The Transfection,Expression Of HBx Gene In HepG₂ Cell, And Effection On Apoptosis Factors

AIM: To investigate the effect of hepatitis B virus (HBV) X gene on apoptosis andexpression of apoptosis factors in X gene-transfected HepG₂ cells.METHODS: The HBV X gene eukaryon expression vector pcDNA₃-X wastransiently transfected into HepG₂ cells by lipid-media transfection. UntransfectedHepG₂ and HepG₂ transfected with pcDNA₃ were used as controls. Expression ofHBV X gene in HepG₂ was identified by RT-PCR. MTT and TUNEL were employedto measure proliferation and apoptosis of cells in three groups. Semi-quantifiedRT-PCR was used to evaluate the expression level of Fas/FasL, Bax/Bcl-xL, c-myc ineach group.RESULTS: HBV X gene was transfected into HepG₂ cells successfully. RT-PCRshowed that HBV X gene was only expressed in HepG₂/pcDNA₃-X cells, but notexpressed in HepG₂ and HepG₂/pcDNA₃ cells. Analyzed by MTT, cell proliferationcapacity was obviously lower in HepG₂/pcDNA₃-X cells (0.08910±0.003164) than inHepG₂ (0.14410±0.004927) and HepG₂/pcDNA₃ cells (0.12150±0.007159) (^aP<0.05,^bP<0.01). Analyzed by TUNEL, cell apoptosis was much more in HepG₂/pcDNA₃-Xcells (980/2000) than HepG₂ (420/2000), HepG₂/pcDNA₃ cells (520/2000) (^aP<0.05,^bP<0.01). Evaluated by semi-quantified RT-PCR, the expression level of Fas/FasLwas significantly higher in HepG₂ cells transfected with HBV X gene than in HepG₂and HepG₂/pcDNA₃ cells (^aP<0.05,^bP<0.01). Bax/Bcl-xL expression level was alsoelevated in HepG₂/pcDNA₃-X cells (^aP<0.05,^bP<0.01). Expression of c-myc wasmarkedly higher in HepG₂/pcDNA₃-X cells than in HepG₂ and HepG₂/pcDNA₃ cells(^aP<0.05,^bP<0.01).CONCLUSION: HBV X gene can impair cell proliferation capacity, improve cellapoptosis, and up-regulate expression of apoptosis factors. The intervention of HBVX gene on the expression of apoptosis factors may be a possible mechanismresponsible for the change in cell apoptosis and proliferation.