A novel syngeneic immunocompetent mouse model of GBC to reveal CXCL5-mediated early tumor progression and demonstrate chemotherapeutic sensitivity.

Abstract

e16264 Background: Gallbladder cancer (GBC) is a highly lethal malignancy with a poor prognosis. Research progress has been critically hampered by the lack of experimental models in immunocompetent hosts, which limits the study of tumor-immune interactions and preclinical therapeutic evaluation. We aimed to establish a novel, immunocompetent mouse model of GBC that recapitulates key features of the human disease, and to utilize it for identifying early drivers of tumorigenesis and assessing therapeutic responses. Methods: We engineered a murine GBC cell line (mGBC1-ZH) from normal gallbladder organoids stably expressing oncogenic Kras and Trp53 mutations. Syngeneic tumor models were established via subcutaneous and orthotopic implantation of mGBC1-ZH cells into immunocompetent C57BL/6J mice. Genomic and transcriptomic profiling was performed to characterize chromosomal stability and transcriptional similarity to human GBC. CXCL5 expression was analyzed in early-stage human GBC tissues. Functional assays included in vitro cell proliferation and migration assays, as well as in vivo tumor growth and metastasis monitoring. Neutrophil infiltration was evaluated via immunophenotyping. Therapeutic sensitivity was assessed by treating tumor-bearing mice with frontline chemotherapy (gemcitabine plus cisplatin), with tumor regression measured as the primary endpoint. Results: The mGBC1-ZH syngeneic model supported robust subcutaneous and orthotopic tumor growth in C57BL/6J mice, recapitulating key hallmark features of human GBC: biliary epithelial differentiation, aggressive histopathological characteristics, and an immunosuppressive tumor microenvironment. Genomic analysis revealed recurrent chromosomal instability, and transcriptomic profiling demonstrated a profound transcriptional resemblance to human GBC. CXCL5 was identified as a key factor significantly upregulated in the early stage of human GBC. Functional studies confirmed that CXCL5 promoted tumor cell proliferation and metastasis in vitro, and enhanced tumor growth and neutrophil infiltration in vivo. Additionally, the model exhibited therapeutic responsiveness to gemcitabine plus cisplatin combination chemotherapy, with treatment inducing significant tumor regression compared to control groups. Conclusions: We have established a novel, immunocompetent syngeneic mouse model of GBC that closely mimics the human disease. This model revealed CXCL5 as a critical mediator of early tumor progression and neutrophil recruitment. It also serves as a robust platform for investigating tumor microenvironment interactions and advancing preclinical therapeutic development.