are competitive inhibitors of MDR1.

First-generation drugs: (including verapamil, tamoxifen, cyclosporine A, quinine).Calcium channel blocker verapamil inhibits MDR1 synthesis and its activity at mRNA level while competing for MDR1 binding sites, thereby reversing drug resistance [27].

Second-generation drugs: (including biricodar, elacridar and valspodar) failed to show overall efficacy improvements in multiple randomized clinical trials due to poor efficacy and increased toxicity.

Third-generation drugs: have high transporter affinity and low pharmacokinetics, including Tariquidar, Zosuquidar and Laniquidar.

Strategies for circumvention of MDR also include small interfering RNA (siRNA) [28] and microRNA (miRNA) to down-regulate the expression of ABC transporters.

Plant Anti-Tumor Drugs: Plant anti-tumor drugs provide new ideas for the development of MDR reversal agents due to their small side effects, natural sources and low cost.

It has been found that artemisinin, quercetin, magnolia officinalis phenol, emodin, zhejiang fritillaria alkaloid, osmanthus cnidii, ginsenoside, total saponin of panax notoginseng, root of mahonia mahogany, ganoderma lucidum and other traditional Chinese medicines or their effective components can reverse the drug resistance of tumor cells by down-regulating the expression of MDR1.

Psoralen, tetramethylpyrazine, tetrandrine, and paeonol are calcium antagonists, which can inhibit the function of pumping drugs out of cells by binding to P-gp, increase the concentration of intracellular chemotherapeutic drugs, and then reverse Resistance.

Studies have found that diosgenin can reverse the resistance of leukemia cells by inhibiting NF-κB down-regulation of MDR1 [29].

7.2 Other

In addition, immunotherapy reversion, gene reversion, somatostatin and its analogues reversion and Chinese herbal reversion were also used to reverse MDR.

The increased oxidative stress and the activated NF-κB transcription factor may be involved in the inhibition of ABCG1 expression by high glucose.

References

[1] Momburg F, Roelse J, Howard J C, et al. Selectivity of MHC-encoded peptide transporters from human, mouse and rat [J]. Nature (London), 1994, 367(6464): 648-651.
[2] Higgins C F. ABC transporters: from microorganisms to man [J]. Annu Rev Cell Biol, 1991, 8(1): 67-113.
[3] Hyde S C, Emsley P, Hartshorn M J, et al. Structural model of ATP-binding proteing associated with cystic fibrosis, multidrug resistance and bacterial transport [J]. Nature, 1990, 346(6282): 362-365.
[4] Fletcher J I, Haber M, Henderson M J, et al. ABC transporters in cancer: more than just drug efflux pumps [J]. Nature Reviews Cancer, 2010, 10(2): 147.
[5] Yazaki K, Shitan N, Sugiyama A, et al. Cell and molecular biology of ATP-binding cassette proteins in plants [J]. Int Rev Cell Mol Biol, 2009, 276: 263-299.
[6] Bessire M, Borel S, Fabre G, et al. A Member of the PLEIOTROPIC DRUG RESISTANCE Family of ATP Binding Cassette Transporters Is Required for the Formation of a Functional Cuticle in Arabidopsis [J]. Plant Cell, 2011, 23(5): 1958-1970.
[7] Cho M, Cho H T. The function of ABCB transporters in auxin transport [J]. Plant Signaling & Behavior, 2013, 8(2): e22990.
[8] He W, You M, Vasseur L, et al. Developmental and insecticide-resistant insights from the de novo assembled transcriptome of the diamondback moth, Plutella xylostella [J]. Genomics, 2012, 99(3): 169-177.
[9] Epis S D, Porretta V, Mastrantonio S, et al. Temporal dynamics of the ABC transporter response to insecticide treatment: insights from the malaria vector Anopheles stephensi [J]. Sci Rep, 2014, 4: 7435-7435.
[10] Oram J F, Heinecke J W. ATP-Binding Cassette Transporter A1: A Cell Cholesterol Exporter That Protects Against Cardiovascular Disease [J]. Physiological Reviews, 2005, 85(4): 1343.
[11] Jiang Z, Zhou R, Xu C, et al. Genetic variation of the ATP-binding cassette transporter A1 and susceptibility to coronary heart disease [J]. Molecular Genetics and Metabolism, 2011, 103(1): 0-88.
[12] Santamarina-Fojo S, Remaley A T, Neufeld E B, et al. Regulation and intracellular trafficking of the ABCA1 transporter [J]. Journal of Lipid Research, 2001, 42(9): 1339-1345.
[13] Brookswilson A, Marcil M, Clee S M, et al. Mutations in ABC1 in Tangier disease and familial high-density lipoprotein deficiency [J]. Nature Genetics, 1999, 22(4): 336-345.
[14] Cenarro A, Artieda M, Castillo S, et al. A common variant in the ABCA1 gene is associated with a lower risk for premature coronary heart disease in familial hypercholesterolaemia [J]. Journal of Medical Genetics, 2003, 40(3): 163-168.
[15] Lahiri D. Apolipoprotein e as a target for developing new therapeutics for Alzheimer’s disease based on studies from protein, RNA, and regulatory region of the gene [J]. Journal of Molecular Neuroscience, 2004, 23(3): 225-234.
[16] Hao X, Cao D, Hu Y, et al. IFN-γ down-regulates ABCA1 expression by inhibiting LXRα in a JAK/STAT signaling pathway-dependent manner [J]. Atherosclerosis, 2009, 203(2): 417-428.
[17] Amalia MartínezMir, Paloma E, Allikmets R, et al. Retinitis pigmentosa caused by a homozygous mutation in the Stargardt disease gene ABCR [J]. Nature Genetics, 1998, 18(1): 11.
[18] Allikmets R. Simple and Complex ABCR: Genetic Predisposition to Retinal Disease [J]. American Journal of Human Genetics, 2000, 67(4): 793-799.
[19] Pauli-Magnus C, Lang T, Meier Y, et al. Sequence analysis of bile salt export pump (ABCB11) and multidrug resistance p-glycoprotein 3 (ABCB4, MDR3) in patients with intrahepatic cholestasis of pregnancy [J]. Pharmacogenetics, 2004, 14(2): 91-102.
[20] Gelissen I C, Harris M, Rye K A, et al. ABCA1 and ABCG1 Synergize to Mediate Cholesterol Export to ApoA-I [J]. Arteriosclerosis Thrombosis & Vascular Biology, 2006, 7(3): 541-541.
[21] Dean M, Annilo T. EVOLUTION OF THE ATP-BINDING CASSETTE (ABC) TRANSPORTER SUPERFAMILY IN VERTEBRATES*[J]. Annu Rev Genomics Hum Genet, 2005, 6(1): 123-142.
[22] Binkhathlan Z, Lavasanifar A. P-glycoprotein Inhibition as a Therapeutic Approach for Overcoming Multidrug Resistance in Cancer: Current Status and Future Perspectives [J]. Curr Cancer Drug Targets, 2013, 13(3):-.
[23] Borst P, Elferink R O. Mammalian ABC transporters in health and disease [J]. Ann Rev Biochem, 2003, 71(1): 537.
[24] Igarashi A, Konno H, Tanaka T, et al. Liposomal photofrin enhances therapeutic efficacy of photodynamic therapy against the human gastric cancer [J]. Toxicology Letters, 2003, 145(2): 133-141.
[25] Chang G, Roth C B. Structure of MsbA from E. coli: a homolog of the multidrug resistance ATP binding cassette (ABC) transporters [J]. Science, 2001, 293(5536): 1793-800.
[26] Nieth C, Priebsch A, Stege A, et al. Modulation of the classical multidrug resistance (MDR) phenotype by RNA interference (RNAi) [J]. Febs Letters, 2003, 545(2): 144-150.
[27] Kohno M, Pouyssegur J. Targeting the ERK signaling pathway in cancer therapy [J]. Annals of Medicine, 2006, 38(3): 200-211.
[28] Abbasi M, Lavasanifar A, Uludag H. Recent attempts at RNAi-mediated P-glycoprotein downregulation for reversal of multidrug resistance in cancer [J]. Medicinal Research Reviews, 2013, 33(1): 33-53.
[29] Wang L, Meng Q, Wang C, et al. Dioscin restores the activity of the anticancer agent adriamycin in multidrug-resistant human leukemia K562/adriamycin cells by down-regulating MDR1 via a mechanism involving NF-κB signaling inhibition [J]. Journal of Natural Products, 2013, 76(5): 909-914.

Transmembrane protein series four: ATP-binding cassette transporters

What is ATP-binding cassette transporters?

Transmembrane proteins span the lipid bilayer. According to the number of transmembrane times, it can be divided into one transmembrane protein or multiple transmembrane proteins. Many naturally occurring transmembrane proteins act as channels for specific substances to pass through the biofilm. Some transmembrane proteins can receive or transmit cellular signals. Transmembrane proteins also play an important role in molecular transport.

ATP-binding cassette (ABC) transporters is a transmembrane protein involved in molecular transport.

ATP-binding cassette transporters are the largest known transmembrane protein superfamily. ABC proteins bind and hydrolyze ATP and use energy to drive various molecules across the plasma membrane as well as the endoplasmic reticulum (ER), peroxisome and mitochondrial inner membrane. It is involved in the transport of specific molecules on the lipid membrane and the resistance in all organisms.

ATP-binding cassette (ABC) transporters and disease

ABC gene mutations are associated with the development of certain diseases. These diseases include adrenal white matter dystrophy, cystic fibrosis, retinal degeneration, hypercholesterolemia and cholestasis, neurological diseases, anemia and drug reactions.

Some common single nucleotide polymorphisms in ABCA1 also affect blood lipid levels, atherogenesis, and the severity of coronary heart disease.

ATP-binding cassette (ABC) transporters and drug resistance

MDR refers to the phenomenon that tumor cells have cross-resistance to multiple chemotherapy drugs. This condition is mainly caused by the efflux of cytotoxic drugs mediated by ATP-binding cassette transporter. In the chemotherapy of liver cancer, pancreatic cancer and other tumors, ATP-binding cassette transporter-mediated MDR seriously restricts the efficacy and prognosis of chemotherapy.

ATP-binding cassette (ABC) transporters inhibitors

Evading MDR can inhibit MDR1 synthesis and its activity at the mRNA level, or compete for MDR1 binding sites. In addition, the reversal methods of MDR include immunotherapy reversal, gene reversal, reversal of somatostatin and its analogues, and reversal of Chinese herbal medicine. More information about ABC, you can have a look at this article: A transport machine — ATP-binding cassette.

In many studies of ABC-related diseases, drug resistance, you may need ABC – related products. CUSABIO has a special transmembrane protein expression system. We could produce 36000+ transmembrane proteins and could also provide marker proteins at mg level for NMR and X-ray studies.

At present, we can produce 133 ABC-related products: 124 antibody products, 5 protein products, 4 ELISA products.

