Abstract: Objective To analyze the expression of nonmuscle myosin heavy chain9 (MYH9) in thehuman hepatocellular carcinoma（HCC） and investigate the effects of silencingMYH9gene on the proliferation and apoptosis ability of HCC cell line SMMC-7721. MethodsImmunohistochemistry and western blot were used to analyze the expression of MYH9 proteinin 50 cases of HCC tissues and paraneoplastic tissues in HCC tissues and cancer-adjacent tissues, and the relationship between MYH9 and clinical pathological parameters was studied. Western blot was also used to analyze the expression of MYH9 protein in HCC cell lines SMMC-7721,HepG2 and normal liver cell LO2.RNA interference targeted silence MYH9 gene was transfected into SMMC-7721 cells. The proliferation and apoptosis of the transfected cells were assessed by CCK-8 assay and flow cytometry.ResultsThe expression of MYH9 in HCC tissues was found to be significantly higher than that of cancer-adjacent tissues(P＜0.05),and the relative amount of MYH9 protein in SMMC-7721 and HepG2 was significantly higher than that in LO2(P＜0.05). It was showed that downregulation of MYH9 inhibited cell proliferation(P＜0.05) and induced the apoptosis(P＜0.05). ConclusionThe expression of MYH9 protein in HCC tissues was significantly higher than that in cancer-adjacent tissues, and RNAi ofMYH9 in the SMMC-7721 cells may inhibit cells proliferation and induce apoptosis.

Key words: Human hepatocellular carcinoma, MYH9, RNAi, proliferation, apoptosis