CKLF-like MARVEL Transmembrane Domain-containing Member Research Articles

Comprehensive analysis of N6-methyladenosine -related long non-coding RNAs and immune cell infiltration in hepatocellular carcinoma

ABSTRACT We aimed to illustrate the influence of N6-methyladenosine (m6A) long non-coding RNAs (lncRNAs) and immune cell infiltration in hepatocellular carcinoma (HCC). The relationship of lncRNAs and m6A was identified through gene expression analysis using PERL and R packages. The Kyoto Encyclopedia of Genes and Genomes gene expression enrichment analysis was performed via gene set enrichment analysis. Lasso regression was utilized to construct prognostic model. Differences in the tumor microenvironment and the immune correlation were analyzed to clarify immune cell infiltration in different clusters and their correlation with the clinical prognosis. Co-expression analysis showed that lncRNA expression was associated closely with m6A. Many lncRNAs were predictive risk factors of prognosis in HCC. m6A-lncRNAs were partially highly expressed in tumor tissue and could be used in a prognostic model to predict HCC prognosis, independent of other clinical characteristics. ‘NOTCH SIGNALING PATHWAY’ was most significantly enriched according to GSEA. CKLF-like MARVEL transmembrane domain-containing member 3 (CMTM3) was overexpressed in tumor tissue. Immune cells, such as activated CD4 memory T cells, CD8 T cells, and follicular helper T cells, highly infiltrated tissues in cluster 2. All related scores were higher in cluster 2, indicating a lower purity of tumor cells and higher density of immune-related cells in the tumor microenvironment. m6A-lncRNAs are closely related to HCC occurrence and progression. Corresponding prognostic models can help predict HCC prognosis. m6A-lncRNAs and the related immune cell infiltration in the tumor microenvironment can provide novel therapeutic targets in HCC that need to be further studied.

CMTM5-v1 inhibits cell proliferation and migration by downregulating oncogenic EGFR signaling in prostate cancer cells.

Anomalous epidermal growth factor receptor (EGFR) signaling plays an important role in the progression of prostate cancer (PCa) and the transformation to castration-resistant PCa (CRPC). A novel tumor suppressor CKLF-like MARVEL transmembrane domain-containing member 5(CMTM5) has a MARVEL domain and may regulate transmembrane signaling. Thus, we postulated that CMTM5 could regulate EGFR and its downstream molecules to affect the biological behaviors of PCa cells. In this study, we found that CMTM5 was expressed in benign prostatic hyperplasia (BPH) tissues but was undetectable in PCa cells. However, the EGFR was upregulated in PCa cells, especially in two metastatic CRPC cell lines, PC3 and DU145. Furthermore, ectopic expression of CMTM5-v1 suppressed cell proliferation and migration and p-EGFR levels. Further investigation revealed that restoration of CMTM5-v1 inhibited not only EGF-mediated proliferation but also chemotactic migration by EGF in PC3 and DU145 cells. Moreover, mechanistic studies showed that CMTM5-v1 attenuated EGF-induced receptor signaling by repressing EGFR and Akt phosphorylation in PCa cells, which were essential for malignant features. Finally, CMTM5-v1can promote the sensitivity of PC3 cells to Gefetinib, a tyrosine kinase inhibitor (TKI) targeting the EGFR. These observations indicate that CMTM5-v1 suppressed PCa cells through EGFR signaling. The loss of CMTM5 may participate in the progression of PCa resulting from deregulated EGFR, and CMTM5 might be associated with the efficacy of TKIs in terms of their potent inhibition of EGFR and human epidermal growth factor-2 (HER2) activation.

Research Advances in CKLF-like MARVEL Transmembrane Domain-containing Family in Non-small Cell Lung Cancer.

