Effect of hepatitis B virus X gene on the apoptosis of HepG2 cells

Objective To investigate the effect of hepatitis B virus X gene on the apoptosis in X gene-transfected HepG2 cells.Methods HBX gene eukaryon expression vector pcDNA3.1-X was transfected into HepG2 cells by lipid-mediated transfection to establish HepG2/HBX cell model for HBX expression.HepG2 transfected with pcDNA3.1 was used as controls.At 24 h,48 h,72 h and 96 h after transfection,cell apoptotic rates were detected by flow cytometry.RT-PCR and Western blot were applied to evaluate the expression levels of HBX,Fas,FasL,and the levels of p-JNK and p-c-Jun protein.Results HBX mRNA was detected in HepG2/HBX cells 24 h after transfection,and the expression of HBX mRNA level was gradually up-regulated after transfection(P0.05);Whereas no expression of HBX gene in the control cells.At 24 h,48 h,72 h and 96 h after transfection,all of the apoptotic rate in HepG2/HBX group were much higher than those in the controls(P0.05),The expression levels of Fas and FasL protein as well as the levels of p-JNK and p-c-Jun protein were significantly higher than those in the controls(P0.05).A positive correlationship was observed between the expression of HBX mRNA level and the hepatocyte apoptotic rate(P0.05),the same correlation of HBX mRNA level with the levels of Fas,FasL,p-JNK and p-c-Jun were also observed.(P0.05).Conclusion HBX can induce hepatocyte apoptosis by up-regulating the levels of p-JNK and p-c-Jun to promote the expression of FasL.