Abstract 287: Engineered 3D tissues facilitate preclinical immunotherapy studies in fully human platforms
Authors: Appleton Kathryn M. , Lassahn Katy A. , Elrod Ashley K. , DesRochers Teresa M. 
Published: June 2022

Abstract
Cancer treatment has evolved with the advent of immunotherapies. This drug class now plays a key role in supplementing or even replacing chemotherapies as first line treatments. Immunotherapies such as immune checkpoint inhibitors, bispecific antibodies, and chimeric antigen receptor T-cells (CAR-T) are just a few of the therapeutic strategies currently utilized to promote an anti-cancer response. Preclinical testing of current and novel immune modulators is necessary to expand our knowledge of these drugs and better predict their efficacy. Animal models have numerous deficiencies and complications that make them insufficient for accurate representation of human response, including an insufficient human immune system and a lack of genomic heterogeneity. Thus, there is an urgent need to develop preclinical models that incorporate human tumors and autologous immune cells together to create an accurate microenvironment for effective monitoring of tumor and immune cell interactions. We have developed a tumor-type agnostic platform in which 3D cell cultures are engineered with cells from resected human tumors. This ex vivo model not only recapitulates the tumor immune microenvironment (TIME), but it includes multiple downstream read-outs to address a single question such as whether an agent or combination of agents stimulates an immune response resulting in an anti-tumor effect. Our model can incorporate tumor and immune cells directly from the TIME or tumor cells from patient-derived xenografts or organoids which are then supplemented with allogenic or autologous immune cells or even CAR-T cells. Immune response can be detected via T-cell activation, degranulation assays, and immune cell-mediated tumor cell killing which can be multiplexed with anti-tumor activity assays. We can measure a reduction in viable tumor cells via flow cytometry following treatment or at increasing effector to target cell ratios, detect fluctuations in production and secretion of granzyme B indicating T-cell cytotoxic activity, and evaluate reduced cell viability for synergy assessments of drug combinations. We have detected increased secretion of IFNγ with combination drug treatment compared to single agent treatment. Macrophage polarization can be monitored with co-culture of CD14+ cells with tumor cells in our system inducing an M2 phenotype from an M1 phenotype. Finally, we can detect dendritic cell maturation following stimulation by measuring increased expression of MHC class II and CD103. Taken together this model system supports complex cell-cell interactions necessary to detect immunotherapy response and represents an ideal preclinical testing platform.
Citation Format: Kathryn M. Appleton, Katy A. Lassahn, Ashley K. Elrod, Teresa M. DesRochers. Engineered 3D tissues facilitate preclinical immunotherapy studies in fully human platforms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 287.