Hot Products

Recombinant Human ABCB8, partial
(CSB-CF868325HU)

Recombinant Human ABCC1, partial
(CSB-EP001056HU)

Recombinant Human ABCD1
(CSB-CF001068HU)

Recombinant Human ABCG1, partial
(CSB-YP001080HU)

ATP-binding cassette (ABC) transporters related proteins for your research

Target Product Name Code Expression System
ABCB1 Recombinant Human Multidrug resistance protein 1(ABCB1),partial CSB-RP117374h(A6) E.coli
ABCB8 Recombinant Human ATP-binding cassette sub-family B member 8, mitochondrial(ABCB8),partial CSB-CF868325HU in vitro E.coli expression system
ABCC1 Recombinant Human Multidrug resistance-associated protein 1 (ABCC1),partial CSB-EP001056HU E.coli
ABCD1 Recombinant Human ATP-binding cassette sub-family D member 1(ABCD1) CSB-CF001068HU in vitro E.coli expression system
ABCG1 Recombinant Human ATP-binding cassette sub-family G member 1(ABCG1),partial

ATP-binding cassette (ABC) transporters related antibodies for your research

Target Product Name Code Species Reactivity Tested Applications
ABCB10 ABCB10 Antibody CSB-PA001047GA01HU Human, Mouse, Rat ELISA, WB
ABCA9 ABCA9 Antibody CSB-PA812864LA01HU Human ELISA, IF
ABCB1 ABCB1 Antibody CSB-PA11737A0Rb Human ELISA, WB, IHC, IF
ABCA3 ABCA3 Antibody CSB-PA859942ESR1HU Human ELISA, IHC
ABCA5 ABCA5 Antibody CSB-PA845163LA01HU Human ELISA, IHC
ABCA2 ABCA2 Antibody CSB-PA887172LA01HU Human ELISA, IHC
ABCA12 ABCA12 Antibody CSB-PA774804LA01HU Human ELISA, IF
ABCA2 ABCA2 Antibody CSB-PA001038GA01HU Human, Mouse, Rat ELISA, WB
ABCB4 ABCB4 Antibody CSB-PA001050LA01HU Human ELISA, IHC, IF
ABCB5 ABCB5 Antibody CSB-PA643574LA01HU Human ELISA, IHC, IF
ABCB6 ABCB6 Antibody CSB-PA001052GA01HU Human, Mouse, Rat ELISA, WB
ABCB7 ABCB7 Antibody CSB-PA001053GA01HU Human, Mouse, Rat ELISA, WB
ABCB7 ABCB7 Antibody CSB-PA001053LA01HU Human ELISA, IHC
ABCB8 ABCB8 Antibody CSB-PA868325ESR1HU Human, Mouse ELISA, WB, IHC
ABCB8 ABCB8 Antibody CSB-PA868325ESR2HU Human ELISA, IHC
ABCB9 ABCB9 Antibody CSB-PA001055GA01HU Human, Mouse, Rat ELISA, WB
ABCB9 ABCB9 Antibody CSB-PA889064LA01HU Human, Mouse ELISA, WB, IF
ABCC11 ABCC11 Antibody CSB-PA846641ESR1HU Human ELISA, IHC
ABCC2 ABCC2 Antibody CSB-PA001061GA01HU Human ELISA, WB
ABCC2 ABCC2 Antibody CSB-PA852918LA01HU Human ELISA, IHC, IF
ABCC3 ABCC3 Antibody CSB-PA001062LA01HU Human ELISA, IF
ABCC4 ABCC4 Antibody CSB-PA001063KA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCC4 ABCC4 Antibody CSB-PA001063LA01HU Human ELISA, IF
ABCC5 ABCC5 Antibody CSB-PA001064LA01HU Human ELISA, IHC, IF
ABCC6 ABCC6 Antibody CSB-PA001065LA01HU Human ELISA, IF
ABCC8 ABCC8 Antibody CSB-PA22439A0Rb Human ELISA, IHC, IF
ABCC9 ABCC9 Antibody CSB-PA001067LA01HU Human ELISA, IHC, IF
ABCD1 ABCD1 Antibody CSB-PA001068GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCD1 ABCD1 Antibody CSB-PA001068LA01HU Human ELISA, IHC
ABCD2 ABCD2 Antibody CSB-PA866202LA01HU Human ELISA, IHC
ABCD4 ABCD4 Antibody CSB-PA001075LA01HU Human ELISA, IHC
ABCE1 ABCE1 Antibody CSB-PA001076GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCE1 ABCE1 Antibody CSB-PA001076ESR2HU Human ELISA, WB, IHC
ABCF1 ABCF1 Antibody CSB-PA001077GA01HU Human, Mouse, Rat ELISA, WB
ABCF2 ABCF2 Antibody CSB-PA001078GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCF2 ABCF2 Antibody CSB-PA871400ESR2HU Human ELISA, WB, IHC
ABCF3 ABCF3 Antibody CSB-PA889115LA01HU Human ELISA, IHC
ABCG1 ABCG1 Antibody CSB-PA001080GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCG1 ABCG1 Antibody CSB-PA001080LA01HU Human ELISA, IHC
ABCG2 ABCG2 Antibody CSB-PA001081GA01HU Human, Mouse, Rat ELISA, WB
ABCG2 ABCG2 Antibody CSB-PA891568LA01HU Human ELISA, IF
ABCG4 ABCG4 Antibody CSB-PA001082GA01HU Human, Mouse, Rat ELISA, WB, IHC
ABCG5 ABCG5 Antibody CSB-PA863956LA01HU Human ELISA, WB, IHC, IF
ABCG8 ABCG8 Antibody CSB-PA875651LA01HU Human, Mouse ELISA, WB, IHC, IF
TAP1 TAP1 Antibody CSB-PA023120GA01HU Human, Mouse, Rat ELISA, WB, IHC, IF
TAP1 TAP1 Antibody CSB-PA023120ESR1HU Human ELISA, IHC
TAP2 TAP2 Antibody CSB-PA22539A0Rb Human ELISA, IHC

ATP-binding cassette (ABC) transporters related ELISA kits for your research

Target Product Name Code Sample Type Sensitivity
ABCB1 Human permeability glycoprotein,P-gp/ABCB1 ELISA Kit CSB-E11709h serum, plasma, ascitic fluid, tissue homogenates 0.78 ng/mL
ABCC5 Human Soluble Mesothelin Related Peptide(SMRP)ELISA Kit CSB-E13725h serum, plasma, tissue homogenates, cell lysates 0.078 pmol/mL
ABCG2 Human ATP-binding cassette transporter G2,ABCG2 ELISA Kit CSB-E11251h serum, plasma, cell lysates, cell culture supernates 0.039 ng/mL
CFTR Human Cystic fibrosis transmembrane conductance regulator(CFTR) ELISA kit CSB-EL005292HU serum, plasma, tissue homogenates, cell lysates 7 pg/mL

Human Leukocyte Antigen: Distinguish between Friend and Foe

MHC proteins are found in all higher vertebrates. The glycoprotein encoded by human MHC is called human leukocyte antigen (HLA), which specifically presents short peptides to T cells and haves a key role in the immune defense of the body [1]. HLA is a protein or antigen found on the surface of cells in the body. The HLA gene is a family of genes that encode HLA complexes. The HLA system and MHC help the body’s immune system distinguish between autogenous and foreign or non-autogenous substances.

1. The Classification of HLA

The HLA antigen was first discovered by JeanDausset in 1958. MHC map to the short arm of chromosome 6, spanning about 3600 kilobase DNA [2], contains more than 200 genes [3]. It is considered to be the most polymorphic genetic system in humans, providing the immune system with the ability to resist multiple antigens. These genes are all located on chromosome 6. According to the differences in antigen structure, function and tissue distribution, HLA/MHC genes are generally divided into three classes: class I, class II and class III.

HLA is mainly divided into three groups: class I, class II and class III

Figure 1 The Classification of HLA

1.1 HLA/MHC Class I

  • Composition: There are 3 major MHC class I genes and 3 minor MHC class I genes in HLA.
    Major MHC class I: HLA-A, HLA-B, HLA-C.
    Secondary genes: HLA-E, HLA-F and HLA-G.
  • Structure: HLA class I proteins consist of a transmembrane heavy chain and three extracellular domains (a1, a2, a3) and b2-microglobulin light chains.
  • Function: HLA class I proteins present expired or defective intracellular proteins and peptides of invasive viruses to T cell receptors (TCR) on CD8+ T cells, resulting in an immune response.
  • Tissue distribution: Almost all nucleated cell surface expression.

1.2 HLA/MHC Class II

Table 1 The composition of HLA/MHC Class II

Composition Structure
HLA-DP α – chain encoded by HLA-DPA1 locus
β – chain is encoded by HLA-DPB1 locus
HLA-DQ α – chain is encoded by HLA-DQA1 locus
β – chain is encoded by HLA-DQB1 locus
HLA-DR α – chain is encoded by HLA-DRA site
4β-chains are encoded by HLA-DRB1DRB3DRB4, and DRB5 sites.
HLA-DM α – chain is encoded by HLA-DMA.
β – chain is encoded by HLA-DMB.
HLA-DO α – chain is encoded by HLA-DOA.
β – chain is encoded by HLA-DOB.
  • Structure: Each HLA class II protein consists of alpha – and beta – chains. Each chain has two extracellular domains.
  • Function: Class II proteins and binding peptides interact with CD4+ T cells (usually helper cells) and their receptors.
  • Tissue distribution: HLA class II protein expression was limited to immune-active cells, B lymphocytes, antigen presenting cells (APC) (monocytes, macrophages and dendritic cells) and activated T lymphocytes. In addition, the expression of other cells is also up-regulated in inflammatory environments

The structure of HLA class I and HLA class II

Figure 2 The structure of HLA class I and HLA class II

2. Antigen Processing Pathway

Cells contain two different antigen-processing pathways that provide peptides to T cells.

  • HLA class I molecules load peptides produced by the proteasome-degrading cytoplasmic protein on the endoplasmic reticulum. These HLA I/peptide complexes are surface expressed and presented to CD8+ T cells.

HLA class I antigen-processing and presentation pathway

Figure 3 HLA class I antigen-processing and presentation pathway
  • The HLA class II molecule exits the endoplasmic reticulum together with the invariant chain (II) which bound to its peptide binding groove. During endocytosis, the invariant chain is degraded by proteases, and the class II related invariant chain peptide (CLIP) remains in the binding groove. HLA-DM mediates the exchange of CLIP and antigenic peptides. HLA-class II peptide complexes are then transported to the cell surface and presented to CD4+ T cells.

HLA class II antigen-processing and presentation pathway

Figure 4 HLA class II antigen-processing and presentation pathway

Therefore, HLA class I usually detects the intracellular environment, while HLA class II detects antigens present in the extracellular environment [5].

3. Population Distribution

The distribution of HLA antigens in different ethnic groups has a unique pattern. Take HLA-B27 as an example, which is a gene associated with the prevalence of AS. The areas with higher B27 positive rates are mainly American Columbia, the Indian population along the coast of Canada and Canadian Haida. The positive rate of B27 in other regions is as follows: It was 6%-8% in European and American Caucasians; less than 1% in Japan and Africa; in Chinese population is 4% ~ 8%.

4. Polymorphism of HLA

MHC gene is the most polymorphic gene in human genome (total HLA allele 13023; HLA I allele 9749 and HLA II allele 3274) [6]. The specific information is shown in table 2 and table 3.

There are two main hypotheses about the polymorphism of HLA:

  • The first view is that polymorphism is maintained by heterozygote dominance. Since HLA gene expression is codominant, HLA heterozygous expression of functional HLA protein types is absolutely more than homozygous expression.
  • The second hypothesis is that HLA polymorphism is the result of frequency-dependent selection during evolution between pathogens and vertebrate immune systems.

The polymorphism of MHC, on the one hand, is an obstacle to finding a match, and on the other hand, it enable the immune system to recognize any invading pathogens.

Table 2 The number of alleles of HLA Class I

HLA Class I
Gene A B C E F G
Alleles 4,638 5,590 4,374 27 31 61
Proteins 3,172 3,923 2,920 8 6 19
Nulls 224 169 171 1 0 3

Table 3 The number of alleles of HLA Class II

HLA Class I
Gene Alleles Proteins Nulls
DRA 7 2 0
DRB 2,639 1,908 84
DQA1 100 36 4
DQB1 1316 878 35
DPA1 73 32 0
DPA2 5 2 0
DPB1 1097 728 34
DPB2 6 3 0
DMA 7 4 0
DMB 13 7 0
DOA 12 3 1
DOB 13 5 0

Data from IMGT – HLA database: https://www.ebi.ac.uk/ipd/imgt/hla/stats.html

5. HLA Test

Various HLA tests mainly include HLA typing, HLA antibody screening and identification.

5.1 HLA Typing

HLA genes play an important role in transplant rejection as well as infective and autoimmune diseases [7]. For these reasons, accurate HLA typing is important both in clinical and research. HLA typing has been performed using a variety of techniques, such as serology, cellular and molecular analysis [8].With the birth of DNA sequencing and polymerase chain reaction (PCR), specific oligonucleotide probe hybridization, sequence specific primer amplification, sequence typing (SBT) and other molecular typing techniques have been developed.

