title: Activation of MEK/ERK and PI3K/Akt pathways by fibronectin requires integrin alphav-mediated ADAM activity in hepatocellular carcinoma: a novel functional target for gefitinib.
abstract: We have shown that the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839) inhibits the development of intrahepatic metastases of hepatocellular carcinoma CBO140C12, and EGFR transactivation by tumor necrosis factor-alpha is a possible target of gefitinib. In the present study, we focused on the fibronectin (FN)-dependent signaling pathway to further elucidate the antimetastatic activity of gefitinib in CBO140C12 cells. We initially observed that FN induced activation of extracellular signal-regulated kinase (ERK), p38 and Akt, as well as cell proliferation and CBO140C12 cell invasion. These responses were mediated by EGFR tyrosine kinase, because gefitinib inhibited these effects of FN. FN-induced ERK, p38 and Akt activation was partly blocked by the Arg-Gly-Asp (RGD)-pseudo-peptide FC-336, anti-alphav integrin antibody RMV-7, the broad-spectrum matrix metalloprotease inhibitor GM6001 and the broad spectrum a disintegrin and metalloprotease (ADAM) inhibitor TAPI-1. But these inhibitors had no effect on EGF-induced signaling pathways, suggesting that integrins and ADAM may be upstream components of EGFR in these responses. These results suggest that FN-induced activation of ERK, p38, Akt, cell proliferation and invasion was mediated, at least in part, via integrins, ADAM and EGFR, and that this FN-induced signaling pathway might be involved in the antimetastatic activity of gefitinib.
authors.affiliation: Department of Anatomy, Faculty of Medicine, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Matsuo
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sakurai
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ueno
authors.forename: Osamu
authors.initials: O
authors.lastname: Ohtani
authors.forename: Ikuo
authors.initials: I
authors.lastname: Saiki
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary; D004359:Drug Therapy, Combination; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D005353:Fibronectins / Q000494:pharmacology*; D000077156:Gefitinib; D039564:Integrin alphaV / Q000378:metabolism*; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D005353:Fibronectins; D039564:Integrin alphaV; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020930:MAP Kinase Kinase Kinases; D051722:ADAM Proteins; D000077156:Gefitinib