Selective apoptosis-inducing effect of adeno-associated virus mediated gene transfer of MDA-7 on human hepatocellular carcinoma cells

Abstract

Objective To investigate the selective apoptosis-inducing effect of adeno-associated virus mediated gene transfer of MDA-7 regulated by PEG promoter on human hepatocellular carcinoma cells.Methods We transduced human hepatocellular carcinoma cell line HepG2 and normal human hepatocytes LO2 with rAAV-PEG-MDA-7 and assessed the cell growth inhibition,cell cycle and apoptosis.MDA-7 protein was detected by Western blotting,cell growth-inhibiting rate evaluated by MTT and cell cycle, Annexin-Ⅴ labeling and mitochondrial transmembrane potential were determined by flow eytometry.The expression of bcl-2 mRNA was determined bv RT-PCR.Results rAAV-PEG-MDA-7 was effectively transfected into HepG2 cells.MDA-7 protein was highly expressed in HepG2 cells in a time-dependent manner.rAAV-PEG-MDA-7 suppressed HepG2 cell growth.The cells accumulated in the gap 0 and gap 1(G0/G1)phases,while reduced in the gap 2 and mitosis(G2/M)pha ses of the cell cycle,and the apoptosis peak significantly occurred.rAAV-PEG-MDA-7 increased the rate of Annexin Ⅴ labeling positive cells while decreased the mitochondrial transmembrane potential of HepG2 cells within 24 h.The expression of anti-apoptotic gene bcl-2 also decreased.However,there were no such effects on normal human hepatocyte LO2.Conclusion rAAV-PEG-MDA-7 selectively inhibits growth and induce apoptosis of human hepatocellular carcinoma cell line.The apoptosis-inducing mechanism is mediated through intrinsic cell apoptotic pathway involved with the gene regularion of the bcl-2 family. Key words: Carcinoma hepatocellular; Melanoma differentiation-associated gene-7; Apoptosis; Selection