Abstract 2767: Understanding the functional fidelity of tumor infiltrated leukocytes (TILs) in a human tumor histo-culture platform
Authors: Basak Nandini Pal , Jaganathan Kowshik , K Vasanth , Govindan Sindhu , Malhotra Ritu , Kar Pradeep Kumar , Rao Rachita , Sankaran Satish 
Published: July 2021

Abstract
There is an unmet need for robust and accurate preclinical model to minimize translational failure especially in immuno-oncology (IO) research. The poor correlation between preclinical data with clinical trials remains a major concern. A near native and biologically relevant model is required for better correlation with an in vivo drug efficacy. FARCASTTM Tumor immune Micro-Environment (TiME) is a human histo-culture platform which retains the tumor and stroma along with the immune compartment post culture. In this study surgical excess head and neck squamous cell carcinoma specimens were obtained from consented patients, explants were generated and cultured over 72 hours. Here we investigate the functional fidelity of TILs by subjecting tumor explants to immune modulators. The immune cell population was found to be well preserved post-culture (correlation coefficient: R2= 0.96) using NanoString cell type analysis. The presence of various T cell sub-populations (CD4+ T helper cells, CD4+Foxp3+ T-regulatory cells and CD8+ Cytotoxic T-cells) and CD68+ Macrophage population post culture was confirmed using multi-color flowcytometry. Tumor explants were treated with anti-CD3 (10ng/ml) + IL2 (100units/ml) for T cell activation and LPS (1μg/ml) for Macrophage stimulation. The culture supernatants collected at 24 hours intervals were evaluated for cytokine release using Luminex platform. We observed increase of Granzyme-B, Perforin and IFNγ by anti-CD3+IL2 activation over the period of culture. On the other hand, LPS stimulation led to similar increase of IL6, IL8, TNFα and IL10. The cytokine release from the treated tumor explant was very specific to the type of stimulation. Thus, the various immune cells were not only preserved within the explant but also responsive to immune modulators. To further characterize the histo-culture platform we evaluated the preservation and response of the tumor compartment by treatment with standard of care drug regimen. Significant tumoricidal effect was observed by an increase of apoptosis (cleaved Caspase3 expression) and decrease in cell viability (PrestoBlue readout) post treatment. This functionally preserved tumor immune microenvironment provides a robust platform for testing various immune-oncology drugs with varied mechanism of actions. Hence, this platform could be effective in evaluating immunotherapeutic agents targeting T-cells and Myeloid populations and their associated tumoricidal effects.
Citation Format: Nandini Pal Basak, Kowshik Jaganathan, Vasanth K, Sindhu Govindan, Ritu Malhotra, Pradeep Kumar Kar, Rachita Rao, Satish Sankaran. Understanding the functional fidelity of tumor infiltrated leukocytes (TILs) in a human tumor histo-culture platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2767.