title: Effect of insulin-like growth factor binding protein-1 on integrin signalling and the induction of apoptosis in human breast cancer cells.
abstract: Interaction of epithelial cells with the extracellular matrix is mediated through integrin receptors, which transmit signals regulating cell growth, differentiation and death. Occupation of these receptors, via Arg-Gly-Asp (RGD) recognition sequences, leads to activation of focal adhesion kinase (FAK). We treated human breast cancer cell lines with RGD-containing peptides, which can disrupt integrin attachment, and investigated alterations in FAK phosphorylation, cell detachment and death. Cells grown in vitro were treated with insulin-like growth factor-binding protein-1 (IGFBP-1) and a small, synthetic RGD-containing peptide (Gly-Arg-Gly-Asp-Thr-Pro) and its negative control peptide RGE (Arg-Gly-Glu-Ser) for either 30 min followed by immunoprecipitation of cell lysates with anti-phosphotyrosine and Western immunoblotting with anti-FAK or for 24 h followed by cell counting, immunocytochemistry and flow cytometry. Both IGFBP-1 (0-800 ng/ml) and the synthetic RGD-containing peptide (1-100 microg/ml) caused significant dephosphorylation of FAK. Furthermore, after 24 h both peptides caused detachment from the matrix and the induction of apoptosis. We conclude from these data that IGFBP-1 can interact with integrin receptors to induce FAK dephosphorylation and subsequently influence attachment and cell death.
authors: Division of Surgery, Department of Hospital Medicine, Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.
authors: C M
authors: CM
authors: Perks
authors: P V
authors: PV
authors: Newcomb
authors: M R
authors: MR
authors: Norman
authors: J M
authors: JM
authors: Holly
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000378:metabolism; D005260:Female; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D007150:Immunohistochemistry; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000494:pharmacology*; D039482:Integrin alpha5; D019012:Integrin beta1 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D018970:Insulin-Like Growth Factor Binding Protein 1; D039482:Integrin alpha5; D019012:Integrin beta1; D016023:Integrins; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human