Figure 3.

ROS scavenger, NAC, reversed the effects of the combination of SAHA and MG-132 in the K562 and K562G CML cell lines. (A) K562 cells were treated with SAHA (1 µM) plus MG-132 (200 nM) for 24 h, with or without 1 h pretreatment with NAC (2 mM), Rosup (50 mg/ml) was used as a positive control. ROS generation was examined using a fluorescence microscope. Representative images from three independent experiments are shown. (B) K562 cells and K562G cells were treated with SAHA (1 µM) or MG-132 (200 nM) alone, or with SAHA plus MG-132 for 48 h, prior to which cells were cultured in the presence or absence of NAC (2 mM) for 1 h. Cell viability was measured using MTT assay. Data are presented as the mean ± standard deviation of three independent experiments. *P<0.0001. (C) K562 cells were cultured with SAHA (1 µM) plus MG-132 (200 nM) for 6 h or 24 h, with or without pretreatment with NAC (2 mM) for 1 h. Western blot analysis was performed, using antibodies against Bcr-Abl and PARP. β-actin was used as a loading control. A representative blot from three independent experiments is shown. SAHA, suberoylanilide hydroxamic acid; CML, chronic myeloid leukemia; Ac-histone, acetylated histone; PARP, poly adenosine diphosphate-ribose polymerase; NAC, N-acetyl-L-cysteine.