Hepatitis B virus X protein suppresses adriamycin-induced apoptosis of hepatocellular carcinoma cells and expression of p53 and PTEN / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells and the expressions of p53 and PTEN.</p><p><b>METHODS</b>HepG2, HepG2/GFP, and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and the apoptotic cell death was determined by observing the morphological changes and flow cytometry. The expressions of p53 and PTEN mRNA in the 3 cells were detected by RT-PCR, and the expressions of p53 and PTEN protein were analyzed by Western blotting.</p><p><b>RESULTS</b>Adriamycin induced significant cell death in HepG2 and HepG2/GFP cells, which became rounded, shrunk, and detached after the treatment; but no significant cell death occurred in HepG2/GFP-HBx cells. Flow cytometry analysis showed that the apoptotic rate was significantly lower in HepG2/GFP-HBx cells (3.94%) than in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 h after the treatment (P<0.001), while no significant difference was observed between HepG2/GFP-HBx (3.94%) and the control cells (2.12%, 2.78%, and 2.55%) (P>0.05). RT-PCR showed lowered expression of PTEN mRNA in HepG2/GFP-HBx cells as compared to that in HepG2 and HepG2/GFP cells, while no significant difference was noted in p53 mRNA. Western blot analysis showed that PTEN protein decreased while p53 protein remain unchanged in HepG2/GFP-HBx cells.</p><p><b>CONCLUSION</b>HBx suppresses adriamycin-induced apoptosis of HepG2 cells and PTEN expression. The inhibitory effect of HBx on the cell apoptosis may be related to the inhibition of p53-PTEN pathway.</p>