不同剂量蛋白酶体抑制剂MG-132在诱导K562细胞株凋亡中的作用

本研究探讨不同剂量蛋白酶体抑制剂MG．132对人慢性粒细胞白血病急性红白血病细胞株K562的干预作用。应用四甲基偶氮唑蓝（MTT）比色法检测不同剂量（0、2、4、8、16、32μmol／L）的MG-132作用48小时对K562细胞株增殖的影响；应用免疫细胞组织化学法检测相同条件下MG-132对K562细胞株中的核因子-κB（NF—κB）及糖皮质激素受体（glucocorticoidreceptor，GR）表达的影响；采用流式细胞术检测相同条件下MG-132对K562细胞株凋亡的影响。结果表明：不同剂量的MG-132作用48小时后K562细胞株的抑制率呈剂量依赖性，实验组的抑制率明显高于对照组，以32μmol／L剂量组的抑制率最高，为（45．24±4．12）％；K562细胞株中的NF—KB、GR的表达水平均表现出对MG-132剂量的依赖性，NF—κB的表达水平实验组明显低于对照组，以32μmol/L剂量组表达最低，为63．60±2．95。GR在16μmol／L剂量组表达最高，为75．62±2．70。K562细胞株的凋亡率亦表现出对MG-132剂量的依赖性，而且在实验组明显高于对照组，以32μmol／L剂量组的凋亡率最高，为（21．37±2．02）％。结论：MG-132可能是通过下调NF—κB、上调GR的表达诱导了K562细胞的凋亡和抑制，其效应表现为剂量的依赖性。

Effect of Proteasome Inhibitors MG-132 at Different Doses on Cultured K562 Cell Apotosis

This study was aimed to investigate the effect of proteasome inhibitor MG-132 at different doses on cultrured K562 cell apotosis. MTT assay was used to observe the activity of K562 cell proliferation inhibition rate after treating for 48 hours at different doses （0, 2, 4, 8, 16, 32 μmol/L）. Immunocytohistochemistry was used to detect the NF-κB activity and glucocorticoid receptor （GR） expression. Flow cytometry was used to determine the K562 cell apotosis. The results indicated that proliferation inhibition rate of K562 cells after treated for 48 hours showed dosedependent, the inhibitory rates of cell proliferation in test groups were significant higher than that in control group, and the effect in 32 μmol/L test group was the most obvious （45.24 ±4.12）% （ p 〈 0.05 ）. The NF-κB activity and GR expression after treating for 48 hours showed dose-dependent. Compared with control group, the NF-κB activities in test groups were lower （p 〈0.05）, and the NF-κB activity in 32μmol/L test group was the lowest （63.60 ±2.95） ; the GR expression in test groups was higher（p 〈 0.05 ）, and the GR expression in 16 μmol/L test group was the hightest （75. 62 ± 2.70）. The K562 cell apotosis rate after treating for 48 hours also showed dose-dependent. Compared with control group, the K562 cell apotosis rates in test groups were higher （p 〈 0.05）, the K562 cell apotosis rate in 32 μmol/L test group was the highest （21. 37 ± 2. 02 ）%. It is concluded that the MG-132 may induce K562 cell apotosis and proliferation inhibition through up-regulation of NF-κB activity and down-regulation of GR expression both in dose- dependent manner.