Metabolic Reprograming Due to Deletion of CISH in Human Natural Killer Cells Promotes in vivo Persistence and Enhances Anti-Tumor Activity

Cytokine-inducible SH2-containing protein (CIS, encoded by the gene CISH) is a key negative regulator of IL-15 signaling in natural killer (NK) cells. Here, we developed human CISH knockout (CISH-/-) NK cells using an induced pluripotent stem cell-derived NK cell (iPSC-NK cell) platform. CISH-/- iPSC-derived NK cells demonstrate increased IL-15 mediated JAK-STAT pathway signaling activity. Consequently CISH-/- iPSC-NK cells exhibit improved expansion and increased cytotoxic activity against multiple tumor cell lines when maintained at low cytokine concentration. CISH-/- iPSC-NK cells display significantly increased in vivo persistence and inhibition of tumor progression in a leukemia xenograft model. Mechanistically, CISH-/- iPSC-NK cells display improved metabolic fitness characterized by a significant increase in basal glycolysis, glycolytic capacity, maximal mitochondrial respiration, ATP-linked respiration and spare capacity respiration which are mediated by mTOR signaling and directly contribute to enhanced NK cell function. In addition, we demonstrate that deletion of CISH in human NK cells increases single-cell polyfunctionality by secreting multiple effector cytokines, a profile has been proven to be positively associated with clinical outcome of CAR-T cells. Together, these studies demonstrate CIS plays a key role to regulate human NK cell metabolic activity and deletion of CIS leads to enhanced anti-tumor activity.