Apoptosis induction by specific and nonspecific inhibitors of the proteasome.

B-CLL cells (dark columns) and PBL cells (light columns) were untreated (lane 1) or treated with 2.5 μmol/L lactacystin (lane 2), 2.5 μmol/L clasto-lactacystin β-lactone (lane 3), 1 μmol/L MG-132 (lane 4), or 25 μmol/L LLnL (lane 5). Apoptotic values were determined 24 hours after cell treatments. The results represent analyses of cells from 50 patients and 20 normal donors. Error bars indicate the standard deviation.