KRAS Withdrawal in Cholangiocarcinoma Leads to Immune Infiltration and Tumor Regression

Abstract Cholangiocarcinoma (CCA) is a liver cancer subtype with poor survival rates. KRAS mutations are found in 15–40% of CCA, representing a new potential treatment target. Whether KRAS inhibition leads to CCA tumor regression is unknown, partly due to the lack of conditional animal models. A conditional TRE. Kras ^G12D / Trp53 knock‐out (TKP) CCA mouse model is engineered using the transposon system and CRISPR‐Cas9. Withdrawal of Kras ^G12D results in >90% tumor regression by day 7, accompanied by infiltration and enrichment of activated CD8 ⁺ T cells, shown by IHC, co‐IF staining, and single‐cell RNA‐Seq. Bulk RNA‐Seq of TKP cell line suggested that Kras ^G12D withdrawal stimulates the transforming growth factor beta pathway and induces senescence. Cytokine array characterizes the secretion of pro‐inflammatory factors, including IL‐15 and CCL17. Lentiviral overexpression of murine IL‐15 and CCL17 delays CCA tumor progression in a syngeneic transplant model. Consistently, expression of IL‐15 resulted in blockade of tumor progression in the TKP CCA model. These findings highlight the importance of oncogenic Kras in CCA tumor maintenance and underscore KRAS inhibition as a potential therapeutic approach for CCA.