Chemokine-like factor-like MARVEL transmembrane domain containing member/chemokine-like factor superfamily member (CMTM/CKLFSF) including CKLF and CMTM1-CMTM8 are a new family of proteins linking chemokines and transmembrane superfamilies. CMTM not only have broad chemotactic activities, but also associate with hematopoietic system, immune system, and tumor development and metastasis closely. CMTM proteins are involved in key biological processes of cancer development, which include activation and recycling of growth factor receptors, cell proliferation and metastasis, and regulation of the tumor immune microenvironment. This is a new focus of research on the relationship between CMTM and tumors, because CMTM4/CMTM6 can be considered as a regulator for programmed cell death ligand 1 (PD-L1). This paper reviews the role of CMTM family members on cancer, especially in tumor growth, metastasis and immune escape, summarize the latest findings on the relationship between CMTM and non-small cell lung cancer, and explores the potential clinical value of CMTM as a novel drug target or biomarker.
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Humans ; Carcinoma, Non-Small-Cell Lung/pathology* ; Lung Neoplasms ; MARVEL Domain-Containing Proteins/metabolism* ; Cell Proliferation ; Chemokines/metabolism* ; Tumor Microenvironment

OBJECTIVE: To investigate whether CKLF-like MARVEL transmembrane domain-containing protein 2 (CMTM2) is involved in spermatogenesis in mice. CMTM2 is highly expressed in testis, and could possibly be a potential spermagogenesis specific gene. METHODS: CMTM2-deficient mouse model was generated. Northern, RT-PCR and Western blotting analysis were performed on total RNA derived from wild-type (WT, CMTM2+/+) and CMTM2+/- (heterozygote) and CMTM2-/-(homozygote) mice to examine the CMTM2 level. The number of litters and the number of pups were counted and pregnancy rates calculated. The motility and morphology of the sperm and the histology of testes were analyzed. Serum testosterone and FSH concentrations were also measured. Standard t-tests were used and standard error of means were calculated. RESULTS: CMTM2 was highly expressed in a finely regulated pattern in the mouse testis during spermatogenesis. The body weight of adult mice with CMTM2 deficiency was not significantly different from that of wild type mice. No obvious anatomical or behavioral abnormalities were observed. The testis of CMTM2-/- was smaller than that of CMTM2+/+ mice. The testis diameter in wild mice and CMTM2 null mice were (11.32±1.21) mm vs. (8.29±1.92) mm (P<0.05), and the weights were (101.63±2.33) mg vs. (85.22±2.84) mg (P<0.05), respectively. Female CMTM2 null mice were fertile, indicating that CMTM2 was not required for female gametogenesis. The CMTM2-/- mice produced virtually no sperm, and CMTM2+/- mice sperm count showed a significant decline. In terms of sperm morphorlogy study, more round spermatids could be observed in the heterozygote group, compared with the wild type group; while in the homozygote group, a large amount of round spermatids could be observed because of complete arrest of spermiogenesis. The hormone levels were not significantly different. The CMTM2-/- male mice were sterile due to a late, complete arrest of spermiogenesis. The organized architecture of the seminiferous epithelium of the seminiferous tubules seen in CMTM2+/+ mice was lost in CMTM2-/- mice. CONCLUSION This study suggests CMTM2 is not required for embryonic development in the mouse but is essential for spermiogenesis, however, further studies are required for more detailed mechanism study.
Animals ; Chemokines/metabolism* ; Female ; Heterozygote ; MARVEL Domain-Containing Proteins/metabolism* ; Male ; Mice ; Mice, Knockout ; Pregnancy ; Spermatogenesis ; Spermatozoa ; Testis

Chemokine-like factor super family member (CMTM) is a novel generic family firstly reported by Peking University Center for Human Disease Genomics. CMTM8 is one member of this family and has exhibited tumor-inhibiting activities. It can encode proteins approaching to the transmembrane 4 superfamily. CMTM8 is down-regulated in most carcinoma cell lines and tissues. Over-expression of CMTM8 may inhibit the proliferation,migration,and invasion of carcinoma cells. However,the exact mechanism of its anti-tumor activity remains unclear. CMTM8 may be involved in various signaling pathways governing the occurrence and development of tumors. CMTM8 may be a new target in the gene therapies for tumors,while further studies on CMTM8 and its anti-tumor mechanisms are warranted.
Chemokines ; metabolism ; Down-Regulation ; Humans ; MARVEL Domain-Containing Proteins ; metabolism ; Neoplasms ; metabolism ; Signal Transduction

