Abstract 4571: A novel ex vivo platform, 3D-EXpress, to rapidly assess the efficacy of KRAS targeting drugs alone and in combination with nivolumab using a biorepository of fresh patient tumoroids with intact tumor microenvironment
Authors: Ehrhart Jared , Ruedlinger Brittney , Rivera Angie , Ezeoke Romanus , Camacho Sharon , Currlin Seth , Altiok Soner 
Published: April 2023

Introduction: 3D-EXpress is a novel ex vivo drug testing platform using a Biorepository of neverdissociated, propagated, or reassembled fresh patient tumoroids with intact tumor microenvironment.Tumoroids measuring 150 µm in size retain tumor cell heterogeneity, tumor-resident innate andadaptive immune cells, stromal components, and cell-extracellular matrix interaction allowing to rapidlytest the efficacy of drugs and drug combinations targeting various components of the TME includingtumor cells, stroma, and immune cell populations. Here we employed the 3D-EXpress platform tocompare the efficacy of different drugs and drug combinations targeting KRAS and PD-1/PD-L1 immunecheckpoint ex vivo.

Materials and Methods: All tumor samples were obtained with patient consent and relevant IRBapproval. Cryopreserved tumoroids with known KRAS mutation status, PD-L1 expression, detailedimmune profiles and clinicopathologic data were selected from Nilogen’s tumoroid Biorepository for theex vivo assays. 3D tumoroids were treated with vehicle only, a SOS1::KRAS inhibitor, BI 1701963, apotent, selective, and covalent KRASG12C inhibitor, MRTX849, and a KRAS G12C inhibitor, sotorasib,alone and in combination with nivolumab for 72h. Treatment-mediated changes in tumor cell killing andtumor immune microenvironment were analyzed.

Results: To quantify treatment-mediated tumor cell killing activity we employed 3D high-contentconfocal imaging using a proprietary algorithm for data analysis. To monitor how ex vivo drugtreatments affect the tumor immune microenvironment culture supernatants isolated from treatedtumoroid samples were used for multiplex cytokine detection including 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, and Perforin.We observed a significant difference in tumor responses among patient samples to ex vivo tested drugsand drug combinations, which were further correlated with tumor resident innate and adaptive immunecell populations detected by a 21-color flow cytometry panel in addition to tumor KRAS mutation status,patient smoking history, tumor characteristics as well as PD-L1 expression levels analyzed on theassociated TMA slides.

Conclusion: Our data demonstrate that the 3D-Express platform, using cryopreserved 3D tumoroidswith intact TME, is an effective tool to assess the efficacy of KRAS and immune checkpoint inhibitorstargeting drugs to identify rational combination therapies and to develop clinically relevant biomarkersfor individualized patients in the future.

Citation Format: Jared Ehrhart, Brittney Ruedlinger, Angie Rivera, Romanus Ezeoke, Sharon Camacho, Seth Currlin, Soner Altiok. A novel ex vivo platform, 3D-EXpress, to rapidly assess the efficacy of KRAS targeting drugs alone and in combination with nivolumab using a biorepository of fresh patient tumoroids with intact tumor microenvironment. [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 4571.