Elucidating the impact of KRAS Gly12 mutants on homeostasis and tumorigenesis in the colonic epithelium

KRAS mutations constitute one of the most prevalent and therapeutically relevant oncogenic drivers in human cancers. Clinical and epidemiological data suggest association between specific KRAS alleles, therapeutic response, and patient outcomes, however, direct experimental validation of these relationships has been limited. In this study, we employed genetically engineered mouse models (GEMMs) to investigate the differential impacts of three most common KRAS Gly12 mutations (KRASG12C, KRASG12D, and KRASG12V) in the context of intestinal homeostasis and tumorigenesis. Although tumors developing from different KRAS Gly12 mutants exhibited no significant histological differences, their effects on survival outcomes of tumor bearing mice and therapeutic response displayed pronounced allele-specific differences. Our transcriptomic analyses revealed both allele-agnostic and allele specific transcriptional programs driven by KRAS Gly12 mutations in colon tumors. The allele-agnostic signature was characterized by enrichment of gene sets associated with MAPK signaling, receptor tyrosine kinase pathways, and immune-modulating pathways, compared to KRAS WT tumors. In contrast, allele-specific signature revealed unique OXPHOS pathway upregulation in KrasG12D tumors and marked enrichment of Notch and Wnt/-catenin signaling pathways in KrasG12C tumors. Inhibition of these pathways, in combination with KRASG12C inhibitor led to either addictive or synergistic reduction in tumor cell viability, in allele-specific manner. Collectively, these findings underscore the importance of understanding the distinct biological effects of KRAS Gly12 mutants on colon tumorigenesis and highlight the therapeutic relevance of allele specific signaling dependencies in colorectal cancer. These results provide key mechanistic insights and provide a foundation for the development of effective, allele-informed therapeutic strategies for KRAS mutant cancers.