Table 4.
Inhibition of Activation of CPP32-like Protease and Apoptosis by Cell-permeable CPP32 Inhibitors
| Cell treatment* | Apoptotic cells | DEVD-pNa cleaving activity | DNA fragmentation | |||
|---|---|---|---|---|---|---|
| % | nmol/h/mg | % | ||||
| — | 0 | 9.5 | 0 | |||
| TNF 2.0 ng/ml | 41 | 78.8 | 48 ± 4.8 | |||
| TNF + cpDEVD-CHO 1.0 μM | 8 | 1.1 | 0 | |||
| TNF + cpDEVD-CHO 0.5 μM | 11 | 38.6 | 21 ± 0.8 | |||
| TNF + cpDEVD-CHO 0.25 μM | 20 | 46.5 | ND | |||
| TNF + cpDEVD-CHO 0.125 μM | 31 | 80.5 | ND | |||
| — | 0 | 0 | 0 | |||
| UV light 0.06 J/cm2 | 58 | 20.4 | 53 ± 4.2 | |||
| UV light + cpDEVD-CHO 1.0 μM | 11 | 3.4 | 12 ± 0.6 | |||
| UV light + cpDEVD-CHO 0.25 μM | 38 | 8.8 | ND | |||
| — | 0 | 3.5 | 0 | |||
| UV light 0.06 J/cm2 | 59 | 80.4 | 46 ± 4.6 | |||
| UV light + DEVD(meth)-cmk 10 μM | 8 | 12.2 | 0 | |||
| UV light + DEVD(meth)-cmk 5 μM | 18 | 27.8 | 0 | |||
| UV light + DEVD(meth)-cmk 2.5 μM | 39 | 46.6 | 15 ± 4.5 |
*
U937 cells were pretreated with inhibitors for 2 h before exposure to TNF or UV light. After 1 h of incubation, cells were pelleted, washed twice in PBS, and lysed to measure protease activity on the DEVD–pNa substrate. The percent morphologically apoptotic cells and percent DNA fragmentation was determined after 1.5 h incubation. ND, not determined.