Bufalin induced apoptosis of bladder carcinoma cells through the inactivation of Na plus K plus -ATPase

Bufalin has been demonstrated to possess a wide range of pharmacological effects. Among these is its antitumour effect, which has been confirmed in multiple organs or tissues and provoked many concerns. However, its cytostatic effect and underlying mechanism in bladder cancer has not thoroughly been elucidated. This study aimed to investigate the hypothesis that Bufalin induces cell apoptosis and inhibits cell growth in bladder cancer through the inactivation of Na+/K+-ATPase (NKA). In the current study, it was demonstrated that Bufalin remarkably inhibited cell viability and induced cell apoptosis in bladder cancer cell line T24. Subsequently, we found that the expression of NKA was significantly supressed in Bufalin-treated cells and the NKA-3 isoform was most sensitive to Bufalin among all subunits of NKA. By transfection with NKA-3 overexpressing plasmids, the expression of the NKA-3 subunit was upregulated and NKA-3 overexpression was found to markedly attenuated Bufalin-induced cell apoptosis in T24 cells, suggesting NKA-3 played a critical role in Bufalin-induced cell apoptosis. Taken together, the present study confirmed that Bufalin promotes tumour apoptosis and inhibits tumour growth in bladder cancer in vitro, and this antitumour effect may be ascribed to the inactivation of NKA.