SUMO2 deletion changes chromatin accessibility and enhances cytotoxic T cell activation and tumor infiltration.

Deleting SUMO2 in CD8+ T cells boosts their activation and antitumor activity. In mouse and human T cells, SUMO2 knockout increased chromatin accessibility at AP-1 family enhancers including BATF and JunB, and in OT1 and CAR T cell models the knockout cells showed higher tumor infiltration and greater tumor growth inhibition than wild-type cells. Single-nucleus RNA sequencing linked the effect to increased TRAIL expression and a more activated antitumor immune microenvironment.