RESUMO
Objective To investigate the expression of DNA methyltransferase 3b (DNMT3B) in hepatocellular carcinoma (HCC) and its effect and mechanism on the proliferation,invasion and migration of HCC cells.Methods The expression of DNMT3B gene was detected by qRT-PCR in 46 cases of HCC tissues and corresponding adjacent tissues;the results and clinical pathological parameters were analyzed.SiRNA targeting DNMT3B was transfected into MHCC97-H cells by RNA interference (RNAi) technique.The mRNA and protein expression levels of related genes were detected by qRT-PCR and Western blot.The cell proliferation was measured by MTT assay,and the invasion and migration abilities were measured by Transwell assay.Results In 46 HCC patients,the expression of DNMT3B (73.91％) was significantly higher in HCC than in adjacent normal tissue.The high expression of DNMT3B gene was associated with histological type and tumor size of HCC (all P＜0.05).Inhibition of DNMT3B gene expression decreased proliferation,invasion and migration of MHCC97-H cells.Interference with DNMT3B gene increased the expressions of tumor suppressor genes RASSFA1,APC and MTSS1 at mRNA and protein levels.Conclusion DNMT3B is associated with the progression of HCC.It may inhibit the proliferation,invasion and migration of HCC cells by regulating the methylation of downstream tumor suppressor gene.