Development of canine urine-derived bladder cancer organoids for in vitro chemosensitivity testing with cisplatin and gemcitabine

Abstract

In humans, bladder cancer is consistently ranked within the top ten most common malignancies in the world, with urothelial carcinoma (UC) being diagnosed in the majority of cases. Due to the current lack of accurate mouse models, the development of a more representative in vitro canine model for UC is necessary. Patient-derived tumor organoids (PDOs) have the potential to serve as an ex vivo model of UC. However, current culture procedures typically rely on the expansion of UC organoids from resected tumors or biopsy specimens, which is invasive and limits clinical application. We hypothesize that culture of canine UC PDOs can be achieved from urine samples and that these PDOs can be used for chemosensitivity testing with various chemotherapeutic agents with the goal of predicating individual patient responses. We were able to successfully isolate and maintain seven canine UC PDO cell lines from free-catch urine samples. One of these samples was isolated from a shipped urine sample while the others were collected in house. All but one of these patients were naive to chemotherapy treatments at the time of isolation. Functional response to chemotherapy (cisplatin and gemcitabine) was further assessed using a cell viability assay in canine UC organoids. UC results were compared to results of canine healthy urinary bladder PDOs. Our data suggest that organoids cultured from the urine of canine UC patients can be successfully used for cell viability testing using various drugs, cell lines, incubation lengths, and drug concentrations. Canine UC urine-derived organoids may provide novel insights to predict therapeutic response to chemotherapy in both canine and human patients in the future.