p210^bcr-abl expression delays apoptosis upstream of procaspase-3 activation and PARP cleavage. (A) Agarose gel electrophoresis of DNA from UT7 and UT7/9 cells treated for indicated times with 100 μmol/L etoposide (UT7, left panel; UT7/9: whole panel) or deprived from GM-CSF for indicated times (UT7, right panel). (B) Western blot analysis of procaspase-2L (the 45-kD long isoform of ICH-1), procaspase-3 (the 32-kD proenzyme CPP32/Yama/Apopain), active caspase-3 fragments and PARP in cell lines treated for indicated times with 100 μmol/L etoposide (UT7, left panel; UT7/9: whole panel) or deprived from GM-CSF for indicated times (UT7, right panel). (Co = control untreated cells = time 0.)