Abstract 13: A non-surgical approach to develop an orthotopic colorectal cancer mouse model

Abstract

Abstract Recapitulating physiologically relevant tumor microenvironment is an important yet a significant challenge in modeling colorectal cancer (CRC) for basic and translational studies. Cecal-wall injection is most widely used for orthotopic animal models of CRC. However, this procedure involves complicated surgical procedures, and its ectotopic nature is a major issue for therapeutic development. Here, we report a non-surgical procedure for establishing orthotopic CRC mouse models, reflecting the appropriate tumor microenvironment to better model the disease development and facilitate translational studies, including drug identification and validation. For this procedure, the mice are fasted overnight. The following day, anesthesia is induced in the study mice (Balb/c or C57BL/6) while placed on a thermostat-controlled heating blanket. Next, a specialized catheter is inserted and distended into the mouse colon to gently block the colon and ensure the localization for tumor development. Hereafter, the colonic epithelium is treated with proteases and mechanical abrasion to cause mild disruption. Following the local gut inflammation, the targeted colon region is incubated with tumor cells, leading to the adhesion of tumor cells (CT26 or MC38) to the colonic epithelium. Based on the animal background and the cell line used, the tumor is developed within 4-6 weeks. Pathological assessment on hematoxylin and eosin stained tumor tissues confirmed the stages of tumor development. Additional adaptations of this procedure include i) tumor development in different mouse strains, ii) local delivery of adeno-Cre in transgenic mice for CRC, and iii) transplantation of tumor organoids in the mouse colon. Overall, our non-surgical procedure overcomes the technical difficulties of surgery and offers several advantages like ease of handling, cost-effectiveness, pain-free with nearly no procedure-associated mortality, and adaptability to several strains. To conclude, this non-surgical procedure is a novel and promising alternative to conventional orthotopic CRC mouse models for translational studies. Citation Format: Samantha Sharma, Kevin Van der Jeught, Zhuolong Zhou, Xinna Zhang, Xiongbin Lu. A non-surgical approach to develop an orthotopic colorectal cancer mouse model [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 13.