Labile Iron Release Primes Pancreatic Cancer for Ferroptosis

Cancers have unique metabolic adaptations in response to cell-intrinsic and environmental stressors, where identifying new strategies to target these adaptions is an area of active research. We previously described a dependency on a cytosolic aspartate aminotransaminase (GOT1)-dependent pathway for NADPH generation in pancreatic cancer. Here, we sought to identify metabolic dependencies following GOT1 inhibition to provide insight into the regulation of redox metabolism. Using pharmacological methods, we identified cysteine, glutathione, and lipid antioxidant function as metabolic vulnerabilities following GOT1 withdrawal. Targeting any of these pathways triggered ferroptosis, an oxidative, non-apoptotic, iron-dependent form of cell death in GOT1 knockdown cells. Mechanistically, GOT1 inhibition promoted a catabolic state and enhanced the availability of labile iron through autophagy and iron uptake. In sum, our study identifies a novel biochemical connection between GOT1, iron regulation, and ferroptosis, and suggests GOT1 plays a role in protecting PDA from metabolic stress. GOT1 was knocked down via doxycycline-inducible shRNA in two human pancreatic cancer cell lines, Tu8902 and MiaPaCa, and subject to RNA-seq. For each cell line, three replicates each of control (-Dox, "mnsdox") and knockdown (+Dox, "plsdox") were sequenced.