LAUSR

Introduction: Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive adenocarcinoma derived from bile ducts within the liver. This malignancy accounts for about 10% of cholangiocarcinoma cases and is the second most common primary liver cancer. Effective treatments for iCCA are limited, and they are primarily treated by tumor surgical resection. Regrettably, surgical resection is limited to early-stage disease and has an unfavorable prognosis. Development of novel therapeutic strategies for iCCA is needed to improve outcomes for non-resectable late stage iCCAs. Therefore, establishing suitable animal models for in vivo investigation of oncology and immuno-oncology treatment strategies for iCCA is critical. Methods: The Pten−/- GEMM was generated by CRISPR-Cas9 and crossed with Alb-Cre and LSL-KrasG12D/+ mice. Pathological examination of liver and blood biochemistry were investigated in thirteen GEMM mice. Liver fragments that were enriched with iCCA lesions were inoculated in syngeneic C57BL/6 mice subcutaneously to establish murine homograft models. The tumor homograft was passaged and expanded in vivo. Stable tumor growth was monitored in different passages. Histopathological studies were conducted for both the original and passaged tumors to confirm the conservation of original features. Genomic mutations and gene expression of homografts were analyzed by whole exome sequencing and RNA-sequencing, and tumor-infiltrating lymphocytes (TILs) were also analyzed by flow cytometry. Therapeutic efficacy of chemotherapies and immune checkpoint inhibitors were evaluated in vivo for tumor growth inhibition. Results: Within 8 weeks, all GEMM models had developed iCCA, resulting in the death of the animals. Hepatomegaly and obvious jaundice were observed in all mice at the study endpoint. Multiple diffuse and firm tumorous lesions were observed on livers. Histological analysis of the liver showed the adenocarcinoma lesions were distributed throughout theliver. Severe liver damage was also reflected by increased ALT, AST and bilirubin levels in serum. Murine subcutaneous homograft models of iCCA were successfully established using the liver fragments abundant within tumorous lesions from the GEMMs. The established homograft models were stably passaged in vivo with pathological features resembling the original GEMM. The various degrees of TILs and response to treatments revealed the potential of this model for in vivo investigation of immune response. Conclusion: Our murine iCCA homograft models exhibited rapid and stable tumor growth in immunocompetent mice, providing an efficient and clinically relevant approach for iCCA drug discovery research. Citation Format: Jinxi Wang, Leilei Chen, Likun Zhang, Lei Zheng, Ludovic Bourre, Jingjing Wang. Characterization of murine intrahepatic cholangiocarcinoma homograft models for therapeutic evaluation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 52.