Apoptosis and its pathway in X gene-transfected HepG2 cells.
OBJECTIVE
To investigate the effect of hepatitis B virus (HBV) X gene on apoptosis and expressions of apoptosis factors in X gene-transfected HepG2 cells.


METHODS
The HBV X gene eukaryon expression vector pcDNA3-X was transiently transfected into HepG2 cells by lipid-media transfection. Untransfected HepG2 and HepG2 transfected with pcDNA3 were used as controls. Expression of HBx in HepG2 was identified by RT-PCR. MTT and TUNEL were employed to measure proliferation and apoptosis of cells in three groups. Semi-quantified RT-PCR was used to evaluate the expression levels of Fas/FasL, Bax/Bcl-xL, and c-myc in each group.


RESULTS
HBV X gene was transfected into HepG2 cells successfully. RT-PCR showed that HBx was only expressed in HepG2/pcDNA3-X cells, but not expressed in HepG2 and HepG2/pcDNA3 cells. Analyzed by MTT, cell proliferation capacity was obviously lower in HepG2/pcDNA3-X cells (0.08910+/-0.003164) than in HepG2 (0.14410+/-0.004927) and HepG2/pcDNA3 cells (0.12150+/-0.007159) (P<0.05 and P<0.01). Analyzed by TUNEL, cell apoptosis was much more in HepG2/pcDNA3-X cells (980/2,000) than HepG2 (420/2,000), HepG2/pcDNA3 cells (520/2,000) (P<0.05 and P<0.01). Evaluated by semi-quantified RT-PCR, the expression level of Fas/FasL was significantly higher in HepG2 cells transfected with HBx than in HepG2 and HepG2/pcDNA3 cells (P<0.05 and P<0.01). Bax/Bcl-xL expression level was also elevated in HepG2/pcDNA3-X cells (P<0.05 and P<0.01). Expression of c-myc was markedly higher in HepG2/pcDNA3-X cells than in HepG2 and HepG2/pcDNA3 cells (P<0.05 and P<0.01).


CONCLUSIONS
HBV X gene can impair cell proliferation capacity, improve cell apoptosis, and upregulate expression of apoptosis factors. The intervention of HBV X gene on the expression of apoptosis factors may be a possible mechanism responsible for the change in cell apoptosis and proliferation.
Lin
Na
N
Department of Gastroenterology, Affiliated Union Hospital, Fujian Medical University, Fuzhou 350001, Fujian Province, China.
Chen
Hong-Ying
HY
Li
Dan
D
Zhang
Sheng-Jun
SJ
Cheng
Zhi-Xin
ZX
Wang
Xiao-Zhong
XZ
D017209:Apoptosis / Q000235:genetics*; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000503:physiopathology* / Q000821:virology; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D015967:Gene Expression Regulation, Viral; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000503:physiopathology* / Q000821:virology; D015534:Trans-Activators / Q000235:genetics*; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins
D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein