miR-221在脑胶质瘤中的表达及调控关系

Expression of miRNA-221 in brain gliomas and its effects on glioma cell line poliferation

目的探讨miR-221在脑胶质瘤组织中的表达变化及其对胶质瘤细胞系细胞增殖的影响。方法收集2014年1月至2015年8月手术切除的胶质瘤标本123例及颅脑损伤行内减压的正常脑组织36例,荧光定量PCR法检测miR-221表达水平。按照miR-221的表达水平将123例胶质瘤病人分为高表达组(miR-221/U6的相对表达量≥0.6,72例)和低表达组(miR-221/U6的相对表达量<0.6,51例),采用Kplan-Meier法分析miR-221表达水平与胶质瘤生存时间的关系。MTT法检测miR-221对胶质瘤细胞系U251、U87细胞增殖的影响,双荧光试验和蛋白印迹法、PCR方法筛选和验证miR-221的靶基因。结果胶质瘤组织miR-221表达水平明显高于正常脑组织(P<0.01);高级别胶质瘤miR-221表达水平明显低于低级别胶质瘤(P<0.01)。miR-221低表达胶质瘤病人生存时间较高表达病人明显延长(P<0.05)。敲除miR-221基因显著抑制U251、U87细胞增殖(P<0.01);而且,U251、U87细胞敲除miR-221基因后,正性调节区锌指蛋白2(PRDM2)mRNA和蛋白表达水平明显增高(P<0.01)。结论miR-221在胶质瘤中异常高表达,可作为胶质瘤预后判断的生物标志物;PRDM2可能是miR-221的靶基因。

Objective To explore the expression of miRNA-221 in human gliomas and its effect on glioma cell line proliferation. Methods The expression levels of miRNA-221 were determined by qRT-PCR in 123 samples of glioma tissues and 36 samples of normal cerebral tissues. The effects of miRNA-221 on U87 and U251 cell proliferation were determined by MIT tests. Dual luciferase assay, qRT-PCR and western blot were used to validate the targets of miRNA-221. Results The expression level of miRNA-221 （0.62± 0.2） was significantly higher in the glioma tissues than that （0.37±0.13） in the normal cerebral tissues （P〈0.01）. The survival time was significantly shorter in 72 glioma patients with higher expression of miRNA-221 than that in 51 glioma patients with lower expression of miRNA-221 after the operation （P〈0.01）. The over expression of miRNA-221 significantly promoted U251 and U87 cells proliferations （P〈0.05）. The depletion of miRNA-221 caused the increases in mRNA and protein of PRDM2 expressions （P〈0.05） in the U251 and U87 cells. Conclusions The upregulation of miRNA-221 may be used as one of diagnostic indexes of human glioma. PRDM2 is one of target genes of miRNA-221.