A 3d In Vitro Culture-Based Method To Visualize And Quantify Effects Of Immuno-Modulatory Drugs

BACKGROUNDUnleashing the full potential of cancer immunotherapy is hampered by a lack of effective in vitro testing methods. 2D cultured cells poorly reflect the in vivo situation and lack the tumour microenvironment whereas humanized animal models are slow, have low throughput and are expensive. 3D cultures, on the other hand, more faithfully reproduce the organization of a tissue, recapitulating the cell-cell connections and cellular heterogeneity found in the tumour and allow for a cost-efficient testing of drug candidates. To address the unmet need of immunotherapy cancer drug developers for robust assays that incorporate the human immune system, with functional read-outs in a high throughput (384well plate) format, we developed an in vitro platform based on 3D co-cultures of cancer tumoroids and immune cells. This assay is designed to test the capacity of small molecules, bi-specific antibodies, checkpoint modulators, vaccines and combinations of thereof to enhance anti-cancer immune responses. METHODSCancer cells of different sources were grown in a hydrogel to form tumoroids and then HLA-matched PBMCs pre-conditioned via different protocols to achieve activated or exhausted T cells, were added in the presence or absence of immune-modulatory drugs. T cell infiltration and subsequent tumoroid killing was quantified using 3D high-content imaging. After ‘optical sectioning’ 3D image stacks were reconstituted and morphometric analysis was performed with OMiner software. RESULTS AND CONCLUSIONS Addition of immune checkpoint inhibitors, pembrolizumab and ipilimumab, led to enhanced T cell infiltration and cytotoxicity of exhausted T cells. These results showed that automated 3D image and data analysis enables discrimination of immune-tumour cell interactions depending on activation status of T cells and permits the visualization of T cell re-gain of function in the presence of checkpoint modulators. A 3D environment allows the different cell types to engage in a more realistic setting than when cells are grow in a monolayer and enables the quantification of spatially resolved information, which is of an utmost importance when studying tumor-immune cell relationships. This new and innovative platform empowers immunotherapy drug developers with a powerful tool to evaluate drug performance. Furthermore, drug combinations can be studied to determine synergistic effects with other checkpoint inhibitors of standard of care compounds in an efficient manner. Citation Format: Lidia Daszkiewicz, Kuan Yan, Maarten Klop, Leo Price. A 3D in vitro culture-based method to visualize and quantify effects of immuno-modulatory drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4611. doi:10.1158/1538-7445.AM2017-4611