Epigenetic reprogramming of CAR T cells for in vivo functional persistence against solid tumors.

Limited CAR T-cell expansion and persistence hinder therapeutic responses in solid cancer patients. To enhance the functional persistence of engineered T-cell therapies, we performed genetic disruption in human CAR T cells of SUV39H1, a histone 3 lysine 9 methyltransferase that promotes heterochromatin formation. This resulted in phenotypic CAR-T reprogramming that elicited optimal and sustained antitumor functionality. Single-cell transcriptomic (scRNA-seq) and chromatin accessibility (scATAC-seq) analyses of tumor-infiltrating CAR T cells showed early reprogramming into self-renewing, stem-like populations with decreased expression of dysfunction genes in all subpopulations. Moreover, we provided evidence that SUV39H1 inactivation elicits potent and durable functional persistence upon multiple tumor rechallenges. This opens a safe path to enhancing adoptive cell therapies for solid tumors.