Effects of caspase inhibitor zVAD-fmk on changes in apoptosis protein levels induced by flavopiridol and UCN-01 in B-CLL cells.

B-CLL cells derived from 6 to 9 patients were cultured with (+) or without (−) 100 μmol/L zVAD-fmk and either 0.1 μmol/L flavopiridol (top) or 1 μmol/L UCN-01 (bottom). After 18 to 24 hours, cell lysates were prepared, normalized for total protein content, and analyzed by immunoblotting with the use of antibodies specific for PARP, Mcl-1, XIAP, or Bag-1. Data were quantified by scanning densitometry and expressed as a percentage relative to control: untreated B-CLL cells. PARP data refer to loss of the full-length 110 kd protein, which undergoes caspase-mediated cleavage. Data were compared by means of a paired t test (Pvalues shown). Bars indicate mean of data points.