Chemokine-like factor 1 (CKLF1) is a newly cloned chemotactic cytokine with CCR4 being its functional receptor. Recent evidence demonstrates a role of CKLF1 in arthritis. The aim of this study was to quantify the expression of CKLF1 as well as assess the correlation between CKLF1 and plasma acute-phase markers. Synovium was obtained from 16 osteoarthritis (OA), 15 rheumatoid arthritis (RA) and 10 ankylosing spondylitis (AS) patients undergoing total joint arthroplasty, with other 11 patients treated for meniscal tears during sport accidents serving as normal controls. Levels of CKLF1 and CCR4 mRNA were detected by qRT-PCR, and the expression of CKLF1 was investigated by immunohistochemistry staining, subsequently analyzed with semiquantitative scores. Plasma acute-phase markers of inflammation were determined by ELISA. CKLF1 was found with a particularly up-regulated expression in synovim from AS and RA patients, and CCR4 mRNA levels increased in RA patients, not in OA or AS patients. Elevated levels of plasma markers of inflammation including CRP, ESR and D-dimer were observed in RA. Further, significantly positive correlations between relative expression levels of CKLF1 and CRP/ESR in RA patients and a positive correlation between CKLF1 and ESR in AS patients were found. There was no detectable correlation between CKLF1 and plasma D-dimer. This study confirms an increased but different level of CKLF1 in RA, OA and AS patients, all significantly higher than that in controls. Additionally, the significant positive correlations between CKLF1 levels and CRP/ESR in RA and between CKLF1 and ESR suggest that CKLF1 might contribute to the inflammation state and clinical symptoms in these rheumatic diseases. Further studies are required to investigate the utility of targeting specific CKLF1 for symptom control or disease modification in RA and AS.
Adult ; Arthritis, Rheumatoid ; metabolism ; Biomarkers ; metabolism ; Case-Control Studies ; Chemokines ; genetics ; metabolism ; Female ; Humans ; MARVEL Domain-Containing Proteins ; genetics ; metabolism ; Male ; Middle Aged ; Osteoarthritis ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Receptors, CCR4 ; genetics ; metabolism ; Spondylitis, Ankylosing ; metabolism ; Synovial Fluid ; metabolism

OBJECTIVETo observe the effects of CMTM2 on cyclophosphamide (CP)-induced reproductive toxicity and the expression of steroidogenic acute regulatory (StAR) protein in the transgenic mouse model.

METHODSTwenty CMTM2 transgenic mice were equally divided into a CMTM2 + CP and a CMTM2 + NS group, the former intraperitoneally injected with CP at 50 mg per kg per d, while the latter with the equivalent dose of normal saline, both for 7 days. Another 20 wild C57BL/6J mice were randomly assigned to a WT + CP and a WT + NS group, treated the same way above. After 30 days, all the mice were sacrificed and their epididymides and testes removed for measurement of the serum testosterone level by radioimmunoassay, determination of sperm concentration and motility by light microscopy and detection of the expression of StAR by Western blot.

RESULTSThe levels of serum testosterone, sperm concentration and sperm motility were significantly decreased in the CMTM2 + CP group as compared with the CMTM2 + NS group ([42.98 +/- 3.25] nmol/L vs [46.74 +/- 3.38] nmol/L, [16.89 +/- 1.17 ] x 10(6)/ml vs [24.68 +/- 0.95 ] x 10(6)/ml, [72.75 +/- 1.25]% vs [85.14 +/- 1.12]%, P < 0.05), but remarkably less than in the WT + CP group ([37.97 +/- 4.17] nmol/L, [12.75 +/- 1.02] x 10(6)/ml, [50.52 +/- 1.37] %) (P < 0.05). However, the expression of StAR was significantly higher in the CMTM2 + CP than in the WT + CP group (1.16 +/- 0.07 vs 0.69 +/- 0.08, P < 0.05).

CONCLUSIONCMTM2 antagonizes cyclophosphamide-induced reproductive toxicity via regulating the expression of StAR, and hence plays a protective role in the reproductive system.

