CMTM3 can affect the transcription activity of androgen receptor and inhibit the expression level of PSA in LNCaP cells

Chemokine-Like Factor-Like MARVEL Transmembrane Domain-Containing Family in Hepatocellular Carcinoma: Latest Advances

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTMs) is a new gene family, consisting of CKLF and CMTM1 to CMTM8, which plays an important role in hematopoiesis system, autoimmune diseases, male reproduction etc. Abnormal expression of CMTMs is also associated with tumor genesis, development and metastasis. In this review, we briefly describe the characteristics of CMTM family, outline its functions in multiple kinds of carcinomas, and summarize the latest research on their roles in hepatocellular carcinoma which are mainly related to the expression, prognostic effect, potential functions, and mechanism of action. The CMTM family is expected to provide new ideas and targets for HCC diagnosis and treatment.

miR-149-5p Regulates Goat Hair Follicle Stem Cell Proliferation and Apoptosis by Targeting the CMTM3/AR Axis During Superior-Quality Brush Hair Formation

The Yangtze River Delta white goat is a unique goat species that can produce superior quality brush hair. CKLF-like MARVEL transmembrane domain-containing 3 (CMTM3), which influences the transcriptional activity of androgen receptor (AR), was identified as a candidate gene related to superior-quality brush hair formation. CMTM3 is generally expressed at low levels, but miR-149-5p is highly expressed in the skin tissues of these goats. The mechanism by which CMTM3 regulates the proliferation and apoptosis of goat hair follicle stem cells has not been elucidated. Here, RT-qPCR, western blotting, 5-ethynyl-2′-deoxyuridine (EdU), cell cycle, apoptosis, and dual-luciferase assays were used to investigate the role and regulatory mechanism of CMTM3 and miR-149-5p. Functional studies showed that CMTM3 overexpression inhibited proliferation and induced apoptosis in cultured hair follicle stem cells, whereas silencing CMTM3 markedly facilitated cell proliferation and deterred apoptosis in cultured hair follicle stem cells. Then, using bioinformatic predictions and the aforementioned assays, including dual-luciferase assays, RT-qPCR, and western blotting, we confirmed that miR-149-5p targets CMTM3 and preliminarily investigated the interaction between CMTM3 and AR in goat hair follicle stem cells. Furthermore, miR-149-5p overexpression significantly accelerated the proliferation and attenuated the apoptosis of hair follicle stem cells. Conversely, miR-149-5p inhibition suppressed the proliferation and induced the apoptosis of hair follicle stem cells. These results reveal a miR-149-5p-related regulatory framework for the miR-149-5p/CMTM3/AR axis during superior quality brush hair formation, in which CMTM3 plays a negative role.

CMTM family proteins 1-8: roles in cancer biological processes and potential clinical value

The CKLF-like MARVEL transmembrane domain containing (CMTM) family of genes comprises CKLF and CMTM1–8 (previously called chemokine-like factor superfamily 1–8, CKLFSF1–8). The CMTM family proteins contain a structurally conserved MAL and related proteins for vesicle trafficking and membrane linking (MARVEL) domain. Dysregulated expression of multiple CMTM family members is a common feature in many human cancer types. CMTM proteins control critical biological processes in cancer development, including growth factor receptor activation and recycling, cell proliferation, apoptosis, metastasis, and immune evasion. Emerging in vivo and in vitro evidence indicates that the mechanisms of action of most CMTM proteins are complex and multifactorial. This review highlights new findings regarding the roles of CMTM1–8 in cancer, particularly in tumor growth, metastasis, and immune evasion. Additionally, the potential clinical value of CMTMs as novel drug targets or biomarkers is discussed.

Novel Mutations Segregating with Complete Androgen Insensitivity Syndrome and their Molecular Characteristics

We analyzed three cases of Complete Androgen Insensitivity Syndrome (CAIS) and report three hitherto undisclosed causes of the disease. RNA-Seq, Real-timePCR, Western immunoblotting, and immunohistochemistry were performed with the aim of characterizing the disease-causing variants. In case No.1, we have identified a novel androgen receptor (AR) mutation (c.840delT) within the first exon in the N-terminal transactivation domain. This thymine deletion resulted in a frameshift and thus introduced a premature stop codon at amino acid 282. In case No.2, we observed a nonsynonymous mutation in the ligand-binding domain (c.2491C>T). Case No.3 did not reveal AR mutation; however, we have found a heterozygous mutation in CYP11A1 gene, which has a role in steroid hormone biosynthesis. Comparative RNA-Seq analysis of CAIS and control revealed 4293 significantly deregulated genes. In patients with CAIS, we observed a significant increase in the expression levels of PLCXD3, TM4SF18, CFI, GPX8, and SFRP4, and a significant decrease in the expression of SPATA16, TSACC, TCP10L, and DPY19L2 genes (more than 10-fold, p < 0.05). Our findings will be helpful in molecular diagnostics of patients with CAIS, as well as the identified genes could be also potential biomarkers for the germ cells differentiation process.

