Silencing of SND1 overcomes the resistance to cisplatin by promoting ferroptosis. (A) T24/R and 5637/R cells were transfected as indicated, and treated with or without cisplatin for 24 h, and cellular death was then assessed. (B) T24/R and 5637/R cells were treated as indicated for 24 h, and the cellular death was assessed. (C) T24/R and 5637/R cells were treated as indicated for 24 h, and the iron levels were determined. (D) T24/R and 5637/R cells were treated as indicated for 12 h, and the reactive oxygen species levels were assessed. (E) T24/R and 5637/R cells were treated as indicated for 24 h, and the glutathione levels were determined. (F) T24/R and 5637/R cells were treated as indicated for 24 h, and the MDA levels were assessed. Data are presented as the mean ± standard deviation. *P<0.05 and **P<0.01. SND1, staphylococcal nuclease and tudor domain containing 1; sh, short hairpin RNA; NC, negative control; ROS, reactive oxygen species; GSH, glutathione; MDA, malondialdehyde.