雷帕霉素对去甲氧柔红霉素诱导急性髓系白血病THP-1细胞凋亡的影响

目的:探讨雷帕霉素（Rapa）对去甲氧柔红霉素（IDA）诱导急性髓系白血病THP-1细胞凋亡的影响及其分子机制。方法:分别用10、20、40、80 nmol/L Rapa处理THP-1细胞1 h，另设未经Rapa处理的细胞。采用蛋白质印迹法检测THP-1细胞自噬标志物LC3蛋白的转换情况（LC3Ⅱ/LC3Ⅰ），采用流式细胞术检测细胞凋亡，确定Rapa处理浓度。用不同浓度IDA作用THP-1细胞24 h，采用CCK-8法检测IDA对THP-1细胞的增殖抑制率，计算半数抑制浓度（ IC50）。以低于 IC50的IDA作用Rapa处理或未处理的THP-1细胞24 h，CCK-8法检测细胞增殖抑制率，流式细胞术检测细胞凋亡情况，实时荧光定量聚合酶链反应检测自噬相关基因Beclin-1、LC3和p62的表达变化，蛋白质印迹法检测自噬标志物LC3蛋白的转换情况。 结果:20 nmol/L Rapa处理的THP-1细胞LC3Ⅱ/LC3Ⅰ高于未处理的细胞（ P=0.002 4）；80 nmol/L Rapa处理的细胞凋亡率高于未处理的细胞（ P=0.007 3）。根据蛋白质印迹法和流式细胞术检测结果，选取20 nmol/L Rapa作为预处理浓度。IDA对THP-1细胞作用24 h的 IC50为59.874 nmol/L。50 nmol/L IDA作用24 h后，Rapa预处理的THP-1细胞增殖抑制率（69.67±5.03）%比（41.67±3.51）%]和细胞凋亡率（74.35±4.83）%比（41.25±5.24）%]均高于未预处理的细胞（均 P<0.05）；Rapa预处理的THP-1细胞Beclin-1、LC3 mRNA表达水平及LC3Ⅱ/LC3Ⅰ均高于未预处理的细胞，p62 mRNA表达水平低于未预处理的细胞（均 P<0.05）。 结论:Rapa能增强较低剂量IDA诱导的THP-1细胞凋亡，此效应可能是通过其引起THP-1细胞过度自噬实现的。

Effect of rapamycin on apoptosis of acute myeloid leukemia THP-1 cells induced by idarubicin

Objective:To investigate the effect of rapamycin (Rapa) on apoptosis of acute myeloid leukemia THP-1 cells induced by idarubicin (IDA) and its molecular mechanism.Methods:The THP-1 cells were treated with 10, 20, 40 and 80 nmol/L Rapa for 1 h, and the cells without Rapa treatment were set up. Western blot was used to detect the conversion of autophagy marker LC3 protein in THP-1 cells (the ratio of LC3Ⅱ/LC3Ⅰ), flow cytometry was used to detect the apoptotic rate, and the pretreatment concentration of Rapa was determined. THP-1 cells were treated with different concentrations of IDA for 24 h, the cell proliferation inhibition rate of IDA for THP-1 cells was detected by CCK-8 method, and the half maximal inhibitory concentration ( IC50) was calculated. THP-1 cells with or without Rapa treatment were treated by IDA with the concentration of lower than IC50 for 24 h, CCK-8 method was used to detect cell proliferation inhibition rate, flow cytometry was used to detect cell apoptosis, real-time fluorescent quantitative polymerase chain reaction was used to detect the expression changes of autophagy-related genes Beclin-1, LC3 and p62, and Western blot was used to detect the conversion of autophagy marker LC3 protein. Results:The ratio of LC3Ⅱ/LC3Ⅰ in THP-1 cells treated by 20 nmol/L Rapa was higher than that in the untreated cells ( P=0.002 4). The apoptotic rate in THP-1 cells treated by 80 nmol/L Rapa was higher than that in the untreated cells ( P=0.007 3). According to the results of Western blot and flow cytometry, 20 nmol/L Rapa was selected as the pretreatment concentration. The IC50 of IDA for THP-1 cells treated with IDA for 24 h was 59.874 nmol/L. After treated with 50 nmol/L IDA for 24 h, the proliferation inhibitory (69.67±5.03)% vs. (41.67±3.51)%] and apoptotic rates (74.35±4.83)% vs. (41.25±5.24)%] in THP-1 cells pretreated by Rapa were higher than those in the unpretreated cells (both P<0.05); the Beclin-1 and LC3 mRNA expression levels and the ratio of LC3Ⅱ/LC3Ⅰ in THP-1 cells pretreated by Rapa were higher than those in the unpretreated cells, and the expression of p62 mRNA was lower than that in the unpretreated cells (all P<0.05). Conclusion:Rapa can enhance the apoptosis of THP-1 cells induced by a relative low dose of IDA, which may be achieved through inducing excessive autophagy in THP-1 cells.