title: Insulin-like growth factor-I (IGF-I) induces epidermal growth factor receptor transactivation and cell proliferation through reactive oxygen species.
abstract: Insulin-like growth factor-I (IGF-I) plays an important role in proliferation of vascular smooth muscle cells (VSMCs). However, the mechanism that IGF-I induces VSMCs proliferation is not completely understood. In this study, we determined (a) whether and how IGF-I induces transactivation of epidermal growth factor receptor (EGFR) in primary rat aortic VSMCs, (b) the contribution of EGFR to IGF-I-stimulated activation of extracellular signal-regulated kinase (ERK) and cell proliferation, and (c) the role of reactive oxygen species (ROS) in the cellular function. We showed that IGF-I induced phosphorylation of EGFR and ERK1/2 in VSMCs. AG1478, an EGFR inhibitor, inhibited IGF-I-induced phoshorylation of EGFR and ERK1/2. IGF-I stimulated ROS production and Src activation. Antioxidants inhibited IGF-I-induced ROS generation and activation of EGFR, ERK, and Src. Src kinase inhibitor PP1 and Src siRNA blocked IGF-I-induced activation of EGFR and ERK1/2. Inhibition of IGF-I-stimulated EGFR activation inhibited IGF-I-induced VSMC proliferation. These results suggest that (1) IGF-I induces EGFR activation through production of ROS and ROS-mediated Src activation in VSMCs, and (2) EGFR transactivation is required for IGF-I-induced VSMC proliferation.
authors.affiliation: The Institute for Nutritional Sciences, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Meng
authors.forename: Xianglin
authors.initials: X
authors.lastname: Shi
authors.forename: Bing-Hua
authors.initials: BH
authors.lastname: Jiang
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D049109:Cell Proliferation; D002478:Cells, Cultured; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011799:Quinazolines; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015533:Transcriptional Activation; D020032:Tyrphostins / Q000494:pharmacology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D017382:Reactive Oxygen Species; D020032:Tyrphostins; C101044:RTKI cpd; D007334:Insulin-Like Growth Factor I; D066246:ErbB Receptors; D019061:src-Family Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3