PDCD5蛋白对地塞米松诱导的多发性 骨髓瘤细胞凋亡的影响及机制初探

目的：观测程序化细胞死亡分子5（programmed cell death 5,PDCD5）表达蛋白对地塞米松诱导人多发性骨髓瘤（multiple myeloma， MM）细胞（KM3）凋亡的影响，并探讨其作用机制。方法：将不同浓度的重组人程序化细胞死亡分子5 (human recombinant PDCD5, rhPDCD5)蛋白单独或/和地塞米松（dexamethasone,DXM）同时加入处于对数生长期的KM3细胞,共同培养一段时间，收集细胞后行以下检测：（1）Annexin V-FITC & PI双染法应用流式细胞术（flowcytometry，FCM）检测KM3细胞凋亡率；（2）蛋白免疫印迹方法检测KM3细胞中caspase-3活性；（3）免疫细胞化学法检测KM3细胞survivin蛋白表达。结果：KM3细胞凋亡率，在rhPDCD5和DXM联用组较单用组明显增加，且浓度较高PDCD5蛋白组作用更明显。KM3细胞caspase-3蛋白活性，在rhPDCD5和DXM联用组较单用组明显上调，高浓度PDCD5蛋白组（20 mg/L）的caspase-3活化较低浓度 (10 mg/L)组明显。KM3细胞survivin蛋白表达，在rhPDCD5和DXM联用组较单用组表达明显下调，并且浓度较高的PDCD5蛋白组survivin表达下调更明显。结论：PDCD5蛋白可直接作用于多发性骨髓瘤细胞使细胞凋亡，并对地塞米松诱导的KM3细胞凋亡有明显的促进作用。PDCD5蛋白可能通过激活caspase-3和下调survivin蛋白表达发挥其促进多发性骨髓瘤细胞凋亡的作用。

Effect of human recombinant PDCD5 protein on cell apoptosis of multiple myeloma KM3 cells induced by dexamethasone and its mechanism

ObjectiveTo observe the effect of programmed cell death 5 (PDCD5) protein on the apoptosis of multiple myeloma KM3 cells induced by dexamethasone and to understand its mechanism. MethodsThe human recombinant PDCD5 (rhPDCD5) protein was added (alone of different concentrations or associated with dexamethasone) into KM3 cells. Cultured together for certain time, the cells were collected for the following experiments:(1)The effect of rhPDCD5 protein and dexamethasone on the apoptotic rate of KM3 cells was determined by flowcytometry (FCM)analysis after the cells were stained by Annexin V-FITC & PI (propidium iodide).(2) Caspase-3 activity of KM3 cells was evaluated by Western blot. (3)The expression of survivin protein in KM3 cells was detected by immunocytochemistry. ResultsThe apoptotic rate of KM3 cells and the activity of caspase-3 increased significantly, and that treated with rhPDCD5 protein and dexamethasone was higher than that treated with rhPDCD5 protein only. The expression of survivin protein in the rhPDCD5 with dexemethas group was down-regulated, and with the concentration of rhPDCD5 and dexamethasone increasing,the changes was more obviously. ConclusionPDCD5 protein can induce the apoptosis of KM3 cells, and accelerate the apoptosis of KM3 cells induced by dexamethasone. PDCD5 protein may reduce the expression of survivin protein and increase activation of caspase-3 to play its role in promoting apoptosis.