Effects of arsenic trioxide combined with bortezomib on proliferation and apoptosis of K562 cells and their mechanism / 中国实验血液学杂志

ABSTRACT

This study was aimed to investigate the effect of arsenic trioxide (As(2)O(3)) alone and in combination with bortezomib (Bor) on proliferation and apoptosis of leukemia cell line K562, and to analyze the potential mechanism. K562 cells were treated with different concentrations of As(2)O(3) or Bor (alone or combination) for 24, 48 h. MTT method was used to detect the cell proliferation. After K562 cells were treated with 0.5 µmol/L As(2)O(3) alone or in combination with 10 nmoL/L Bor, the apoptosis rate and cell cycle were measured by flow cytometry, and the activity of NF-κB was analyzed by SP immunohistochemistry. The results indicated that the different concentrations of As(2)O(3) and Bor could inhibit the K562 cell proliferation in a time- and dose-dependent manners (P < 0.05). The IC(50) of Bor and As(2)O(3) in 48 h were 20 nmol/L and 0.6 µmol/L respectively. When K562 cells were treated with As(2)O(3) or Bor alone for 24 h, the apoptotic rate of K562 cells increased, and the apoptotic rate in combination group was higher than that in As(2)O(3) or Bor group. The cells were apparently arrested in G(2)/M phase in Bor group and G(0)/G(1) phase in As(2)O(3) group. The activity of NF-κB decreased significantly in As(2)O(3) or Bor group (P < 0.05), this effect was most significant in the combination group (P < 0.01). It is concluded that both As(2)O(3) and Bor can inhibit the proliferation and induce apoptosis of K562 cells, a synergistic effect can be observed when a low dose of As(2)O(3) combined with low dose of Bor. The different cell cycle block site and the decrease of activity of NF-κB may be one of the mechanisms underlying their synergic effect.