Mechanistic insights into a novel GPX4 inhibitor Compound AI-3p reversing cisplatin-resistance in ovarian cancer cells

BACKGROUND: Ferroptosis has been correlated with the cancer chemotherapy resistance, and inducing ferroptosis has been demonstrated to reverse drug resistance. The GPX4-mediated signaling pathway is one of the most central pathways regulating ferroptosis. However, most currently available GPX4 inhibitors are covalent inhibitors, with limited structural diversity. RESULTS: Here, we explored the potential and related molecular mechanisms of Compound AI-3p, a novel GPX4 inhibitor designed by linking an isoxazole pharmacophore to an anthraquinone core, for the treatment of cisplatin (DDP)-resistant ovarian cancer. Compound AI-3p showed significant cytotoxicity against DDP-resistant ovarian cancer cells (SKOV3/DDP), with a higher selectivity index against SKOV3/DDP and lower cytotoxicity against normal ovarian epithelial cells (IOSE80) than DDP. Molecular docking revealed that AI-3p forms a hydrogen bond with Leu130 in the catalytically active tetramer of GPX4, as well as carbon-hydrogen bonds with Sec 46, Gln81, and Lys135. Further validation via molecular dynamics simulations and Cellular Thermal Shift Assay (CETSA) confirmed that AI-3p can form a stable complex with GPX4. Mechanistic study revealed that Compound AI-3p could trigger the ferroptosis via inhibition of the GPX4/GSH axis, inducing reactive oxygen species (ROS) production, Lipid peroxidation, iron ion accumulation, Labile Iron Pool accumulation (LIP) accumulation, and a reduction in GSH content. CONCLUSIONS: This study identifies Compound AI-3p as a novel GPX4 inhibitor that triggers ferroptosis, offering a potential breakthrough in the development of future drugs to combat cisplatin-resistant ovarian cancer development.