Figure 2. PTC596 induces mitochondrial apoptosis in mantle cell lymphoma cells.

(A-B) BAX conformational changes, caspase-3 cleavage and Δψm loss were determined by flow cytometry in Z-138 cells (A) or REC-1 cells (B) after 18-h (BAX activation) or 20-h (caspase-3 cleavage and Δψ_m loss) exposure to PTC596. The results are expressed as the mean ± SD. (C) Z-138 and REC-1 cells were treated for 24 hours with 300 nM PTC596, after which BCL-2, BCL-X_L and MCL-1 protein levels were determined. In BMI-1, slow migrating phosphorylated BMI-1 bands are indicated by the open arrowhead, and non-phosphorylated BMI-1 is indicated by the closed arrowhead. The intensities of immunoblot signals were quantified and normalized to those of β-ACTIN. Levels in untreated cells were set at 1.0. Results are representative of three independent experiments.