title: Endothelial progenitor cell-dependent angiogenesis requires localization of the full-length form of uPAR in caveolae.
abstract: Endothelial urokinase-type plasminogen activator receptor (uPAR) is thought to provide a regulatory mechanism in angiogenesis. Here we studied the proangiogenic role of uPAR in endothelial colony-forming cells (ECFCs), a cell population identified in human umbilical blood that embodies all of the properties of an endothelial progenitor cell matched with a high proliferative rate. By using caveolae-disrupting agents and by caveolin-1 silencing, we have shown that the angiogenic properties of ECFCs depend on caveolae integrity and on the presence of full-length uPAR in such specialized membrane invaginations. Inhibition of uPAR expression by antisense oligonucleotides promoted caveolae disruption, suggesting that uPAR is an inducer of caveolae organization. Vascular endothelial growth factor (VEGF) promoted accumulation of uPAR in ECFC caveolae in its undegraded form. We also demonstrated that VEGF-dependent ERK phosphorylation required integrity of caveolae as well as caveolar uPAR expression. VEGF activity depends on inhibition of ECFC MMP12 production, which results in impairment of MMP12-dependent uPAR truncation. Further, MMP12 overexpression in ECFC inhibited vascularization in vitro and in vivo. Our data suggest that intratumor homing of ECFCs suitably engineered to overexpress MMP12 could have the chance to control uPAR-dependent activities required for tumor angiogenesis and malignant cells spreading.
authors.affiliation: Department of Experimental Pathology and Oncology, University of Florence Istituto Toscano Tumori, Florence, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Margheri
authors.forename: Anastasia
authors.initials: A
authors.lastname: Chillà
authors.forename: Anna
authors.initials: A
authors.lastname: Laurenzana
authors.forename: Simona
authors.initials: S
authors.lastname: Serratì
authors.forename: Benedetta
authors.initials: B
authors.lastname: Mazzanti
authors.forename: Riccardo
authors.initials: R
authors.lastname: Saccardi
authors.forename: Michela
authors.initials: M
authors.lastname: Santosuosso
authors.forename: Giovanna
authors.initials: G
authors.lastname: Danza
authors.forename: Niccolò
authors.initials: N
authors.lastname: Sturli
authors.forename: Fabiana
authors.initials: F
authors.lastname: Rosati
authors.forename: Lucia
authors.initials: L
authors.lastname: Magnelli
authors.forename: Laura
authors.initials: L
authors.lastname: Papucci
authors.forename: Lido
authors.initials: L
authors.lastname: Calorini
authors.forename: Francesca
authors.initials: F
authors.lastname: Bianchini
authors.forename: Mario
authors.initials: M
authors.lastname: Del Rosso
authors.forename: Gabriella
authors.initials: G
authors.lastname: Fibbi
mesh_terms: D000818:Animals; D021941:Caveolae / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D053508:Matrix Metalloproteinase 12 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000235:genetics / Q000502:physiology*; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport; D055293:Receptors, Urokinase Plasminogen Activator / Q000378:metabolism*; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: D020033:Protein Isoforms; D055293:Receptors, Urokinase Plasminogen Activator; D053508:Matrix Metalloproteinase 12