Abstract 422: Aurora kinase A inhibition overcome adaptive resistance to KRAS G12C inhibitor by replication stress-induced genomic instability and mitotic cell death

Cancer cells develop drug-tolerant states, enabling them to evade therapies. In response to KRAS G12C inhibitors (G12Ci), non-small cell lung cancer (NSCLC) cells harboring KRAS mutations sustain a drug-tolerant phenotype through the activation of aurora kinase A (AURKA). AURKA phosphorylates c-Raf, thereby sustaining KRAS signaling under G12Ci treatment. However, the molecular mechanism by which G12Ci treatment induces dependency on AURKA remains poorly understood, and there is currently a lack of molecular biomarkers that predict sensitivity to combined G12Ci and AURKA inhibitor (AURKAi) therapy. We show that the selective AURKAi (LSN3321213) induces mitotic catastrophe and subsequent cell death in NSCLC cells resistant to the G12Ci (LY3499446). Machine learning-based single-cell image tracking revealed that G12Ci-treated cancer cells overcome G1 arrest-induced apoptosis. When treated with AURKAi, these cells undergo mitotic stalling and subsequent mitotic slippage, allowing them to evade cell death. In contrast, simultaneous treatment with both inhibitors results in catastrophic mitotic cell death. G12Ci induces DNA damage as a result of replication stress, leading to increased apoptotic priming during mitosis, which may shift the cellular response towards mitotic catastrophe rather than slippage. Approximately 40% of genetic alterations in NSCLC are associated with replication stress, including MYC amplification. Our findings indicate that MYC amplification is associated with enhanced synergy between G12Ci and AURKAi in NSCLC. Furthermore, induction of CMYC expression in CMYC wild-type cell lines leads to mitotic catastrophe in response to G12Ci + AURKAi, suggesting that CMYC induces replication stress, thereby promoting a dependency on AURKAi. This study reveals a novel relationship between replication stress-induced genomic instability and mitotic defects in KRAS G12C NSCLC and identifies MYC amplification as a potential biomarker for guiding the selection of combined G12Ci and AURKAi therapy in patients with KRAS mutations and MYC amplification. Citation Format: Chendi Li, Varuna Nangia, Christopher J. Graser, Jeremy Chang, Anahita Nimbalkar, Mohammad U. Syed, Melissa Vieira, Yi Shen, Steve Altschuler, Lani Wu, Franziska Michor, Sabrina L. Spencer, Aaron N. Hata. Aurora kinase A inhibition overcome adaptive resistance to KRAS G12C inhibitor by replication stress-induced genomic instability and mitotic cell death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 422.