Abstract 360: Dissecting the role of oncogenic KRAS and ferroptosis within colorectal cancer

Abstract Introduction: Ferroptosis is a novel iron-dependent regulated cell death mechanism triggered by a toxic accumulation of membrane lipid peroxidation. This mechanism is counteracted by ferroptosis defense systems, such as the GPX4/GSH system, which function as antioxidants that limit lipid peroxidation. Oncogenic KRAS (KRASmut) is a key driver for many aggressive cancers, including colorectal cancer (CRC). Previous studies have suggested that oncogenic KRAS plays a pleiotropic role in the ferroptosis pathway. Yet, the interplay between oncogenic KRAS and ferroptosis has not been fully elucidated in CRC. Here, we aimed to dissect the role of oncogenic KRAS in ferroptosis using CRC as a cancer model. Methods: Cells from a KRAS-inducible model (iKAP) were seeded and treated with ferroptosis-inducing drugs (e.g., Erastin and RSL3) and/or a KRAS inhibitor (MRTX1133). Lipid peroxidation was then measured by BODIPY assay followed by flow cytometry to detect the quantity of BODIPY-stained cells. Protein expression of known ferroptosis defense mechanisms was also profiled (e.g., SLC7A11 [xCT] and GPX4). Results: Results from this study demonstrate that KRASmut activation leads to a reduction in mean fluorescence intensity when compared to KRASWT of BODIPY-stained cells. This decreased mean fluorescence intensity is indicative of lower levels of lipid peroxidation and, consequently, ferroptosis. KRASmut cells were also found to be resistant to ferroptosis following treatment with ferroptosis inducers. To replicate a pharmacologically induced KRASWT phenotype, iKAP cells were treated with MRTX1133, which led to a significant decrease in viability when combined with RSL3. We observed a decreased protein expression of the membrane antiporter xCT following treatment with MRTX1133, which we believe works synergistically with the GPX4 inhibition of RSL3. Conclusion: We observed that KRASmut may induce resistance to ferroptosis in vitro in CRC cells. Genetic and pharmacological inhibition of KRAS resulted in sensitization to ferroptosis inducers. Future work will uncover mechanisms through which oncogenic KRAS leads to ferroptosis resistance in CRC. More importantly, understanding the interaction between ferroptosis, oncogenic KRAS, and its antagonist systems has significant therapeutic potential in oncology. Citation Format: Alexandra Rosa-Vázquez, Vincent Bernard-Pagan, Jasper Chen, Cullen Taniguchi. Dissecting the role of oncogenic KRAS and ferroptosis within colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 360.