PT  - JOURNAL ARTICLE
AU  - Cheng-Hsien Chen
AU  - Tzu-Hurng Cheng
AU  - Heng Lin
AU  - Neng-Lang Shih
AU  - Yen-Ling Chen
AU  - Yee-Shiuan Chen
AU  - Ching-Feng Cheng
AU  - Wei-Shiung Lian
AU  - Tzu-Ching Meng
AU  - Wen-Ta Chiu
AU  - Jin-Jer Chen
TI  - Reactive Oxygen Species Generation Is Involved in Epidermal Growth Factor Receptor Transactivation through the Transient Oxidization of Src Homology 2-Containing Tyrosine Phosphatase in Endothelin-1 Signaling Pathway in Rat Cardiac Fibroblasts
AID  - 10.1124/mol.105.017558
DP  - 2006 Apr 01
TA  - Molecular Pharmacology
PG  - 1347--1355
VI  - 69
IP  - 4
4099  - http://molpharm.aspetjournals.org/content/69/4/1347.short
4100  - http://molpharm.aspetjournals.org/content/69/4/1347.full
SO  - Mol Pharmacol2006 Apr 01; 69
AB  - Endothelin-1 (ET-1) is implicated in fibroblast proliferation, which results in cardiac fibrosis. Both reactive oxygen species (ROS) generation and epidermal growth factor receptor (EGFR) transactivation play critical roles in ET-1 signal transduction. In this study, we used rat cardiac fibroblasts treated with ET-1 to investigate the connection between ROS generation and EGFR transactivation. ET-1 treatment was found to stimulate the phosphorylation of EGFR and ROS generation, which were abolished by ETA receptor antagonist N-(N-(N-((hexahydro-1H-azepin-1-yl)carbonyl)-l-leucyl)-d-tryptophyl)-d-tryptophan (BQ485). NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI), ROS scavenger N-acetyl cysteine (NAC), and p47phox small interfering RNA knockdown all inhibited the EGFR transactivation induced by ET-1. In contrast, EGFR inhibitor 4-(3′-chloroanilino)-6,7-dimethoxyquinazoline (AG-1478) cannot inhibit intracellular ROS generation induced by ET-1. Src homology 2-containing tyrosine phosphatase (SHP-2) was shown to be associated with EGFR during ET-1 treatment by EGFR coimmunoprecipitation. ROS have been reported to transiently oxidize the catalytic cysteine of phosphotyrosine phosphatases to inhibit their activity. We examined the effect of ROS on SHP-2 in cardiac fibroblasts using a modified malachite green phosphatase assay. SHP-2 was transiently oxidized during ET-1 treatment, and this transient oxidization could be repressed by DPI or NAC treatment. In SHP-2 knockdown cells, ET-1-induced phosphorylation of EGFR was dramatically elevated and is not influenced by NAC and DPI. However, this elevation was suppressed by GM6001 [a matrix metalloproteinase (MMP) inhibitor] and heparin binding (HB)-epidermal growth factor (EGF) neutralizing antibody. Our data suggest that ET-1-ETA-mediated ROS generation can transiently inhibit SHP-2 activity to facilitate the MMP-dependent and HB-EGF-stimulated EGFR transactivation and mitogenic signal transduction in rat cardiac fibroblasts.