Animals ; Cyclophosphamide ; toxicity ; MARVEL Domain-Containing Proteins ; genetics ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Repressor Proteins ; genetics ; Sperm Count ; Sperm Motility ; Testis ; drug effects ; metabolism

CKLF-like MARVEL transmembrane domain containing member(CMTM)is a novel generic family firstly reported by Peking University Center for Human Disease Genomics. CMTM5 belongs to this family and has exhibited tumor-inhibiting activities. It can encode proteins approaching to the transmembrane 4 superfamily(TM4SF). CMTM5 is broadly expressed in normal adult and fetal human tissues, but is undetectable or down-regulated in most carcinoma cell lines and tissues. Restoration of CMTM5 may inhibit the proliferation, migration, and invasion of carcinoma cells. Although the exact mechanism of its anti-tumor activity remains unclear, CMTM5 may be involved in various signaling pathways governing the occurrence and development of tumors. CMTM5 may be a new target in the gene therapies for tumors, while further studies on CMTM5 and its anti-tumor mechanisms are warranted.
Chemokines ; genetics ; metabolism ; Humans ; MARVEL Domain-Containing Proteins ; genetics ; metabolism ; Neoplasms ; genetics ; metabolism ; Signal Transduction ; Tumor Suppressor Proteins ; genetics ; metabolism

OBJECTIVETo investigate the inhibitory effect of CKLF-like MARVEL transmembrane domain containing 5 (CMTM5) on xenografted human prostatic cancer in nude mice and its action mechanism.

METHODSWe established a model of xenografted prostatic cancer by inoculating PC-3 cells subcutaneously into nude mice, and 3 weeks later injected CMTM5 adenovirus locally into the tumor followed by daily observation of the tumor volume and body weight of the experimental animals. All the rats were killed 2 weeks after CMTM5 injection and the tumor tissue harvested for detection of the inhibitory effect of CMTM5 on the expressions of VEGF and NF-kappaB proteins by immunohistochemistry.

RESULTSThe tumor volume was significantly smaller and body weight of the CMTM5-treated mice were (573.39 +/- 175.24) mm3 and (0.55 +/- 0.11) g, respectively, significantly decreased as compared with those of the controls ([1482.50 +/- 327.86] mm3 and [1.31 +/- 0.29] g) (P = 0.03 and P = 0.027). Immunohistochemistry showed that the expressions of VEGF and NF-kappaB were obviously down-regulated in the CMTM5 group in comparison with the control group.

CONCLUSIONCMTM5 suppresses the growth of prostate cancer by down-regulating the expressions of VEGF and NF-kappaB.

Adenoviridae ; genetics ; Animals ; Cell Line, Tumor ; Chemokines ; genetics ; pharmacology ; Gene Expression Regulation, Neoplastic ; Humans ; MARVEL Domain-Containing Proteins ; genetics ; pharmacology ; Male ; Mice ; Mice, Nude ; NF-kappa B ; metabolism ; Prostatic Neoplasms ; metabolism ; Tumor Suppressor Proteins ; genetics ; pharmacology ; Vascular Endothelial Growth Factor A ; metabolism ; Xenograft Model Antitumor Assays

BACKGROUNDThe CKLF-like MARVEL transmembrane domain-containing family (CMTM) is a novel family of proteins linking chemokines and TM4SF. Different members exhibit diverse biological functions. In this study, the effect of intracellular CMTM2 on regulating human immunodeficiency virus type-1 (HIV-1) transcription was evaluated.

METHODSThe effects of CMTM2 on regulating full-length HIV-1 provirus and the HIV-1 long terminal repeat (LTR)-directed transcription were assessed by luciferase assay. Transcription factor assays, using the luciferase reporter plasmids of AP-1, CRE, and NF-κB were conducted to explore the signaling pathway(s) that may be regulated by CMTM2. The potential relationship between CMTM2 and the transcription factor AP-1 was further analyzed by Western blotting analyses to investigate the effect of CMTM2 on PMA-induced ERK1/2 phosphorylation.

RESULTSThe results from the current study revealed that CMTM2 acts as a negative regulator of HIV-1 transcription. CMTM2 exerted a suppressive action on both full-length HIV-1 provirus and HIV-1 LTR-directed transcription. Transcription factor assays showed that CMTM2 selectively inhibited basal AP-1 and CREB activity. Co-expression of HIV-1 Tat, a potent AP-1 and CREB activator, can not reverse CMTM2-mediated AP-1 and CREB inhibition, suggesting a potent and specific effect of CMTM2 on negatively regulating these two signaling pathways.

CONCLUSIONIntracellular CMTM2 can negatively regulate HIV-1 transcription, at least in part, by targeting the AP-1 and CREB pathways. Exploring the mechanisms further may lead to new ways to control HIV-1 replication.

