Effect of caspase-9 in the apoptosis of hepatoma cells induced by flurouracil

Objective To determine the effect of caspase 9 in the apoptosis of hepatoma cells induced by flurouracil , and to investigate the activity alteration and proteolytic cleavage of caspase 9. Methods The human hepatoma HepG2 cells were treated with flurouracil for 2,4,8,16,24h respectively. The caspase 9 activity was detected using caspase 9 Fluorescent Assay Kit.Proteolytic cleavage of caspase 9 was analyzed by Western blot.The apoptotic rates of HepG2 cells induced by flurouracil with or without caspase 9 inhibitor treatment were measured by flow cytometry. Results Four hours after being treated with flurouracil, the caspase 9 activity in HepG2 cells increased gradually and reached the peak at 16h.Compared with the control group, the difference was significant (P0.01). In Western blot analysis, caspase 9 was found cleaved into 10 KD fragment. In the presence of caspase 9 inhibitor, the apoptotic rates of HepG2 cells induced by flurouracil decreased.Significant difference existed between the flurouracil group and the inhibitor treatment group (P0.05). Conclusions Caspase 9 is activated in the apoptosis of HepG2 cells induced by flurouracil ,and the activity of caspase 9 is enhanced remarkably,suggesting that caspase 9 may be involved in the apoptosis of hepatoma cells induced by flurouracil.