Ncoa2 promotes CD8+ T cell-mediated anti-tumor immunity by stimulating T-cell activation via upregulation of PGC-1α critical for mitochondrial function: Noca2 in CD8+ T-cell activation and antitumor response

Nuclear receptor coactivator 2 (Ncoa2) is a member of the Ncoa family of co-activators, and we previously showed that Ncoa2 regulates the differentiation of induced regulatory T cells. However, it remains unknown if Ncoa2 plays a role in CD8 + T-cell function. Here, we show that Ncoa2 promotes CD8 + T cell-mediated immune responses against tumors by stimulating T-cell activation via upregulating PGC-1α expression to enhance mitochondrial function. Mice deficient in Ncoa2 in T cells ( Ncoa2 fl/fl /CD4 Cre ) displayed defective immune responses against implanted MC38 tumors, which associated with significantly reduced tumor-infiltrating CD8 + T cells and decreased IFNγ production. Consistently, CD8 + T cells from Ncoa2 fl/fl /CD4 Cre mice failed to reject tumors after adoptive transfer into Rag1 −/− mice. Further, in response to TCR stimulation, Ncoa2 fl/fl /CD4 Cre CD8 + T cells failed to increase mitochondrial mass, showed impaired oxidative phosphorylation, and had lower expression of PGC-1α, a master regulator of mitochondrial biogenesis and function. Mechanically, T cell activation-induced phosphorylation of CREB triggered the recruitment of Ncoa2 to bind to enhancers, thus, stimulating PGC-1α expression. Forced expression of PGC-1α in Ncoa2 fl/fl /CD4 Cre CD8 + T cells restored mitochondrial function, T-cell activation, IFNγ production, and anti-tumor immunity. This work informs the development of Ncoa2-based therapies that modulate CD8 + T cell-mediated anti-tumor immune responses.