Figure 5.
Role of ICE-like protease activity in p42-ETS1-mediated Fas-induced apoptosis. DLD1 cells expressing the p42-ETS1 gene (▴, ΔVII-19) and control Jurkat cells (□, Jurkat) were incubated with Fas antibody CH-11 (100 ng/ml). Approximately 2 × 105 cells were collected and lysed at the indicated times, and equal amounts of protein (100 μg per reaction) were incubated for 2 hr with Ac-YVAD-AMC (substrate for caspase-1; 25 μM) or Ac-DEVD-AMC (substrate for caspase-3; 20 μM). The activities of caspase-1 (a) and caspase-3-like (b) proteases were measured as described in Materials and Methods. Data presented are means derived from two independent experiments. The inhibitors of ICE-like protease Ac-YVAD-CHO (caspase-1 specific) and Ac-DEVD-CHO (caspase-3 specific) were incubated with p42-ETS1-expressing cells 2 hr before adding anti-Fas antibody. After 18 hr, cell viability was measured by MTT assay (c). These results represent two independent experiments.