The role of hepatitis B virus X gene and p53 on hepatocellular carcinoma cell growth / 中华病理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To explore the effects of hepatitis B virus X gene and p53 on hepatocellular growth.</p><p><b>METHODS</b>Two kinds of plasmids containing sense and antisense human wild p53 gene respectively were constructed. SMMU-7721 cells were transfected with HBx, sense-wtp53 antisense-wtp53 separately or cotransfected with either HBx and sense-wtp53 or HBx and antisense-wtp53. Flow cytometry was adopted to measure the apoptosis rates and the effects of HBx on cell cycle progression. The activity of p21(Waf1) promoter-luciferase construct was detected. Growth curves for SMMU-7721 stably transfected with pcDNA3 and pcDNA3HBx were analyzed.</p><p><b>RESULTS</b>After doxorubicin administration, HBx was noticed able to initiate apoptosis of the liver cells. The apoptosis rate was 5.32% in the pcDNA3 transfected and 12.66% in the pcDNA3HBx transfected groups respectively. HBx could also abrogate p53-mediated apoptosis. The apoptosis rate in groups transfected with pcDNA3, pcDNA3wtp53 and pcDNA3HBx + pcDNA3wtp53 was 5.32%, 11.72% and 4.67% respectively. In compared with the normal group, the number of cells in transiently HBx-expressed group and HBx-transfected group decreased 4.79% and 10.25% respectively. HBx inhibited the activity of p21(Waf1) promoter-luciferase constructed (P < 0.05) and promoted cell growth. The growth rate of HBx expression cells was faster.</p><p><b>CONCLUSION</b>Under DNA damage, HBx reduced expression of p21(Waf1) by repressing the activity of p53 protein, followed by disturbing the regulation of G(0)-G(1) cell cycle checkpoint, and promoted the growth rate of hepatoma cells.</p>