Abstract 5673: Ferroptosis induction synergizes with KRAS inhibitors in KRAS -mutant lung adenocarcinoma.

Abstract Background: KRAS inhibitors hold substantial potential for the treatment of numerous malignancies harboring activating KRAS mutations, including non-small cell lung cancer (NSCLC). KRAS mutations are present in 25-30% of patients with non-squamous NSCLC, most commonly in the form of G12C mutations. Unfortunately, patients with inactivating mutations in KEAP1, which is frequently co-mutated with KRAS and STK11/LKB1, respond poorly to KRAS G12C inhibitors. KEAP1 inactivation impairs NRF2 protein degradation, leading to enhanced antioxidant and ferroptosis response in the tumor cells. Whether ferroptosis resistance mediates resistance to KRAS G12C and G12D inhibitors in lung adenocarcinoma cells harboring these mutations is unknown. Methods: DepMap was used to retrieve the drug sensitivity data for RSL3, erastin, ML162, ML210, sotorasib, and MRTX1133 as well as CRISPR and RNAi screen data in NSCLC human cell lines. A NSCLC ferroptosis resistance gene signature was constructed using genes that positively correlated (Pearson correlation z-score 3) with resistance to both RSL3 and erastin in human NSCLC cell lines accessed from the Cancer Therapeutics Response Portal. We knocked-out Keap1 and Stk11 from murine LKR13 KRAS G12D and KRAS G12C cells using CRISPR-Cas9, to create isogenic models of KrasMUT (K), KrasMUT/Keap1KO (KK), KrasMUT/Lkb1KO (KL), and KrasMUT/Lkb1KO/Keap1KO (KLK) tumor cells. Lipid peroxidation was quantified by flow cytometry using BODIPY™ 581/591 C11. Results: We determined that KEAP1-mutant, but not LKB1-mutant, NSCLC cell lines were resistant to ferroptosis inducers RSL3, ML162, ML210, and erastin. KEAP1 deficiency also correlated with poor response to KRAS G12C inhibitors (sotorasib and adagrasib) and the KRAS G12D inhibitor MRTX1133 in human and murine cell lines, suggesting that ferroptosis resistance may contribute to KRAS inhibitor resistance. Treatment of KRAS mutant tumor cells with adagrasib or MRTX1133 induced lipid peroxidation- the biochemical defining feature of ferroptosis. In KRAS G12D mutant LKR13 cells, MRTX1133-induced cell death could be partially reversed by the ferroptosis inhibitor ferrostatin-1, but not by apoptosis or necroptosis inhibitors. Moreover, a higher NSCLC ferroptosis resistance gene expression signature correlated with reduced sensitivity to KRAS gene disruption in CRISPR and RNAi screens in KRAS-mutant NSCLC cell lines. Finally, ferroptosis inducers erastin and RSL3 synergized with adagrasib and MRTX1133 in LKR13 K cell lines. Conclusions: KRAS inhibition induces ferroptosis in KRAS-mutant lung adenocarcinoma cell lines and ferroptosis resistance correlates with resistance to KRAS inhibitors. Combining ferroptosis induction strategies could potentially enhance the effectiveness of KRAS targeting treatments. Citation Format: Amirali Karimi, Yu Qian, David Molkentine, Alvaro Guimaraes Paula, Busra Ernhofer, David Hwa Peng, Monique B. Nilsson, John V. Heymach. Ferroptosis induction synergizes with KRAS inhibitors in KRAS-mutant lung adenocarcinoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5673.