Abstract 41: Generation and multiomic profiling of a<i>APC/TP53</i>double knockout normal colon organoid

Abstract Colorectal cancer frequently arises from early tumorigenic events driven by mutations in the APC and TP53 genes. To elucidate mechanisms underlying early colon tumorigenesis, we established normal colon organoids with APC and TP53 double knockouts (DKO). Through integrated multi-omics analyses, including RNA-seq, ATAC-seq, methylation-seq, and H3K27ac ChIP-seq, we identified significant upregulation of the KIT gene in DKO organoids compared to controls. Subsequent KIT knockout generated APC/TP53/KIT triple knockout (TKO) organoids, which exhibited markedly reduced migratory capacity and Ki-67 tumor intensity, highlighting a pivotal role for KIT in early tumorigenic processes. Proteomic analysis further revealed that GSK3β phosphorylation was significantly reduced in TKO organoids compared to DKO organoids, suggesting a mechanistic link between KIT expression and downstream signaling pathways critical for early tumor progression. Notably, treatment with the KIT inhibitor imatinib phenocopied the effects of KIT knockout, reinforcing KIT's role as a driver of early colon tumorigenesis. These findings provide critical insights into the molecular mechanisms of early tumorigenesis in APC and TP53 mutant contexts, identifying KIT as a promising therapeutic target for intervention in early-stage colorectal cancer. Citation Format: Younghee Choi, Eunju Kim, Jihyun Park, Sang-Hyun Song, Tae-You Kim. Generation and multiomic profiling of aAPC/TP53double knockout normal colon organoid [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 41.