Integrated Analyses of Phenotype and Quantitative Proteome of CMTM4 Deficient Mice Reveal Its Association with Male Fertility

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family that has been implicated in male reproduction. CMTM4 is an evolutionarily conserved member that is highly expressed in the testis. However, its function in male fertility remains unknown. Here, we demonstrate that CMTM4 is associated with spermatogenesis and sperm quality. Using Western blotting and immunohistochemical analyses, we found CMTM4 expression to be decreased in poor-quality human spermatozoa, old human testes, and testicular biopsies with nonobstructive azoospermia. Using CRISPR-Cas9 technology, we knocked out the Cmtm4 gene in mice. These Cmtm4 knockout (KO) mice showed reduced testicular daily sperm production, lower epididymal sperm motility and increased proportion of abnormally backward-curved sperm heads and bent sperm midpieces. These mice also had an evident sub-fertile phenotype, characterized by low pregnancy rates on prolonged breeding with wild type female mice, reduced in vitro fertilization efficiency and a reduced percentage of acrosome reactions. We then performed quantitative proteomic analysis of the testes, where we identified 139 proteins to be downregulated in Cmtm4-KO mice, 100 (71.9%) of which were related to sperm motility and acrosome reaction. The same proteomic analysis was performed on sperm, where we identified 3588 proteins with 409 being differentially regulated in Cmtm4-KO mice. Our enrichment analysis showed that upregulated proteins were enriched with nucleosomal DNA binding functions and the downregulated proteins were enriched with actin binding functions. These findings elucidate the roles of CMTM4 in male fertility and demonstrates its potential as a promising molecular candidate for sperm quality assessment and the diagnosis or treatment of male infertility.

[Pathophysiologic mechanism of CMTM5 low expression in multiple myeloma progression]

目的

探索趋化素样因子超家族成员CMTM5表达对多发性骨髓瘤（MM）细胞增殖活性的影响及其机制。

方法

去甲基化药物地西他滨处理MM细胞系U266细胞，采用实时荧光定量PCR法检测处理前后U266细胞CMTM5、caspase3、caspase9的表达水平并分析其相关性；pcDNA3.1质粒转染U266细胞使CMTM5过表达后，采用CCK-8法检测细胞增殖活性变化。

结果

①与对照组相比，U266细胞中CMTM5、caspase3和caspase9的mRNA表达水平与地西他滨呈浓度和时间依赖性，随浓度加大和时间延长表达水平增高更加显著（P值均<0.01）；U266细胞中CMTM5表达水平与caspase3（r=0.937）、caspase9（r=0.945）呈正相关（P值均<0.001）。②过表达质粒转染的U266细胞，其CMTM5表达水平为133.10±10.35，较空白对照组（0.63±0.14）和质粒对照组（0.64±0.11）显著增高，差异有统计学意义（P值均<0.001）；CMTM5过表达U266细胞组72 h细胞增殖活性为0.89±0.08，较对照组（1.32±0.02，t=5.005，P=0.008）和空载质粒组（1.30±0.03，t=4.700，P=0.009）显著降低，差异有统计学意义。

结论

MM细胞中CMTM5的缺失能够被去甲基化药物地西他滨逆转，其变化水平与caspase3、caspase9呈正相关。过表达CMTM5能够抑制U266细胞增殖。

Chemokine-like factor-like MARVEL transmembrane domain-containing 3 expression is associated with a favorable prognosis in esophageal squamous cell carcinoma

