Methylation regulation of liver specific miRNA-122 expression and its effect on proliferation and apoptosis of a hepatocellular carcinoma cell / 中华肝胆外科杂志

ABSTRACT

Objective miRNA-122 levels may correlate with liver cancer prognosis,and therefore understanding its expression is crucial for future treatment.This study investigates the effect of DNA methylation on the expression of liver specific miRNA-122 and its effects on proliferation and apoptosis of hepatocellular carcinoma cells.Methods Methylation sequencing detected the methylation of the miRNA-122 promoter region,and the level of miRNA-122 expression was measured by using real-time quantitative PCR.The proliferation and apoptosis of hepatocellular cell lines were detected by flow cytometry and CCK8.Results Compared with human primary hepatocytes [(21.9 ± 11.4)％],the level of miRNA-122 promoter methylation in Huh7,HepG2,and QSG-7701 cell lines were (87.6±9.3) ％,(89.0 ± 14.3)％,and (69.5 ±11.5)％,respectively.This represents a significant increase (P=0.000),especially in Huh7 and HepG2 cell lines.Compared with human primary hepatocytes (2.83× 104 ±3746),the levels of miR-122 expression in the above three cell lines were significantly decreased,especially in Huh7 and HepG2 cell lines (P=0.007).After treatment with 5-Aza-dc,the degree of methylation in Huh7 and HepG2 cell lines were significantly lower than that of the blank group (P=0.038,P=0.025),and the levels of miRNA-122 expression were significantly elevated (P=0.008,P=0.003).Also,compared with the control groups,the apoptosis of Huh7 cells and HepG2 cells were significantly increased (P=0.001,0.027).Conclusion The expression of miRNA-122 is regulated by DNA methylation and correlated with the apoptosis of liver cancer cells.Therfore,the methylation regulation of miRNA-122 expression might be involved in the occurrence and development of hepatocellular carcinoma.