ID #288 The ferroptosis iron metabolism axis is a therapeutic target in atypical teratoid/rhabdoid tumor

Background Atypical teratoid/rhabdoid tumors (AT/RTs) are highly malignant brain tumors that predominantly affect children under three years old. Multi-modal therapies remain suboptimal due to severe toxicities and long-term morbidity. These limitations underscore the need for novel targeted therapies grounded in a mechanistic understanding of AT/RT biology. Metabolic pathways are frequently rewired in cancer to sustain rapid proliferation and invasion. Iron metabolism, in particular, regulates ferroptosis, a novel iron-dependent form of regulated cell death, whereby lipid peroxides cannot be metabolized appropriately, resulting in cellular toxicity. These metabolic pathways can be reprogrammed in cancer, thus enabling tumor cells to evade ferroptosis; however, there are no current efforts to understand the role of iron metabolism and ferroptosis in AT/RT. Methodology To identify and validate whether iron metabolism is a therapeutic vulnerability in AT/RT, we harnessed an integrative approach using in silico analysis, CRISPR/Cas9-mediated knockout, pharmacologic inhibition, metabolic and functional assays, and RNA-sequencing in patient-derived AT/RT neurosphere models. Results RNA-sequencing data across pediatric brain tumor cell lines in the Childhood Cancer Model Atlas revealed that AT/RT cell lines, unlike other pediatric brain tumors, exhibit high expression of ferrochelatase (FECH), the enzyme that catalyzes the insertion of iron into protoporphyrin to form heme. Analysis of genome-scale CRISPR/Cas9 loss-of-function screens in AT/RT cells revealed that FECH is a top dependency, suggesting that FECH may represent a unique therapeutic vulnerability in AT/RT. Consistently, CRISPR/Cas9 knockout and pharmacologic inhibition of FECH in patient-derived AT/RT neurospheres significantly reduced cell viability and neurosphere formation. Furthermore, FECH inhibition induced lipid peroxidation, glutathione depletion, and oxidative stress, indicating increased ferroptosis. Ongoing transcriptomic profiling will define gene expression changes mediated by FECH inhibition. Conclusion These findings indicate that FECH and iron metabolism play a central role in driving AT/RT and may contribute to ferroptosis resistance in AT/RT cells.