title: A novel RGD antagonist that targets both alphavbeta3 and alpha5beta1 induces apoptosis of angiogenic endothelial cells on type I collagen.
abstract: Integrin-mediated cell adhesion is necessary for endothelial cell proliferation and apoptosis, which is a major determinant in tumor-induced angiogenesis. In this study, we compared two novel, structurally similar, Arg-Gly-Asp (RGD) peptidomimetic compounds having different integrin selectivities, for their inhibition of endothelial cell proliferation and induction of apoptosis on functionally relevant extracellular matrices (ECM) for angiogenesis. BCH-14661 was specific for integrin alphavbeta3, whereas BCH-15046 nonselectively antagonized integrins alphavbeta3, alphavbeta5, and alpha5beta1. Both compounds were potent inducers of endothelial cell apoptosis when plated on RGD-dependent ECM (vitronectin, VN), which was dependent on the ability to induce cell detachment. However, with endothelial cells plated on RGD-independent ECM (type I collagen, COL), only BCH-15046 was able to significantly prevent growth and induce apoptosis. This effect was not dependent on the induction of detachment. Experiments using the matrix metalloproteinase (MMP) inhibitor GM 6001 revealed that cleavage of COL was not required for the ability of BCH-15046 to induce apoptosis. However, the inhibition of growth factor-stimulated endothelial cell proliferation, required MMPs, and correlated with BCH-15046s' potent inhibition of endothelial cell attachment to denatured collagen. Antibody inhibition experiments showed that adhesion to denatured collagen required integrins alphavbeta3 and beta1, but not alphavbeta5. In addition, BCH-15046 exerted a significant inhibition of VEGF-stimulated angiogenesis in the chick chorioallontoic membrane in vivo. These results suggest that integrin antagonism of both alphavbeta3 and alpha5beta1 are important for MMP-independent induction of apoptosis on COL and MMP-dependent inhibition of endothelial cell-denatured collagen interactions required for proliferation.
authors.affiliation: Department of Cancer Biology, Shire-BioChem Inc., 275 Armand Frappier Boulevard, Laval, Quebec, Canada H7V 4A7. karen.meerovitch@phytobiotech.com
authors.forename: Karen
authors.initials: K
authors.lastname: Meerovitch
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bergeron
authors.forename: Lorraine
authors.initials: L
authors.lastname: Leblond
authors.forename: Brigitte
authors.initials: B
authors.lastname: Grouix
authors.forename: Cathy
authors.initials: C
authors.lastname: Poirier
authors.forename: Monica
authors.initials: M
authors.lastname: Bubenik
authors.forename: Laval
authors.initials: L
authors.lastname: Chan
authors.forename: Henriette
authors.initials: H
authors.lastname: Gourdeau
authors.forename: Terry
authors.initials: T
authors.lastname: Bowlin
authors.forename: Giorgio
authors.initials: G
authors.lastname: Attardo
mesh_terms: D023102:Anoikis; D017209:Apoptosis; D002448:Cell Adhesion; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D024042:Collagen Type I / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D005109:Extracellular Matrix / Q000502:physiology; D006146:Guanidines / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D039081:Integrin alpha5beta1 / Q000037:antagonists & inhibitors* / Q000502:physiology; D039302:Integrin alphaVbeta3 / Q000037:antagonists & inhibitors* / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins; D018716:Molecular Mimicry; D009389:Neovascularization, Pathologic / Q000473:pathology; D009842:Oligopeptides / Q000737:chemistry*; D010455:Peptides / Q000494:pharmacology; D011971:Receptors, Immunologic; D013449:Sulfonamides / Q000737:chemistry / Q000494:pharmacology*; D019096:Vitronectin / Q000378:metabolism
chemical_list: C479522:BCH 14661; C479523:BCH 15046; D024042:Collagen Type I; D006146:Guanidines; D039081:Integrin alpha5beta1; D039302:Integrin alphaVbeta3; D036341:Intercellular Signaling Peptides and Proteins; D009842:Oligopeptides; D010455:Peptides; D011971:Receptors, Immunologic; D013449:Sulfonamides; D019096:Vitronectin; C057986:echistatin; C047981:arginyl-glycyl-aspartic acid