Notwithstanding that high rates of glucose uptake and glycolysis are common in neoplasia, pharmacological efforts to inhibit glucose utilization for cancer treatment have not been successful. Recent evidence suggests that in addition to classical glucose transporters, sodium-glucose transporters (SGLTs) are expressed by cancers. We therefore investigated the possibility that SGLT inhibitors, which are used in treatment of type 2 diabetes, may exert antineoplastic activity by limiting glucose uptake. We show that the SGLT2 inhibitor canagliflozin inhibits proliferation of breast cancer cells. Surprisingly, the antiproliferative effects of canagliflozin are not affected by glucose availability nor by the level of expression of SGLT2. Canagliflozin reduces oxygen consumption and glutamine metabolism through the citric acid cycle. The antiproliferative effects of canagliflozin are linked to inhibition of glutamine metabolism that fuels respiration, which represents a previously unanticipated mechanism of its potential antineoplastic action.
Keywords: Breast cancer; Canagliflozin; Dapagliflozin; Glutamine; Tumor metabolism.
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