3-Cl-AHPC activates caspases. (A-B) M07e (A) and leukemic cells (patient 1) (B) were treated with 3-Cl-AHPC or vehicle alone, and caspase (cas) activation was assessed as described in “Materials and methods.” (C) The 3-Cl-AHPC activation of caspase-3. Leukemic cells obtained from patient 1 were treated with 1 μM 3-Cl-AHPC or vehicle alone, and the cells were harvested at 24 or 48 hours. Caspase-3 proenzyme levels were determined by means of Western blot as described in “Materials and methods.” Actin levels were used to assess loading. The results are representative of 2 independent experiments.