title: Gas1 is induced by VE-cadherin and vascular endothelial growth factor and inhibits endothelial cell apoptosis.
abstract: The junctional membrane protein vascular endothelial (VE)-cadherin mediates contact inhibition of growth and inhibits apoptosis of endothelial cells. In this article we show that VE-cadherin induces expression of growth arrest-specific 1 (Gas1), an integral membrane protein up-regulated in nonproliferating cells. By comparing syngenic endothelial cell lines, we found that Gas1 mRNA was increased by 3-fold in VE-cadherin-positive cells in comparison to VE-cadherin-null cells. Ectopic expression of Gas1 in endothelial or 293 cells strongly reduced apoptosis without affecting cell growth. Addition of vascular endothelial growth factor (VEGF) also up-regulated Gas1 and this effect was augmented more so in confluent nonproliferating cells than in sparse cultures. VE-cadherin-blocking antibody partially inhibited VEGF-induced Gas1, suggesting that VE-cadherin clustering is required for an optimal response to this stimulus. Inhibition of phosphoinositole-3-OH kinase (PI3-kinase) pathway by Wortmannin prevented Gas1 synthesis and the antiapoptotic effect of VEGF, but, in cells ectopically expressing Gas1, Wortmannin was ineffective. Furthermore, inhibition of Gas1 expression by short interfering RNA (siRNA) both in vitro and in allantois organ cultures made endothelial cells refractory to the antiapoptotic effect of VEGF. Overall these data indicate that Gas1 induction by VE-cadherin and VEGF in endothelial cells requires activation of PI3-kinase. Gas1 expression positively correlates with inhibition of endothelial cell apoptosis and may contribute to the integrity of resting endothelium.
authors.affiliation: Italian Foundation for Cancer Research (FIRC) Institute of Molecular Oncology, Milan, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Spagnuolo
authors.forename: Monica
authors.initials: M
authors.lastname: Corada
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Orsenigo
authors.forename: Lucia
authors.initials: L
authors.lastname: Zanetta
authors.forename: Ulrich
authors.initials: U
authors.lastname: Deuschle
authors.forename: Peter
authors.initials: P
authors.lastname: Sandy
authors.forename: Claudio
authors.initials: C
authors.lastname: Schneider
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Drake
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Breviario
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Dejana
mesh_terms: D000818:Animals; D015703:Antigens, CD; D017209:Apoptosis / Q000187:drug effects; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002460:Cell Line; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D058851:GPI-Linked Proteins; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D018797:Cell Cycle Proteins; D058851:GPI-Linked Proteins; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; D042461:Vascular Endothelial Growth Factor A; D000099152:Cadherin 5; C096192:GAS1 protein, human; C501180:Gas1 protein, mouse