3-Cl-AHPC activation of p38, ERK, and JNK. M07e and leukemic cells were exposed to 1 μM 3-Cl-AHPC or vehicle alone in the presence and absence of the capsase inhibitor Z-VAD-fmk (50 μM). Phospho-p38 (A) and phospho-ERK (B) levels were assessed with the use of anti-phospho-p38 and anti-phospho-ERK antibodies in conjunction with Western blots as described in “Materials and methods.” (C) JNK kinase activation was determined by measuring JNK kinase activity with c-Jun as the substrate, as described in “Materials and methods.”