Effect of 8-pCPT-2′-O-Me-cAMP on the adhesion of EPCs on HUVEC or matrix proteins. (A,B) EPCs were preincubated in suspension for 15 minutes with the indicated concentrations of 8-pCPT-cAMP or PBS (control). After washing out 8-pCPT-2′-O-Me-cAMP, EPCs were added to the HUVEC monolayers. (A) Nonstimulated HUVECs (n = 9). (B) TNFα stimulated HUVECs (n = 6, *P < .05 vs control). (C) EPCs were preincubated in suspension with 8-pCPT-2′-O-Me-cAMP (100 μM) for 15 minutes. After washing out 8-pCPT-2′-O-Me-cAMP, EPCs were added to TNFα-stimulated HUVECs in the presence of blocking monoclonal β2-integrin antibodies or murine isotype control antibodies and incubated for 20 minutes at 37°C (n = 3, *P < .05 vs control + IgG; **P< .01 vs 8-pCPT-cAMP + IgG). (D) EPCs were stimulated with the indicated 8-pCPT-2′-O-Me-cAMP concentrations for 15 minutes before adhesion or with 8-Br-cAMP and 6-Bnz-cAMP. Adhesion of EPC to ICAM-1-coated plates was detected after 15 minutes (n = 9, *P < .05 vs control; **P< .01 vs contol). (E) EPCs were stimulated with 8-pCPT-2′-O-Me-cAMP (100 μM) for 15 minutes before adhesion. Adhesion of EPC to fibronectin-P-coated plates was detected after 15 minutes (n = 7, *P < .05 vs control). (F) MSCs were stimulated with 8-pCPT-2′-O-Me-cAMP (100 μM) or 6-Bnz-cAMP (100 μM) for 15 minutes before adhesion. Adhesion of EPC to fibronectin-coated plates was detected after 15 minutes (n = 5, *P < .05 vs control). Error bars represent SEM.