RESUMO
To observe the alteration in the expression of DNA repair enzymes hOGG1 and hMYHα and the change in 8-OHdG levels in the HBx gene-transfected cells HepG2/HBx and to explore the mechanisms of the HBV-associated hepatocellular carcinoma,the gene-transfected cells HepG2/HBx which stably expressed HBx was established,and the effect of HBx on the cell cycle and proliferation of HepG2 was examined.By using the β-actin as the interior control,real-time polymerase chain reaction (Real-time qPCR) was employed to quantitatively detect the expression of DNA repair enzymes hOGG1 and hMYHα in the HepG2/HBx,the control cells HepG2 and HepG2 transfected with pcDNA3.1 vector (HepG2/pDNA3.1).The 8-OHdG levels were determined by HPLC/ECD in the established gene-transfected cells HepG2/HBx and the control cells HepG2 and HepG2/pcDNA3.1.Our results showed that the expression of DNA repair enzyme hMYHα in the HepG2/HBx (0.021±0.007) was significantly lower than that of HepG2 (0.099±0.041) (P<0.05) and HepG2/pDNA3.1 (0.121±0.005) (P<0.05).However,the no significant differences existed in the expression of DNA repair enzyme hOGG1 among the three cell strains (P>0.05).The 8-OHdG level in the HepG2/HBx was significantly higher than that in HepG2 and HepG2/pcDNA3.1 (P<0.05).It is concluded that HBx gene may inhibit the expression of DNA repair enzyme hMYHα mRNA to impair the ability to repair the intracellular DNA oxidative damage,to increase the oxidative DNA-adduct 8-OHdG and to affect the nucleotide excision repair function,thus participate in the occurrence and development of hepatocellular carcinoma.