[An experimental study of bladder cancer cell apoptosis induced by cinobufacin].

Aim: To study the mechanism of cinobufacin-induced apoptosis in BIU87 cell.

Methods: Growth inhibition of bladder cancer cells in vitro were estimated using MTT assay. Apoptotic cells were detected by in-situ cell apoptosis detection kit, and confirmed by flow cytometry. The mRNA level affected by cinobufacin was determined with RT-PCR. Caspase-3 activity was estimated with chromometry.

Results: Cinobufacin inhibited the proliferation of BIU87 cells and induced apoptosis. More than 50% cells were killed with 0.2 mg/L of cinobufacin for 72 h. S-phase and G2-phase arrest was induced. There were significant changes of Bcl-2, caspase-3 mRNA and caspase-3 activity; while no changes of bax was found.

Conclusion: Cinobufacin can inhibit the proliferation of BIU87 cells by inducting apoptosis, which may be related with S- and G2-phase arrest, down-regulation of Bcl-2, and increasing caspase-3 expression and its activity.