地西他滨对人急性髓系白血病细胞株HL-60的调控作用及其机制研究

目的 研究地西他滨(DAC)对人急性髓系白血病细胞株HL-60体外生长及自然杀伤(NK)细胞活化性受体配体(NKG2DL)表达的调节作用,并探讨JAK-STAT3-SOCS信号通路相关的分子机制.方法 CCK-8法检测DAC对HL-60细胞增殖活性的影响,Annexin-V/PI双标法检测细胞凋亡,流式细胞术检测HL-60细胞表面NKG2DL分子MICA/B、ULBP的表达,羧基荧光素双乙酸盐(CFSE)法检测NK细胞的杀伤活性,蛋白印迹法分析细胞内JAK-STAT3通路中STAT3、STAT3上游激酶JAK1、JAK2及STAT3活性负调控因子细胞因子信号抑制物(SOCS)-1、SOCS-3的蛋白表达水平,甲基化敏感性高分辨率熔解曲线分析(MS-HRM)检测DAC处理后SOCS-1、SOCS-3基因甲基化程度.结果 DAC可抑制HL-60细胞活性:0.2、0.5和1.0 μmol/L DAC处理48 h,HL-60细胞活性较对照组分别下降(25±11)%、(39±8)%和(50±7)%(P<0.01);48 h时,细胞凋亡发生率分别为(24.77±7.50)%、(27.10±4.48)%和(30.53±3.93)%,均较对照组细胞的(3.11±0.50)%增加(P<0.01).DAC可诱导HL-60细胞表面MICA/B、ULBP-1及ULBP-3分子的表达增高,增强HL-60细胞对NK细胞的杀伤敏感性.DAC处理后HL-60细胞内STAT3、JAK1、JAK2及p-STAT3、p-JAK1、p-JAK2表达下降,SOCS-1和SOCS-3蛋白表达增高.DAC可抑制SOCS-3基因甲基化.结论 DAC抑制人急性髓系白血病细胞株HL-60增殖,上调HL-60细胞对NKG2DL的表达,增强NK细胞对其的杀伤活性,其机制可能与细胞内JAK-STAT3-SOCS信号通路的活性调控有关.

Regulatory effect of decitabine on human acute myeloid leukemia cell line HL-60 and its mechanism

Objective To investigate the effect of decitabine (DAC) on human acute myeloid leukemia (AML) cell line HL-60 and the regulating of natural killer (NK) cell activating receptor (NKG2D) ligands(NKG2DL), and to detect the molecular mechanism of JAK-STAT3-SOCS signaling pathway. Methods The effect of DAC on the proliferation of HL-60 was detected by using CCK-8 assay. The cell apoptosis was analyzed by using Annexin-V/PI double standard method. The expressions of receptor NKG2DL including MICA/B and ULBPs in HL-60 cells were detected by using flow cytometry (FCM). The killing activity of NK cells was analyzed by using carboxy fluorescein diacetate succinimidyl ester (CFSE). The expressions of JAK/STAT3 signaling pathway or molecules including STAT3, its upstream kinases JAK1, JAK2 and the negative regulator of STAT3,SOCS-1,SOCS-3 were examined by Western blot.Methylation level of the SOCS-1,SOCS-3 gene after the treatment of DAC was analyzed by using methylation-sensitive high resolution melting(MS-HRM). Results There was an obvious inhibitory effect of DAC on HL-60 cells. The cell viability of HL-60 treated with 0.2, 0.5, and 1.0 μmol/L DAC for 48 h was decreased by (25±11) %, (39±8) % and (50±7)%(P<0.01)respectively compared with those cells without DAC treatment.The incidence of apoptosis was (24.77±7.50) %, (27.10±4.48) % and (30.53±3.93) % after DAC treatment for 48h respectively, which were higher than that of untreated cells(3.11±0.50)%](P<0.01).DAC induced a significant up-regulation of MICA/B, ULBP-1, ULBP-3 in HL-60 cells, and enhanced the sensitivity of HL-60 cells to NK cytotoxicity. Western blot results showed that a down-regulating expression of STAT3 and JAK1, JAK2 protein was detected, in addition to the phosphor-STAT3 and phosphor-JAKs in HL-60 cells after DAC treatment, but the expressions of SOCS-1 and SOCS-3 protein were increased. HRM results showed that DAC could inhibit the methylation of SOCS-3 gene. Conclusion DAC can inhibit the proliferation of HL-60 cells, upregulate the expression of NKG2DL and enhance the cytotoxicity of NK targeted to HL-60 cells, which might be related to the activity regulation of intracellular JAK-STAT3-SOCS signaling pathway.