Preferential inhibition of the platelet-derived growth factor receptor tyrosine kinase by staurosporine.
Ligand stimulation of the platelet-derived growth factor receptor (PDGF-R) results in rapid activation of the receptor tyrosine kinase, stimulation of phosphoinositide hydrolysis, an increase in intracellular free Ca2+ concentration ([Ca2+]i), and, ultimately, cellular proliferation. In a previous study, we demonstrated that staurosporine, a known inhibitor of protein kinase C, blocked PDGF-induced [Ca2+]i increases in Swiss mouse 3T3 fibroblasts by a mechanism that appeared unrelated to inhibition of protein kinase activity (Olsen, R., Melder, D., Seewald, M., Abraham, R., and Powis, G. (1990) Biochem. Pharmacol. 39, 968-972). In the present study, we report that staurosporine inhibits ligand-dependent PDGF-R tyrosine kinase activation in cell-free receptor preparations and in intact Swiss 3T3 cells. At the same concentrations (10(-8)-10(-6) M), staurosporine suppressed both the tyrosine phosphorylation of phospholipase C activity and the hydrolysis of phosphoinositides induced by PDGF stimulation of intact cells. In contrast, guanine nucleotide-binding protein-dependent phospholipase C activation induced by bradykinin or fluoroaluminate anion was relatively insensitive to staurosporine. A preferential inhibitory effect of staurosporine on signal generation by the PDGF-R was indicated by findings that epidermal growth factor receptor (EGF-R) tyrosine kinase activity and EGF-dependent phospholipase C in A-431 carcinoma cells were approximately 100-fold less sensitive to this drug. These data indicate that submicromolar concentrations of staurosporine inhibit PDGF-dependent phosphoinositide hydrolysis and Ca2+ mobilization through a proximal inhibitory effect on ligand-induced activation of the PDGF-R tyrosine kinase.
Secrist
J P
JP
Department of Pharmacology, Mayo Foundation, Rochester, Minnesota 55905.
Sehgal
I
I
Powis
G
G
Abraham
R T
RT
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007294:Inositol / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors; D011956:Receptors, Cell Surface / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor; D019311:Staurosporine; D010738:Type C Phospholipases / Q000378:metabolism
D000470:Alkaloids; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D010982:Platelet-Derived Growth Factor; D047428:Protein Kinase Inhibitors; D011956:Receptors, Cell Surface; D007294:Inositol; D017479:Receptors, Platelet-Derived Growth Factor; D010738:Type C Phospholipases; D019311:Staurosporine; D002118:Calcium