Abstract 4612: Development and validation of a screening platform for the identification of novel immuno-oncology targets

Abstract

Abstract Although immune therapy of cancer, including immune-checkpoint blockade have demonstrated therapeutic benefit in patients with various advanced cancers, further understanding of human immune pathology triggered by the tumor microenvironment, is essential to improve these therapeutic approaches. In order to shed light on novel immune suppressive mechanisms in tumor, iTeos Therapeutics developed a target discovery and drug repurposing platform based on phenotypic screening assays. We established a co-culture assay combining tumor immune suppressive cells and T-cells. This assay is flexible to allow the screening of chemicogenomics, shRNA and cDNA libraries. Multi-parameter readouts are combined to assess both T cell activation and proliferation, through high content imaging of T cell clusters formation, complemented with detection of IFNγ secretion and tumor cell death, as assessed using a cytotoxicity assay. The 96-well format of the assay allows medium-throughput testing of up to 3000 samples/screen. From the technical point of view we were able to adapt the assay to low level of automation, making it affordable to the biotech start-ups and academic laboratories. As a proof-of-concept we evaluated the assay for its ability to detect metabolic immune-oncology targets in A549 cells, a lung cancer immune suppressive cell line. A549 express indoleamine-2,3-dioxygenase 1 (IDO1), an enzyme expressed in many cancers that mediates local T-cell suppression through depleting the essential amino acid tryptophan. The assay conditions were validated with an IDO1 inhibitor as positive control and subsequently scaled up for automation. A commercially available small molecule library of 1900 compounds, with a high percentage of clinically tested drugs was screened. The library was tested at two different concentrations (0.3μM and 3μM), with two independent T-cell donors and spiked with IDO1 inhibitor as control. Combined analysis of T-cell activity and tumor killing led to the identification of 42 compounds with activity on multiple, potential immune suppressive pathways, including metabolism, epigenetics, autophagy, TGFβ, Wnt/β-catenin and TNFα/NF-κB signaling. Citation Format: Ariane Scoumanne, Virginie Rabolli, Lea Legrand, Murielle Martini, marie-claire Letellier, Stefano Crosignani, Christophe Quéva, Michel Detheux, Sandra Cauwenberghs, Jakub Swiercz. Development and validation of a screening platform for the identification of novel immuno-oncology targets [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4612. doi:10.1158/1538-7445.AM2017-4612