Phyto-sesquiterpene Lactones DET and DETD-35 Induce Ferroptosis in Vemurafenib Sensitive and Resistant Melanoma Via GPX4 Inhibition and Metabolic Reprogramming

Acquired resistance to vemurafenib (PLX4032) is a thorny issue in BRAF mutant melanoma therapy. Ferroptotic programmed cell death is a potential strategy for combating therapy-resistant cancers. This study uncovers the adaptation and abnormal upregulation of PUFAs and bioactive oxylipin metabolism in PLX4032 resistant melanoma cells. Phyto-sesquiterpene lactone, DET, and its derivative, DETD-35, induced lipid ROS accumulation and triggered ferroptotic cell death in PLX4032 sensitive (A375) and resistant (A375-R) BRAF melanoma cells by reprogramming glutathione and primary metabolisms, lipid/oxylipin metabolism, and causing mitochondrial damage in which DETD-35 showed superior efficiency to DET. We discovered that DET and DETD-35 are a new type of GPX4 enzyme inhibitor through non-covalent binding. This study provides new insight into the therapeutic mechanisms of both DET and DETD-35 to combat PLX4032 sensitive/resistant BRAF mutant melanomas via targeting GPX4 and ferroptosis.