核糖核苷酸还原酶小亚基M2在多发性骨髓瘤患者中的表达及抑制肿瘤细胞增殖的相关机制

Expression of Ribonucleotide Reductase M2 in Patients with Multiple Myeloma and Its Mechanism Inhibiting Tumor Cell Proliferation

目的:探讨核糖核苷酸还原酶小亚基M2(ribonucleotide reductase M2,RRM2)在多发性骨髓瘤细胞中的表达及抑制肿瘤细胞增殖的相关机制。方法:选取2016年7月至2018年9月在本院初诊的多发性骨髓瘤患者36例为MM组,选取同期纯缺铁性贫血的患者16例作为对照组。应用RT-qPCR、Western blot检测所收集病例中骨髓单个核细胞内RRM2的表达。用siRNAs转染多发性骨髓瘤细胞株RPMI8226建立RRM2表达缺失的细胞模型,并用CCK8检测细胞的增殖,流式细胞术分析敲低RRM2表达对细胞周期的影响,并应用Western blot分析周期相关调控蛋白的变化。结果:RT-qPCR及Western blot结果显示,多发性骨髓瘤患者样品中的RRM2相对表达水平比对照组明显升高(P<0.05)。进一步分析证明,多发性骨髓瘤患者单个核细胞中RRM2的表达量与临床肿瘤分期、骨质破坏及髓外浸润等关系密切(P<0.05)。在多发性骨髓瘤细胞株内,利用siRNA干扰下调RPMI8226细胞内RRM2蛋白表达,可以明显抑制RPMI8226细胞的增殖能力;流式细胞术检测细胞周期的结果发现,RRM2干扰组细胞周期阻滞于S期(P<0.05);进一步的研究证明,RRM2干扰可以影响细胞周期调控相关蛋白的表达。结论:RRM2在多发性骨髓瘤单个核细胞内呈高表达,且与患者肿瘤恶性程度密切相关。干扰细胞内RRM2表达可通过阻滞细胞周期抑制细胞增殖。RRM2可能成为评估多发性骨髓瘤进展的新指标及药物开发的新靶点。

Objective:To investigate the expression of ribonucleotide reductase M2(RRM2)in patients with multiple myeloma and its mechanism of inhibiting human multiple myeloma cell proliferation.Methods:Thirty-Six patients with multiple myeloma in our hospital from July 2016 to September 2018 were selected as MM group,at the same time simple iron deficiency anemia patients were taken as the control group.RT-qPCR and Western blot techniques were used to determine the mRNA and protein expression of RRM2 in bone marrow mononuclear cells,respectively.siRNAs oligos targeting RRM2 was transfected into RPMI8226 cells to establish the RRM2 silence model.CCK-8 and flow cytometry were used to analyze the cell proliferation and the cell cycle,and Western blot was used to detect the expression of cell cycle related proteins.Results:The expression level of RRM2 mRNA and the expression level of RRM2 protein in multiple myeloma group were significantly higher than those in control group(P<0.05).Further analysis indicated that the level of RRM2 expression closely correlated with ISS staging,bone destruction and extramedullary infiltration(P<0.05).Transfection with siRNAs targeting RRM2 could significantly down regulate the RRM2 expression.And the RRM2 down regulation inhibited the cell proliferation and arrested the cell cycle at S stage(P<0.05).Further study indicated that RRM2 silencing influenced cell cycle-related proteins expression.Conclusion:RRM2 overexpressies in bone marrow mononuclear cells of MM patients,moreover significantly relates with the degree of malignancy.The silencing RRM2 in multiple myeloma cells can inhibit cell proliferation through arresting cell cycle at S phase.RRM2 may be a marker to predict the prognosis of patients with multiple myeloma and novel target for new drug development.