Abstract A013: Targeted therapy-induced chromosomal instability dictates mitotic dependency on Aurora Kinase A

Abstract Targeted therapies are designed to eliminate cancer cells by directly inhibiting oncogenic driver proteins. In addition to their primary inhibitory effects on oncogenic signaling, these agents frequently impose collateral cellular stresses, such as DNA damage. KRAS-targeted therapies, particularly KRAS G12C inhibitors (G12Ci), represent a major therapeutic advance but remain limited in efficacy. Previous reports of targeted therapy-induced DNA damage, including studies of TKIs and MAPK inhibitors, have primarily been based on cytotoxic dosing conditions. Far less is known about whether DNA damage can also be induced by targeted therapies in less sensitive cancer models, particularly under sublethal doses that better mimic clinical responses. Failure to repair DNA damage can lead to chromosomal instability (CIN) and chromosomal aberrations. CIN is widely recognized to promote tumor evolution by enhancing cellular plasticity and adaptability, thereby contributing to therapeutic resistance and metastatic progression. However, it remains unknown how KRAS G12C inhibition influences CIN and whether G12Ci-induced CIN might generate unique, exploitable vulnerabilities. In this study, we profiled 15 KRAS G12C-mutant NSCLC cell lines representing diverse mutational backgrounds. We treated these models with the KRAS G12Ci LY3499446 and comprehensively assessed their DNA damage responses, CIN phenotypes, and sensitivities to combination therapies with agents that perturb chromosomal stability. We observed heterogeneous induction of DNA damage and CIN across these cell lines. Notably, we identified the strongest correlation between G12Ci-induced CIN and synergistic interaction with the Aurora kinase A inhibitor (AURKAi) LSN3321213. Machine learning-based single-cell image tracking and DNA barcoding analyses revealed that AURKA inhibition alone causes mitotic arrest followed by mitotic slippage, allowing cells to evade death, whereas combined G12Ci and AURKAi treatment triggers catastrophic mitotic cell death. Mechanistically, we found that G12Ci stabilizes Cyclin B1 through mitotic activation of ATR/ATM DNA repair signaling, thereby prolonging mitotic arrest. Under conditions of combined inhibition of KRAS G12C and AURKA, in which Cyclin B1 degradation is impaired, cells fail to exit mitosis and undergo catastrophic cell death. Together, our findings identify CIN as a predictive marker of response to combined KRAS G12C and AURKA inhibition, providing mechanistic rationale to enhance the therapeutic window of AURKA inhibitors when used with targeted therapies. Citation Format: Chendi Li, Varuna Nangia, Melissa Vieira, Anahita Nimbalkar, Christopher J. Graser, Jeremy Chang, Mohammad U. Syed, Yi Shen, Radhika Koranne, Lee Zou, Sabrina L. Spencer, Aaron Hata. Targeted therapy-induced chromosomal instability dictates mitotic dependency on Aurora Kinase A [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RAS Oncogenesis and Therapeutics; 2026 Mar 5-8; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(5_Suppl_1):Abstract nr A013.