Improving the activity of chimeric antigen receptor T (CAR-T) cell therapy in solid cancers represents a critical unmet need in oncology. Because nuclear factor of activated T cells (NFAT) signaling governs multiple aspects of T cell behavior, we proposed that selective control of NFAT activity via inhibition of c-Jun N-terminal kinases (JNK) could reprogram CAR-T cells toward superior tumor-eliminating capacity. A lentiviral system encoding short-hairpin RNA was established to achieve durable JNK suppression in CAR-T cells. Human epidermal growth factor receptor 2–specific CAR-T cells were generated from peripheral blood T cells and evaluated using functional assays in vitro as well as two independent human ovarian cancer xenograft models.
CAR-T cells with reduced JNK expression exhibited diminished antigen-driven activation and lower helper T cell cytokine output but demonstrated markedly enhanced cytotoxic activity against tumor cells both in culture and in vivo. Mechanistic analyses showed that JNK silencing reoriented NFAT signaling toward preferential NFATc1-dependent transcription, resulting in increased granzyme B production. JNK functions as a central signaling checkpoint that restrains CAR-T cell cytotoxicity, and its inhibition offers a rational strategy to directly amplify CAR-T antitumor efficacy in human cancer treatment.
