title: Transactivation of EGFR/PI3K/Akt involved in ATP-induced inflammatory protein expression and cell motility.
abstract: Phenotype transition of vascular smooth muscle cells (VSMCs) is important in vascular diseases, such as atherosclerosis and restenosis. Once released, ATP may promote activation of VSMCs by stimulating cyclooxygenase-2 (COX-2), cytosolic phospholipase A(2) (cPLA(2)) expression and prostaglandin (PG)E(2) synthesis via activation of MAPKs and NF-κB. However, whether alternative signaling pathways participated in regulating COX-2 and cPLA(2) expression associated with cell migration were investigated in rat VSMCs. Western blot analysis, RT-PCR, promoter assay and PGE(2) ELISA were used to determine expression of COX-2, cPLA(2) and PGE(2). Specific inhibitors and siRNAs against various protein kinases or transcription factors were used to investigate the related signaling components in inflammatory protein induction by ATPγS. We found that ATPγS-induced COX-2 and cPLA(2) expression and PGE(2) release was attenuated by the pharmacological inhibitors or transfection with siRNA against PKCδ, c-Src, EGFR, PI3-K, Akt, p44/p42 MAPK or Elk-1. Moreover, ATPγS-stimulated phosphorylation of PKCδ, c-Src, EGFR, Akt, p42/p44 MAPK and Elk-1, suggesting the participation of PKCδ/c-Src/EGFR/PI3-K/Akt/p42/p44 MAPK cascade in mediating Elk-1 activities in VSMCs. In addition, migration assay revealed that ATPγS promoted cell mobility through up-regulation of COX-2 and cPLA(2) expression and PGE(2) release, which was attenuated by pretreatment with PGE(2) receptor antagonists. Taken together, these data showed that ATPγS up-regulated the expression of COX-2 and cPLA(2) through transactivation of PKCδ/c-Src/EGFR/PI3K/Akt/Elk-1 pathway. Newly synthesized PGE(2) acted on its receptors to promote cell motility of ATPγS-stimulated VSMCs.
authors.affiliation: Department of Anesthetics, Chang Gung Memorial Hospital and Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
authors.forename: Chih-Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Wei-Ning
authors.initials: WN
authors.lastname: Lin
authors.forename: Shin-Ei
authors.initials: SE
authors.lastname: Cheng
authors.forename: Wei-Hsuan
authors.initials: WH
authors.lastname: Tung
authors.forename: Hui-Hsin
authors.initials: HH
authors.lastname: Wang
authors.forename: Chuen-Mao
authors.initials: CM
authors.lastname: Yang
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D000081247:CSK Tyrosine-Protein Kinase; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D015232:Dinoprostone / Q000096:biosynthesis; D066246:ErbB Receptors / Q000235:genetics*; D018836:Inflammation Mediators / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008954:Models, Biological; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D054510:Phospholipases A2, Cytosolic / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects; D050807:ets-Domain Protein Elk-1 / Q000378:metabolism; D019061:src-Family Kinases
chemical_list: D000255:Adenosine Triphosphate; D000081247:CSK Tyrosine-Protein Kinase; D051546:Cyclooxygenase 2; D017931:DNA Primers; D015232:Dinoprostone; D066246:ErbB Receptors; D018836:Inflammation Mediators; D019869:Phosphatidylinositol 3-Kinases; D054510:Phospholipases A2, Cytosolic; D051745:Protein Kinase C-delta; D011505:Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D050807:ets-Domain Protein Elk-1; D019061:src-Family Kinases; C494114:Elk1 protein, rat; C022571:adenosine 5'-O-(3-thiotriphosphate); C489691:Ptgs2 protein, rat