title: Herbimycin A inhibits angiogenic activity in endothelial cells and reduces neovascularization in a rat model of retinopathy of prematurity.
abstract: The pathogenesis of retinopathy of prematurity involves dysregulated angiogenesis resulting in pre-retinal growth of new vessels. Inhibition of tyrosine kinase-dependent pro-angiogenic signals may provide a rational therapeutic approach to the reduction of pre-retinal neovascularization. Vascular endothelial growth factor stimulates endothelial cell mitogenesis, differentiation and migration, by binding and activating the receptor tyrosine kinases vascular endothelial growth factor receptor-1 and vascular endothelial growth factor receptor-2. One of the vascular endothelial growth factor receptor substrates implicated in vascular endothelial growth factor signal transduction is c-Src. The ability of herbimycin A, a c-Src-selective tyrosine kinase inhibitor, to inhibit vascular endothelial growth factor-induced bovine retinal microvascular endothelial cell proliferation and tube formation was investigated. The ability of the compound to inhibit pathologic angiogenesis was tested in a rat model of retinopathy of prematurity. Exposure of neonatal rats to oxygen concentrations cycling between 10 and 50% induced severe pre-retinal neovascularization in all rats. Some of the eyes of these variable oxygen-exposed rats were herbimycin A-injected or vehicle-injected 1 or 3 days post-oxygen exposure while some eyes were non-injected. All rats were sacrificed for assessment 6 days post-exposure. Herbimycin A inhibited both vascular endothelial growth factor-induced bovine retinal microvascular endothelial cell proliferation and capillary tube formation in a dose-dependent manner. Injection of herbimycin A into oxygen-treated rats 1 day post-oxygen exposure produced a 63% decrease in pre-retinal neovascularization relative to vehicle (P = 0.0029). There was a 41% decrease in pre-retinal neovascularization in herbimycin-injected eyes relative to vehicle-injected eyes 3 days post-oxygen (P = 0.031). Pre-retinal neovascularization was reduced in vehicle-injected eyes relative to non-injected eyes at both injection times. There were no significant differences in retinal vascular area between any of the experimental groups. Based on the results of this study, herbimycin A inhibits endothelial cell proliferation and tube formation at non-toxic concentrations and reduces pre-retinal neovascularization in a rat model of retinopathy of prematurity. Reduction of angiogenesis by the inhibition of tyrosine kinase activity may be a viable route to the development of effective chemotherapies applicable to eye disease.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, 8016 Medical Center East, Nashville, TN 37232-8808, USA.
authors.forename: Gary W
authors.initials: GW
authors.lastname: McCollum
authors.forename: Veera S
authors.initials: VS
authors.lastname: Rajaratnam
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Bullard
authors.forename: Rong
authors.initials: R
authors.lastname: Yang
authors.forename: John S
authors.initials: JS
authors.lastname: Penn
mesh_terms: D000818:Animals; D016227:Benzoquinones; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D006801:Humans; D007231:Infant, Newborn; D047029:Lactams, Macrocyclic; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011809:Quinones / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015861:Retinal Neovascularization / Q000517:prevention & control*; D012171:Retinal Vessels / Q000187:drug effects; D012178:Retinopathy of Prematurity / Q000517:prevention & control*; D017828:Rifabutin / Q000031:analogs & derivatives; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology
chemical_list: D016227:Benzoquinones; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D042461:Vascular Endothelial Growth Factor A; D017828:Rifabutin; C020754:herbimycin; D011505:Protein-Tyrosine Kinases