Abstract B137: Visualization and quantification of tumor-immune cell interactions in 3D cultures

Introduction: Despite the broad expansion of immunotherapies in cancer research field and drug discovery pipelines in the recent years, the actual number of patients who benefit from them is still extremely low and clinical trial failure rate is quite high. The main reason is that these treatments modalities enter the clinical space without proper understanding of mechanism of action and with a very weak rationale for combinations. However the progress in this direction is hampered by a lack of appropriate pre-clinical models, which remains one of the major bottlenecks in the immune-oncology research. Our goal is to address this issue by developing in vitro models that are both clinically relevant and suitable for routine screening of drug candidates. Experimental Procedures: To ensure the most accurate representation of the tumor biology, cancer cells are co-cultured with immune cells in a 3D setting. Tumor 3D cultures were generated from established cancer cell lines (e.g. breast, prostate) and colorectal cancer organoids (from HUB Organoid Technology) and seeded in 3D ECM-like matrix constituted from protein hydrogel. Different immune cells, such as PBMCs, purified T cells, dendritic cells or macrophages were added to the 3D tumor culture together with different immune-modulators and their effects on the infiltration of the immune cells into tumoroids and their killing was visualized using high-content imaging system. The quantification of these effects was achieved with morphometric analysis with proprietary OMinerTM software. Results: Multiparametric image-based analysis enabled the discrimination of complex immune-tumor cell interactions in 3D co-cultures. The effect of immune cell targeting on the tumor progression was clearly demonstrated by enhanced infiltration of T cells into the tumoroids and their increased killing in the presence of T cell engager. ADCC mechanism could be also depicted with this system. The reported here robust in vitro assay allows image based analysis of 3D cultures in a high-throughput manner. The 3D setting offers possibility to study active migration of immune cells towards tumoroids, infiltration of immune cells into the tumoroids and reduction of tumor volume; all of the functional read-ouds that are based on spatially resolved information. Conclusions: The developed image-based 3D platform allows for analysis of complex immunotherapy effects on different cell types that engage in a more physiologically relevant spatial setting compared to traditional 2D cultures. Preserving the third dimension also in the data analysis process provides a unique opportunity to measure spatially resolved information, not accessible by conventional monolayer cultures or biochemical assays. Visualization and quantification of tumor-immune cells interactions offer a highly powerful tool for cancer immunotherapy drug developers and brings a better understanding of the mechanism of action of novel treatments, which is ultimately translating to better clinical outcomes. Citation Format: Lidia Daszkiewicz, Gera Goverse, Nataliia Beztsinna, Kuan Yan, Emma Spanjaard, Leo Price. Visualization and quantification of tumor-immune cell interactions in 3D cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B137. doi:10.1158/1535-7163.TARG-19-B137