Masakazu Kamata

JNK knockdown enhances CAR-T cell cytotoxicity through elevated NFATc1-dependent transcription in preclinical ovarian cancer models

Background Boosting the performance of chimeric antigen receptor T (CAR-T) cell therapy in solid tumors may provide a substantial advantage for patients with cancer. Recognizing the vital role of the nuclear factor of activated T cells (NFAT) in T cell function, we hypothesized the strategic regulation of NFAT activity by targeting c-Jun N-terminal kinases (JNK) can bolster the tumor-eradicating potential of CAR-T cells. Methods We developed a lentivirally encoded short-hairpin RNA for stable knockdown of JNK in CAR-T cells. CAR-T cells targeting human epidermal growth factor receptor 2 were produced from human peripheral blood. Functionality was tested in vitro and in two xenograft models of human ovarian cancer. Results JNK knockdown in CAR-T cells suppressed antigen-induced stimulation and helper T cell cytokine production, while enhancing antitumor cytotoxicity in vitro and in ovarian cancer xenograft experiments. Mechanistically, JNK knockdown altered NFAT signaling to facilitate NFATc1-dependent transcription, leading to elevated levels of granzyme B expression. Conclusions JNK signaling is a significant regulator of CAR-T cell cytotoxicity, offering a potential strategy to directly enhance CAR-T effectiveness in human cancer therapies.