CKLF-like MARVEL transmembrane domain-containing member (CMTM) is a new gene family first cloned and reported in 2001. The CMTM family consists of nine members including CKLF and CMTM1-CMTM8, which are located on different chromosomes. Besides exhibiting extensive chemotactic activity, the CMTM family plays an important role in the hematopoiesis system, the immune system, the cardiovascular system and the male reproductive system. Recent in-depth research has also revealed that CMTM is closely associated with the genesis, development and metastasis of tumors, displaying opposing activities in diverse human tumors. In this review, we discuss the structural and functional characteristics of the CMTM family and summarize latest research findings of the relationship between several CMTM members and non-small cell lung cancer.

AB179. CMTM3 is reduced in prostate cancer and inhibits migration, invasion and growth of LNCaP cells

ObjectiveA novel tumor suppressor gene (TSG) CKLF-like MARVEL transmembrane domain-containing member 3 (CMTM3) is reduced or undetectable in many kinds of cancers and relates tumor malignant features. We detected its role in prostate cancer for possibility of target therapy as accumulating evidence has shown that CMTM3 is a promising TSG for gene therapy.MethodsThe expression of CMTM3 detected in prostate tissue microarray, specimens and cell lines were evaluated by immunohistochemistry and semi-quantitative PCR and Western blot, respectively. After being transfected with CMTM3 adenovirus or vector (mock), the proliferation and migration and invasion of LNCaP cells were detected by transwell assay and matrigel assay, respectively. Furthermore, the effects of CMTM3 on tumor growth were performed in nude mice xenograft in vivo.ResultsWe found CMTM3 was reduced in PCa tissues and cells, compared with BPH tissues, and its expression in PCa tissues was related to the Gleason score. Moreover, after being transfected with adenovirus, ectopic expression of CMTM3 in LNCaP cells led to significant inhibition of cell proliferation and migration and invasion compared with the control (P<0.05), which may be attributed to decreased Erk1/2 activity as p-Erk1/2 was remarkably reduced when CMTM3 was overexpressed. Finally, restoration of CMTM3 significantly suppressed xenograft tumor growth in vivo (P<0.01).ConclusionsCMTM3 is reduced in prostate cancer and acts an important role in vivo and ex vivo. Prostate cancer is an urgently need to be cured disease in man’s urogenital system. CMTM3 maybe one of the key point worth further research and application.

CMTM3 is reduced in prostate cancer and inhibits migration, invasion and growth of LNCaP cells

A novel tumor suppressor gene CKLF-like MARVEL transmembrane domain-containing member 3 (CMTM3) is reduced or undetectable in many kinds of cancers and relates tumor malignant features. We detected its role in prostate cancer for possibility of target therapy as accumulating evidence has shown that CMTM3 is a promising tumor suppressor gene (TSG) for gene therapy. The expression of CMTM3 detected in prostate tissue microarray, specimens and cell lines were evaluated by immunohistochemistry and semi-quantitative PCR and Western blot, respectively. After being transfected with CMTM3 adenovirus or vector (mock), the proliferation and migration and invasion of LNCaP cells were detected by transwell assay and matrigel assay, respectively. Furthermore, the effects of CMTM3 on tumor growth were performed in nude mice xenograft in vivo. We found CMTM3 was reduced in PCa tissues and cells compared with BPH tissues, and its expression in PCa tissues was related to the Gleason score. Moreover, after being transfected with adenovirus, ectopic expression of CMTM3 in LNCaP cells led to significant inhibition of cell proliferation and migration and invasion compared with the control (P<0.05), which may be attributed to decreased Erk1/2 activity as p-Erk1/2 was remarkably reduced when CMTM3 was overexpressed. Finally, restoration of CMTM3 significantly suppressed xenograft tumor growth in vivo (P<0.01).

CMTM3 inhibits cell growth and migration and predicts favorable survival in oral squamous cell carcinoma.