Decreased expression of human chemokine-like factor-like MARVEL transmembrane domain-containing 3 (CMTM3) has been identified in a number of human tumors and tumor cell lines, including gastric and testicular cancer, and PC3, CAL27 and Tca-83 cell lines. However, the association between CMTM3 expression and the clinicopathological features and prognosis of esophageal squamous cell carcinoma (ESCC) patients remains unclear. The aim of the present study was to investigate the correlation between CMTM3 expression and clinicopathological parameters and prognosis in ESCC. CMTM3 mRNA and protein expression was analyzed in ESCC and paired non-tumor tissues by quantitative real-time polymerase chain reaction, western blotting and immunohistochemical analysis. The Kaplan-Meier method was used to plot survival curves and the Cox proportional hazards regression model was also used for univariate and multivariate survival analysis. The results revealed that CMTM3 mRNA and protein expression levels were lower in 82.5% (30/40) and 75% (30/40) of ESCC tissues, respectively, when compared with matched non-tumor tissues. Statistical analysis demonstrated that CMTM3 expression was significantly correlated with lymph node metastasis (P=0.002) and clinical stage (P<0.001) in ESCC tissues. Furthermore, the survival time of ESCC patients exhibiting low CMTM3 expression was significantly shorter than that of ESCC patients exhibiting high CMTM3 expression (P=0.01). In addition, Kaplan-Meier survival analysis revealed that the overall survival time of patients exhibiting low CMTM3 expression was significantly decreased compared with patients exhibiting high CMTM3 expression (P=0.010). Cox multivariate analysis indicated that CMTM3 protein expression was an independent prognostic predictor for ESCC after resection. This study indicated that CMTM3 expression is significantly decreased in ESCC tissues and CMTM3 protein expression in resected tumors may present an effective prognostic biomarker.

CMTM4 is frequently downregulated and functions as a tumour suppressor in clear cell renal cell carcinoma

BACKGROUND

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family involved in multiple malignancies. CMTM4 is a member of this family and is located at chromosome 16q22.1, a locus that harbours a number of tumour suppressor genes. It has been defined as a regulator of cell cycle and division in HeLa cells; however, its roles in tumourigenesis remain poorly studied.

METHODS

An integrated bioinformatics analysis based on the array data from the GEO database was conducted to view the differential expression of CMTM4 across multiple cancers and their corresponding control tissues. Primary clear cell renal cell carcinoma (ccRCC) and the paired adjacent non-tumour tissues were then collected to examine the expression of CMTM4 by western blotting, immunohistochemistry, and quantitative RT-PCR. The ccRCC cell lines A498 and 786-O and the normal renal tubular epithelial cell line HK-2 were also tested for CMTM4 expression by western blotting. Cell Counting Kit-8 (CCK-8) and viable cell counting assays were used to delineate the growth curves of 786-O cells after CMTM4 overexpression or knockdown. Wound healing and transwell assays were performed to assess the cells' ability to migrate. The effects of CMTM4 on cellular apoptosis and cell cycle progression were analysed by flow cytometry, and cell cycle hallmarks were detected by western blotting and RT-PCR. The xenograft model in nude mice was used to elucidate the function of CMTM4 in tumourigenesis ex vivo.

RESULTS

By omic data analysis, we found a substantial downregulation of CMTM4 in ccRCC. Western blotting then confirmed that CMTM4 was dramatically reduced in 86.9 % (53/61) of ccRCC tissues compared with the paired adjacent non-tumour tissues, as well as in the 786-O and A498 ccRCC cell lines. Restoration of CMTM4 significantly suppressed 786-O cell growth by inducing G2/M cell cycle arrest and p21 upregulation, and cell migration was also inhibited. However, knockdown of CMTM4 led to a completely opposite effect on these cell behaviours. Overexpression of CMTM4 also markedly inhibited the tumour xenograft growth in nude mice.

CONCLUSIONS

CMTM4 is downregulated and exhibits tumour-suppressor activities in ccRCC, and could be exploited as a target for ccRCC treatment.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

CMTM3 inhibits human testicular cancer cell growth through inducing cell-cycle arrest and apoptosis

Human CMTM3 has been proposed as a putative tumor suppressor gene. The loss of CMTM3 has been found in several carcinomas. However, the regulation of CMTM3 expression and its function in tumor progression remain largely unknown. Here, we investigated the regulation of CMTM3 expression, function and molecular mechanism in human testicular cancer cells. CMTM3 was frequently downregulated or silenced in testicular cancer cell lines and tumor tissues but highly expressed in normal testis tissues. The re-expression of CMTM3 significantly suppressed the colony formation, proliferation, and migration capacity of testicular cancer cells by inducing a G2 cell cycle arrest and apoptosis. Moreover, the re-expression of CMTM3 activated the transcription of p53, induced p53 accumulation, up-regulated the expression of p21, and increased the cleavage of caspase 9, 8, 3, and PARP. The downregulation of CMTM3 in clinical tumor tissues was associated with the methylation of a single CpG site located within the Sp1/Sp3-responsive region of the core promoter. These results indicate that CMTM3 can function as tumor suppressor through the induction of a G2 cell cycle arrest and apoptosis. CMTM3 is thus involved in testicular cancer pathogenesis, and it is frequently at least partially silenced by the methylation of a single, specific CpG site in tumor tissues.

