Cellular features predicting susceptibility to ferroptosis

Ferroptosis is a novel non-apoptotic, oxidative form of regulated cell death that can be triggered by diverse small-molecule ferroptosis inducers (FINs) and genetic perturbations. Current lack of insights into the cellular contexts governing sensitivity to ferroptosis has hindered both translation of FINs as anti-cancer agents for specific indications and the discovery of physiological contexts where ferroptosis may function as a form of programmed cell death. This dissertation describes the identification of cellular features predicting susceptibility to ferroptosis from data generated through a large-scale profiling experiment that screened four FINs against a panel of 860 omically-characterized cancer cell lines (Cancer Therapeutics Response Portal Version 2; CTRPv2 at http://www.broadinstitute.org/ctrp/). Using correlative approaches incorporating transcriptomic, metabolomic, proteomic, and gene-dependency feature types, I uncover both pan-lineage and lineage-specific features mediating cell-line response to FINs. The first key finding from these analyses implicates high expression of sulfur and selenium metabolic pathways in conferring resistance to FINs across lineages. In contrast, the transsulfuration pathway, which enables de novo cysteine synthesis, appears to plays a role in ferroptosis resistance in a subset of lineages. The second key finding from these studies identifies cancer cells in a high mesenchymal state as being uniquely primed to undergo ferroptosis. This susceptibility stems from a specific dependency of high mesenchymal-state cancer cells on the lipid hydroperoxide quenching mechanisms inhibited by FINs and is conserved across cancer cell lines of mesenchymal origin, epithelial-derived cancer cell lines that have undergone an epithelial-to-mesenchymal-transition, and patient-derived cancer cells exhibiting mesenchymal state-mediated resistance to anti-cancer therapies. The work presented herein formalizes frameworks for studying small molecule inducers of cell death through cell-line profiling. The results advance current mechanistic understanding of the cellular circuitry underlying ferroptosis sensitivity and lay the foundation for a novel therapeutic approach using ferroptosis inducers to target high mesenchymal-state cancer cells.