Diffuse large-B cell line (RL). (A) Assessment of the mitochondrial membrane potential (Δøm). AT-101 (1 μM, 3 μM, 10 μM) from 1 hour to 24 hours of exposure. (B) Confocal microscopic detection of apoptosis in a large B-cell lymphoma line (RL) treated with AT-101 for 24 hours. YO-PRO-1 (nuclei of apoptotic cells, green); Hoechst 33342 (nuclei, blue), MitoTracker Red (active mitochondria). AT-101 induces apoptosis in a large B-cell lymphoma cell line (RL) after exposure for 24 hours. Control, AR=3%; AT-101 10 μM, AT=38.7%. (C) Immunoblotting for Bcl-2 following treatment with AT-101in a large B-cell lymphoma line (RL). AT-101 does not affect levels of Bcl-2. (D) Cytotoxicity assay for AT-101 combined with 4-HC in a large B-cell lymphoma line (RL). Model of in vitro exposure to AT-101 and other drugs; a preexposure to AT-101 for up to 48 hours before adding 4-HC for an additional 24 hours revealed a synergistic interaction of the combination.