PGE2 enhanced the expression of functional CXCR4 on HMECs at similar levels to those induced by VEGF and bFGF. (A) Flow cytometric analysis CXCR4 cell surface expression on HMECs without stimulation (gray line histograms) and after 24 hours of stimulation with bFGF (10 ng/mL, 625 nM), VEGF (10 ng/mL, 217 nM), or PGE2 (10–6 and 10–9 M; black line histograms). Control IgG2a is depicted by filled histograms. The figure shows one representative experiment of 3. (B) Comparative MFI of the CXCR4 expression on HMECs after bFGF (10 ng/mL), VEGF (10 ng/mL), or PGE2 (10–6 to 10–10 M). The control antibody (mouse IgG2a) under each stimulus was subtracted from the MFI obtained after each condition with anti-CXCR4 (12G5 mAb). The mean + SEM of 3 experiments is shown. *P < .01, **P < .05. (C) Comparative chemotactic responses of HMECs stimulated with VEGF, bFGF, or PGE2 in response to SDF-1α. HMECs were stimulated as described. The number of migrating endothelial cells per × 10 field was quantitated as described in “Materials and methods.” Statistical analysis was performed using ANOVA relative to the basal migration of HMECs. The mean + SEM of 3 experiments is shown. *P < .01, **P < .05.
