CRISPR screens in human tumor model to identify factors regulating the antitumor activity of dendritic cells

Dendritic cells (DCs) are antigen-presenting innate immune cells that regulate T cell responses, including those against cancer. DCs can promote the activation of potent antitumor T cells and immune responses through numerous mechanisms. However, they can also be influenced by tumor-mediated factors to contribute to immune tolerance and cancer progression. Consequently, the state of DCs is a key determinant of the efficacy of immunotherapies. Potentiating the antitumor functions of DCs has immense but as-yet underexploited therapeutic potential. In this project we will establish a 3D human tumor model in which iPSC-derived DCs are activated within the core of growing tumoroids, uptake tumor antigen and present it to primary T cells, which then eradicate the tumoroids. We will optimize the model for high-throughput arrayed CRISPR screens (Aim 1). In Aim 2, we will perform CRISPR activation and knockout screens in cancer cells as well as in iPSC-derived dendritic cells to identify genes that influence and govern the antitumor functions of DCs. In Aim 3, we will validate these targets in primary human dendritic cells as well as in mouse tumor models. We expect that this project will improve our understanding of genes regulating antitumor functions of DCs, and potentially identify therapeutic targets in DCs that potentiate antitumor immunity.