Abstract 87: Integrated pipeline for immuno-oncology drug testing: from patient-derived organoid assays with reconstituted TME to fresh ex vivo patient tissue cultures
Authors: Aksoy Ezgi Kaya , Abiega Sergei Chavez , Stessuk Talita , De Man Saskia , Putker Marrit , Basten Sander , Meesters Niels , Spanjaard Emma , Price Leo S. , Goverse Gera , Beztsinna Nataliia 
Published: March 2024

Abstract
Introduction: Successful pre-clinical evaluation of immuno-oncology drugs requires complex models to accurately represent all components of the human tumor microenvironment (TME). Patient-derived organoids (PDO) are known to reflect genetic and morphological profiles of the original patient’s tumors. In our immuno-oncology in vitro assays, PDOs can be combined with immune cells and fibroblasts to re-constitute the TME and study drug efficacy and mechanism of action. Alternatively, we have developed assays with fresh tumor material containing native TME in the 3D Ex Vivo Patient Tissue (EVPT) platform. Both types of assays have advantages and limitations. Here, we will present a case study displaying both capabilities and benchmarking the technologies against each other.
Methods: Patient tumor tissues were obtained from tissue providers and processed within 24 hours to preserve the TME. Freshly isolated ex vivo tumor clusters were embedded in a protein-rich hydrogel and exposed to drug panels in a 384-well format for 5-7 days. Phenotypic effects of therapies on morphological features were measured using our proprietary automated high content imaging (HCI) analysis platform. IHC, FACS, or sequencing, were used for in-depth sample characterization. In parallel, PDOs were generated, biobanked and characterized from same ex vivo samples. Allogenic or autologous PBMCs were isolated from blood. PDOs and PBMCs were then co-cultured together in presence of immuno-oncology drugs, and drug effects were analyzed by the same automated HCI analysis platform.
Results: Samples from ovarian, head and neck, breast, prostate, lung cancer, and melanoma were used in the pipeline. Fresh ex vivo culture of a melanoma sample presented here has shown mild responses (tumoroid size reduction) to immunomodulatory treatments (SEA and Pembrolizumab) and strong responses to targeted therapy treatment (Dabrafenib and Trametinib). Genetic characterization of the sample identified heterozygous BRAF V600E mutation and IHC analysis showed a large proportion of immune cells (CD3, CD4, CD8, CD80 and CD68 positive cells) present, confirming the observed ex vivo drug responses. Part of the melanoma sample was allocated for PDO generation and biobanking. Established PDOs were used in co-culture with allogeneic and autologous PBMCs and treatment responses to SEA stimulation and CD3/CD28 beads as well as increased PBMC infiltration rates were observed.
Conclusion: Choice of the pre-clinical model for immuno-oncology studies relies on multiple factors such as biological relevance, replicability, TME representation, and scalability. Here we present a spectrum of assays ranging from complex ex vivo systems (EVPT) for ‘close to the clinic’ scenarios to more scalable PDOs co-cultured with allogeneic and/or autologous PBMCs for high-throughput mechanistic drug screenings.
Citation Format: Ezgi Kaya Aksoy, Sergei Chavez Abiega, Talita Stessuk, Saskia De Man, Marrit Putker, Sander Basten, Niels Meesters, Emma Spanjaard, Leo S. Price, Gera Goverse, Nataliia Beztsinna. Integrated pipeline for immuno-oncology drug testing: from patient-derived organoid assays with reconstituted TME to fresh ex vivo patient tissue cultures [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 87.