HLA antibody test: an HLA antibody test is performed on the recipient of a transplant to determine whether antibodies against the donor tissue or organ exist to determine whether they can be successfully transplanted to another individual.

5.2 The Application of HLA

The clinical application of HLA is mainly the matching of donor and recipient in organ transplantation [9]. Human leukocyte antigen (HLA) typing can be used to match patients and donors of bone marrow or cord blood transplantation.

Transplant

  • Bone marrow transplantation
    In bone marrow transplantation, the donor and the recipient must have the same or matching HLA gene, so that the transplantation can be successful and the donor tissue cannot be attacked or rejected by the recipient’s immune system.
  • Kidney transplant
    In addition to the classical HLA-A, HLA-B and HLA-DR antigens, the role of HLA-C and HLA-DQ antigens in graft survival or sensitization is now well documented [10] [11].
  • Hematopoietic stem cell transplantation
    HLA molecular allelic typing is often performed to provide HLA class I and class II allele matching.
  • HLA and clinical blood transfusion
    HLA is closely related to blood transfusion, mainly due to the immune response of HLA. Due to the high immunogenicity of HLA antigen, HLA antibody can be produced by immunizing the body through pregnancy, blood transfusion, transplantation and other ways. Heterologous HLA immunization causes various problems in transfusion therapy, such as platelet transfusion refractoriness (RTR), febrile non-hemolytic transfusion (FNHTR), transfusion-related acute lung injury (TRA-LI), Transfusion-associated graft-versus-host disease (TA-GVHD). In order to avoid these situations, HLA detection very necessary HLA detection is required for this situation.
    HLA genotyping plays an important role in determining the immune compatibility between donor and recipient, and is also part of the diagnosis of some autoimmune diseases.

Disease Diagnosis

HLA-B27 is a human leukocyte antigen and belongs to the MHC class I gene. In clinical work, B27 positive can help us diagnose ankylosing spondylitis (AS). However, the diagnosis of AS needs to be judged by combining clinical symptoms, physical examination, imaging examination and laboratory examination. HLA-B27 alone cannot diagnose and exclude AS. Nevertheless, B27 still has an important auxiliary value for the diagnosis of AS.

Currently, there are four commonly used methods for B27 detection: flow cytometry, PCR-SSP, ELISA and microcytotoxic assay. Flow cytometry is currently the most ideal method to detect B27, and it is also recommended internationally to detect B27.

6. HLA-Associated Diseases

Many HLA genes are linked to human diseases, including some autoimmune diseases and cancer. But the underlying mechanism has not been fully explained.

Human diseases associated with the HLA gene:

  • HLA-B* 2702, HLA-B* 2705 are associated with ankylosing spondylitis (AS).
  • HLA-DRB1 alleles (DRB1 * 04:01, DRB1 * 04:04 DRB1 * 04:05, DRB1 * 01:01) are associated with rheumatoid arthritis (RA) [1].
  • Celiac disease are associated with HLA-DQB1*02.
  • HLA-A1, B8, and DR17 haploids are often associated with autoimmune diseases;
  • Type I diabetes is associated with HLA-DR3 [1].
  • Psoriasis are associated with HLA-C.
  • Multiple sclerosis are associated with HLA-DR2.
  • Rheumatoid arthritis are associated with HLA-DR4.

7. HLA and HIV/AIDS

Many studies have shown that HLA alleles are associated with various aspects of HIV disease. Existing evidence indicates that HLA is the most important site for human HIV differential control [12]. Kaslow et al. evaluated the role of HLA I alleles in HIV infection and found that HLA B27 and B57 were closely related to the slow progress of AIDS [13].

HLA homozygous individuals are more likely to become infected with HIV than HLA heterozygous individuals. The reason is that individuals heterozygous at HLA sites will be able to provide T cells with a wider pool of antigenic peptides than homozygous individuals, thus exerting greater pressure on pathogens.

8. HLA and Pregnancy

Problems that can occur in pregnant women: recurrent miscarriage, pre-eclampsia, or hemolytic disease in the newborn. These conditions are considered to be an immune rejection.

Some mechanisms have been proposed to explain the immune privilege state of the diaphragm. Different assumptions can be grouped into five main points:

  • The mechanical barrier effect of the trophoblast.
  • Inhibition of the maternal immune system during pregnancy.
  • Deletion of HLA class I molecules in trophoblasts.
  • Cytokine changes.
  • Local immunosuppression mediated by Fas/FasL system.

There is such an interesting phenomenon in fetal tissues: low HLA – C expression, lack of highly polymorphic HLA – A molecule.

However, the tissues of fetal origin in the placenta expressed low polymorphism of HLA class I B molecules, HLA – E, HLA – F and HLA – G, which made people more and more interested in the immunological effects of these three proteins during pregnancy [14].

9. HLA and Drug Sensitivity

Allergic drug reactions usually occur in low molecular weight drugs. There are several explanations for the mechanism of drug allergy associated with HLA.

  • Drugs and their metabolites are too small to produce their own immunogenicity, but it can be used as a hapten to modify certain autologous proteins in the host, leading to immune recognition of the hapten produced: self – peptide complex as a new antigen [15]. An example of drug haptens is penicillin, which has chemical activity and stable covalent binding with proteins or polypeptides to produce immunogenic self-proteins [16].
  • Drugs can bridge TCR and HLA molecules without directly binding to peptide antigens. Drug complexes can directly activate the immune response of T cells without the need for specific peptide ligands [17]. For example, sulfamethoxazole can bind non-covalently to antigen-presenting structures (such as TCR or HLA) and directly cause irritation of immune responses.

10. HLA and Social Behavior

There is a certain correlation between the human leukocyte antigen and mate selection [18]. Individuals prefer to have a partner that is relatively different from their own HLA genotype. Choosing a different HLA partner can increase the heterozygosity of the offspring on HLA, potentially increasing the resistance of the offspring to the pathogen.

11. HLA and Longevity

Human life span may be directly related to the optimal function of the immune system. Studies conducted in mice have shown that HLA, which is known to control multiple immune functions, is associated with the lifespan of strains. But a conflicting results have been found in a number of cross-sectional studies comparing the frequency of HLA antigens in young and old people.

References

[1] Holoshitz J. The quest for better understanding of HLA-disease association: scenes from a road less travelled by [J]. Discovery Medicine, 2013, 16(87): 93-101.
[2] Beck S, Trowsdale J. THE HUMAN MAJOR HISTOCOMPATIBILITY COMPLEX: Lessons from the DNA Sequence [J]. Annu Rev Genomics Hum Genet, 2000, 1(1): 117-137.
[3] Jr C A J, Travers P, Walport M, et al. The major histocompatibility complex and its functions – Immunobiology – NCBI Bookshelf [J]. Garland Science, 2001.
[4] Shankarkumar U, Ghosh K, Mohanty D. The human leucocyte antigen (HLA) system [J]. Journal of the Association of Physicians of India, 2002, 50(50): 916.
[5] Wagner C S, Grotzke J E, Cresswell P. Intracellular events regulating cross-presentation [J]. Frontiers in Immunology, 2012, 3: 138.
[6] Robinson J, Halliwell J A, Hayhurst J D, et al. The IPD and IMGT/HLA database: allele variant databases [J]. Nucleic Acids Research, 2015, 43(D1): D423-D431.
[7] Matzaraki V, Kumar V, Wijmenga C, et al. The MHC locus and genetic susceptibility to autoimmune and infectious diseases [J]. Genome Biology, 2017, 18(1): 76.
[8] Lind C, Ferriola D, Mackiewicz K, et al. Next-generation sequencing: the solution for high-resolution, unambiguous human leukocyte antigen typing [J]. Human Immunology, 2010, 71(10): 0-1042.
[9] Bhadran Bose D W J, Campbell S B. Transplantation Antigens and Histocompatibility Matching [J]. Intech, 2013.
[10] Tran T H , Döhler, Bernd, Heinold A , et al. Deleterious Impact of Mismatching for Human Leukocyte Antigen-C in Presensitized Recipients of Kidney Transplants [J]. Transplantation, 2011, 92(4): 419.
[11] Tambur A R, Leventhal J R, Friedewald J J, et al. The Complexity of Human Leukocyte Antigen (HLA)-DQ Antibodies and Its Effect on Virtual Crossmatching [J]. Transplantation, 2016, 90(10): 1117-1124.
[12] Martin M P, Carrington M. Immunogenetics of HIV disease [J]. Immunological Reviews, 2013, 254(1): 245-264.
[13] Kaslow R A, Carrington M, Apple R, et al. Influence of combinations of human major histocompatibility complex genes on the course of HIV-1 infection [J]. Nature Medicine, 1996, 2(4): 405.
[14] Dahl M, Hviid T V F. Human leucocyte antigen class Ib molecules in pregnancy success and early pregnancy loss [J]. Human Reproduction Update, 2012, 18(1): 92.
[15] Yawalkar N, Pichler W J. Pathogenesis of Drug-Induced Exanthema [J]. International Archives of Allergy and Immunology, 2001, 124(1-3): 336-338.
[16] Warrington R. Drug allergy: causes and desensitization [J]. Human Vaccines & Immunotherapeutics, 2012, 8(10): 1513.
[17] Pichler W J, Beeler A, Keller M, et al. Pharmacological interaction of drugs with immune receptors: the p-i concept [J]. Allergology International, 2006, 55(1): 17-25.
[18] Havlicek J, Roberts S C. MHC-correlated mate choice in humans: A review [J]. Psychoneuroendocrinology,2009, 34(4): 497-512.

Transmembrane protein series five: Human leukocyte antigen (HLA)

What is Human leukocyte antigen?

Transmembrane proteins cross the phospholipid bilayer of the membrane, which determines the strong hydrophobicity of the transmembrane region. The transmembrane region of a transmembrane protein is completely or partially inserted into the membrane. The diversity of transmembrane proteins determines the diversity of their functional characteristics. It has the ability of material transport and signal transduction. In addition, transmembrane proteins also play an important role in the immune response.

Human leukocyte antigen is a kind of transmembrane protein, which is a protein or antigen present on the cell surface of the body. It plays a key role in the body’s immune defense. The HLA system and MHC help the body’s immune system distinguish between autologous substances and foreign or non-autologous substances.

Distribution of Human leukocyte antigen (HLA) in the population

HLA antigen has different distribution in different nationalities. Take HLA-B*27 as an example. In the US Columbia, Canadian coastal Indians and Canadian haida people, its positive rate is as high as 50%; among caucasians in Europe and the United States, the B27 positive rate was 6 to 8 percent; while the positive rate of B27 in Japanese and African blacks was less than 1%.

Human leukocyte antigen (HLA) application

The clinical application of HLA is mainly the matching of donor and recipient in organ transplantation and blood transfusion.

In organ transplantation, the donor and the recipient must have the same or matching HLA gene, so that the donor tissue is not attacked or rejected by the recipient’s immune system.

In clinical transfusion, allogeneic HLA immunity causes various problems in transfusion therapy, such as platelet transfusion refractoriness, fever-induced non-hemolytic transfusion reaction, transfusion-related acute lung injury, transfusion-related graft-versus host disease, etc. Therefore, HLA detection is necessary.

Human leukocyte antigen (HLA) and disease

The HLA gene is associated with autoimmune diseases and cancer.

Many studies have shown that HLA is associated with HIV disease. In addition, HLA is strongly associated with recurrent miscarriage during pregnancy, pre-eclampsia, or hemolytic disease in the newborn. HLA is also one of the causes of drug sensitivity.