CMTM3 inhibits cell migration and invasion and correlates with favorable prognosis in gastric cancer

The CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) gene is a novel tumor suppressor with frequent epigenetic inactivation. In this study, we showed the role played by CMTM3 in gastric cancer cells as a tumor suppressor gene, and examined the correlation between CMTM3 expression and clinicopathological parameters using immunohistochemistry in gastric cancer patients with different pathological stages (n = 350). We found that CMTM3 expression was reduced or silenced by epigenetic regulation in gastric cell lines, and dramatically downregulated in primary gastric cancer tissues. Restoration of CMTM3 significantly affected migration and invasion of AGS and SGC-7901 cells (P < 0.001). In vivo experiments showed that peritoneal disseminated metastases were significantly suppressed by CMTM3 (P < 0.001). We further showed that the expression of MMP2 and the phosphorylation of Erk1/2 were decreased when CMTM3 was restored. In addition, by immunohistochemical staining, we found that the expression of CMTM3 was remarkably weaker in gastric cancer tissues than in normal mucosae (P = 0.008), and was significantly correlated with gender (P = 0.033), tumor depth (P = 0.049), stage (P = 0.021), and histological grade (P = 0.022). More importantly, CMTM3 expression was associated with prognosis in gastric cancer patients (P = 0.041), and was a significant independent prognostic indicator (hazard ratio = 0.704, 95% confidence interval, 0.498–0.994; P = 0.046). Our findings indicate that CMTM3 regulates migration and invasion of gastric cancer cells. Moreover, CMTM3 is a candidate marker for prognosis of gastric cancer in the clinic.

Interleukin-30 expression in prostate cancer and its draining lymph nodes correlates with advanced grade and stage

PURPOSE

The interleukin (IL)-27 cytokine subunit p28, also called IL-30, has been recognized as a novel immunoregulatory mediator endowed with its own functions. These are currently the subject of discussion in immunology, but completely unexplored in cancer biology. We set out to investigate the role of IL-30 in prostate carcinogenesis and its effects on human prostate cancer (hPCa) cells.

EXPERIMENTAL DESIGN

IL-30 expression, as visualized by immunohistochemistry and real-time reverse transcriptase PCR on prostate and draining lymph nodes from 125 patients with prostate cancer, was correlated with clinicopathologic data. IL-30 regulation of hPCa cell viability and expression of selected gene clusters was tested by flow cytometry and PCR array.

RESULTS

IL-30, absent in normal prostatic epithelia, was expressed by cancerous epithelia with Gleason ≥ 7% of 21.3% of prostate cancer stage I to III and 40.9% of prostate cancer stage IV. IL-30 expression by tumor infiltrating leukocytes (T-ILK) was higher in stage IV that in stage I to III prostate cancer (P = 0.0006) or in control tissue (P = 0.0011). IL-30 expression in prostate draining lymph nodes (LN)-ILK was higher in stage IV than in stage I to III prostate cancer (P = 0.0031) or in control nodes (P = 0.0023). The main IL-30 sources were identified as CD68(+) macrophages, CD33(+)/CD11b(+) myeloid cells, and CD14(+) monocytes. In vitro, IL-30 stimulated proliferation of hPCa cells and also downregulated CCL16/LEC, TNFSF14/LIGHT, chemokine-like factor (CKLF), and particularly CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) and greatly upregulated ChemR23/CMKLR.

CONCLUSIONS

We provide the first evidence that IL-30 is implicated in prostate cancer progression because (i) its expression by prostate cancer or T- and LN-ILK correlates with advanced disease grade and stage; and (ii) IL-30 exerts protumor activity in hPCa cells.

