Tumor cells often have very high energy demands. Inhibition of glucose uptake is therefore a possible approach to limit the proliferation and survival of transformed cells. However, immune cells also require energy to initiate and to maintain anti-tumor immune reactions. Here, we investigate the effect of Glutor, an inhibitor of glucose transporters, on the function of human Natural Killer (NK) cells, which are important for the immunosurveillance of cancer. Glutor treatment effectively inhibits glycolysis in NK cells. However, acute treatment with the inhibitor has no effect on NK cell effector functions. Prolonged inhibition of glucose uptake by Glutor prevents the proliferation of NK cells, increases their pro-inflammatory regulatory function and reduces the stimulation-dependent production of IFN-γ. Interestingly, even after prolonged Glutor treatment NK cell cytotoxicity and serial killing activity were still intact, demonstrating that cytotoxic NK cell effector functions are remarkably robust against metabolic disturbances.
Keywords: cytokines; degranulation; glucose transporter; metabolism; natural killer cells.