Tumor site-directed A1R expression enhances CAR T cell function and improves efficacy against solid tumors
Kevin Sek, Amanda X. Y. Chen, Thomas Cole, Jesse Armitage, Junming Tong, Kah Min Yap, Isabelle Munoz, Phoebe Dunbar, Sean Wu, Marit J van Elsas, Olivia Hidajat, C. Scheffler, Lauren Giuffrida, Melissa A. Henderson, Déborah Meyran, Fernando Souza-Fonseca-Guimarães, Dat Quoc Nguyen, Yukuan Huang, Maria N. de Menezes, Emily B. Derrick, Cheok Weng Chan, Kirsten L. Todd, Jack D. Chan, Jasmine Li, Junyun Lai, Emma V. Petley, Sherly Mardiana, Anthony Bosco, Jason Waithman, Ian A. Parish, Christina Mølck, Gregory D. Stewart, Lev M. Kats, Imran G. House, Phillip K. Darcy, Paul A. Beavis
Abstract
Abstract The efficacy of Chimeric Antigen Receptor T cells against solid tumors is limited by immunosuppressive factors in the tumor microenvironment including adenosine, which suppresses Chimeric Antigen Receptor T cells through activation of the A 2A receptor. To overcome this, Chimeric Antigen Receptor T cells are engineered to express A 1 receptor, a receptor that signals inversely to A 2A receptor. Using murine and human Chimeric Antigen Receptor T cells, constitutive A 1 receptor overexpression significantly enhances Chimeric Antigen Receptor T cell effector function albeit at the expense of Chimeric Antigen Receptor T cell persistence. Through a CRISPR/Cas9 homology directed repair “knock-in” approach we demonstrate that Chimeric Antigen Receptor T cells engineered to express A 1 receptor in a tumor-localized manner, enhances anti-tumor therapeutic efficacy. This is dependent on the transcription factor IRF8 and is transcriptionally unique when compared to A 2A receptor deletion. This data provides a novel approach for enhancing Chimeric Antigen Receptor T cell efficacy in solid tumors and provides proof of principle for site-directed expression of factors that promote effector T cell differentiation.