CMTM3 is frequently reduced in clear cell renal cell carcinoma and exhibits tumor suppressor activities

PURPOSE

CKLF-like MARVEL transmembrane domain containing member 3 (CMTM3) is silenced in many kinds of cancers and inhibits tumor cells growth. We investigated the expression and role of CMTM3 in clear cell renal cell carcinoma (ccRCC).

METHODS

The expression of CMTM3 was detected in ccRCC tissue microarray, specimens, and cell lines by immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. After transfected with CMTM3 plasmid or vector, the proliferation and migration of ccRCC 786-0 cells were determined by MTT assay and transwell assay, respectively. Furthermore, the anchorage-independent growth of transfected cells was assessed using soft agar colony formation assay.

RESULTS

CMTM3 was down-regulated in 84 % (63/75) of ccRCC tissues and its expression had no correlation with the gender, age, clinical staging and histologic grade. CMTM3 protein was undetectable by western blot in most detected ccRCC specimens and two RCC cell lines (786-0 and ACHN). qRT-PCR analysis showed that CMTM3 mRNA was dramatically down-regulated in 40 ccRCC cancer tissues as compared with the paired adjacent normal ones. Restoration of CMTM3 significantly suppressed the anchorage-independent growth, proliferation and migration of 786-0 cells.

CONCLUSION

These results indicate that CMTM3 is significantly down-regulated in ccRCC and exerts remarkable tumor-suppressive functions in 786-0 cells. Reduction of CMTM3 expression may contribute to the pathogenesis of ccRCC and CMTM3 may be a potentially target for therapeutic strategy.

A novel 3p22.3 gene CMTM7 represses oncogenic EGFR signaling and inhibits cancer cell growth

Deletion of 3p12-22 is frequent in multiple cancer types, indicating the presence of critical tumor-suppressor genes (TSGs) at this region. We studied a novel candidate TSG, CMTM7, located at the 3p22.3 CMTM-gene cluster, for its tumor-suppressive functions and related mechanisms. The three CMTM genes, CMTM6, 7 and 8, are broadly expressed in human normal adult tissues and normal epithelial cell lines. Only CMTM7 is frequently silenced or downregulated in esophageal and nasopharyngeal cell lines, but uncommon in other carcinoma cell lines. Immunostaining of tissue microarrays for CMTM7 protein showed its downregulation or absence in esophageal, gastric, pancreatic, liver, lung and cervix tumor tissues. Promoter CpG methylation and loss of heterozygosity were both found contributing to CMTM7 downregulation. Ectopic expression of CMTM7 in carcinoma cells inhibits cell proliferation, motility and tumor formation in nude mice, but not in immortalized normal cells, suggesting a tumor inhibitory role of CMTM7. The tumor-suppressive function of CMTM7 is associated with its role in G1/S cell cycle arrest, through upregulating p27 and downregulating cyclin-dependent kinase 2 (CDK2) and 6 (CDK6). Moreover, CMTM7 could promote epidermal growth factor receptor (EGFR) internalization, and further suppress AKT signaling pathway. Thus, our findings suggest that CMTM7 is a novel 3p22 tumor suppressor regulating G1/S transition and EGFR/AKT signaling during tumor pathogenesis.

Divergence of mammalian higher order chromatin structure is associated with developmental loci

Several recent studies have examined different aspects of mammalian higher order chromatin structure - replication timing, lamina association and Hi-C inter-locus interactions - and have suggested that most of these features of genome organisation are conserved over evolution. However, the extent of evolutionary divergence in higher order structure has not been rigorously measured across the mammalian genome, and until now little has been known about the characteristics of any divergent loci present. Here, we generate a dataset combining multiple measurements of chromatin structure and organisation over many embryonic cell types for both human and mouse that, for the first time, allows a comprehensive assessment of the extent of structural divergence between mammalian genomes. Comparison of orthologous regions confirms that all measurable facets of higher order structure are conserved between human and mouse, across the vast majority of the detectably orthologous genome. This broad similarity is observed in spite of many loci possessing cell type specific structures. However, we also identify hundreds of regions (from 100 Kb to 2.7 Mb in size) showing consistent evidence of divergence between these species, constituting at least 10% of the orthologous mammalian genome and encompassing many hundreds of human and mouse genes. These regions show unusual shifts in human GC content, are unevenly distributed across both genomes, and are enriched in human subtelomeric regions. Divergent regions are also relatively enriched for genes showing divergent expression patterns between human and mouse ES cells, implying these regions cause divergent regulation. Particular divergent loci are strikingly enriched in genes implicated in vertebrate development, suggesting important roles for structural divergence in the evolution of mammalian developmental programmes. These data suggest that, though relatively rare in the mammalian genome, divergence in higher order chromatin structure has played important roles during evolution.

