Srour, N.; Luo, K.; Allard, D.; Xiong, Y.; Yu, Z.; Papadopoulos, T.; Santinon, F.; Hsieh, C.-H.; Stagg, J.; Barsyte-Lovejoy, D.; del Rincon, S. V.; Jin, J.; Richard, S.

Abstract New therapeutics are needed to enhance cytotoxic T lymphocyte (CTL) expansion and effector function for effective tumor control. Here, we show that T cell specific deletion of Prmt7 using CD4-Cre mice increases CD8+ effector differentiation, cytokine secretion, cytolytic activity, and anti-tumor responses. Prmt7 deficiency transcriptionally reprogrammed CD8+ T cells by activating the NF-{kappa}B pathway, boosting proliferation, and elevating effector molecules such as CD25, CD69, and IFN{gamma}. Mechanistically, PRMT7 associated with RelA and restricted its nuclear translocation. To enable therapeutic translation, we developed a PRMT7-targeting PROTAC degrader (MS54). MS54-treated CTLs exhibited NF-{kappa}B pathway activation similar to Prmt7-deficient CTLs. Adoptive transfer of MS54-treated OT-I CTLs significantly improved tumor control in a syngeneic melanoma model. In human CTLs, MS54 enhanced proliferation, activation markers (CD69, CD137), IFN{gamma} production, and cytotoxicity toward melanoma. Together, these findings identify PRMT7 as a negative regulator of CD8+ T cell immunity and highlight MS54 as a promising strategy to improve adoptive T cell therapy.