In your experiment, you may need HLA products to assist your research. CUSABIO can help you. We have established a special transmembrane protein expression system. HLA related products are listed as follows:

Hot Products

Recombinant Human HLA class II histocompatibility antigen, DQ alpha 1 chain (HLA-DQA1),partial
(CSB-RP148394h)

Recombinant Human HLA class I histocompatibility antigen, alpha chain E (HLA-E), partial
(CSB-EP320269HU)

Recombinant Human HLA class I histocompatibility antigen, alpha chain G (HLA-G)
(CSB-EP010509HUa2)

Recombinant Human HLA class I histocompatibility antigen, alpha chain G (HLA-G)
(CSB-EP010509HU)

Human leukocyte antigen (HLA) related proteins for your research

Target Product Name Code Expression System
HLA-E Recombinant Human HLA class I histocompatibility antigen, alpha chain E(HLA-E),partial CSB-BP320269HU Baculovirus
HLA-E Recombinant Human HLA class I histocompatibility antigen, alpha chain E(HLA-E) ,partial CSB-EP320269HU E.coli
HLA-DRA Recombinant Human HLA class II histocompatibility antigen, DR alpha chain(HLA-DRA) CSB-YP360793HU Yeast
HLA-DRA Recombinant Human HLA class II histocompatibility antigen, DR alpha chain(HLA-DRA),partial CSB-RP179394h E.coli
HLA-DRA Recombinant Human HLA class II histocompatibility antigen, DR alpha chain(HLA-DRA) CSB-EP360793HU E.coli
HLA-DQB1 Recombinant Human HLA class II histocompatibility antigen,DQ beta 1 chain(HLA-DQB1),partial CSB-EP355782HU E.coli
HLA-DQA1 Recombinant Human HLA class II histocompatibility antigen, DQ alpha 1 chain(HLA-DQA1),partial CSB-RP148394h E.coli
HLA-A Recombinant Human HLA class I histocompatibility antigen,A-1 alpha chain(HLA-A),partial CSB-EP328989HU E.coli

Human leukocyte antigen (HLA) related antibodies for your research

Target Product Name Code Species Reactivity Tested Applications
HLA-E HLA-E Antibody, HRP conjugated CSB-PA320269LB01HU Human ELISA
HLA-E HLA-E Antibody CSB-PA320269LA01HU Human ELISA
HLA-DRB3 HLA-DRB3 Antibody, FITC conjugated CSB-PA302920LC01HU Human ELISA
HLA-DRB3 HLA-DRB3 Antibody, Biotin conjugated CSB-PA302920LD01HU Human ELISA
HLA-DRB3 HLA-DRB3 Antibody, HRP conjugated CSB-PA302920LB01HU Human ELISA
HLA-DRB3 HLA-DRB3 Antibody CSB-PA302920LA01HU Human, Mouse ELISA, WB, IF
CD38 CD38 Antibody CSB-PA004929ESR1HU Human ELISA, IHC
CD37 CD37 Antibody, Biotin conjugated CSB-PA004928LD01HU Human ELISA
CD37 CD37 Antibody, FITC conjugated CSB-PA004928LC01HU Human ELISA
CD37 CD37 Antibody, HRP conjugated CSB-PA004928LB01HU Human ELISA
CD37 CD37 Antibody CSB-PA004928LA01HU Human, Mouse ELISA, WB, IHC, IF
HLA-DRB4 HLA-DRB4 Antibody, Biotin conjugated CSB-PA03909D0Rb Human ELISA
HLA-DRB4 HLA-DRB4 Antibody, FITC conjugated CSB-PA03909C0Rb Human ELISA
HLA-DRB4 HLA-DRB4 Antibody, HRP conjugated CSB-PA03909B0Rb Human ELISA
HLA-DRB4 HLA-DRB4 Antibody CSB-PA03909A0Rb Human ELISA, WB, IHC
HLA-DRA HLA-DRA Antibody, Biotin conjugated CSB-PA17939D0Rb Human ELISA
HLA-DRA HLA-DRA Antibody, FITC conjugated CSB-PA17939C0Rb Human ELISA
HLA-DRA HLA-DRA Antibody, HRP conjugated CSB-PA17939B0Rb Human ELISA
HLA-DRA HLA-DRA Antibody CSB-PA17939A0Rb Human ELISA, IHC
HLA-DQB1 HLA-DQB1 Antibody, Biotin conjugated CSB-PA14849D0Rb Human ELISA
HLA-DQB1 HLA-DQB1 Antibody, FITC conjugated CSB-PA14849C0Rb Human ELISA
HLA-DQB1 HLA-DQB1 Antibody, HRP conjugated CSB-PA14849B0Rb Human ELISA
HLA-DQB1 HLA-DQB1 Antibody CSB-PA14849A0Rb Human, Mouse ELISA, WB, IHC
HLA-DQA1 HLA-DQA1 Antibody, Biotin conjugated CSB-PA14839D0Rb Human ELISA, IHC
HLA-DQA1 HLA-DQA1 Antibody, FITC conjugated CSB-PA14839C0Rb Human ELISA
HLA-DQA1 HLA-DQA1 Antibody, HRP conjugated CSB-PA14839B0Rb Human ELISA
HLA-DQA1 HLA-DQA1 Antibody CSB-PA14839A0Rb Human ELISA, IHC
HLA-E HLA-E Antibody, FITC conjugated CSB-PA320269LC01HU Human ELISA
HLA-E HLA-E Antibody, Biotin conjugated CSB-PA320269LD01HU Human ELISA
HLA-F HLA-F Antibody CSB-PA335552LA01HU Human ELISA, IF
HLA-F HLA-F Antibody, HRP conjugated CSB-PA335552LB01HU Human ELISA
HLA-F HLA-F Antibody, FITC conjugated CSB-PA335552LC01HU Human ELISA
HLA-F HLA-F Antibody, Biotin conjugated CSB-PA335552LD01HU Human ELISA

Human leukocyte antigen (HLA) related ELISA kits for your research

Target Product Name Code Sample Type Sensitivity
HLA-B Human leucocyte antigen B27,HLA-B27 ELISA Kit CSB-E08607h serum, urine, cerebrospinal fluid (CSF) 0.078 ng/mL
HLA-DRA Human HLA class II histocompatibility antigen, DR alpha chain (HLA-DRA) ELISA kit CSB-EL010497HU serum, plasma, tissue homogenates 4.68 pg/mL
HLA-E Human major histocompatibility complex, class I, E (HLA-E) ELISA kit CSB-EL010507HU serum, plasma, cell culture supernates, tissue homogenates 7.81 pg/mL

Related Products of CUSABIO Chemokine Receptor

What are Chemokine receptors?

Chemokine receptors are G protein-coupled receptors and consists of approximately 350 amino acids. The chemokine receptors are all seven-transmembrane (7TM) receptors with seven helical membrane-spanning regions that are found predominantly on the surface of leukocytes, making it one of the rhodopsin-like receptors. Recently, the chemokine receptors have come to attract more attention than cytokines themselves, partly because of their remarkable characteristics, and partly because a deficiency of cytokine receptors has now been directly linked to certain debilitating immunodeficiency states.

What are the function of chemokine receptors?

Chemokine receptor consists of approximately 350 amino acids and a class of GTP-protein-coupled transmembrane receptors (GPCRs) that mediate the function of chemokines and are normally expressed on cell membranes such as immune cells and endothelial cells.

The structure of chemokine receptors

As mentioned before, Chemokine receptors are cytokine receptors expressed on the cell surface as 7-transmembrane proteins that interact with a type of cytokine called a chemokine. The seven transmembrane regions divide the protein into several sections, including extracellular free N-terminals, three extracellular loops, three intracellular loops, and a C-terminus containing serine and threonine residues that act as phosphorylation sites during receptor regulation.

If you want to obtain more information about chemokine receptors, you can click here to read the article entilted Chemokine Receptors – One Kind of Powerful Seven Transmembrane Spanning G Protein-coupled Receptor.

The features of CUSABIO chemokine receptors proteins

At present, we can provide a series of chemokine receptors related products, involving proteins, antibodies and ELISA kits. Among the three types of products, CUSABIO chemokine receptors proteins are more popular than others with the following features:

  • Full-length transmembrane protein
  • Seven-times transmembrane
  • High Purity (>85%)
  • Active Verification

Part of Hot Products

Recombinant Human Atypical chemokine receptor 2(ACKR2) (CSB-CF004618HU)

Recombinant Human C-C chemokine receptor type 2(CCR2) (CSB-CF004841HU)

Chemokine receptors related proteins for your research

Target Product Name Code Expression System
ACKR1 Recombinant Human Atypical chemokine receptor 1(ACKR1) CSB-CF624105HU in vitro E.coli expression system
ACKR2 Recombinant Human Atypical chemokine receptor 2(ACKR2) CSB-CF004618HU in vitro E.coli expression system
ACKR3 Recombinant Human Atypical chemokine receptor 3(ACKR3) CSB-CF006257HU in vitro E.coli expression system
ACKR4 Recombinant Human Atypical chemokine receptor 4(ACKR4) CSB-CF865095HU in vitro E.coli expression system
ADRB2 Recombinant Human Beta-2 adrenergic receptor(ADRB2) CSB-CF001392HU in vitro E.coli expression system
Agtr2 Recombinant Rat Type-2 angiotensin II receptor(Agtr2) ,partial CSB-EP001466RA E.coli
C5AR2 Recombinant Human C5a anaphylatoxin chemotactic receptor 2(C5AR2) CSB-CF868390HU in vitro E.coli expression system
CCR1 Recombinant Human C-C chemokine receptor type 1(CCR1) CSB-CF004839HU in vitro E.coli expression system
CCR10 Recombinant Human C-C chemokine receptor type 10(CCR10) CSB-CF004840HU in vitro E.coli expression system
CCR2 Recombinant Human C-C chemokine receptor type 2(CCR2) CSB-CF004841HU in vitro E.coli expression system
CCR3 Recombinant Human C-C chemokine receptor type 3(CCR3) CSB-CF004842HU in vitro E.coli expression system
CCR4 Recombinant Human C-C chemokine receptor type 4(CCR4) CSB-CF004842HU in vitro E.coli expression system
CCR5 Recombinant Human C-C chemokine receptor type 5(CCR5) CSB-CF004844HU in vitro E.coli expression system
CCR6 Recombinant Human C-C chemokine receptor type 6(CCR6) CSB-CF004845HU in vitro E.coli expression system
CCR7 Recombinant Human C-C chemokine receptor type 7(CCR7) CSB-CF004846HU in vitro E.coli expression system
CCR8 Recombinant Human C-C chemokine receptor type 8(CCR8) CSB-CF004847HU in vitro E.coli expression system
CCR9 Recombinant Human C-C chemokine receptor type 9(CCR9) CSB-CF004848HU in vitro E.coli expression system
CCRL2 Recombinant Human C-C chemokine receptor-like 2(CCRL2) CSB-CF004852HU in vitro E.coli expression system
CREB1 Recombinant Human Cyclic AMP-responsive element-binding protein 1(CREB1) CSB-EP005947HU E.coli
CRHR1 Recombinant Human Corticotropin-releasing factor receptor 1(CRHR1),partial CSB-EP005965HU E.coli
CX3CR1 Recombinant Human CX3C chemokine receptor 1(CX3CR1) CSB-CF006236HU in vitro E.coli expression system
CXCR1 Recombinant Human C-X-C chemokine receptor type 1(CXCR1) CSB-CF006236HU in vitro E.coli expression system
CXCR2 Recombinant Human C-X-C chemokine receptor type 2(CXCR2) CSB-CF011673HU in vitro E.coli expression system
CXCR3 Recombinant Human C-X-C chemokine receptor type 3(CXCR3) CSB-CF006253HU in vitro E.coli expression system
CXCR4 Recombinant Human C-X-C chemokine receptor type 4(CXCR4) CSB-CF006254HU in vitro E.coli expression system
CXCR5 Recombinant Human C-X-C chemokine receptor type 5(CXCR5) CSB-CF006255HU in vitro E.coli expression system
CXCR6 Recombinant Human C-X-C chemokine receptor type 6(CXCR6) CSB-CF006256HU in vitro E.coli expression system
DGKE Recombinant Human Diacylglycerol kinase epsilon(DGKE) CSB-CF006835HU in vitro E.coli expression system
FPR1 Recombinant Human fMet-Leu-Phe receptor(FPR1),partial CSB-EP008854HU1d1 E.coli
Fpr2 Recombinant Mouse Formyl peptide receptor 2(Fpr2),partial CSB-EP008855MO1 E.coli
FSHR Recombinant Human Follicle-stimulating hormone receptor(FSHR),partial CSB-EP009021HU E.coli
Gcgr Recombinant Mouse Glucagon receptor(Gcgr),partial CSB-EP009316MO E.coli
GLP1R Recombinant Human Glucagon-like peptide 1 receptor(GLP1R) CSB-CF009514HU(A4) in vitro E.coli expression system
GNAI3 Recombinant Human Guanine nucleotide-binding protein G(k) subunit alpha(GNAI3) CSB-EP009591HU E.coli
GNAZ Recombinant Human Guanine nucleotide-binding protein G(z) subunit alpha(GNAZ) CSB-EP009601HU E.coli
GPR157 Recombinant Human G-protein coupled receptor 157(GPR157) CSB-CF713185HU in vitro E.coli expression system
HCRTR1 Recombinant Human Orexin receptor type 1(HCRTR1) CSB-YP010231HU1 Yeast
HTR1F Recombinant Human 5-hydroxytryptamine receptor 1F(HTR1F) CSB-CF010886HU in vitro E.coli expression system
HTR2B Recombinant Human 5-hydroxytryptamine receptor 2B(HTR2B) CSB-CF010888HU in vitro E.coli expression system
HTR7 Recombinant Human 5-hydroxytryptamine receptor 7(HTR7) CSB-CF010899HU in vitro E.coli expression system
LGR5 Recombinant Human Leucine-rich repeat-containing G-protein coupled receptor 5(LGR5),partial CSB-EP012906HU E.coli
NPFFR2 Recombinant Human Neuropeptide FF receptor 2(NPFFR2) CSB-YP015983HU Yeast
OR1A1 Recombinant Human Olfactory receptor 1A1(OR1A1) CSB-CF865201HU in vitro E.coli expression system
P2RY12 Recombinant Human P2Y purinoceptor 12(P2RY12) CSB-CF861997HU in vitro E.coli expression system
XCR1 Recombinant Human Chemokine XC receptor 1(XCR1) CSB-CF026188HU in vitro E.coli expression system

