Objective: To investigate the potential antitumour effects of polyphyllin Ⅰ(PPⅠ) on urothelial carcinoma of the bladder. Method: Urothelial carcinoma of bladder cell lines BIU-87 were cultured with or without PPⅠ. Cell proliferation were measured by MTT assay. Cell apoptosis and cell cycle were measured by flow cytometry. The changes of cell morphology were observed by transmission electron microscopy. The expression of Bcl-2 was detected by real-time PCR and western blot. Result: The results showed that the proliferation of BIU-87 cells were significantly inhibited by PPⅠ. The 50% inhibitory concentrations (IC50) of PPⅠ were 9.71

5.91

4.68 μmol·L-1 at 24

48

72 h. The inhibition rate of PPⅠwas in a manner of dose- and time-dependent. The treatment of PPⅠ led to activation of apoptosis. After being treated with PPⅠ

the apoptotic rate of BIU-87 cells was remarkably higher than that of the control. The results of real-time PCR and western blot showed that the expression of Bcl-2 was decreased in the group of PPⅠ treated. Conclusion: These results suggest that PP Ⅰpotentially has anticancer effects on urothelial carcinoma of the bladder cells in vitro. To deregulate the expression of Bcl-2 is one of the potential mechanisms.