Role of caveolae and uPAR in in vitro ECFC-dependent angiogenesis. In vitro angiogenesis was measured by Matrigel invasion and by capillary morphogenesis of ECFCs after modification of caveolar rafts or of uPAR expression. In all the experiments, results are the mean of 3 different experiments performed in triplicate in 3 different ECFC preparations. The histograms on the right of each panel refer to the relative quantification and are expressed as mean value ± SD. *P < .05, significantly different from control. In all the histograms, Matrigel invasion is expressed as the absolute number of migrated cells, by directly counting the migrated cells on the filters, whereas capillary morphogenesis is quantified by measuring the percentage field occupancy of capillary projections, assuming the control as 100%. Six to 9 photographic fields from 3 plates were scanned for each point. (A) Effects of caveolar raft modification. Top part: Matrigel invasion of ECFCs before and after treatment with 5mM β-MCD, in control and after VEGF stimulation (50 ng/mL). Bottom part: Capillary morphogenesis at 6 hours in the same conditions (symbols as in Figure 1). (B) The experimental conditions were the same as in panel A, but cells were treated with anti-uPAR antibodies (antibody R3) instead of β-MCD. Top panels: Matrigel invasion. Bottom panels: Capillary morphogenesis under the same experimental conditions. (C) Silencing of uPAR gene using the anti-uPAR aODN. Top panels: Matrigel invasion of control (DOTAP) untreated and 4 days ODN-treated ECFCs in the presence of DOTAP. The same experimental conditions were used for capillary morphogenesis (bottom panels).