Vanadyl(IV)-trehalose complex stimulates GSK3-beta phsophorylation and glucose consumption in UMR106 osteoblast-like cells. Putative pathways for its biological effects

BARRIO DA, MOLINUEVO MS, CORTIZO AM, ETCHEVERRY SB

Montreasl, Canada

Conferencia; 12th Internationl conference on second messengers and phosphoproteins; 2004

Vanadium is an ultramicrotrace bioelement with interesting biological properties like insulin-mimetic activity in different cell types and animal models. The vanadyl(IV)-trehalose complex (TreVO) presents interesting metabolic and mitogenic effects in UMR106 osteoblast-like cells. In the present study, we have investigated the possible pathways involved in the TreVO-induced enhancement of glucose consumption in these cells. Assays of protein phosphorylation, glucose consumption and different inhibitors were used. Glucose consumption was stimulated 130 % (p<0.001) over basal by 25 microM TreVO. The TreVO-induced glucose consumption was inhibited in a dose-dependent manner by staurosporine, an inhibitor of protein kinase C (PKC) and a cytosolic kinase; and by wortmannin, a phosphatidylinositol-3-kinase (PI3-K) inhibitor. In addition, forbol-12-myristate-13-acetate (PMA), which down regulates PKC; H-89, a protein kinase A (PKA) inhibitor and Pertussis toxin, a protein G uncoupling agent, did not affect the TreVO-induced glucose consumption in UMR106 cells. On the other hand, TreVO (1mM) induced GSK3-beta phosphorylation and this effect was inhibited by staurosporine. In conclusion, PI3-K and a staurosporine-sensitive pathway seem to be involved in the TreVO-induced glucose consumption. In addition, GSK3-beta may be related with this effect.