ECRG4 is a candidate tumor suppressor gene frequently hypermethylated in colorectal carcinoma and glioma

Abstract

BackgroundCancer cells display widespread changes in DNA methylation that may lead to genetic instability by global hypomethylation and aberrant silencing of tumor suppressor genes by focal hypermethylation. In turn, altered DNA methylation patterns have been used to identify putative tumor suppressor genes.MethodsIn a methylation screening approach, we identified ECRG4 as a differentially methylated gene. We analyzed different cancer cells for ECRG4 promoter methylation by COBRA and bisulfite sequencing. Gene expression analysis was carried out by semi-quantitative RT-PCR. The ECRG4 coding region was cloned and transfected into colorectal carcinoma cells. Cell growth was assessed by MTT and BrdU assays. ECRG4 localization was analyzed by fluorescence microscopy and Western blotting after transfection of an ECRG4-eGFP fusion gene.ResultsWe found a high frequency of ECRG4 promoter methylation in various cancer cell lines. Remarkably, aberrant methylation of ECRG4 was also found in primary human tumor tissues, including samples from colorectal carcinoma and from malignant gliomas. ECRG4 hypermethylation associated strongly with transcriptional silencing and its expression could be re-activated in vitro by demethylating treatment with 5-aza-2'-deoxycytidine. Overexpression of ECRG4 in colorectal carcinoma cells led to a significant decrease in cell growth. In transfected cells, ECRG4 protein was detectable within the Golgi secretion machinery as well as in the culture medium.ConclusionsECRG4 is silenced via promoter hypermethylation in different types of human cancer cells. Its gene product may act as inhibitor of cell proliferation in colorectal carcinoma cells and may play a role as extracellular signaling molecule.

C2ORF40suppresses breast cancer cell proliferation and invasion through modulating expression of M phase cell cycle genes

“…15 Finding new prognostic markers has important clinical implications in identifying breast cancer patients at high risk of metastasis and in predicting postsurgical this hypothesis, we showed that downregulation of C2ORF40 is negatively correlated UBE2C expression in more than 1,000 primary breast cancer tissues from five independent cohorts of patients and overexpression of C2ORF40 in breast cancer cells markedly suppresses UBE2C expression. As C2ORF40 gene product was reported as a secretary molecule 5 and can be detected in cell culture medium, 7 it is very likely that C2ORF40 exerts its inhibitory function through binding to cell membrane surface molecules to transduce inhibitory signals into adjacent cells. 20 Moreover, further processing of this 148-amino acid molecule into smaller peptides is reportedly required for its inhibitory function 24 and smaller processed peptides are found in cell culture medium.…”

“…3 Although the expression of C2ORF40 was ubiquitously detected in normal tissues, 4,5 it is frequently downregulated or absent in esophageal cancer, colorectal carcinomas and glioma, probably due to promoter hypermethylation, 6,7 and its expression is thought to be a prognostic factor for ESCC and prostate cancer patients. 8,9 Restoration of C2ORF40 expression in cell lines could inhibit esophageal, colorectal and glioma tumor cell growth 7,9-11 and glioma cell migration.…”

Ecrg4 contributes to the anti-glioma immunosurveillance through type-I interferon signaling

“…2 Thereafter, it has been reported that ecrg4 expression was downregulated in various types of tumors such as colorectal cancer, glioma, prostate cancer, and breast cancer because of hypermethylation of its promoter. [3][4][5][6] Moreover, several papers have shown the growth inhibitory effect of Ecrg4 when overexpressed in cancer cell lines. [7][8][9] Together, these findings suggested Ecrg4 as a tumor suppressor.…”

Soluble purified recombinant C2ORF40 protein inhibits tumor cell growth in vivo by decreasing telomerase activity in esophageal squamous cell carcinoma

“…The C2ORF40 gene is important in processes associated with physiological functional regulation, including inflammation, injury, senescence, the neuroendocrines environment, differentiation and apoptosis (5)(6)(7)(8)(9)(10)(11)(12)(13). Notably, previous studies have indicated that C2ORF40 is a candidate tumor suppressor gene associated with prognosis in a variety of tumors (4,(14)(15)(16)(17)(18)(19)(20)(21)(22). In addition, C2ORF40 has been demonstrated to be chemosensitive to 5-fluorouracil and cisplatin (23,24).…”