Figure 7.

Caspase inhibitors protect G85R-expressing cells against X/XO-induced loss of cell viability, caspase-1/ICE cleavage, and increased IL-1β secretion. (a) Differentiated G85R-expressing cells were preincubated for 30 min at 37°C with the inhibitor before addition of X/XO (100 μM X, 10 milliunits/ml XO), in the presence of inhibitors. Cell viability then was determined by the MTT assay as described and expressed as a percentage of untreated cells. Data are the mean ± SEM of five independent experiments for ZVAD-FMK and four independent experiments for Ac-YVAD-CHO. (b) Levels of IL-1β were measured as described above in the medium of G85R cells treated with X/XO in the presence or absence of caspase inhibitors. Data represent the mean ± SEM of nine observations of three independent experiments. (c) Differentiated G85R-positive cells were treated as described in a. After lysis, processing of ICE was detected by Western immunoblot as described above.