Syngeneic Murine Models with Distinct Immune Microenvironments Represent Subsets of Human Intrahepatic Cholangiocarcinoma

Background & Aims: Cholangiocarcinoma (CCA) is a poorly immunogenic malignancy associated with limited survival. Syngeneic immunocompetent mouse models of CCA are an essential tool to elucidate the tumor immune microenvironment (TIME), understand mechanisms of tumor immune evasion, and test novel immunotherapeutic strategies. The scope of this study was to develop and characterize immunocompetent CCA models with distinct genetic drivers, and correlate tumor genomics, immunobiology, and therapeutic response. Methods: A multifaceted approach including scRNA-seq, CITE-seq, whole exome and bulk RNA sequencing was employed. FDA -approved PD-1/PD-L1 antibodies were tested in humanized PD-1/PD-L1 mice (HuPD-H1). Results: A genetic mouse model of intrahepatic CCA (iCCA) driven by intrabiliary transduction of Fbxw7 D F/ Akt that mimics human iCCA was generated. From the Fbxw7 D F/ Akt tumors, a murine cell line (FAC) and syngeneic model with genetic and phenotypic characteristics of human iCCA were developed. Established SB1 ( YAP S127A / Akt ) and KPPC ( Kras G12D p53 L/L ) models were compared to the FAC model. Although the models had transcriptomic similarities, they had substantial differences as well. Mutation patterns of FAC, SB1, and KPPC cells matched different mutational signatures in Western and Japanese CCA patient cohorts. KPPC tumors had a high tumor mutation burden. FAC tumors had a T cell -infiltrated TIME, while SB1 tumors had a preponderance of suppressive myeloid cells. FAC, SB1, and KPPC tumors matched different immune signatures in human iCCA cohorts. Moreover, FAC, SB1, and KPPC tumor -bearing HuPD-H1 mice displayed differential responses to nivolumab or durvalumab. Conclusions: Syngeneic iCCA models display a correlation between tumor genotype and TIME phenotype, with differential responses to FDA -approved immunotherapies. This study underscores the importance of leveraging multiple preclinical models to understand responses to immunotherapy in different genetic subsets of human CCA. (c) 2024 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.