Chemokine receptors related antibodies for your research

Target Product Name Code Species Reactivity Tested Applications
ACKR1 ACKR2 Antibody CSB-PA001619 Human ELISA, WB, IHC, IF
CCR1 CCR1 Antibody CSB-PA004839LA01HU Human ELISA, IHC, IF
CCR10 CCR10 Antibody CSB-PA004840LA01HU Human ELISA, WB, IHC, IF
CCR2 CCR2 Antibody CSB-PA004841GA01HU Human ELISA, WB
CCR2 CCR2 Antibody CSB-PA004841LA01HU Human ELISA, IF
CCR3 CCR3 Antibody CSB-PA004842LA01HU Human, Mouse ELISA, WB, IHC, IF
CCR5 CCR5 Antibody CSB-PA004844GA01HU Human, Mouse, Rat ELISA, WB
CCR6 CCR6 Antibody CSB-PA004845EA01HU Human ELISA, WB
CCR8 CCR8 Antibody CSB-PA091770 Human ELISA, WB, IHC
CCR8 CCR8 Antibody CSB-PA172806 Human ELISA, WB, IHC
CCR9 CCR9 Antibody CSB-PA035070 Human, Mouse ELISA, IHC
CCR9 CCR9 Antibody CSB-PA293047 Human, Mouse ELISA, IHC
CCRL2 CCRL2 Antibody CSB-PA004852LA01HU Human ELISA, WB, IHC
CX3CR1 CX3CR1 Antibody CSB-PA006236GA01HU Human, Mouse, Rat ELISA, WB
CX3CR1 CX3CR1 Antibody CSB-PA006236LA01HU Human ELISA, IHC, IF
CXCR2 Phospho-CXCR2 (S347) Antibody CSB-PA009566 Human, Mouse ELISA, WB, IHC, IF
CXCR2 CXCR2 Antibody CSB-PA011673GA01HU Human ELISA, WB, IF
CXCR2 CXCR2 Antibody CSB-PA011673HA01HU Human ELISA, IHC, IF
CXCR3 CXCR3 Antibody CSB-PA006253LA01HU Human ELISA, WB, IHC, IF
CXCR4 Phospho-CXCR4 (S339) Antibody CSB-PA060127 Human, Mouse, Rat, Monkey ELISA, WB, IHC, IF
CXCR4 CXCR4 Antibody CSB-PA006254GA01HU Human, Mouse, Rat ELISA, WB
CXCR4 CXCR4 Antibody CSB-PA006254YA01HU Human, Mouse ELISA, WB, IHC, IF
CXCR5 CXCR5 Antibody CSB-PA006255LA01HU Human ELISA, IHC, IF
CXCR6 CXCR6 Antibody CSB-PA224134 Human, Mouse ELISA, WB, IHC
CXCR6 CXCR6 Antibody CSB-PA188638 Human, Mouse ELISA, WB, IHC

Chemokine receptors related ELISA kits for your research

Target Product Name Code Sample Type Sensitivity
CCR2 Human CC-Chemokine Receptor 2,CCR2 ELISA Kit CSB-E14200h serum, plasma, tissue homogenates, cerebrospinal fluid (CSF) 5.86 pg/mL
CCR2 Mouse C-C chemokine receptor type 2(CCR2) ELISA kit CSB-EL004841MO serum, plasma, tissue homogenates 3.9 pg/mL
CX3CR1 Human CX3C-chemokine receptor 1,CX3CR1 ELISA Kit CSB-E09942h serum, plasma, tissue homogenates 7.8 pg/mL

Chemokine Receptors – One Kind of Powerful Seven Transmembrane Spanning G Protein-coupled Receptor

Chemokine Receptors – One Kind of Powerful Seven Transmembrane Spanning G Protein-coupled Receptor

Chemokine receptors are cytokine receptors expressed on the cell surface as 7-transmembrane proteins that interact with a type of cytokine called a chemokine. Recently, the chemokine receptors have come to attract more attention than cytokines themselves, partly because of their remarkable characteristics, and partly because a deficiency of cytokine receptors has now been directly linked to certain debilitating immunodeficiency states.

Some time ago, a guy from CUSABIO has written an article named “The Overview of Chemokine”. The article involves the definition, function, family and signaling pathway of chemokines. Here, we focus on chemokine receptor, including function, structure, family, signaling pathway and related diseases and so on.

1. What is the function of chemokine receptors?

Chemokine receptors are a class of GTP-protein-coupled transmembrane receptors (GPCRs) that mediate the function of chemokines and are normally expressed on cell membranes such as immune cells and endothelial cells.

2. What is the structure of chemokine receptors?

Chemokine receptor are G protein-coupled receptors and consists of approximately 350 amino acids. The chemokine receptors are all seven-transmembrane (7TM) receptors with seven helical membrane-spanning regions that are found predominantly on the surface of leukocytes, making it one of the rhodopsin-like receptors. The seven transmembrane regions divide the protein into several sections, including extracellular free N-terminals, three extracellular loops, three intracellular loops, and a C-terminus containing serine and threonine residues that act as phosphorylation sites during receptor regulation. As the figure 1 shows:

Schematic presentation of the chemokine receptor structure

Figure 1. Schematic presentation of the chemokine receptor structure

The N terminus and three ECLs are exposed outside the cell, whereas the C terminus and three intracellular loops face the cytoplasm [1]. The first two extracellular loops of chemokine receptors are linked together by disulfide bonding between two conserved cysteine residues. The N-terminal end of a chemokine receptor binds to chemokine(s) and is important for ligand specificity. G-proteins couple to the C-terminal end, which is important for receptor signaling following ligand binding. The intracellular second loop has a characteristic aspartate-arginine-tyrosine box (DRY box) amino acid sequence.

Although chemokine receptors share high amino acid identity in their primary sequences, they typically bind a limited number of ligands. Chemokine receptors are redundant in their function as more than one chemokine is able to bind to a single receptor.

3. What are the members of chemokine receptor family?

According to the classification of chemokines, receptors that bind to CC-like chemokines are called CC receptors (CCR), and receptors that bind to CXC-like chemokines are called CXC-like receptors (CXCR). C and CX3C receptors (CR, CX3CR). Approximately 20 signaling chemokine receptors have been reported as well as 3 non-signaling scavenger receptors that dampen the immune response by binding, internalizing, and, in the case of D6, degrading chemokines [2] [3] [4] (Table 1).

Table 1. Chemokine receptors and their ligands

Chemokine Receptors Ligands
CCR1 CCL3, CCL5, CCL7, CCL13, CCL14, CCL15, CCL16, CCL23
CCR2 CCL2, CCL7, CCL8, CCL13, CCL16
CCR3 CCL5, CCL7, CCL8, CCL11, CCL13, CCL15, CCL16, CCL24, CCL26, CCL28
CCR4 CCL17, CCL22
CCR5 CCL3, CCL4, CCL5, CCL8, CCL11, CCL14, CCL16
CCR6 CCL20
CCR7 CCL19, CCL21
CCR8 CCL1
CCR9 CCL25
CCR10 CCL27, CCL28
CXCR1 CXCL6, CXCL7, CXCL8
CXCR2 CXCL1, CXCL2, CXCL3, CXCL6, CXCL7, CXCL8
CXCR3-A CXCL9, CXCL10, CXCL11
CXCR3-B CXCL4, CXCL9, CXCL10, CXCL11
CXCR4 CXCL12
CXCR5 CXCL13
CXCR6 CXCL6
CXCR7 CXCL12
XCR1 XCL1, XCL2
CX3CR1 CX3CL1
CCX-CKR CXCL9, CCL21, CCL25
D6 CCL2, CCL3L1, CCL4, CCL5, CCL7, CCL8, CCL11, CCL13, CCL14, CCL17, CCL22
DARC/Duffy

CCL2, CCL7, CCL8, CCL11, CCL13, CCL14, CCL16, CCL17, CXCL1, CXCL5, CXCL6,

CXCL7, CXCL8, CXCL9, CXCL11, CXCL13

*The content of Table 1 is derived from reference No. 1.

4. Chemokine receptor signaling

Chemokine receptors are also called G protein–coupled receptors (GPCRs). Intracellular signaling by chemokine receptors is dependent on G-protein which exists as a (αβγ) heterotrimer [5]. They are composed of three distinct subunits.

The Gα subunit interacts directly with the chemokine receptor intracellular loops and with the Gβ subunit, which in turn forms a tight complex with the Gγ subunit. The Gα subunit contains a GTPase domain involved in binding and hydrolysis of GTP. When the molecule GDP is bound to the G-protein subunit, the G-protein is in an inactive state.

When a chemokine ligand binds a chemokine receptor, it induces the chemokine receptor into a conformation that activates the heterotrimeric G protein inside the cell, causing the exchange of GDP for another molecule called GTP. Gα-GTP then dissociates from the receptor and from the Gβγ heterodimer, and the subunit called Gα activates an enzyme known as Phospholipase C (PLC) that is associated with the cell membrane.

PLC cleaves Phosphatidylinositol (4,5)-bisphosphate (PIP2) to form two second messenger molecules called inositol triphosphate (IP3) and diacylglycerol (DAG); DAG activates another enzyme called protein kinase C (PKC), and IP3 triggers the release of calcium from intracellular stores. These events promote many signaling cascades, effecting a cellular response [6] [7]. You can click here to view the signaling pathway.

5. Chemokine receptor and diseases

Many tumor cells over-express functional chemokine receptors, undetectable on their normal counterparts. These receptors respond to chemokine signals by promoting cell survival, proliferation, adhesion, or migration, but also direct metastasis formation on tissues or organs where the corresponding ligands are secreted [8] [9]. Here, we focus on the infectious diseases (such as HIV) and cancer.

5.1 Chemokine receptor and HIV

HIV, an abbreviation of Human Immunodeficiency Virus, is a lentivirus that belongs to the class of retroviruses. Since its discovery in 1983 as the etiological agent of AIDS, the disease has spread in successive waves in various regions around the world. Two major subtypes of HIV, HIV-1 and HIV-2, have been characterized. HIV-1 is the predominant HIV type throughout the world [10]. Click the article entitled “One World, One Hope——What Can We Do about AIDS?”, and you can view more information about HIV, including its history, classification, structure and testing.

