title: Hydrogen peroxide activates focal adhesion kinase and c-Src by a phosphatidylinositol 3 kinase-dependent mechanism and promotes cell migration in Caco-2 cell monolayers.
abstract: Recent studies showed that c-Src and phosphatidylinositol 3 (PI3) kinase mediate the oxidative stress-induced disruption of tight junctions in Caco-2 cell monolayers. The present study evaluated the roles of PI3 kinase and Src kinase in the oxidative stress-induced activation of focal adhesion kinase (FAK) and acceleration of cell migration. Oxidative stress, induced by xanthine and xanthine oxidase system, rapidly increased phosphorylation of FAK on Y397, Y925, and Y577 in the detergent-insoluble and soluble fractions and increased its tyrosine kinase activity. The PI3 kinase inhibitors, wortmannin and LY294002, and the Src kinase inhibitor, 4-amino-5[chlorophyll]-7-[t-butyl]pyrazolo[3-4-d]pyrimidine, attenuated tyrosine phosphorylation of FAK. Oxidative stress induced phosphorylation of c-Src on Y418 by a PI3 kinase-dependent mechanism, whereas oxidative stress-induced activation of PI3 kinase was independent of Src kinase activity. Hydrogen peroxide accelerated Caco-2 cell migration in a concentration-dependent manner. Promotion of cell migration by hydrogen peroxide was attenuated by LY294002 and PP2. Reduced expression of FAK by siRNA attenuated hydrogen peroxide-induced acceleration of cell migration. The expression of constitutively active c-Src(Y527F) enhanced cell migration, whereas the expression of dominant negative c-Src(K296R/Y528F) attenuated hydrogen peroxide-induced stimulation of cell migration. Oxidative stress-induced activation of c-Src and FAK was associated with a rapid increase in the tyrosine phosphorylation and the levels of paxillin and p130(CAS) in actin-rich, detergent-insoluble fractions. This study shows that oxidative stress activates FAK and accelerates cell migration in an intestinal epithelium by a PI3 kinase- and Src kinase-dependent mechanism.
authors.affiliation: Department of Physiology, University of Tennessee Health Science Center, 894 Union Ave., Memphis, TN 38163, USA.
authors.forename: Shyamali
authors.initials: S
authors.lastname: Basuroy
authors.forename: Mitzi
authors.initials: M
authors.lastname: Dunagan
authors.forename: Parimal
authors.initials: P
authors.lastname: Sheth
authors.forename: Ankur
authors.initials: A
authors.lastname: Seth
authors.forename: R K
authors.initials: RK
authors.lastname: Rao
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D002465:Cell Movement / Q000187:drug effects*; D002645:Chickens; D050719:Crk-Associated Substrate Protein / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D009154:Mutation; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D051419:Paxillin / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D021381:Protein Transport; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects*; D013997:Time Factors; D014443:Tyrosine; D016596:Vinculin / Q000378:metabolism; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D050719:Crk-Associated Substrate Protein; D051417:Focal Adhesion Kinase 1; D006861:Hydrogen Peroxide; D016877:Oxidants; D051419:Paxillin; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D016392:Proto-Oncogene Proteins pp60(c-src); D014443:Tyrosine; D016596:Vinculin; D019820:Xanthine; D014969:Xanthine Oxidase; C493841:BCAR1 protein, human; C496061:PXN protein, human; C488955:VCL protein, human; C496050:PTK2 protein, human