title: A small-molecule RGD-integrin antagonist inhibits cell adhesion, cell             migration and induces anoikis in glioblastoma cells.
abstract: In cancer cells integrins modulate important cellular events that regulate the metastasic cascade which involves detachment from the tumor mass, dissemination and attachment to the oncogenic niche. The α5β1, αvβ3 and αvβ5 integrins are widely expressed in different cancer types and recognize the tripeptide Arg-Gly-Asp (RGD) motif present in several extracellular matrix proteins. In human glioblastoma, αvβ3 integrin expression correlates with tumor grade, suggesting that this integrin may play a crucial role in the highly infiltrative behavior of high grade gliomas. However, few selective RGD-like antagonists have been developed and few studies have investigated their effects in in vitro models of human glioblastoma. In this study, we investigated several cellular effects and the underlying molecular mechanisms exerted by a new small-molecule RGD antagonist, 1a-RGD, in the U251 and U373 human glioblastoma cell lines. Treatment with 1a-RGD (20 µM) demonstrated a weak effect on cell viability and cell proliferation but strongly inhibited cell attachment and cell migration together with actin cytoskeleton disassembly. Prolonged 1a-RGD treatment (72 h) induced anoikis, assessed by Annexin staining and nucleosome assay, particularly in the detached cells. When integrin-linked transduction pathways were investigated, 1aRGD was found to exert a marked reduction in focal adhesion kinase (FAK) phosphorylation without affecting the AKT- and ERK-dependent pathways. Our data indicate that 1a-RGD, probably via modulation of the FAK-dependent pathway, inhibits cell migration and attachment and induces anoikis in glioblastoma cells. This novel finding suggests that the development of an RGD-like molecule may represent a promising tool for the pharmacological approach aimed at reducing the malignancy of glioblastoma cells.
authors.affiliation: Department of Developmental and Molecular Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA.
authors.forename: Marika A
authors.initials: MA
authors.lastname: Russo
authors.forename: Mayra
authors.initials: M
authors.lastname: Paolillo
authors.forename: Yuly
authors.initials: Y
authors.lastname: Sanchez-Hernandez
authors.forename: Daniela
authors.initials: D
authors.lastname: Curti
authors.forename: Emilio
authors.initials: E
authors.lastname: Ciusani
authors.forename: Massimo
authors.initials: M
authors.lastname: Serra
authors.forename: Lino
authors.initials: L
authors.lastname: Colombo
authors.forename: Sergio
authors.initials: S
authors.lastname: Schinelli
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D023102:Anoikis / Q000187:drug effects*; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D002448:Cell Adhesion / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D039302:Integrin alphaVbeta3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D019030:Receptors, Vitronectin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D039302:Integrin alphaVbeta3; D009842:Oligopeptides; D012333:RNA, Messenger; D019030:Receptors, Vitronectin; C064660:integrin alphaVbeta5; C047981:arginyl-glycyl-aspartic acid; D051416:Focal Adhesion Protein-Tyrosine Kinases