Abstract 1946: Elucidating the mechanisms of acquired resistance to AMG510 in cancer models harboring KRAS G12C mutations

Abstract GTPase KRas (KRAS), a critical oncogene, is known for its frequent mutations across a wide array of human cancers, most notably in pancreatic, lung, and colorectal cancers. Recent advancements in the field have led to the successful development of numerous inhibitors targeting the mutant KRAS. Clinical application of KRAS G12C inhibitors, such as AMG510 and MTRX849, represents major breakthroughs in addressing previously 'undruggable' cancer targets. Nevertheless, a subset of patients initially responsive to these inhibitors eventually exhibit treatment resistance. Uncovering the underlying mechanism would help to develop novel therapies that overcome the acquired drug resistance. To elucidate the underlying mechanisms, we generated AMG510-resistant tumor models, namely AMG510-R-MIA PaCa-2 and AMG510-R CT26 KRAS G12C, by continuous administration of AMG510 to tumor-bearing mice. Upon comparison of sensitive parental tumors and resistant tumors, we found that highly expressed KRAS and constant activation of RAS-MAPK signaling pathway are critical for resistant tumor progression following AMG510 treatment. In addition, resistant tumor cells are responsible for the elevated secretion of CXCL2/3/5, which dramatically reconditions the tumor immune microenvironment and recruits immunosuppressive cells. In summary, the exploration of the resistance mechanism in AMG510-induced resistant models provides insight into the development of new-generation KRAS-G12C inhibitors and novel combinatorial therapies. Citation Format: Ting Ni, Tongxin Huo, Yawen Zhang, Jingjing Wang, Gaoxiang Liu, Wenting Shi, Qingyang Gu. Elucidating the mechanisms of acquired resistance to AMG510 in cancer models harboring KRAS G12C mutations 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 (6Suppl): Abstract nr 1946.