Acute regulation of glucose transport in a human megakaryocytic cell line: difference between growth factors and H2O2

The present study was undertaken to: (i) compare the effect of some hematopoietic growth factors, like interleukine-3, thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, stem cell factor, and reactive oxygen species such as H2O2 on glucose uptake in a human leukemic megakaryocytic cell line, M07; (ii) investigate the changes in kinetic parameters of the transport activity induced by these stimuli; and (iii) evaluate the effect of genistein, a tyrosine kinase inhibitor, on the glucose uptake activation by the cited agents. The results are as follows: (i) exposure of M07 cells to thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, and stem cell factor resulted in a rapid stimulation of glucose transport; interleukine-3-treated cells exhibited no increase in the rate of glucose uptake, although M07 proliferation is interleukine-3 dependent; a rapid glucose transport enhancement was also observed when M07 cells were exposed to low doses of H2O2; (ii) the transport kinetic parameters point out that an important difference exists between the effect of cytokines and that of H2O2: cytokines increased predominantly the affinity for glucose, while H2O2 raised both the Vmax and Km values; (iii) the isoflavone genistein, at a very low concentration, inhibited the stem cell factor- or H2O2-induced stimulation of hexose transport, reversing the variations of Km and Vmax, but it did not affect the transport activity of granulocyte-megakaryocyte colony-stimulating factor-treated cells; and (iv) catalase completely abolished the stimulatory action of H2O2 on glucose transport and slightly prevented the effect of stem cell factor, while caffeic acid phenethyl ester was only able to affect the activation due to stem cell factor.