3D model for CAR-mediated cytotoxicity using patient-derived colorectal cancer organoids

Immunotherapy using chimeric antigen receptor (CAR)-engineered lymphocytes has shown impressive results in leukemia. However, for solid tumors such as colorectal cancer (CRC), new preclinical models are needed that allow to test CAR-mediated cytotoxicity in a tissue-like environment. Here, we developed a platform to study CAR cell cytotoxicity against 3-dimensional (3D) patient-derived colon organoids. Luciferase-based measurement served as a quantitative read-out for target cell viability. Additionally, we set up a confocal live imaging protocol to monitor effector cell recruitment and cytolytic activity at a single organoid level. As proof of principle, we demonstrated efficient targeting in diverse organoid models using CAR-engineered NK-92 cells directed toward a ubiquitous epithelial antigen (EPCAM). Tumor antigen-specific cytotoxicity was studied with CAR-NK-92 cells targeting organoids expressing EGFRvIII, a neoantigen found in several cancers. Finally, we tested a novel CAR strategy targeting FRIZZLED receptors that show increased expression in a subgroup of CRC tumors. Here, comparative killing assays with normal organoids failed to show tumor-specific activity. Taken together, we report a sensitive in vitro platform to evaluate CAR efficacy and tumor specificity in a personalized manner.

Source: EMBO Journal - June 16, 2019 Category: Molecular Biology Authors: Schnalzger, T. E., de Groot, M. H., Zhang, C., Mosa, M. H., Michels, B. E., Röder, J., Darvishi, T., Wels, W. S., Farin, H. F. Tags: Cancer, Immunology, Methods & Resources Source Type: research