Preparation and analysis of monotypic and organotypic tumor spheroids.

Patient-derived tumor models are emerging as promising tools to explore patient-specific tumor behavior and to address a central gap in tumor immunology and immunotherapy drug development - the need for clinically relevant tumor models that recapitulate the complexity of the human tumor ecosystem, in which cancer cells are interacting with various immune and stromal elements. Patient-derived organotypic tumor spheroids (PDOTS), a biomimetic 3D-patient tumor avatar (3D-PTA), are comprised of cancer cells and autologous tumor-infiltrating immune and stromal cells that are grown within collagen hydrogels embedded in a 3D microfluidic culture device to model physiologic conditions and enable the study of tumor-immune dynamics. PDOTS and their murine counterparts (MDOTS, murine-derived organotypic tumor spheroids) are responsive to immune checkpoint blockade (ICB) and mirror in vivo response dynamics. We have also confirmed the utility of MDOTS/PDOTS in examining novel therapeutic strategies to overcome ICB resistance and testing the efficiency of T cell-based immunotherapies, demonstrating the utility of PDOTS profiling in examining the tumor-immune dynamics of immunotherapy response and resistance. Here, we provide a detailed protocol for processing, ex vivo culture, and analysis of patient-derived tumor organotypic tumor spheroids (PDOTS) in 3D microfluidic culture for immuno-oncology applications. The protocol can be readily adapted for ex vivo profiling of murine-derived organotypic tumor spheroids (MDOTS) and cancer cell line-derived monotypic tumor spheroids (MTS) for robust and iterative testing of immuno-oncology targets.