title: Signal transduction in endothelial cells by the angiogenesis inhibitor histidine-rich glycoprotein targets focal adhesions.
abstract: Histidine-rich glycoprotein (HRGP) is an abundant heparin-binding plasma protein. We have shown that a fragment released from the central histidine/proline-rich (His/Pro-rich) domain of HRGP blocks endothelial cell migration in vitro and vascularization and growth of murine fibrosarcoma in vivo. The minimal active HRGP domain exerting the anti-angiogenic effect was recently narrowed down to a 35 amino acid peptide, HRGP330, derived from the His/Pro-rich domain of HRGP. By use of a signal transduction antibody array representing 400 different signal transduction molecules, we now show that HRGP and the synthetic peptide HRGP330 specifically induce tyrosine phosphorylation of focal adhesion kinase and its downstream substrate paxillin in endothelial cells. HRGP/HRGP330 treatment of endothelial cells induced disruption of actin stress fibers, a process reversed by treatment of cells with the FAK inhibitor geldanamycin. In addition, VEGF-mediated endothelial cell tubular morphogenesis in a three-dimensional collagen matrix was inhibited by HRGP and HRGP330. In contrast, VEGF-induced proliferation was not affected by HRGP or HRGP330, demonstrating the central role of cell migration during tube formation. In conclusion, our data show that HRGP targets focal adhesions in endothelial cells, thereby disrupting the cytoskeletal organization and the ability of endothelial cells to assemble into vessel structures.
authors.affiliation: Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala, Sweden.
authors.forename: Chunsik
authors.initials: C
authors.lastname: Lee
authors.forename: Johan
authors.initials: J
authors.lastname: Dixelius
authors.forename: Asa
authors.initials: A
authors.lastname: Thulin
authors.forename: Harukiyo
authors.initials: H
authors.lastname: Kawamura
authors.forename: Lena
authors.initials: L
authors.lastname: Claesson-Welsh
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Olsson
mesh_terms: D000199:Actins / Q000378:metabolism; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D016227:Benzoquinones; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D022001:Focal Adhesions / Q000187:drug effects*; D006801:Humans; D047029:Lactams, Macrocyclic; D051379:Mice; D010455:Peptides / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D040081:Protein Array Analysis; D011506:Proteins / Q000494:pharmacology*; D011809:Quinones / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D022502:Stress Fibers / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology; D000099053:Histidine-Rich Glycoprotein
chemical_list: D000199:Actins; D020533:Angiogenesis Inhibitors; D016227:Benzoquinones; D047029:Lactams, Macrocyclic; D010455:Peptides; D010750:Phosphoproteins; D011506:Proteins; D011809:Quinones; D042461:Vascular Endothelial Growth Factor A; D000099053:Histidine-Rich Glycoprotein; D019000:Phosphotyrosine; D051416:Focal Adhesion Protein-Tyrosine Kinases; C001277:geldanamycin