Fig. 3.

Induction of apoptosis in HUVECs treated with P11. A, Activities of caspases-3, -8, and caspase-9 in P11-treated HUVECs. The caspase activities were measured by determining the ability of cell extracts to cleave the colorimetric substrates DEVD-pNA (for caspase-3 activity), IETD-pNA (for caspase-8 activity), and LEHD-pNA (for caspase-9 activity). Comparison of the absorbance of pNA from a P11-treated sample with an untreated control allows determination of the fold increase in caspase activity. Results are mean ± S.D. (from four separate experiments). B, In situ apoptosis TUNEL assay detection of apoptosis in HUVECs treated with P11. We treated bFGF (10 ng/ml) in the presence or absence of P11 (50 μg/ml) in HUEVCs. After overnight incubation, we performed the TUNEL assay as described in Materials and Methods. We used the label solution as a negative control and DNase I (50 unit/ml) as a positive control, respectively.