American Society of Hematology

Figure 6.

$Figure 6. Involvement of ROS in the drug-induced p53 accumulation in leukemic cells and activated T lymphocytes. (A) Increased NAO red fluorescence indicates decreased mitochondrial ROS levels in the presence of oligomycin. MOLT-3 cells were incubated with oligomycin (10 μg/mL) and/or with etoposide (1 μM) for 3 hours and assessed for NAO fluorescence. Open bars indicate -oligomycin; gray bars indicate +oligomycin. (B) NAC prevents etoposide-induced p53 accumulation and apoptosis. MOLT-3 cells were incubated with NAC (10 mM) and/or with etoposide (1 μM) and assessed for p53 protein levels after 3 hours of incubation and for apoptosis (JC-1 and annexin/PI staining) after 6 hours of incubation (JC-1, caspase-3, annexin V, and PI fluorescence: 4-decade log scaling). NAC did not affect MTMP levels, as indicated by JC-1 red-green fluorescence ratios in viable cell fractions (indicated by arrows). (C) NAC (10 mM) prevents etoposide-induced p53 accumulation in activated T cells. T cells were incubated with NAC (10 mM) and/or etoposide (30 μM) for 6 hours and assessed for p53 levels. Hatched bars indicate medium; black bars, etoposide; and gray bars, etoposide plus NAC. (D) NAC (10 mM) differentially prevents etoposide-induced p53 accumulation in a series of ALL samples. ALL cells were incubated with NAC (10 mM) and/or etoposide (30 μM) for 6 hours and assessed for p53 levels. Each individual leukemic sample is presented as a point, positioned according to the value of drug-specific p53 accumulation in the presence (y-axis) and absence (x-axis) of NAC.$

Involvement of ROS in the drug-induced p53 accumulation in leukemic cells and activated T lymphocytes. (A) Increased NAO red fluorescence indicates decreased mitochondrial ROS levels in the presence of oligomycin. MOLT-3 cells were incubated with oligomycin (10 μg/mL) and/or with etoposide (1 μM) for 3 hours and assessed for NAO fluorescence. Open bars indicate -oligomycin; gray bars indicate +oligomycin. (B) NAC prevents etoposide-induced p53 accumulation and apoptosis. MOLT-3 cells were incubated with NAC (10 mM) and/or with etoposide (1 μM) and assessed for p53 protein levels after 3 hours of incubation and for apoptosis (JC-1 and annexin/PI staining) after 6 hours of incubation (JC-1, caspase-3, annexin V, and PI fluorescence: 4-decade log scaling). NAC did not affect MTMP levels, as indicated by JC-1 red-green fluorescence ratios in viable cell fractions (indicated by arrows). (C) NAC (10 mM) prevents etoposide-induced p53 accumulation in activated T cells. T cells were incubated with NAC (10 mM) and/or etoposide (30 μM) for 6 hours and assessed for p53 levels. Hatched bars indicate medium; black bars, etoposide; and gray bars, etoposide plus NAC. (D) NAC (10 mM) differentially prevents etoposide-induced p53 accumulation in a series of ALL samples. ALL cells were incubated with NAC (10 mM) and/or etoposide (30 μM) for 6 hours and assessed for p53 levels. Each individual leukemic sample is presented as a point, positioned according to the value of drug-specific p53 accumulation in the presence (y-axis) and absence (x-axis) of NAC.

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