Fig. 3.

Vitamin K1 inhibits ferroptosis induced by inhibition of FSP1 or DHODH. NIH3T3 and HT-1080 cells were treated as indicated at 37 °C for 24 h with a sublethal dose of 0.1 µM (NIH3T3) or 1 µM RSL3 (HT-1080). The cell death-aggravating impact of a 10 µM iFSP1 or b 50 µM brequinar (BQR) is clearly evident under these conditions. Addition of 1 µM ferrostatin-1 (Fer-1) or 10 µM vitamin K1 (vit.K1) demonstrates that cell death perpetuated by iFSP1 or BQR is based on preventable ferroptosis. Cell death was quantified by FACS analysis using 7-amino-actinomycin D (7-AAD) and phosphatidylserine accessibility (Annexin V staining) as markers. FACS dot plots of one representative experiment are shown (n = 3 independent repeats)