Abstract 2753: Engineering patient-derived tumors to enable high-throughput screening: Immuno-oncology workflows

Aim/Introduction: In recent years, cancer immunotherapy has become one of the fastest-growing areas in cancer research. Selecting suitable and cost-effective experimental models for developing and validating immunotherapies is one of the major obstacles researchers face today. To overcome this, patient-derived tumor models are of increasing interest because they can better recapitulate many of the properties and the heterogeneity exhibited by the tumor microenvironment at a relatively low cost. Hereby, we propose a high throughput screening platform for an effective and efficient evaluation of cancer immunotherapies in patient-derived tumor models. Methods: Tumor models were established in vitro from patient-derived tumor biopsies. Established tumoroids were engineered using a luciferase-green fluorescent protein (GFP) lentivirus to generate a reporter pool. Transduced pools were enriched for GFP via flow cytometry and characterized using RNA/scRNA-seq and biomarker-based sequencing. Natural Killer (NK) cells were co-cultured with the enriched pool in various effector-to-target ratios and recorded using a live cell imaging and analysis platform. Cytotoxicity and cell health were measured by GFP intensity, luciferase activity, and caspase-based live staining. Results: A patient-derived tumoroid reporter pool was successfully generated through GFP enrichment using a flow cytometer. The killing efficiency of immune cells with various effector(E) to target(T) ratios has been successfully captured in a ratio-dependent manner via the live cell imaging and analysis platform. NK cell-mediated cytotoxicity was successfully measured through GFP intensity, luciferase, and caspase activity. Conclusions: Traditional cell line generation can be used in patient-derived tumoroid models to generate enriched reporter cell pools without selection pressure. Outside of establishing screening platforms, scientists can use this approach to efficiently engineer patient-derived tumoroid models to meet their specific research goals. Here, we used the reporter pool to develop a multiplex-killing assay to measure cell viability and toxicity. This platform can be used in a variety of immune cell workflows, providing a method that can predict tissue-specific responses, and evaluate solid tumor immunotherapies in high throughput cell-based assays. Citation Format: Andrew Tsao, Xiaoyu Yang, Garrett Wong, Vivek Chandra, Jacob Delgadillo, Lindsay Bailey Steinitz, Brittany Balhouse, Colin P