过表达程序性细胞死亡基因5 提高脑神经胶质瘤细胞对替莫唑胺的化疗敏感性

摘要] 目的：探讨抑癌基因程序性细胞死亡基因5（programmed cell death 5 gene, PDCD5）对脑神经胶质瘤细胞增殖及替莫唑胺（temozolomide,TMZ）化疗敏感性的影响。方法：收集吉林大学第一临床医院神经外科2009 年1 月至2014 年12 月间收治的脑神经胶质瘤患者116 例。分别利用qPCR、WB及免疫组化方法检测神经胶质瘤细胞系U87、U251、稳定克隆U87-PDCD5 细胞、转染si-PDCD5 后的脑胶质瘤细胞以及原发性神经胶质瘤组织中PDCD5 mRNA及蛋白质的表达情况。MTT法检测过表达或敲降PDCD5 对胶质瘤细胞生长及TMZ化疗敏感性的影响。建立脑胶质瘤细胞系U87 裸鼠皮下荷瘤模型,随机分为对照组、TMZ组、PDCD5 组和TMZ+外源性PDCD5 重组表达载体联合组,治疗20 d 后断颈处死动物,切取瘤组织,测量瘤体积并称瘤质量。采用qPCR、WB 法检测移植瘤组织中PDCD5 的表达水平,分析PDCD5 联合TMZ 治疗对脑神经胶质瘤生长的影响。结果：PDCD5 mRNA和蛋白在U87 细胞中的相对表达量明显低于在U251 细胞中的相对表达量（均P<0.05）;在高级别脑神经胶质瘤组织中,PDCD5 mRNA和蛋白的表达明显低于低级别组织（均P<0.05）;U87-PDCD5 和U251 细胞对TMZ的敏感性均高于U87 细胞（均P<0.05）,U87-PDCD5-siRNA、U251-siRNA 组细胞对TMZ的敏感性均明显低于对照组（均P<0.05）。比较裸鼠移植瘤的瘤体积和质量,对照组>TMZ组>PDCD5 组>联合组（均P<0.05）;各组移植瘤组织内PDCD5 mRNA及蛋白的表达水平趋势与之相反（均P<0.05）。结论：PDCD5 过表达可增强脑神经胶质瘤细胞对TMZ的化疗敏感性,而沉默PDCD5 表达作用则相反,PDCD5 与TMZ联合应用可更好地抑制脑神经胶质瘤裸鼠移植瘤的生长。

Over-expression of programmed cell death 5 gene enhances chemosensitivity of brain glioma cells to temozolomide

Abstract] Objective: To explore the role of tumor suppressor gene programmed cell death 5 gene (PDCD5) in the growth and temozolomide (TMZ) sensitivity of brain glioma cells. Methods: A total of 116 patients with cerebral glioma admitted to the Department of Neurosurgery, First Clinical Hospital of Jilin University from January 2009 to December 2014 were enrolled in this study. QPCR, WB and immunohistochemistry method were used to detect the mRNA and protein expressions of PDCD5 in glioma cell lines (U87, U251),U87 cell line with stable PDCD5 expression (U87-PDCD5), glioma cells with si-PDCD5 transfection and primary cerebral glioma tissues,respectively. MTT assay was used to detect the effect of over-expression or knockdown of PDCD5 on the growth and TMZ-sensitivity of glioma cells. The subcutaneous tumor-bearing model of glioma cell line U87 was established in nude mice, and then the experimental mice were randomly divided into control group, TMZ group, PDCD5 group and TMZ+exogenous PDCD5 recombinant expres-sion vector group. After 20 days, the animals were sacrificed by cervical dislocation and the tumor tissue was excised to measure the tumor volume and weigh. The expression of PDCD5 in tumor tissues was detected by qPCR and WB methods, and the effects of PDCD5 combined with TMZ on the growth of gliomas were also analyzed. Results: The relative mRNA and protein expressions of PDCD5 in U87 cells were significantly lower than those in U251 cells (both P<0.05), and the mRNA and protein expressions of PDCD5 in high level glioma tissues were significantly lower than those in low level tissues (all P<0.05). The sensitivity of U87-PDCD5 cells and U251 cells to TMZ was higher than that of U87 cells (all P<0.05). The sensitivity of cells to TMZ in U87-PDCD5-siRNA group and U251-siRNA group was significantly lower than that of the control group (both P<0.05). The tumor volume and weight of nude mice xenografts were compared, and the results showed control group>TMZ group>PDCD5 group>combined group (all P<0.05); however, the mRNAand protein expressions of PDCD5 in the transplanted tumor tissues of each group showed the opposite trend (all P<0.05). Conclusion:PDCD5 over-expression can enhance the chemosensitivity of brain glioma to the chemotherapy drug TMZ, while silencing of PDCD5 expression exerts the opposite effect.Thecombination of PDCD5 and TMZ can better inhibit the growth of xenografts in nude mice.