蛋白酶体抑制剂MG-132诱导K562细胞株凋亡的时程效应

目的研究不同时间蛋白酶体抑制剂MG-132对人慢性粒细胞白血病急性红白血病变细胞株K562的干预作用。方法采用四甲基偶氮唑蓝（MTT）比色法检测16μmol／LMG-132作用不同时间（0、24、48、72、96h5个时间点）对K562细胞株增殖的影响，免疫细胞组织化学法检测MG-132作用不同时间后核因子-κB（NF—κB）及糖皮质激素受体（GR）的表达，采用流式细胞术检测MG-132不同作用时间对凋亡的影响。结果MTT：MG-132干预K562细胞株不同时间后K562细胞株的抑制率表现为对时间的依赖性，实验组明显高于对照组（P均〈0．05），以干预72h时抑制率最高，为（63．33±1．52）％。免疫细胞组织化学法：MG-132干预K562细胞不同时间后，K562细胞株中的NF—κB、GR的表达水平均表现为对时间的依赖性；对于NF—κB，实验组明显低于对照组（均P〈0．05），以干预96h时表达最低，为51．15±1．64；对于GR，以干预72h时表达最高，为89．21±3．49。流式细胞术：MG-132干预K562细胞株不同时间后K562细胞株的凋亡率表现为对时间的依赖性，实验组明显高于对照组（P均〈0．05），以干预72h时，凋亡率最高，为（17．57±1．45）％。结论MG-132可能是通过下调NF—κB、上凋GR的表达诱导了K562细胞的凋亡和抑制，并表现出对时间的依赖性。

Effect of proteasome inhibitor MG-132 on induction of K562 cell apoptosis at different times

Objective To investigate the effects of proteasome inhibitor MG - 132 on internening K562 cell apoptosis at different times. Methods MTT assay was used to observe the effect of K562 cell proliferation after 16μmoL/L MG -132 treatment at different time points （0, 24, 48, 72 and 96 h） ; immunohistochemistry was employed to detect the expressions of nuclear factor kappa - light - chain - enhancer of activated B cells （ NF - κB） and glueocortieoid receptor （GR）, respectively, and flowcytometry was applied to detect the K562 cell apoptosis. Results MTT： Following MG - 132 intervention at different time points, the inhibition rate of K562 cell proliferation K562 cell exhibited time dependence, of which the results in the experiment groups were markedly higher than those in the control group （ P 〈 0.05 each） , with its peak, （63.33 ± 1.52）% at 72 h. Immunohistochemistry： After MG - 132 treatment, the expression levels of NF - κB and GR in the K562 cells showed time dependence. Compared with the control group, the NF - κB expression in experiment groups was down -regulated, with its nadir, （51.15 ± 1.64）% at 96 h （P 〈0.05）. As compared to the control group, the GR expression in experiment groups was up - regulated, with its peak, （ 89.21± 3.49 ） % at 72h （P 〈 0.05 ）. Flowcytometry： After MG - 132 treatment, the apoptosis rate of K562 cells were in a time - dependent manner, and the K562 cell apoptosis rate in test groups was higher than that in the control group, with its peak, （ 17.57 ±1.45 ） % at 72 h （ P 〈 0.05 ）. Conclusion MG - 132 may induce K562 cell apoptosis and inhibition of prolif- eration by down - regulating the NF - κB expression and up - regulating the GR expression in a time - dependent manner.