DNMT1 inhibits hepatocellular carcinoma cells by altering the epigenetic modification of Marveld1 gene

Abstract

Objective to study the effect of DNA methyltransferase (DNMT1) on Marveld1 in hepatocellular Carcinoma (HCC), and explore its role in the molecular mechanism of HCC occurrence and development.Methods The expression level of Dnmt1 and Marveld1 genes was detected by RT-PCR in the intraoperative pathological specimens. The human hepatoma Bel7402 and SMMC7721 cell lines down-regulated by DNMT1 gene expression were constructed by SiRNA transfection. The methylation level of Marveld1 promoter region was detected after RT-PCR and West-blot verification. The expression of Marveld1 gene, cell proliferation, invasion and change of cell cycle were detected by RT-PCR and West-blot. The expressions of P53, CyclinD1, P21 and P16 protein were detected by West-blot method.Results The expression of DNMT1 gene in human hepatocarcinoma tissues was higher than that in adjacent tissues. The methylation level of the Marveld1 gene promoter region in human hepatoma cell line down-regulated by DNMT1 gene expression was decreased, the expression level of Marveld1 gene was increased, and the proliferation and invasion ability of cells were weakened. The cell cycle was showed as G1-S phase arrest; P53 and P16 protein expressions were up-regulated, and CyclinD1 and P21 protein expressions were down-regulated.Conclusions Dnmt1 gene is highly expressed in human hepatocarcinoma tissues. Down-regulation of DNMT1 gene expression can decrease the methylation level of Marveld1 promoter region, up-regulate Marveld1 gene and human P53 and P16 proteins expressions, and down-regulate CyclinD1 and P21 proteins expressions, inhibit the proliferation and invasion of human hepatoma cells and can cause cell cycle G1-S arrest.