st-638 and Disease-Models--Animal

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) still remains a serious late complication. Many growth factors induced in restenotic lesions may be responsible for restenosis after PTCA. Most of the receptors for such growth factors possess tyrosine kinase activity. This study was designed to determine whether or not a specific tyrosine kinase inhibitor, ST 638, can prevent (re)stenotic changes of the coronary artery after balloon injury.. A segment of the porcine coronary artery was aseptically wrapped with cotton mesh absorbing either ST 638 or vehicle, followed by balloon injury. Two weeks after the procedure, coronary stenosis and vasoconstricting responses were examined by coronary arteriography and (re)stenotic changes of the coronary artery were histologically examined. Antiphosphotyrosine immunoblotting was also performed to examine the inhibitory effects of ST 638.. Coronary arteriography showed the development of mild stenotic lesions at the balloon-injured sites, where hyperconstrictive responses were repeatedly induced by intracoronary serotonin and histamine. Histologically, neointimal formation was noted at the balloon-injured site, where the total vessel area also tended to decrease (geometric remodeling). The treatment with ST 638 suppressed all the hyperconstrictive responses, the neointimal formation, and the geometric remodeling induced by balloon injury. Immunoblotting for phosphotyrosine proteins demonstrated the elevation of proteins at the balloon-injured site, which was suppressed by ST 638.. These results indicate that tyrosine kinases are activated at the balloon-injured site and the inhibition of such kinase activities is effective in reducing both the (re)stenotic changes (neointimal formation and geometric remodeling) and the hyperconstrictive responses of the coronary artery after balloon injury.

Topics: Angioplasty, Balloon, Coronary; Animals; Cinnamates; Coronary Angiography; Coronary Disease; Disease Models, Animal; Male; Protein-Tyrosine Kinases; Recurrence; Sulfides; Swine

Severe chronic asthma is associated with structural changes in the airway wall including airway smooth muscle (ASM) hyperplasia. We have used cultured ASM cells isolated from rabbit trachealis as a model with which to investigate possible mechanisms of accelerated ASM growth to mitogenic stimuli. To elucidate the role that protein kinase C (PKC)- and protein tyrosine kinase (PTK)-dependent pathways play in the control of ASM mitogenesis, we have investigated the effect of reportedly selective inhibitors of PKC (3-[1-[3-(amidinothio)propyl]-3-indolyl]-4-(1-methyl-3-indolyl)-1H - pyrrole-2,5-dionemethanesulfonate [Ro31-8220] and 3-[1-(aminopropyl)indolyl]-4-(1-methyl-3-indolyl)-1H-pyrrole-2,5-dione acetate [Ro31-7549]) and PTK (alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide [ST638]) on partially purified PKC, fetal calf serum (FCS)-stimulated protein phosphotyrosine content and on FCS-induced proliferation. Anion-exchange chromatography of lysed ASM cells resolved two peaks of Ca(2+)-activated, phospholipid-dependent PKC activity and one peak of Ca(2+)- and phospholipid-independent PKC activity. The selective PKC inhibitors, Ro31-8220 and Ro31-7549, abolished the main peak of PKC activity and the Ca(2+)- and phospholipid-independent peak that co-eluted with the main peak. The inhibition was dependent on the concentration of ATP in the reaction cocktail (IC50: 10 microM ATP: Ro31-8220 0.026 microM, Ro31-7549 0.073 microM; 100 microM ATP: Ro31-8220 0.065 microM, Ro31-7549 0.271 microM), consistent with these compounds inhibiting PKC at the ATP-binding site. Ro31-8220 was more potent (2- to 3-fold) than Ro31-7549. Concentrations of each inhibitor that produced maximal inhibition of the pooled kinase activity also abolished the second peak of Ca(2+)-dependent activity. The PTK inhibitor, ST638, had no effect on the kinase activity associated with any of the Ca(2+)-dependent or -independent peaks that eluted from the column. ST638, however, maximally inhibited FCS-stimulated PTK activity (IC50 25 microM). FCS-stimulated PTK was also inhibited by Ro31-8220 (IC50 0.15 microM), but only by 60%, revealing an Ro31-8220-insensitive component to the response. The ability of each protein kinase inhibitor to inhibit proliferation was also studied using four independent indices of ASM cell growth and division: 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) dye conversion, Coomassie blue protein determination, hemacytometer cell counts, an

Topics: Animals; Asthma; Cell Division; Cells, Cultured; Cinnamates; Culture Media; Disease Models, Animal; DNA; Humans; Indoles; Maleimides; Muscle, Smooth; Protein Kinase C; Protein-Tyrosine Kinases; Rabbits; Sulfides; Tetradecanoylphorbol Acetate; Trachea