Effect of tunicamycin and thapsigargin on spontaneous B-CLL cell apoptosis. (A-C) Freshly isolated B-CLL cells were cultured for 24 hours in complete medium with the indicated concentrations of tunicamycin (Tm), thapsigargin (Tg), or DMSO as control (n = 6). Apoptosis was evaluated by flow cytometric analysis of hypodiploid nuclei (A) and annexin V/PI staining (B). (A) Data are mean ± SD of all 6 patients examined. *P < .05, **P < .01 (each agent vs DMSO) according to Student t test. (B) Results are the percentage of viable (annexin V⁻/PI⁻), early apoptotic (annexin V⁺/PI⁻), late apoptotic (annexin V⁺/PI⁺), and necrotic cells (annexin V⁻/PI⁺). (C) The expression of CHOP/GADD153 and BiP/GRP78, and the cleavages of caspase-3, -4, -8, and -9 and Bap31 were analyzed by Western blot (40 μg whole-cell lysates for CHOP/GADD153 and 20 μg for all other proteins). Protein loading was assessed by reprobing the blots with an anti–β-actin mAb. (B-C) Data shown for patient 21 are representative of 6 patients.