In recent years, accumulating evidence has uncovered that chemokine receptors are the human cofactors required along with CD4 for fusion and infection by HIV [11]. This discovery has opened new directions in AIDS research on mechanisms of viral entry, tropism, and pathogenesis [12].

HIV entry into cells is a multistep process. First, the viral envelope protein gp120 binds to CD4 receptor on the host cell surface, which induces conformational changes in the gp120 subunit setting free the co-receptor binding site on gp120. After binding of the glycoprotein with the co-receptor, HIV-1 gp41 ‘unfolds’ by a hinge mechanism followed by insertion of the fusion peptide into the cell membrane, anchoring the virus to the cellular membrane. Then, gp41 folds into a ‘hairpin structure’ and brings the cell membrane and the viral membrane into close proximity whereafter fusion can take place. Following membrane fusion, the viral contents are expelled into the cell [13]. As the figure 2 shows:

Schematic presentation of the HIV-1 entry process

Figure 2. Schematic presentation of the HIV-1 entry process

The chemokine receptors CXCR4 and CCR5 are the main co-receptors used by the T-cell-tropic (CXCR4-using, X4) and macrophage tropic (CCR5-using, R5) HIV-1 strains, respectively, for entering their CD4+ target cells, although it has been postulated that other receptors, including the non-signaling chemokine receptor D6, may also play a role.

Based on these discoveries, several low-molecular weight CCR5 and CXCR4 antagonistic compounds have been described with potent antiviral activity. The best CXCR4 antagonists described are the bicyclam derivatives, which consistently block X4 but also R5/X4 viral replication in PBMCs. We believe that chemokine receptor antagonists will become important new antiviral drugs to combat AIDS. Both CXCR4 and CCR5 chemokine receptor inhibitors will be needed in combination and even in combinations of antiviral drugs that also target other aspects of the HIV replication cycle to obtain optimum antiviral therapeutic effects.

5.2 Chemokine receptor and Cancer

As you know, chemokines, a family of small chemotactic cytokines, play a central role in homeostasis and the maintenance of innate and acquired immunity by controlling leukocyte trafficking and recruitment [14]. The biological effects of chemokines are exerted through their interaction with chemokine receptors. Chemokines and their receptors have been implicated in the pathogenesis of many inflammatory and infectious diseases, but also in cancer [15] [16].

Expression of chemokines and their receptors play a dual role in tumorigenicity. On one hand, chemokines, secreted by either the cancer-initiating cells or the normal cells surrounding them, can limit tumor development by increasing leukocyte migration toward the site, and induce long-term anti-tumor immunity. On another hand, they may facilitate survival, proliferation, and metastatic potential of tumor cells [17] [18].

The most frequently over-expressed chemokine receptor in malignant cells is CXCR4 [19]. It presents in over 23 different types of human cancer, such as lung, brain, prostate, breast, pancreas, ovarian, colorectal, leukemia, and melanomas [20]. CXCR4 expression on malignant cells correlates with cell survival, tumor growth, angiogenesis, higher metastatic potential, and resistance to therapeutic agents. Its ligand, CXCL12, is secreted in large amounts by bone marrow, lymphnode, liver, and lung cells.

During the last years, a broad effort has been centered on targeting regulatory molecules from the host immune system that act as “immune checkpoints” with mAbs. With the monoclonal technology development, monoclonal antibodies against CXCR4, CCR2, and CCR4 have entered clinical trials for cancer therapy.

References

[1] Samantha J. Allen, Susan E. Crown, et al. Chemokine: Receptor Structure, Interactions, and Antagonism [J]. Annu. Rev. Immunol. 2007. 25:787–820.
[2] Graham GJ, McKimmie CS. Chemokine scavenging by D6: a movable feast [J]? Trends Immunol. 2006, 27:381–86.
[3] Weber M, Blair E, et al. The chemokine receptor D6 constitutively traffics to and from the cell surface to internalize and degrade chemokines [J]. Mol. Biol. Cell. 2004, 15:2492–508.
[4] Nibbs R, Graham G, et al. Chemokines on the move: control by the chemokine“interceptors” Duffy blood group antigen and D6 [J]. Semin. Immunol. 2003, 15:287–94.
[5] Lefkowitz RJ. Historical review: a brief history and personal retrospective of seventransmembrane receptors [J]. Trends Pharmacol. Sci. 2004, 25:413–22.
[6] Murdoch.Craig, Finn. Adam. Chemokine receptors and their role in inflammation and infectious diseases [J]. Blood. 2000, 95: 3032–3043.
[7] Annelien J.M. Zweemer, Jimita Toraskar, et al. Bias in chemokine receptor signaling [J]. Trends in Immunology. 2014, 35 (6):243-252.
[8] MukaidaN, BabaT. Chemokines in tumor development and progression [J]. Exp CellRes. 2012, 318(2):95–102.
[10] MariaVela, Mariana Aris, et al. Chemokine receptor-specific antibodies in cancer immunotherapy: achievements and challenges [J]. 2015, 6 (12): 1-15.
[11] Katrien Princen, Dominique Schols. HIV chemokine receptor inhibitors as novel anti-HIV drugs [J]. Cytokine & Growth Factor Reviews. 2005, 16: 659–677.
[12] Broder CC, Collman RG. Chemokine receptors and HIV [J]. J Leukoc Biol. 1997, 62(1):20-9.
[13] Doms RW. Beyond receptor expression: the influence of receptor conformation, density, and affinity in HIV-1 infection [J]. Virology. 2000, 276:229–37.
[14] RotA, von Andrian UH. Chemokines in innate and adaptive host defense: basic chemokinese grammar for immune cells [J]. Annu Rev Immunol. 2004, 22: 891–928.
[15] WhiteGE, IqbalAJ,et al.CC chemokine receptors and chronic inflammation therapeutic opportunities and pharmacological challenges [J]. Pharmacol Rev. 2013, 65(1):47–89.
[16] BarbieriF, BajettoA, et al. Role of chemokine network in the development and progression of ovarian cancer: a potential novel pharmacological target [J]. J Oncol. 2010, 42: 56-69.
[17] Balk will F. Chemokine biology in cancer [J]. Semin Immunol. 2003, 15(1):49–55.
[18] Viola A, Sarukhan A, et al. The pros and cons of chemokines in tumor immunology [J]. Trend sImmunol. 2012, 33(10):496–504.
[19] Burger JA, Kipps TJ. CXCR4: a key receptor in the crosstalk between tumor cells and their micro environment [J]. Blood. 2006, 107(5):1761–7.
[20] Balkwill F. The significance of cancer cell expression of the chemokine receptor CXCR4 [J]. Semin Cancer Biol. 2004, 14(3):171–9.

A Resume for Transmembrane Proteins

Transmembrane protein (TP), also known as intact protein, is a type of membrane protein exists in the whole biofilm, that is, transmembrane proteins span from one side of the membrane to another side. Transmembrane proteins play an important role in molecular transport, signal transduction, energy utilization and other basic physiological processes.

For example, many natural transmembrane proteins act as channels for specific substances to pass through the biofilm, and some transmembrane proteins receive or transmit cellular signals. The strong attachment of the transmembrane protein to the biofilm is due to the hydrophobic interaction of the membrane lipid with the hydrophobic region of the protein.

High-resolution solution structure of outer membrane protein A transmembrane domain

Figure 1 The structure of outer membrane protein A transmembrane domain

2. Classification of Transmembrane Proteins

2.1 Alpha Helix

Most of the transmembrane regions are alpha – helical. This protein is present in the inner membrane of bacterial cells or in the plasma membrane of eukaryotic cells and sometimes in the outer membrane of eukaryotic cells. It is estimated that 27% of all proteins in the body are alpha – helical membrane proteins.

2.2 β – Barrel Membrane Protein

So far, such proteins have been found only in the outer membrane of gram-negative bacteria, the cell wall of gram-positive bacteria, and the outer membrane of mitochondria and chromatin. All β – tubular transmembrane proteins have common evolutionary origins and similar folding mechanisms.

2.3 Other Classification

It can also be classified according to the position of its N-terminal and C-terminal domains.

Type I transmembrane proteins are anchored to the lipid membrane by stop-transport anchoring sequences, and their N-terminal domains target the endoplasmic reticulum cavity during synthesis.

Types II and III are anchored by signal anchoring sequences. The type II targets the ER cavity with its C-terminal domain. Type III targets the ER cavity with its N-terminal domain.

There are two subtypes of type IV: IV-a and IV-b. IV-a targets the cytoplasm with its N-terminal domain, while IV-b targets the cavity with its N-terminal domain.

In these four types, type I, II and III are single-transmembrane proteins, while type IV is multi-transmembrane proteins.

Schematic representation of transmembrane proteins

Figure 2 Schematic representation of transmembrane proteins
①1a single transmembrane α-helix.
②2a polytopic transmembrane α-helical protein.
③3a polytopic transmembrane β-sheet protein.
Note: This image is from wikipedia

3. Studies on Transmembrane Proteins

3.1 Studies on Transmembrane Proteins

Transmembrane proteins are located at the interface between cells and the outside world, mediating the signal transduction between cells and the outside world, and performing many important cellular biological functions.

For example, it is a receptor for various signaling molecules, hormones and other substrates; it is involved in the exchange of substances, energy and signal between the inside and outside of the cell membrane; it constitutes a channel for various ion transmembranes, which inputs nutrients and some inorganic electrolytes into cells, and discharges toxic or useless metabolites into cells; and it constitutes respiratory chains and transporters.

The function of transmembrane proteins: Transport, signal transduction, enzymatic activity, Cell-Cell recognition, etc.

Figure 3 The function of transmembrane proteins

Different transmembrane proteins also have different functional characteristics, and understanding the functions of these membrane proteins provides clues to further elucidate the functions of different membrane systems [1].

Interferon Induces Transmembrane Proteins

IFITM1 is a member of the interferon-induced transmembrane protein family, and its gene product is one of the leukocyte antigens involved in the transmission of anti-proliferation and homogenous anti-adhesion signal complexes on lymphocytes [2]. Studies have found that IFITM protein can help inhibit viral infection caused by viral bacteria in the cell, which is the most effective method for HIV transmission [3]. IFITM proteins, especially IFITM2 and IFITM3, block HIV cell-to-cell transmission. IFITM proteins often affect the lipid properties of cell membranes and impede the fusion of different viruses with host cells.

In recent years, studies on high expression of IFITM1 have reported in colon cancer, lung cancer, rectal cancer, gastric cancer and head and neck squamous cell carcinoma. Its role in the occurrence, proliferation and invasion of malignant tumors is attracting more and more attention. Studies on gene expression analysis of ovarian cancer showed that IFITM1 was the most promising new molecular marker [4].

Experiments show that [5] IFITM1 mRNA is overexpressed in both early and late stages of murine and human intestinal tumors. In humans, its mechanism is activated by Wnt/β-catenin signaling pathway, and IFITM1 is a candidate target gene. It can be used as a genetic marker for clinical diagnosis of colorectal cancer.

Transmembrane Protein Gp41

AIDS is an acquired immune deficiency syndrome (AIDS) caused by human immune deficiency virus (HIV) infection. Early diagnosis of AIDS allows patients to be treated early and prevents further spread of HIV. High purity specific HIV antigen is necessary for the development of HIV diagnostic kit. The transmembrane protein Gp41 is a key protein in the fusion process between the HIV-1 envelope and the target cell membrane. Gp41 is exposed to the surface of HIV and is the dominant epitope for inducing antibodies in the body. It is therefore the preferred target for HIV antibody detection and an epitope for protein vaccine development [6] [7].

Gp41, with a conserved sequence and no homology with human proteins, is considered to be an ideal target for HIV-1 fusion inhibitors. Currently, the developed peptides hiv-1 fusion inhibitor Fuzeon (enfuvirtide, T-20) targeting Gp41 has been approved by FDA, which is the first and the only anti-HIV-l fusion inhibitor applied in clinical practice.

