RevCAR-mediated T-cell response against PD-L1-expressing cells turns suppression into activation.

Abstract

Applying CAR T-cell therapy to treat solid tumors is especially challenging due to the immunosuppressive tumor microenvironment (TME). While our modular RevCAR system enhances the safety and controllability of CAR T-cell therapy, effectively targeting solid tumors remains difficult. Since PD-L1 is an immune checkpoint frequently upregulated by cancer cells and their microenvironment, it is a relevant target for solid tumors. Here, we introduce a novel PD-L1 RevTM capable of redirecting RevCAR T-cells to specifically target and kill PD-L1-expressing tumor cells, becoming activated and secreting pro-inflammatory cytokines. This is shown in vitro with monolayer and 3D models, including patient-derived cultures, and in vivo. Furthermore, we demonstrate in vitro and in vivo an AND-gated targeting of cells simultaneously expressing PD-L1 and another tumor-associated antigen by the Dual RevCAR system. Our findings suggest that RevCAR-mediated targeting of PD-L1 could be a promising therapeutic approach for modulating the TME and improving solid tumor treatment.