Human stanniocalcin-1 interacts with nuclear and cytoplasmic proteins and acts as a SUMO E3 ligase

Human stanniocalcin-1 (STC1) is a glycoprotein that has been implicated in different physiological process, including angiogenesis, apoptosis and carcinogenesis. Here we identified STC1 as a putative molecular marker for the leukemic bone marrow microenvironment and identified new interacting protein partners for STC1. Seven selected interactions retrieved from yeast two-hybrid screens were confirmed by GST-pull down assays in vitro. The N-terminal region was mapped to be the region that mediates the interaction with cytoplasmic, mitochondrial and nuclear proteins. STC1 interacts with SUMO-1 and several proteins that have been shown to be SUMOylated and localized to SUMOylation related nuclear bodies. Although STC1 interacts with SUMO-1 and has a high theoretical prediction score for a SUMOylation site, endogenous co-immunoprecipitation and in vitro SUMOylation assays with the purified recombinant protein could not detect STC1 SUMOylation. However, when we tested STC1 for SUMO E3 ligase activity, we found in an in vitro assay, that it significantly increases the SUMOylation of two other proteins. Confocal microscopic subcellular localization studies using both transfected cells and specific antibodies for endogenous STC1 revealed a cytoplasmic and nuclear deposition, the latter in the form of some specific dot-like substructure resembling SUMOylation related nuclear bodies. Together, these findings suggest a new role for STC1 in SUMOylation pathways, in nuclear bodies.

Identification and characterization of CMTM4, a novel gene with inhibitory effects on HeLa cell growth through Inducing G2/M phase accumulation

Human CMTM is a novel gene family consisting of CKLF and CMTM1-8. CMTM4 is the most conserved gene and has three RNA splicing forms designated as CMTM4-v1, -v2 and -v3, but in many types of tissue and cell lines, only CMTM4-v1 and -v2 could be detected. CMTM4-v2 is the full length cDNA product, which has been highly conserved during evolution. CMTM4-v1 and -v2 are broadly expressed in normal types of tissue. They are distributed on the cell membrane and across the cytoplasm in a speckled pattern. Overexpression of CMTM4-v1 and -v2 can inhibit HeLa cell growth via G2/M phase accumulation without inducing apoptosis. Therefore, CMTM4 might be an important gene involved in cell growth and cell cycle regulation.

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.

Identification and characterization of MARVELD1, a novel nuclear protein that is down-regulated in multiple cancers and silenced by DNA methylation

MARVELD1 (MARVEL domain-containing 1) is a member of MARVEL domain-containing proteins and located on human chromosome 10q24.2. MARVELD1 has no significant similarity with other members of MARVEL domain family at amino acid level. Gene expression arrays demonstrated that MARVELD1 is widely expressed in normal human tissues and is down-regulated in primary multiple tumors derived from ovary, vulva, uterus, cervix, breast, testis, kidney, bladder and liver. The down-regulation of MARVELD1 was further identified by real-time PCR and immunohistochemical staining in primary breast cancer. In addition, we identified the reduced expression of MARVELD1 is owing to DNA methylation and could be reversed by pharmacologic demethylation. Finally, our results showed that MARVELD1 protein is located in nucleus instead of cell membrane.

A systems approach to prion disease

Prions cause transmissible neurodegenerative diseases and replicate by conformational conversion of normal benign forms of prion protein (PrP^C) to disease-causing PrP^Sc isoforms. A systems approach to disease postulates that disease arises from perturbation of biological networks in the relevant organ. We tracked global gene expression in the brains of eight distinct mouse strain–prion strain combinations throughout the progression of the disease to capture the effects of prion strain, host genetics, and PrP concentration on disease incubation time. Subtractive analyses exploiting various aspects of prion biology and infection identified a core of 333 differentially expressed genes (DEGs) that appeared central to prion disease. DEGs were mapped into functional pathways and networks reflecting defined neuropathological events and PrP^Sc replication and accumulation, enabling the identification of novel modules and modules that may be involved in genetic effects on incubation time and in prion strain specificity. Our systems analysis provides a comprehensive basis for developing models for prion replication and disease, and suggests some possible therapeutic approaches.