Human Metastatic Cholangiocarcinoma Patient-Derived Xenografts and Tumoroids for Preclinical Drug Evaluation

Purpose: Cholangiocarcinoma (CCA) is usually diagnosed at advanced stages, with limited therapeutic options. Preclinical models focused on unresectable metastatic CCA are necessary to develop rational treatments. Pathogenic mutations in IDH1/ 2, ARID1A/B, BAP1, and BRCA1/2 have been identified in 30%- 50% of patients with CCA. Several types of tumor cells harboring these mutations exhibit homologous recombination deficiency (HRD) phenotype with enhanced sensitivity to PARP inhibitors (PARPi). However, PARPi treatment has not yet been tested for effectiveness in patient-derived models of advanced CCA. Experimental Design: We have established a collection of patient-derived xenografts from patients with unresectable metastatic CCA (CCA-PDX). The CCA-PDXs were characterized at both histopathologic and genomic levels. We optimized a protocol to generate CCA tumoroids from CCA-PDXs. We tested the effects of PARPis in both CCA tumoroids and CCA-PDXs. Finally, we used the RAD51 assay to evaluate the HRD status of CCA tissues. Results: This collection of CCA-PDXs recapitulates the histopathologic and molecular features of their original tumors. PARPi treatments inhibited the growth ofCCAtumoroids and CCA-PDXs with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1. In line with these findings, only CCA-PDX and CCA patient biopsy samples with mutations of BRCA2 showed RAD51 scores compatible with HRD. Conclusions: Our results suggest that patients with advanced CCA with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1, are likely to benefit from PARPi therapy. This collection of CCA-PDXs provides new opportunities for evaluating drug response and prioritizing clinical trials.