Natural Product Erianin Inhibits Bladder Cancer Cell Growth by Inducing Ferroptosis via NRF2 Inactivation

Erianin, a natural product derived from Dendrobium chrysotoxum Lindl , has been proved to play antitumor activity in various cancers. However, the effects and molecular mechanisms of erianin in bladder cancer cells remain unexplored. In this study, we found that erianin triggered cell death and cell cycle arrest in bladder cancer cells. Then we demonstrated that erianin could promote the accumulation of lethal lipid-based reactive oxygen species (ROS) and the depletion of glutathione (GSH), suggesting the induction of ferroptosis. In the further study, the ferroptosis inhibitor deferoxamine (DFO), N-Acetylcysteine (NAC) and GSH but not necrostatin-1, CQ or Z-VAD-FMK rescued erianin-caused cell death, showing ferroptosis played a major role in erianin-caused cell death. In vivo , we also showed that erianin suppressed the tumor growth by inducing ferroptosis. Mechanistically, we demonstrated that nuclear factor E2-related factor 2 (NRF2) inactivation was a key determinant of ferroptosis caused by erianin. In bladder cancer cells, the compound tert-butylhydro-quinone (TBHQ), an activator of NRF2, suppressed erianin-induced ferroptosis. Whereas, NRF2 inhibition used shRNA augmented the ferroptosis response induced by erianin treatment. In conclusion, our data provide the first evidence that erianin can initiate ferroptosis-like cell death and lipid peroxidation in bladder cancer, which will hopefully become a promising anticancer compound for the treatment of bladder cancer.