Rewiring endogenous genes in CAR T cells for tumour-restricted payload delivery
Amanda X. Y. Chen, Kah Min Yap, Joelle S. Kim, Kevin Sek, Yukuan Huang, Phoebe Dunbar, Volker Wiebking, Jesse Armitage, Isabelle Munoz, Kirsten L. Todd, Emily B. Derrick, Dat Quoc Nguyen, Junming Tong, Cheok Weng Chan, Thang X. Hoang, Katherine M. Audsley, Marit J van Elsas, Jim Middelburg, Joel N. Lee, Maria N. de Menezes, Thomas Cole, Jasmine Li, C. Scheffler, Andrew M. Scott, Laura K. Mackay, Jason Waithman, Jane Oliaro, Simon J. Harrison, Ian A. Parish, Junyun Lai, Matthew H. Porteus, Imran G. House, Phillip K. Darcy, Paul A. Beavis
Abstract
The efficacy of chimeric antigen receptor (CAR) T cell therapy in solid tumours is limited by immunosuppression and antigen heterogeneity1–3. To overcome these barriers, ‘armoured’ CAR T cells, which secrete proinflammatory cytokines, have been developed4. However, their clinical application has been limited because of toxicity related to peripheral expression of the armouring transgene5. Here, we have developed a CRISPR knock-in strategy that leverages the regulatory mechanisms of endogenous genes to drive transgene expression in a tumour-localized manner. By screening endogenous genes with tumour-restricted expression, we have identified the NR4A2 and RGS16 promoters as promising candidates to support the delivery of cytokines such as IL-12 and IL-2 directly to the tumour site, leading to enhanced antitumour efficacy and long-term survival of mice in both syngeneic and xenogeneic models. This effect was concomitant with improved CAR T cell polyfunctionality, activation of endogenous antitumour immunity and a favourable safety profile, and was applicable in CAR T cells from patients. A CRISPR knock-in strategy that uses endogenous gene regulatory mechanisms can engineer ‘armoured’ CAR T cells that secrete proinflammatory cytokines directly within a tumour without causing toxicity, leading to prolonged survival in mice.