Abstract 4552: 3D-EXplore platform of fresh patient tumoroids with intact TME allows assessment of the efficacy of drugs targeting the tumor stroma on ex vivo tumor immunotherapy
Authors: Currlin Seth , Ruedlinger Brittney , Camacho Sharon , Rivera Angie , D'Andrea Jasmin , Ehrhart Jared , Altiok Soner 
Published: April 2023

Introduction: Cancer associated fibroblasts (CAFs) are a major component of the tumormicroenvironment (TME) and exhibit diverse tumorigenic functions such as immunosuppressionand extracellular matrix (ECM) remodeling. Treatment of solid tumors is often hindered by acomplex TME, which persists despite effective tumor-cell directed therapies. Therefore,treatment of solid tumors in combination with stromal-targeting therapies is essential toovercome CAF-facilitated tumor growth, and immunosuppression. Herein we interrogate theimpact of tumor stroma targeting therapeutics, in combination with nivolumab, on the efficacy oftumor cell killing (TCK) in a 3D human tumoroid ex vivo culture model (3D-EXplore). Resultingdata suggests that impairing the recruitment and activation of CAFs within the TME leads toenhanced TCK when combined with immune checkpoint blockade therapy.

Materials and Methods: All patients tumor samples were collected with patient consent andrelevant IRB approval. 3D tumoroids measuring 150 microns in size were generated from freshpatient tumors including endometrial, ovarian, and colorectal cancer tissues. Tumoroids werethen treated with stromal targeting strategies for TGF-beta (galunisertib), the FGF pathway(Dovitinib), FAK inhibitors (defactinib), and cell adhesion modulators (plerixafor) alone or incombination with nivolumab for 72-hours ex vivo. Tumor responses to ex vivo treatments wereassessed using a proprietary tumor cell killing assay and 21-color flow cytometry analysis.

Results and Summary: Here we evaluated the impact of stromal targeting therapeutics onCAFs and associated tumor cell killing as well as overcoming immune evasion mechanismspreserved in the tumoroid models. Furthermore, we used a multicolor flow panel to analyzewhether combination of stromal targeting drugs enhances nivolumab’s effect on the activation oftumor resident CD4, CD8 T-cells, NKT, and NK cell populations as well as on macrophagepolarization. Treatment-mediated changes in the tumor immune microenvironment was furthercorroborated by a multiplex cytokine release assay detecting GM-CSF, sCD137, IFNγ, sFas,sFasL, Granzyme A, Granzyme B, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, MIP-1α, MIP-1β, TNF-α,Perforin in tumoroid culture media and correlated with clinicopathologic findings and PD-L1expression for individual tumnors. Further, this 3D-tumoroid platform provides unique insightinto the microenvironment of both treatment responsive and non-responsive tumors and can aidin the development of patient-centered therapeutic regimens.

Citation Format: Seth Currlin, Brittney Ruedlinger, Sharon Camacho, Angie Rivera, Jasmin D'Andrea, Jared Ehrhart, Soner Altiok. 3D-EXplore platform of fresh patient tumoroids with intact TME allows assessment of the efficacy of drugs targeting the tumor stroma on ex vivo tumor immunotherapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4552.