title: Focal adhesion kinase, a downstream mediator of Raf-1 signaling, suppresses cellular adhesion, migration, and neuroendocrine markers in BON carcinoid cells.
abstract: We have recently reported that activation of the Raf-1/mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase 1/2 (MEK1/2)/ERK1/2 signaling cascade in gastrointestinal carcinoid cell line (BON) alters cellular morphology and neuroendocrine phenotype. The mechanisms by which Raf-1 mediates these changes in carcinoid cells are unclear. Here, we report that activation of the Raf-1 signaling cascade in BON cells induced the expression of focal adhesion kinase (FAK) protein, suppressed the production of neuroendocrine markers, and resulted in significant decreases in cellular adhesion and migration. Importantly, inactivation of MEK1/2 by 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene or abolition of FAK induction in Raf-1-activated BON cells by targeted siRNA led to reversal of the Raf-1-mediated reduction in neuroendocrine markers and cellular adhesion and migration. Phosphorylation site-specific antibodies detected the phosphorylated FAK(Tyr407), but not FAK(Tyr397), in these Raf-1-activated cells, indicating that FAK(Tyr407) may be associated with changes in the neuroendocrine phenotype. Overexpression of constitutively active FAK plasmids (wild-type FAK or FAK(Tyr397) mutant) into BON cells reduced neuroendocrine markers, whereas the FAK(Tyr407) mutant plasmid did not show any decrease in the levels of neuroendocrine markers, indicating that phosphorylation of FAK at the Tyr(407) residue may be important for these effects. Our results showed for the first time that FAK is an essential downstream effector of the Raf-1/MEK1/2/ERK1/2 signaling cascade and negatively regulated the neuroendocrine and metastatic phenotype in BON cells.
authors.affiliation: Endocrine Surgery Research Laboratories, Department of Surgery, University of Wisconsin School of Medicine and Public Health and University of Wisconsin Carbone Cancer Center, Madison, Wisconsin, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Ning
authors.forename: Herbert
authors.initials: H
authors.lastname: Chen
authors.forename: Muthusamy
authors.initials: M
authors.lastname: Kunnimalaiyaan
mesh_terms: D014408:Biomarkers, Tumor / Q000037:antagonists & inhibitors*; D002276:Carcinoid Tumor / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D002448:Cell Adhesion / Q000502:physiology; D045744:Cell Line, Tumor; D002464:Cell Migration Inhibition / Q000502:physiology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D005770:Gastrointestinal Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology; D055099:Neuroendocrine Cells / Q000378:metabolism / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000201:enzymology / Q000473:pathology; D010641:Phenotype; D019908:Proto-Oncogene Proteins c-raf / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019908:Proto-Oncogene Proteins c-raf; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human
references.citation: Surg Oncol Clin N Am. 2006 Jul;15(3):463-78
references.pmid: 16882492
references.citation: Surgery. 2002 Dec;132(6):1035-9; discussion 1039
references.pmid: 12490852
references.citation: Oncogene. 2006 Sep 21;25(42):5726-40
references.pmid: 16652152
references.citation: Biochim Biophys Acta. 2004 Jul 5;1692(2-3):103-19
references.pmid: 15246682
references.citation: Int J Cancer. 1996 Oct 9;68(2):164-71
references.pmid: 8900422
references.citation: Mol Cell Biol. 1996 Oct;16(10):5623-33
references.pmid: 8816475
references.citation: Curr Cancer Drug Targets. 2005 Dec;5(8):629-43
references.pmid: 16375667
references.citation: Mol Cell. 2004 Oct 22;16(2):257-67
references.pmid: 15494312
references.citation: J Cell Biol. 2004 Jul 19;166(2):157-9
references.pmid: 15263014
references.citation: Clin Cancer Res. 2006 Jun 1;12(11 Pt 1):3233-7
references.pmid: 16740741
references.citation: Nat Rev Mol Cell Biol. 2005 Jan;6(1):56-68
references.pmid: 15688067
references.citation: Mol Endocrinol. 2002 Dec;16(12):2802-18
references.pmid: 12456801
references.citation: Surgery. 2008 Dec;144(6):920-4; discussion 924-5
references.pmid: 19040998
references.citation: Cancer Res. 2006 Jul 15;66(14):7103-10
references.pmid: 16849556
references.citation: J Biol Chem. 2007 Apr 6;282(14):10398-404
references.pmid: 17303567
references.citation: J Clin Endocrinol Metab. 2005 Jul;90(7):4350-6
references.pmid: 15870121
references.citation: Oncogene. 2007 May 14;26(22):3279-90
references.pmid: 17496922
references.citation: Clin Cancer Res. 2000 Jun;6(6):2417-23
references.pmid: 10873094
references.citation: Am J Gastroenterol. 2007 Jul;102(7):1464-73
references.pmid: 17391319
references.citation: Am J Physiol Gastrointest Liver Physiol. 2003 Aug;285(2):G245-54
references.pmid: 12851216
references.citation: J Biol Chem. 2006 Dec 29;281(52):39819-30
references.pmid: 17090547
references.citation: Prostate. 2002 Oct 1;53(2):124-32
references.pmid: 12242727
references.citation: Biochem Biophys Res Commun. 2008 Feb 8;366(2):476-82
references.pmid: 18073135
references.citation: Curr Opin Genet Dev. 2004 Feb;14(1):92-101
references.pmid: 15108811
references.citation: Mol Cell Biol. 2003 Jan;23(2):543-54
references.pmid: 12509453
references.citation: J Biol Chem. 2003 Jun 20;278(25):22631-43
references.pmid: 12692126
references.citation: Anticancer Res. 2004 Mar-Apr;24(2B):921-7
references.pmid: 15161045
references.citation: Oncologist. 2008 Dec;13(12):1255-69
references.pmid: 19091780
references.citation: Curr Opin Cell Biol. 2006 Oct;18(5):516-23
references.pmid: 16919435
references.citation: Clin Cancer Res. 2001 Oct;7(10):3106-12
references.pmid: 11595702