Downregulation of CKLF-like MARVEL transmembrane domain-containing member 3 (CMTM3) has been reported in a number of human tumors. However, the role of CMTM3 in oral squamous cell carcinoma (OSCC) remains largely unknown. In this study, we showed that the expression of CMTM3 was significantly reduced in OSCC cell lines and primary tumor specimens (P < 0.001). Methylation-specific PCR showed hypermethylation in CMTM3 promoter in a significant proportion of tumor tissues (61 %). The expression of CMTM3 was associated with T stage, lymph node metastasis, tumor node metastasis (TNM) stage, and recurrence of OSCC patients (P < 0.05, n = 201). More importantly, CMTM3 expression was associated with the prognosis of OSCC patients (P < 0.001) and was an independent prognostic factor (hazard ratio = 0.593, 95 % confidence interval, 0.272-1.292; P = 0.039). Overexpression of CMTM3 inhibited the growth and migration of OSCC cells. In vivo experiments also showed that the growth of OSCC xenografts in nude mice was significantly inhibited by CMTM3 overexpression. These findings indicate that downregulation of CMTM3 due to promoter hypermethylation contributed to the proliferation and migration of OSCC cells and suggest that CMTM3 is an independent prognostic factor for the evaluation of the survival of OSCC patients.

CMTM5 is reduced in prostate cancer and inhibits cancer cell growth in vitro and in vivo.

A novel tumor suppressor CKLF-like MARVEL transmembrane domain-containing member 5 (CMTM5) is reduced or undetectable in many kinds of cancers and inhibits tumor cells' malignant features. To explore its role in prostate cancer (PCa), we detected its expression patterns in prostate tissues and PCa cells, and determined its anti-proliferation functions in PCa cells in vitro and in vivo. The expression of CMTM5 in prostate tissue microarray, specimens and cell lines was evaluated by immunohistochemistry and Western blot, respectively. After being transfected with CMTM5 adenovirus or vector, the proliferation and migration of DU145 cells were detected by MTT assay and transwell assay, respectively. Furthermore, the effects of CMTM5 on tumor growth were performed in nude mice xenograft in vivo. We found CMTM5 was reduced in PCa tissues and cells compared with BPH tissues, and its expression in PCa tissues was related to the Gleason score. Moreover, after being transfected with adenovirus, ectopic expression of CMTM5-v1 in DU145 cells led to significant inhibition of cell proliferation and migration compared with the control, which may be attributed to decreased Akt activity. Finally, restoration of CMTM5 significantly suppressed tumor growth in vivo. These results indicate that CMTM5 is down-regulated in PCa and exhibit tumor suppressor activities in androgen-independent PCa cells. Loss of CMTM5 protein may be contributed to the development of PCa and it is a potential therapeutic target for castration-resistant prostate cancer.

CMTM5 exhibits tumor suppressor activity through promoter methylation in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common types of malignancies in the head and neck region. CKLF-like MARVEL transmembrane domain-containing member 5 (CMTM5) has been recently implicated as a tumor suppressor gene in several cancer types. Herein, we examined the expression and function of CMTM5 in oral squamous cell carcinoma. CMTM5 was down-regulated in oral squamous cell lines and tumor samples from patients with promoter methylation. Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored CMTM5 expression. In the OSCC cell lines CAL27 and GNM, the ectopic expression of CMTM5-v1 strongly inhibited cell proliferation and migration and induced apoptosis. In addition, CMTM5-v1 inhibited tumor formation in vivo. Therefore, CMTM5 might act as a putative tumor suppressor gene through promoter methylation in oral squamous cell carcinoma.

Research advances in CKLF-like MARVEL transmembrane domain containing member 5

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.

