title: Local delivery of platelet-derived growth factor receptor-specific tyrphostin inhibits neointimal formation in rats.
abstract: Signal transduction through the platelet-derived growth factor (PDGF)/PDGF receptor (PDGFR) system is involved in the process of postangioplasty restenosis. Tyrphostins are low molecular weight inhibitors of protein tyrosine kinases. We assessed the antiproliferative effects of PDGFRbeta-specific tyrphostin AG-1295 in vitro and in vivo. AG-1295 significantly inhibited rat smooth muscle cell growth stimulated by PDGF-BB or FCS. This antiproliferative effect was paralleled by reversible reduction of the total phosphotyrosine level and the degree of PDGFRbeta phosphorylation by the drug in vitro. Local sustained delivery of the drug from perivascularly implanted polymeric matrices resulted in focal AG-1295 levels of 711 and 29.1 ng/mg of dry arterial tissue 1 and 14 days after implantation in rats. AG-1295 delivered from polymeric matrices resulted in a 35% reduction of neointimal formation on day 14 after balloon injury in the rat carotid model. Tyrosine phosphorylation of certain transduction proteins in arterial tissue extracts was significantly upregulated by balloon injury on day 3 but was essentially returned to or below basal levels 14 days after injury. Tyrphostin treatment decreased tyrosine phosphorylation at both time points below the basal levels. Moreover, the enhancement of PDGFRbeta expression 3 and 14 days after arterial injury was strongly inhibited by AG-1295 treatment. It can be concluded that AG-1295 reduces neointimal formation by inhibiting PDGFbeta-triggered tyrosine phosphorylation.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Faculty of Medicine, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Fishbein
authors.forename: J
authors.initials: J
authors.lastname: Waltenberger
authors.forename: S
authors.initials: S
authors.lastname: Banai
authors.forename: L
authors.initials: L
authors.lastname: Rabinovich
authors.forename: M
authors.initials: M
authors.lastname: Chorny
authors.forename: A
authors.initials: A
authors.lastname: Levitzki
authors.forename: A
authors.initials: A
authors.lastname: Gazit
authors.forename: R
authors.initials: R
authors.lastname: Huber
authors.forename: U
authors.initials: U
authors.lastname: Mayr
authors.forename: S D
authors.initials: SD
authors.lastname: Gertz
authors.forename: G
authors.initials: G
authors.lastname: Golomb
mesh_terms: D000800:Angioplasty, Balloon; D000818:Animals; D001011:Aorta / Q000737:chemistry / Q000166:cytology / Q000201:enzymology; D001158:Arteries / Q000166:cytology / Q000201:enzymology; D002339:Carotid Arteries / Q000737:chemistry / Q000201:enzymology / Q000473:pathology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003251:Constriction, Pathologic; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000201:enzymology* / Q000293:injuries / Q000473:pathology*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000032:analysis / Q000378:metabolism*; D012008:Recurrence; D017539:Tunica Intima / Q000201:enzymology / Q000293:injuries / Q000473:pathology; D014443:Tyrosine / Q000378:metabolism; D020032:Tyrphostins / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: C407689:6,7-dimethoxy-2-phenylquinoxaline; D004791:Enzyme Inhibitors; D020032:Tyrphostins; C075061:tyrphostin 8; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D020797:Receptor, Platelet-Derived Growth Factor beta