Direct Inhibition of the Hexose Transporter GLUT1 by Tyrosine Kinase Inhibitors

Abstract

The facilitative hexose transporter GLUT1 is a multifunctional protein that transports hexoses and dehydroascorbic acid, the oxidized form of vitamin C, and interacts with several molecules structurally unrelated to the transported substrates. Here we analyzed in detail the interaction of GLUT1 with a group of tyrosine kinase inhibitors that include natural products of the family of flavones and isoflavones and synthetic compounds such as the tyrphostins. These compounds inhibited, in a dose-dependent manner, the transport of hexoses and dehydroascorbic acid in human myeloid HL-60 cells, in transfected Chinese hamster ovary cells overexpressing GLUT1, and in normal human erythrocytes, and blocked the glucose-displaceable binding of cytochalasin B to GLUT1 in erythrocyte ghosts. Kinetic analysis of transport data indicated that only tyrosine kinase inhibitors with specificity for ATP binding sites inhibited the transport activity of GLUT1 in a competitive manner. In contrast, those inhibitors that are competitive with tyrosine but not with ATP failed to inhibit hexose uptake or did so in a noncompetitive manner. These results, together with recent evidence demonstrating that GLUT1 is a nucleotide binding protein, support the concept that the inhibitory effect on transport is related to the direct interaction of the inhibitors with GLUT1. We conclude that predicted nucleotide-binding motifs present in GLUT1 are important for the interaction of the tyrosine kinase inhibitors with the transporter and may participate directly in the binding transport of substrates by GLUT1.

Low Sugar Diet: A New Tool in War Against Tumorigenesis

“…Numerous strategies are used for inhibition of glucose transporters such as treatment with nutraceutical Genistein, quercetin, myricetin, morin, rhamnetin and isorhamnetin [49][50][51]. Implementation of keto diet is another approach to curtail glucose availability to cancer cells.…”

Resolution of the direct interaction with and inhibition of the human GLUT1 hexose transporter by resveratrol from its effect on glucose accumulation

“…D-Glucose-displaceable binding of cytochalasin B to functional glucose transporter was estimated from the difference between cytochalasin B bound in the presence of 500 mM D-sorbitol and 500 mM D-glucose. The amount of specifically bound cytochalasin B was estimated by the quantity of radioactive ligand associated with the membrane pellet (64).…”

“…The kinetic properties of the glucose transport have been extensively studied, as red blood cells have provided a good experimental system due to the high expression of this carrier in their plasma membrane (14,15). Likewise, these investigations have revealed a set of different natural and artificial inhibitors of GLUT1, which do not share structural similarities with glucose (6,9,34,36,64). These blockers differ not only in their structure but also in their mode of action.…”

“…The exact mechanism of action of resveratrol remains unclear, but in vivo and in vitro studies have suggested that this compound somehow affects glucose metabolism (7,10,33,41,58,66) perhaps by inhibiting GLUT1 activity. Resveratrol is structurally similar to several flavonoids that have been identified as efficient inhibitors of GLUT1 (62,63), and the available data show that resveratrol causes a competitive inhibition of facilitated transport of glucose in leukemic cells (42) and hinders glucose metabolism in human ovarian cancer cells (29). However, those studies were performed measuring the uptake of 2-deoxy-D-glucose (2DG) during 5-10 min, which does not give a clear distinction between cellular trapping of 2DG induced by its intracellular phosphorylation (11,56,68) and GLUT1-mediated glucose transport, which normally occurs within 1 min (22,65).…”

Alternative Approaches to Modeling Hereditary Dystonias

“…GLUT1 has been known and studied for a long time. Furthermore, compounds, such as ML-9, verapamil, and tyrphostins, can block GLUT1 [97,98]. Therefore, it is possible to attempt acute and partial pharmacological block of GLUT1 to determine whether this is sufficient to induce the symptoms of DYT18.…”