中文摘要：

目的检测CBX7在人神经胶质瘤中的表达,研究人神经胶质瘤中异常表达的microRNA对CBX7的可能调控作用。方法采用半定量逆转录聚合酶链反应（RT-PCR）和Western blot检测2例正常脑组织、9例胶质瘤组织和3株胶质瘤细胞系中CBX7mRNA和蛋白水平的表达变化。结合Miranda和改良的机器学习法预测调控CBX7的miRNA。采用real-time PCR检测上述组织和细胞系中miR-9的表达,然后在细胞中过表达或敲低miR-9,结合荧光素酶实验和Western blot检测miR-9对CBX7表达的影响。采用MTT实验和流式细胞术分析miR-9敲低后对T98G细胞生长的影响。结果在胶质瘤组织和细胞系中,CBX7的mRNA水平改变不明显,而蛋白水平却明显下调。生物信息学预测CBX7可能受包括miR-9在内的多个miRNAs调控。与正常组织相比,miR-9在胶质瘤中表达明显增高。在293ET细胞中,过表达miR-9能抑制CBX7-3UTR报告基因活性。在T98G细胞中,敲低miR-9可增加CBX7-3UTR报告基因活性,对内源性CBX7的mRNA水平无明显影响,但使CBX7蛋白表达增加。敲低miR-9后,T98G存活细胞数增加,而且G1期细胞数比对照组明显减少。结论由于受到miR-9转录后水平的抑制,CBX7在人神经胶质瘤中表达下调甚至缺失。

英文摘要：

Objective To detect the expression of CBX7 in human glioma and investigate the potential regulatory effect of abnormally expressed microRNAs on CBX7 expression. Methods Semi-quantitative reverse transcription polymerase chain reaction （RT-PCR） and Western blot were applied to detect the expression pattern of CBX7 in 2 human normal brain tissues, 9 glioma tissues, and 3 glioma cell lines. Miranda algorithm and Ensemble Machine Learning algorithm were combined to predict miRNAs that target human CBX7. The expression of miR-9 in those tissues and cell lines were detected by real-time PCR. After miR-9 overexpression in 293ET and miR-9 knock-down in T98G, luciferase assay and Western blot were used to confirm the effect of miR-9 on CBX7 expression. MTr assay and flow cytometry were applied to detect the effect of miR-9 knockdown on T98G cells. Results No obvious difference in the CBX7 mRNA level between normal and tumor tissues was observed, while the protein level of CBX7 was abrogated or markedly reduced in glioma tissues and cell lines. Several miRNAs including miR-9 may target CBX7 by bioinformatics prediction. MiR-9 was up-regulated in glioma tissues and cell lines. In 293ET cell, luciferase activity of CBX7-3＇UTR reporter was decreased to 24% after miR-9 overexpression. After miR-9 knock-down in T98G cell, the luciferase activity was increased by 1.8 fold and there was no change of CBX7 mRNA, while the protein level of endogenous CBX7 was significantly increased. The number of survival T98G cells increased and cells in G1 phase decreased after miR-9 knock-down. Conclusion In human glioma, CBX7 is down-regulated by the inhibition of miR-9 at posttranscriptional level.