Activation of KIT signaling promotes early tumorigenesis through the AP-1 pathway in APC/TP53 double-knockout human colon organoids.

Colorectal cancer (CRC) develops through a series of progressive genetic mutations, with alterations in APC and TP53 being the most frequently observed in the early stages. Although the loss of APC is recognized as a significant initiating event, the epigenetic processes through which the simultaneous inactivation of APC and TP53 facilitates the onset of colorectal tumorigenesis remain poorly characterized. To address this gap, we developed a human colon organoid model using CRISPR-Cas9 to achieve a double knockout of APC and TP53. Through extensive multi-omics profiling, we characterized the epigenetic landscape distinctive of early-stage CRC. We identified KIT, a receptor tyrosine kinase, as a critical oncogenic driver that is significantly upregulated in ΔDKO (APC and TP53 double knockout) organoids, thereby activating the MAPK and Wnt signaling pathways to augment proliferation and tumorigenesis. Furthermore, AP-1 transcription factors (FOS/JUN) regulate KIT expression via chromatin remodeling. Functional analyses indicated that KIT is integral to sustaining the elevated proliferation rates observed in ΔDKO organoids. These findings reveal a novel AP-1/KIT signaling axis that is central to the early progression of CRC, thereby presenting a promising avenue for therapeutic intervention.