Transmembrane 4 superfamily

The four-pass transmembrane protein is a protein that can be linked to intramembrane-transmembrane and extramembranous proteins, and plays the role of connecting biological signals inside and outside the membrane. CD151 is one of the important members of the four-transmembrane protein superfamily, which has been confirmed to play an important role in the invasion and metastasis of liver cancer, and the overexpression of CD151 can promote the invasion and metastasis of liver cancer [8].

Tetraspanins are evolutionarily highly conserved four-time transmembrane proteins that interact with surrounding molecules to form a broad molecular network of interactions, namely four transmembrane protein networks (TEMs). Tetraspanins are associated with the pathogenesis of malignant tumors, the immune system, and infectious diseases, so they have become potential targets for the treatment of these diseases. It is currently known that TEMs can provide access to or exit for human papillomavirus (HPV) and human immunodeficiency virus (HIV) [9] and other viruses [10] [11].

CD81, a member of the Tetraspanins family, is a four-transmembrane protein molecule with multiple biological activities. It plays a role in many different cell types, such as brain development, retinal pigment epithelial cell development and fertilization.

In addition, CD81 plays an important role in hepatitis c virus (HCV) infection, plasmodium falciparum parasitism and listeria monocyte proliferation. The results showed that [12] CD81 could provide a platform for the endocytosis triggered by HPV pseudovirus (PsV).

In Drosophila, a large transmembrane protein uninflatable (Uif) with EGF like repeats is shown to combat classical Notch signals [13].

3.2 Applied Research on Transmembrane Proteins

Membrane proteins play an important role in life sciences, but only a few of them have been studied thoroughly due to their difficulty in expression and activity in vitro. In order to maintain the hydrophobic structure and protein activity of membrane proteins, integrated membrane proteins with lipids and detergents have been studied. The integration of transmembrane proteins into vesicles for structural and functional studies is a hot topic in membrane protein research.

There are several advantages to properly integrating membrane proteins into vesicles:

  • Studies on transport and catalytic functions can be carried out without interference from other membrane components.
  • A large number of membrane proteins are integrated into the vesicles to form a crystal structure, which solves the problem that the hydrophobic membrane protein cannot form a crystal structure and a natural conformation in an aqueous solution.

In addition, scientists have demonstrated that it is now possible to accurately design complex multi-transmembrane proteins that can be expressed in cells [14]. This will make it possible for researchers to design transmembrane proteins with novel structures and functions. These proteins, like naturally occurring transmembrane proteins, can pass through the membrane multiple times and assemble into a stable multiprotein complex.

4. Transcription Factor

Transmembrane proteins are widely present in plants and play important physiological functions. In current genomic data, 20%-30% of gene products are predicted to be transmembrane proteins [15]. As a special class of proteins, transmembrane proteins have some special physical and chemical properties, which may make it difficult to study. Nevertheless, the expression of plant membrane proteins in different systems (e.g., yeast, insect cells, etc.) has been successfully used to study the transport activities of ions and solute transporters in cells.

Currently, there are five main expression systems: E. coli expression system, yeast expression system, insect cell expression system, mammalian cell expression system and cell-free protein expression system.

The cell-free protein expression system is particularly suitable for the expression of transmembrane proteins and toxic proteins. In recent years, proteins that are difficult to express by conventional intracellular means have been successfully expressed in cells in vitro [16] [17] [18].

The cell-free protein expression system is also known as the in vitro translation system. The cell-free protein synthesis system is a rapid and efficient method for synthesizing target proteins by supplementing various substrates and energy substances required for transcription and translation in the enzyme system of cell extracts. In recent years, the advantages of cell-free protein expression systems in the expression of complex proteins, toxic proteins and membrane proteins have gradually emerged, demonstrating their potential applications in the biopharmaceutical field.

Cell-free technology can easily and controllably add a variety of unnatural amino acids to achieve complex modification processes that are difficult to solve after conventional recombinant expression [19]. Cell-free protein expression systems have high application value and potential for drug delivery and vaccine development using viroid-like particle VLPs. A large number of membrane proteins have been successfully expressed in cells free.

CUSABIO’s cell-free expression platform can provide you with complete technical services. It can solve specific problems related to protein expression, such as low protein yield, expression of special proteins (such as membrane proteins, toxic proteins, etc.), protein complexes production, parallel synthesis of many different proteins.

There are some features of cell-free protein expression systems as follows:

  • Compared with the traditional protein expression system, many processes are omitted, such as transformation of plasmids, cell culture, collection, crushing and centrifugation etc., which greatly improves the working efficiency.
  • The reaction system is small and can simultaneously parallel synthesizing many different proteins.
  • Short reaction cycles, meeting the scientific requirements for high-throughput ligand screening and proteomics.
  • The open reaction system is more easy change the reaction conditions and is conducive to the regulation of gene transcription, protein synthesis and post-translational modifications, and avoids the formation of inclusion bodies.
  • Stable reaction system, can be coupled with other processes to form automated, procedural, and scale production and accelerate the purification, functional characterization and subsequent structural analysis of recombinant proteins.
  • No cell structures restriction, can be used to produce exogenous proteins that are toxic to the host as it seeks to avoid the lethal effect of protein expression on host cells.
  • Add unnatural amino acids or isotopically labeled amino acids to express specific proteins.
  • Significant improvements have been made in items that have difficulty to express in common cell lines due to multiple transmembrane or hydrophobic conditions.

Based on these advantages, CUSABIO can express 36000+ multiple transmembrane proteins, mainly including:

  • G-protein-coupled receptors (GPCR).
  • Aquaporin (AQP).
  • Ion channel.
  • ATP-Binding Cassette (ABC).
  • Human leucocyte antigen (HLA).
  • Others.

Product applications include: Antibody production; protein crystallization; immunoprecipitation; receptor-ligand interaction studies; mass spectrometry; NMR; protein array construction.

References
[1] Cui S, Huang F, Wang J, et al. A proteomic analysis of cold stress responses in rice seedlings [J]. Proteomics, 2005, 5(12): 3162-3172.
[2] Deblandre G A, Marinx O P, Evans S S, et al. Expression Cloning of an Interferon-inducible 17-kDa Membrane Protein Implicated in the Control of Cell Growth [J]. Journal of Biological Chemistry, 1995, 270(40): 23860-23866.
[3] Yu J, Li M, Wilkins J, et al. IFITM Proteins Restrict HIV-1 Infection by Antagonizing the Envelope Glycoprotein [J]. Cell Reports, 2015, 13(1): 145-156.
[4] Maria Rosa Bani. Gene expression correlating with response to paclitaxel in ovarian carcinoma xenografts [J]. Molecular Cancer Therapeutics, 2004, 3(2): 111-121.
[5] Andreu P, Colnot S, Godard C, et al. Identification of the IFITM family as a new molecular marker in human colorectal tumors [J]. Cancer Research, 2006, 66(4): 1949.
[6] Huang X, Xu J, Qiu C, et al. Mucosal priming with PEI/DNA complex and systemic boosting with recombinant TianTan vaccinia stimulate vigorous mucosal and systemic immune responses [J]. Vaccine, 2007, 25(14): 0-2629.
[7] Keenan P A, Keenan J M, Branson B M. Rapid HIV testing. Wait time reduced from days to minutes [J]. Postgraduate Medicine, 2005, 117(3): 47-52.
[8] Ai-Wu K, Guo-Ming S, Jian Z, et al. CD151 amplifies signaling by integrin α6β1 to PI3K and induces the epithelial-mesenchymal transition in HCC cells [J]. Gastroenterology, 2011, 140(5): 1629-1641.e15.
[9] Krementsov D N, Rassam P, Margeat E, et al. HIV-1 Assembly Differentially Alters Dynamics and Partitioning of Tetraspanins and Raft Components [J]. Traffic, 2010, 11(11): 1401-1414.
[10] Spriel A B V, Figdor C G. The role of tetraspanins in the pathogenesis of infectious diseases [J]. Microbes & Infection, 2010, 12(2): 106-112.
[11] Monk P N, Partridge L J. Tetraspanins – Gateways for Infection [J]. Infectious Disorders – Drug Targets, 2012, 12(1):-.
[12] Homsi Y, Schloetel J G, Scheffer K, et al. The Extracellular δ-Domain is Essential for the Formation of CD81 Tetraspanin Webs [J]. Biophysical Journal, 2014, 107(1): 100-113.
[13] Krogh A, Larsson B, Heijne G V, et al. Predicting transmembrane protein topology with a hidden markov model: application to complete genomes [J]. Journal of Molecular Biology, 2001, 305(3): 0-580.
[14] Peilong Lu, Duyoung Min, Frank DiMaio, et al. Accurate computational design of multipass transmembrane proteins. Science, 2018, 359(6379): 1042-1046.
[15] Xie G, Zhang H, Du G, et al. Uif, a Large Transmembrane Protein with EGF-Like Repeats, Can Antagonize Notch Signaling in Drosophila [J]. PLOS ONE, 2012, 7.
[16] Goerke A R, Swartz J R. Development of cell-free protein synthesis platforms for disulfide bonded proteins [J]. Biotechnology and bioengineering, 2008, 99(2): 351-367.
[17] Kanter G, Yang J, Voloshin A, et al. Cell-free production of scFv fusion proteins: An efficient approach for personalized lymphoma vaccines [J]. Blood, 2007, 109(8): 3393-3399.
[18] Yang J, Kanter G, Voloshin A, et al. Rapid expression of vaccine proteins for B-cell lymphoma in a cell-free system [J]. Biotechnology & Bioengineering, 2010, 89(5): 503-511.
[19] Jennings G T, Bachmann M F. The coming of age of virus-like particle vaccines [J]. Biological Chemistry, 2008, 389(5).

Neurological Research

Neuroscience, also known as a science of nervous system, is a branch of medicine dealing with disorders of the nervous system. Neurology deals with the diagnosis and treatment of all categories of conditions and disease involving the central and peripheral nervous systems (and their subdivisions, the autonomic and somatic nervous systems), including their coverings, blood vessels, and all effector tissue, such as muscle.

Do You Really Know Neurons and Glia Cells in Nerve System?

The nervous system is a system that plays a leading role in the regulation of physiological function. It is mainly composed of nerve tissue and is divided into two parts: the central nervous system and the peripheral nervous system. The central nervous system includes the brain and spinal cord, and the peripheral nervous system includes the brain and spinal nerves. Both the central nervous system and the peripheral nervous system are consist of two types of cells in nervous system, including neuron and neuroglia. One of them, neuron, also known as nerve cell, is a type of electrically excitable cell that receives, processes, and transmits information through electrical and chemical signals, and it is a specific feature of nervous system. Another one, neuroglia, also known as glial cell or glia, is non-neuronal cell in the central nervous system (brain and spinal cord) and the peripheral nervous system. Its main function is maintaining homeostasis, myelin formation, and providing support and protection for neurons[1]. In this article, we focus on the markers of them, we are prepared a table for you, which contains the hot research markers of neuron and neuroglia. We hope this form will facilitate your neurological research.

Classification

Both neurons and neuroglia have several different subtypes. Neurons exist in a number of different shapes and sizes and can be classified by their morphology and function. Neuroglia can be classified by their morphology.

1. The neuron classification

Neurons can be classified by function, locality, cell morphology and neurotransmitter, respectively. In this part, we illustrate the four different classification of neurons in details.

Function

Firstly, according to various function, the neurons are divided into three subtypes, named sensory neurons, motor neurons and interneurons. Among of them, sensory neurons, also known as afferent neurons, respond to one particular type of stimulus such as touch, sound and all other stimuli affecting the cells of the sensory organs or tissues, and converts it into an electrical signal via transduction, which is then sent to the central nervous. The second one, motor neurons, also known as efferent neurons, receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. As opposed to sensory neurons that arrive at the region. The third one, Interneurons, also called internuncial neuron, create neural circuits and connect neurons to other neurons within specific regions of the central nervous system. Interneurons can be further split into two subtypes through diversity structures: local interneurons and relay interneurons[2]. Local interneurons have short axons and form circuits with nearby neurons to analyze small pieces of information[3]. Relay interneurons have long axons and connect circuits of neurons in one region of the brain with those in other regions.