Chemokines ; physiology ; Cyclic AMP Response Element-Binding Protein ; antagonists & inhibitors ; HIV Long Terminal Repeat ; HIV-1 ; genetics ; Humans ; Intracellular Space ; metabolism ; Jurkat Cells ; MARVEL Domain-Containing Proteins ; Tetradecanoylphorbol Acetate ; pharmacology ; Transcription Factor AP-1 ; antagonists & inhibitors ; Transcription, Genetic ; U937 Cells

This study was aimed to detect the expression level of cmtm 5 (CKLF-like MARVEL transmembrane domain containing member 5) gene in the bone marrow cells from patients with multiple myeloma (MM), and to investigate the correlation between the expression level of cmtm5 and various clinical characteristics. Real-time quantitative reverse transcription polymerase chain reaction (RQ-RT-PCR) was used to measure the expression levels of cmtm5 gene in the bone marrow cells collected from MM patients, and the MM cell lines, namely, RPMI8226 and CZ1 cells. The normal donor marrow specimens were used as the reference. The ratio of cmtm5 copy number to abl (Abelson murine leukemia viral oncogene homolog) gene copy number was used for indicating the expression level. The results showed that the expression level of cmtm5 gene was significantly down-regulated in bone marrow cells of 51 untreated or relapsed/refractory MM patient as compared to those of normal donor marrow cells (0.047+/-0.062 for the untreated or relapsed/refractory MM patients versus 0.255+/-0.333 for the normal, p<0.01). According to the International Staging System (ISS), the cmtm5 expression level in marrow cells of patients in ISS III stage was significantly lower than that in patients in ISS I stage (0.034+/-0.034 for the ISS III stage versus 0.103+/-0.109 for ISSI stage, p<0.01). Similarly, lower expression levels of cmtm5 gene were also found in two human MM cell lines (0.014+/-0.009 for RPMI8226 cells and 0.004+/-0.006 for CZ1 cells). After the MM patients were effectively treated, their expression levels of cmtm5 gene significantly increased (0.020+/-0.005 for the untreated patients versus 0.227+/-0.038 for the effectively treated patients, p<0.01). A significant negative correlation was observed between the expression level of cmtm5 gene and the number of bone marrow plasma cells (r=-0.307, p<0.05). However, the correlation was not found between the expression level of cmtm5 gene and the clinical characteristics, such as gender, age, hemoglobin level, or M-protein level, etc. It is concluded that the expression level of cmtm5 gene is abnormally lower in the bone marrow cells from the MM patients, and are associated with ISS stages. Furthermore, the expression level of cmtm5 gene is negatively correlated with the number of bone marrow abnormal plasma cells in MM patients, which suggests that the abnormally lower expression of cmtm5 may be involved in the pathogenesis of the MM patients.
Adult ; Aged ; Aged, 80 and over ; Bone Marrow Cells ; metabolism ; pathology ; Case-Control Studies ; Chemokines ; genetics ; metabolism ; Female ; Humans ; MARVEL Domain-Containing Proteins ; Male ; Middle Aged ; Multiple Myeloma ; metabolism ; pathology ; Neoplasm Staging ; Tumor Suppressor Proteins ; genetics ; metabolism ; Young Adult

OBJECTIVETo evaluate the difference of the expression level of chemokine-like factor 1 (CKLF1) mRNA and protein between human atherosclerotic plaques and normal arteries.

METHODSReal-time quantitative PCR was performed with experimental group (24 cases of atherosclerotic plaques) specimens and control group (25 cases of normal arteries) specimens. Serial microscopic sections were used for immunohistochemistry with CKLF1 antibody in 17 experimental group specimens and 10 control group specimens.

RESULTSThe endothelial cell, vascular smooth muscle cell (VSMC) and macrophage were CKLF1 positive expression cells in atherosclerotic plaques. There was a foundational expression of CKLF1 mRNA in control group (RQ(Median) = 2.4), and the expression of CKLF1 mRNA in experimental group is up-regulated significantly (RQ(Median) = 132.2, P < 0.05). The VSMC positive expression rate of CKLF1 protein was 100% in experimental group and 70% in control group, the former was up-regulated significantly.

CONCLUSIONSThe expression of CKLF1 is up-regulated in atherosclerotic plaques. It may play an important role in the process of immune and inflammatory responses of atherogenesis.

Adult ; Arteries ; metabolism ; Atherosclerosis ; metabolism ; Case-Control Studies ; Chemokines ; genetics ; metabolism ; Humans ; MARVEL Domain-Containing Proteins ; Plaque, Atherosclerotic ; metabolism ; RNA, Messenger ; genetics ; Young Adult