Comparison of engineered caspases with endogenous caspase-3 and cleavage of PARP by engineered caspases. A. Western blot analysis using anti-caspase-3 antibody. H, unstimulated HL-60 cell lysate; E, HL-60 cell lysate stimulated with etoposide; lane 1, purified wild-type caspase-3 (I); lane 2, purified II; lane 3, purified III; lane 4, VI; lane 5, purified IV; lane 6, VII; lane 7, purified V; lane 8, VIII. B. Western blot analysis of PARP cleavage by wild-type and engineered caspases (VI and VIII). HL-60 cell lysates were treated with each caspase in the presence and absence of caspase-3 inhibitor (z-DEVD-fmk) and Western blot analysis was carried out using an anti-PARP antibody which recognizes the full length (115 kDa) PARP and its cleavage product (24 kDa). H, unstimulated HL-60 cell lysate; E, HL-60 cell lysate stimulated with etoposide.