GPX4 and prostate cancer: To examine the induction of ferroptosis in vitro in cell-based assays, we treated a panel of human prostate cancer cell lines with a GPX4 inhibitor and widely used in vitro ferroptosis inducer, RSL3, in the absence or presence of inhibitors of either ferroptosis (ferrostatin-1 and deferoxamine) or apoptosis (Z-VAD-FMK).