Fangchinoline Induces Apoptosis, Autophagy and Energetic Impairment in Bladder Cancer.

Tetrandrine and Fangchinoline (Fcn) are two natural products that are found in Stephania tetrandra. Tetrandrine is a known anti-bladder cancer compound, but the effects of Fcn on bladder cancer have been previously unclear. In the present study, we focused on the anti-tumor effects of Fcn on bladder cancer. We treated T24 and 5637 bladder cancer cell lines with Fcn in vitro. We observed that Fcn inhibited the viability of bladder cancer cells in a concentration-dependent manner. The expression of PCNA, a biomarker of proliferation, was down-regulated. Fcn treatment induced both apoptosis and autophagy in bladder cancer cells, as shown by the increased cleavage of caspase-3, an up-regulated LC3-II/LC3-I ratio and the down-regulated p62 level. Blocking autophagy with 3-MA (3-Methyladenine) enhanced Fcn-induced apoptosis, indicating that Fcn-induced autophagy was adaptive. Additionally, we observed that Fcn treatment inhibited mTOR and reduced the intracellular ATP levels. The exogenous addition of methyl pyruvate (MP) to compensate metabolic substrates alleviated Fcn-induced apoptosis and autophagy. Our data indicated that Fcn caused an impairment in energy generation, which led to apoptosis and adaptive autophagy in bladder cancer. These results demonstrated that Fcn may be a potential candidate for use in the prevention and treatment of bladder cancer.