Locality

Secondly, the neurons can be sorted through distrinct locality, including central neurons and peripheral neurons. Moreover, central neurons can be further divided into several groups – spinal cord neurons, cortical neurons, hippocampal neurons, thalamic neurons, et al. – based on the different parts of brain.

Cell Morphology

Thirdly, most neurons can be anatomically characterized as unipolar, bipolar and multipolar in cell morphology. Morphologically similar neurons tend to be concentrated in a specific region of the nervous system and have similar functions. General speaking, a unipolar neuron is a type of neuron in which only one protoplasmic process extends from the cell body and is common in invertebrate nervous system. A bipolar neuron, also called bipolar cell, is a type of neuron which has two extensions, a dendrite and an axon, and is a prototype of neuron. Bipolar cells are specialized sensory neurons for the transmission of special senses, including hearing, seeing and smelling. A multipolar neuron, also known as multipolar neuron, is a type of neuron that possesses a single axon and many dendrites (and dendritic branches), allowing for the integration of a great deal of information from other neurons. These processes are projections from the nerve cell body. Multipolar neurons constitute the majority of neurons in the central nervous system.

Neurotransmitter

Finally, the most important one, neurons are classified by different neurotransmitters production. Early biologists believed that a neuron can only secrete a neurotransmitter, and neurons are classified into GABAergic neurons, glutamatergic neurons, cholinergic neurons, Dopaminergic neurons, and serotonergic neurons according to their secreted transmitters. Although it has been found that a variety of neurotransmitters can coexist in a single neuron, this classification remains useful. As shown in the Table 1, GABAergic neurons—gamma aminobutyric acid. GABA is one of two neuroinhibitors in the central nervous system (CNS), the other being Glycine. Glutamatergic neurons—glutamate. Glutamate is one of two primary excitatory amino acid neurotransmitter, the other being Aspartate. Cholinergic neurons—acetylcholine. Acetylcholine is released from presynaptic neurons into the synaptic cleft. Dopaminergic neurons—dopamine. Dopamine is a neurotransmitter that acts on D1 type (D1 and D5) Gs coupled receptors, which increase cAMP and PKA, and D2 type (D2, D3, and D4) receptors, which activate Gi-coupled receptors that decrease cAMP and PKA. Serotonergic neurons—serotonin. Serotonin (5-Hydroxytryptamine, 5-HT) can act as excitatory or inhibitory.

2. The Neuroglia Classification

Neuroglia, also called glial cells, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system. As the different structures, the neuroglia can be classified into three groups, astrocyte, microgalia and oligodendrocyte.

Microglia

Microglia is a type of neuronal support cell (neuroglia) in the central nervous system of invertebrates and vertebrates that functions primarily as an immune cell. As the name microglia indicates, these cells are the smallest of all the neuroglia. Microglia nuclei are typically oval-shaped, and projecting out from their cell bodies are slender elongated processes that enable the cells to move via chemotaxis (moved along a chemical gradient). For many years the function of microglia was unclear. However, today it is known that microglia mediates immune responses in the central nervous system via acting as macrophages, clearing cellular debris and dead neurons from nervous tissue through the process of phagocytosis (cell eating)[12]. The phagocytic role of microglia is displayed during early embryonic brain development in which the microglia ingests cellular debris of excess neurons that have undergone programmed cell death. Microglia are involved in multiple sclerosis, including Parkinson’s disease, Alzheimer’s disease, retinal degenerative diseases, HIV dementia, and many other conditions.

Astrocyte

Astrocyte are characteristic star-shaped glial cells in the brain and spinal cord. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS. Astrocytes respond to all forms of CNS insults through a process referred to as reactive astrogliosis, which has become a pathological hallmark of CNS structural lesions[4]. Previously in medical science, the neuronal network was considered the only important function of astrocytes, and they were looked upon as gap fillers. Recently, emerging numerous evidences reveal that astrocyte plays a number of active roles in the brain and includes maintenance of the blood–brain barrier[5], transmitter uptake and release[6], regulation of ion concentration in the extracellular space[7], modulation of synaptic transmission[8], nervous system repair[9], et al. Besides that, accumulating studies have demonstrated that astrocyte plays a key role in several neurologic diseases, including Astrocytomas[10], autism spectrum disorders (ASDs), schizophrenia[11], and so on.

Oligodendrocyte

Oligodendrocytes, highly specialized neural cells, are the myelinating cells of the central nervous system (CNS), and like Schwann cells in the peripheral nervous system (PNS), ensheathe axonal processes by their processes[13][14]. They are the end product of a cell lineage which has to undergo a complex and precisely timed program of proliferation, migration, differentiation, and myelination to finally produce the insulating sheath of axons. In addition to myelinating oligodendrocytes, oligodendrocyte progenitor cells persist in the adult brain and are capable of regenerating myelinating oligodendrocytes. The key issues are to determine the factors that regulate oligodendrocyte differentiation and myelination, which are relevant to demyelinating diseases and basic neurobiology, such as multiple sclerosis.

The Markers and Function of The Cells in Nerve System

In this part, we conclude the markers of the specific neurons and neuroglia and show them in the table 1.

Table 1a The Markers of Neurons

types Function Target
Cholinergic neurons A cholinergic neuron is a nerve cell which mainly utilizes the neurotransmitter acetylcholine (ACh) to send its messages and provides the primary source of acetylcholine to the cerebral cortex, and promote cortical activation during both wakefulness and rapid eye movement sleep. ACHE SLC5A7
CHAT SLC18A3
Dopaminergic neurons Dopaminergic neurons of the midbrain are the main source of dopamine (DA) in the mammalian central nervous system. Dopamine is connected to mood and behavior and modulates both pre and post synaptic neurotransmission. Their loss is associated with one of the most prominent human neurological disorders. DBH SLC6A2
SLC6A3 NR4A2
FOXA2 PRKN
KCNJ6 TH
LMX1B TOR1A
GABAergic neurons GABAergic neuron is one type of nerve cells, generates gamma aminobutyric acid (GABA) which is one of the two inhibitory neurotransmitters in the central nervous system (CNS), the other being Glycine. GABA is synthesized from glutamate neurotransmitters by the enzyme glutamate decarboxylase. ABAT GABBR1
PPP1R1B GABBR2
SLC6A1 GAD2
SLC6A13 GAD1
SLC32A1
Glutamatergic neurons Glutamatergic neurons produce glutamate, which is one of two primary excitatory amino acid neurotransmitter in the central nervous system (CNS), the other being Aspartate. Glutamate receptors are one of four categories, three of which are ligand-gated ion channels and one of which is a G-protein coupled receptor (often referred to as GPCR). Glutamate can cause excitotoxicity when blood flow to the brain is interrupted, resulting in brain damage. FOLH1 SLC17A8
GRIN1 HDLBP
GRIN2B GLS
SLC14A2 SLC1A1
SLC17A7 SLC1A6
SLC17A6 GOT1
Serotonergic neurons Serotonergic neurons produce serotonin, which can act as excitatory or inhibitory. Of the four 5-HT receptor classes, 3 are GPCR and 1 is ligand gated cation channel. FEV TPH2
SLC6A4

Table 1b The Markers of Neuroglia

types Function Target
Astrocyte Astrocyte, also known collectively as astroglia, star-shaped cell that is a type of neuroglia found in the nervous system in both invertebrates and vertebrates. They perform many functions, including biochemical support of endothelial cells that form the blood–brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, and a role in the repair and scarring process of the brain and spinal cord following traumatic injuries. Astrocytes can be subdivided into fibrous and protoplasmic types. ALDH1L1 GFRA2
ATP1A3 GFRA3
TUBB3 GFRA4
ITGAM GFAP
CORO1A PINK1
SLC1A3 S100B
SLC1A2 SOX2
LGALS3 BIRC5
GAP43 TNFRSF19
GFRA1 VIM
SLC7A11
Microglia Microglia, known to react quickly in response to CNS injury or disease, proliferating and migrating into an injury site, are one of the three types of glial cells in the central nervous system (CNS). In contrast to neurons, astrocytes, and oligodendrocytes, they are not of ectodermal but rather of mesodermal origin. CD40LG CD68
PTPRC SLC2A5
AIF1
Oligodendrocyte Oligodendrocytes are neuroectodermally derived glial cells that have the major role of myelinating central axons. Their main functions are to provide support and insulation to axons in the central nervous system of some vertebrates, equivalent to the function performed by Schwann cells in the peripheral nervous system. Oligodendrocytes are found only in the central nervous system, which comprises the brain and spinal cord. ABCA2 RTN4R
CNTNAP2 OLIG1
CNP OLIG2
GALC OLIG3
MAG OMG
MBP CLDN11
RANGRF PDGFRA
RNF5 SOX10

References

[1] Jessen KR, Mirsky R. Glial cells in the enteric nervous system contain glial fibrillary acidic protein [J]. Nature. 1980, 286 (5774): 736–7.
[2] Carlson, Neil R. Physiology of Behavior (11th ed.) [M]. Pearson Higher Education. 2013, p. 28.
[3] Kandel, Eric; Schwartz, James; et al (2000). Principles of Neural Science (4th ed.) [M]. New York City, New York: McGraw Hill Companies. 2000, p. 25.
[4] Michael V. and Harry V. Vinters. Astrocytes: biology and pathology [J]. Acta Neuropathol. 2010 Jan; 119(1): 7–35.
[5] Figley CR, Stroman PW. The role(s) of astrocytes and astrocyte activity in neurometabolism, neurovascular coupling, and the production of functional neuroimaging signals [J]. The European Journal of Neuroscience. 2011, 33 (4): 577–88.
[6] Agulhon C, Fiacco T, et al. Hippocampal short- and long-term plasticity are not modulated by astrocyte Ca2+ signaling[J]. Science. 2010, 327 (5970): 1250–1257.
[7] Gabriel S, Njunting M, et al. Stimulus and Potassium-Induced Epileptiform Activity in the Human Dentate Gyrus from Patients with and without Hippocampal Sclerosis [J]. The Journal of Neuroscience. 2004, 24 (46): 10416–10430.
[8] Pascual O, Casper KB, et al. Astrocytic purinergic signaling coordinates synaptic networks [J]. Science. 2005, 310 (5745): 113–6.
[9] Anderson MA, Burda JE, et al. Astrocyte scar formation aids central nervous system axon regeneration [J]. Nature. 2016, 532 (7598): 195–200.
[10] Barker, AJ, Ullian, EM. New roles for astrocytes in developing synaptic circuits [J]. Communicative & integrative biology. 2008, 1 (2): 207–11.
[11] Sloan, SA, Barres, BA. Mechanisms of astrocyte development and their contributions to neurodevelopmental disorders [J]. Current Opinion in Neurobiology. 2014, 27C: 75–81.
[12] Nicolas G.Bazan, AnashehHalabi, et al. Basic Neurochemistry (Eighth Edition) [M]. 2012, Pages 610-620.
[13] B.M.Reuss. Encyclopedia of Neuroscience [M]. 2009, Pages 819-825.
[14] Monika Bradl, Hans Lassmann. Oligodendrocytes: biology and pathology [J]. Acta Neuropathol. 2010 Jan; 119(1): 37–53.

Neuronal Markers and Neurodegenerative Diseases

Neurons are highly specialized nerve cells that receive and transmit electrical or chemical signals to coordinate all of the necessary functions for life. Neurons are typically composed of a cell body, dendrites, an axon, and presynaptic terminals. The cell body contains a nucleus, Golgi body, endoplasmic reticulum, mitochondria, and other components. It is responsible for the synthesis of almost all neuronal proteins and membranes. Branch-like dendrites receive signals from other neurons and transmit signals to the cell body. The long tube-like axon, extending from the cell body, carries electrical impulses from the cell body to the axon terminals, which further passes the impulse to another neuron. The presynaptic terminals are structures on the end of an axon that can form