The impact of K-Ras Gly12 mutants on homeostasis and tumorigenesis in the colonic epithelium

Abstract K-Ras represents one of the most frequently mutated and therapeutically relevant oncogenic drivers. Clinical and epidemiological data suggest association between specific KRAS alleles, therapeutic responses, and patient outcomes, however, direct experimental validation of these relationships has been limited. In this study, we investigate the differential impacts of three most common K-Ras G12 mutants (K-Ras G12C , K-Ras G12D , and K-Ras G12V ) in the colon using in vivo models. Although tumors harboring different Gly12 mutants exhibited no obvious histological differences, their effects on survival outcomes and therapeutic responses displayed pronounced allele specific differences. Transcriptomic analyses revealed an allele-agnostic signature enriched for gene sets associated with MAPK signaling, receptor tyrosine kinase pathways, and immune-modulating pathways, relative to K-Ras WT tumors. In contrast, the allele-specific signature revealed marked enrichment of Notch and Wnt/β-catenin signaling pathways in K-Ras G12C tumors. Pharmacological inhibition of these pathways, in combination with a K-Ras G12C inhibitor, led to either addictive or synergistic reduction in tumor cell viability, in an allele-specific manner. These findings highlight the distinct biological consequences of individual K-Ras G12 mutations in colonic tumorigenesis and underscore therapeutic relevance of allele-specific signaling dependencies, offering a foundation for the development of effective, allele-informed therapeutic strategies for K-Ras mutant cancers.