Precision Cut Cancer Tissue slices as human model for the testing of immune-modulatory compounds

The goal of personalized medicine is to stratify individual patients to the appropriate treatment. This approach depends on extensive characterization of individual tumors and their sensitivity to therapeutics. In the context of the immunotherapy of cancer, information on the localization, abundance and activation of immune cells within individual tumors gained in importance. Here we present a preclinical drug testing model to monitor individual drug responses of patients to targeted immunotherapy with the checkpoint inhibitor Nivolumab (anti- PD-1) and subsequent applications. In this study, we were able to determine different populations of infiltrating immune cells within viable tumors from colorectal cancer patients using our drug testing platform and a variety of subsequent applications. Analysis of immune cells was conducted on disaggregated cells from viable tumor slices. Disaggregation of precision cut cancer tissue slices was performed using the GentleMACS from Miltenyi. Immune cell subsets were analyzed by flow cytometric multiplexing of CD3, CD4, CD8 and CD45. Furthermore, we identified PD-1 positive cells among the CD45+/CD3+ lymphocyte population, indicating relevance for anti-PD-1 targeted therapy in colorectal cancer. Presence and localization of immune cells (CD45+) was confirmed by immunohistochemistry of tumor tissue slices. In addition, protein expression of CD8 and PD-1 was analyzed by Simple Western Size analyses. Cytokine secretion affected by Nivolumab treatment was analyzed in supernatants of tissue cultures using the proinflammatory panel from Meso Scale Discovery. The results demonstrated that immune cell compositions were stable and uniform within our precision cut cancer tissue slices both pre- and post-cultivation, and pre- and post-treatment with Nivolumab.