Effect of inhibition of 3-Cl-AHPC-mediated JNK activation on 3-Cl-AHPC-mediated apoptosis. Patient 1 cells (A), M07e cells (B), or KG-1 cells (C) were exposed to 1μM 3-Cl-AHPC, the JNK kinase inhibitors PD169316 (20 μM) or SP600125 (30 μM), and the combination 3-Cl-AHPC (1 μM) and either PD169316 (20 μM) or SP600125 (30 μM). JNK kinase activity (upper panels) and the percentage of apoptotic cells (histograms, lower panels) were assessed as described in “Materials and methods.” ^**Significantly less than apoptosis mediated by 3-Cl-AHPC alone (P < .01). Error bars represent standard deviation of 3 separate experiments.