- Hendricks, Joseph;
- Doubravsky, Cody;
- Wehri, Eddie;
- Li, Zhipeng;
- Roberts, Melissa;
- Deol, Kirandeep;
- Lange, Mike;
- Lasheras-Otero, Irene;
- Momper, Jeremiah;
- Dixon, Scott;
- Bersuker, Kirill;
- Schaletzky, Julia;
- Olzmann, James
Ferroptosis is a regulated form of cell death associated with the iron-dependent accumulation of phospholipid hydroperoxides. Inducing ferroptosis is a promising approach to treat therapy-resistant cancer. Ferroptosis suppressor protein 1 (FSP1) promotes ferroptosis resistance in cancer by generating the antioxidant form of coenzyme Q10 (CoQ). Despite the important role of FSP1, few molecular tools exist that target the CoQ-FSP1 pathway. Through a series of chemical screens, we identify several structurally diverse FSP1 inhibitors. The most potent of these compounds, ferroptosis sensitizer 1 (FSEN1), is an uncompetitive inhibitor that acts selectively through on-target inhibition of FSP1 to sensitize cancer cells to ferroptosis. Furthermore, a synthetic lethality screen reveals that FSEN1 synergizes with endoperoxide-containing ferroptosis inducers, including dihydroartemisinin, to trigger ferroptosis. These results provide new tools that catalyze the exploration of FSP1 as a therapeutic target and highlight the value of combinatorial therapeutic regimes targeting FSP1 and additional ferroptosis defense pathways.