Expressional and functional studies of CKLF1 during dendritic cell maturation

Chemokine-like factor 1 (CKLF1) was the first member of the CKLF-like MARVEL transmembrane domain containing member (CMTM) family to be discovered. Its expression level is increased clearly in peripheral blood lymphocytes upon phytohemagglutinin stimulation, but little is known about the expression and function of CKLF1 in dendritic cells (DCs), which are the most potent antigen-presenting cells. In the present study, we showed that CKLF1 was highly expressed in monocytes. During differentiation from monocytes to immature DCs, CKLF1 was increased dramatically on day 2 and then decreased from day 3 to 5. Upon maturation with different stimuli, CKLF1 was down-regulated. Two peptides of CKLF1, C19 and C27, stimulated the effect of immature DCs (imDCs) on T-cell proliferation and IFN-γ production. Further study on DC maturation showed that C19 and C27 up-regulated HLA-DR expression and IL-12 secretion, with no obvious effects on CD80, CD83 or CD86. Thus, CKLF1-C19 and -C27 can stimulate antigen-presenting capability of imDCs.

CMTM5 induces apoptosis of pancreatic cancer cells and has synergistic effects with TNF-α

Our previous data show that CKLF-like MARVEL transmembrane domain-containing member 5 ( CMTM5) is a potential tumor suppressor gene, but its function in pancreatic cancer is unknown. Herein we first report that CMTM5 is also absent in pancreatic cancer cell lines with promoter methylation. Compared with normal pancreatic tissues, CMTM5 is significantly decreased in cancer tissues. Restoration of CMTM5-v1 not only induces MIA PaCa-2 cell apoptosis with activation of caspase 3, 8 and 9, but also has synergistic effects with TNF-α. Thus, CMTM5 may play a role in the pancreatic cancer.

CMTM3, Located at the Critical Tumor Suppressor Locus 16q22.1, Is Silenced by CpG Methylation in Carcinomas and Inhibits Tumor Cell Growth through Inducing Apoptosis

Closely located at the tumor suppressor locus 16q22.1, CKLF-like MARVEL transmembrane domain-containing member 3 and 4 (CMTM3 and CMTM4) encode two CMTM family proteins, which link chemokines and the transmembrane-4 superfamily. In contrast to the broad expression of both CMTM3 and CMTM4 in normal human adult tissues, only CMTM3 is silenced or down-regulated in common carcinoma (gastric, breast, nasopharyngeal, esophageal, and colon) cell lines and primary tumors. CMTM3 methylation was not detected in normal epithelial cell lines and tissues, with weak methylation present in only 5 of 35 (14%) gastric cancer adjacent normal tissues. Furthermore, immunohistochemistry showed that CMTM3 protein was absent in 12 of 35 (34%) gastric and 1 of 2 colorectal tumors, which was well correlated with its methylation status. The silencing of CMTM3 is due to aberrant promoter CpG methylation that could be reversed by pharmacologic demethylation. Ectopic expression of CMTM3 strongly suppressed the colony formation of carcinoma cell lines. In addition, CMTM3 inhibited tumor cell growth and induced apoptosis with caspase-3 activation. Thus, CMTM3 exerts tumor-suppressive functions in tumor cells, with frequent epigenetic inactivation by promoter CpG methylation in common carcinomas.

CMTM5-v1 induces apoptosis in cervical carcinoma cells

CMTM5 (CKLF-like MARVEL transmembrane domain-containing member 5) exhibits tumor inhibition activity with frequent epigenetic inactivation in various tumor cell lines including cervical carcinoma (CC) cells. In this paper, we examined the function of CMTM5-v1 (the primary RNA splicing form) in both HeLa and SiHa cells. Overexpression of CMTM5-v1 in both cells can induce apoptosis, but the effects are more obvious in SiHa than that in HeLa. In SiHa cells, restoration of CMTM5-v1 caused disruption of mitochondrial transmembrane potential, release of cytochrome c, activation of caspase3 and cleavage of PARP. General caspase inhibitor almost prevented apoptosis of SiHa cells, suggesting that CMTM5-v1 induces apoptosis mainly through caspase-dependent pathway. These findings verify that CMTM5-v1 inhibits the growth of CC cell lines via inducing apoptosis.