Contribution of reactive oxygen species to the regulation of Glut1 in two hemopoietic cell lines differing in cytokine sensitivity

Glucose transport activity and its possible regulation by reactive oxygen species in two Glut1-expressing megakaryocytic cell lines, MO7e and B1647, differing in cytokine sensitivity were compared. Results show that: (1) In MO7e, cells, glucose transport rate increased in response to thrombopoietin, granulocyte-macrophage colony-stimulating factor, or stem cell factor, due to a decreased K-m. (2) A higher V-max value was determined in B1647 cells, owing to the relative higher abundance of Glut1 on the plasmalemma; in these cells no change in glucose transport rate was observed on cytokine treatment. (3) The basal level of intracellular ROS was higher in B1647 than in M07e cells, where ROS production was enhanced on cytokine exposure. (4) Basal or stimulated ROS production and Glut1 activity were significantly reduced by pretreating both cell lines with EUK-134, a superoxide dismutase and catalase mimetic. (5) In M07e cells, EUK-134 brought back to control levels the K-m values obtained on cytokine treatment, whereas in B 1647 cells the antioxidant drastically reduced V-max by decreasing the Glut1 content of the plasma membrane. Our data suggest that differences in acute regulation of glucose transport activity in the two cell lines may be related to differences in amplitude and spatial organization of ROS production. (C) 2004 Elsevier Inc. All rights reserved.