Inhibition of Beclin-1-Mediated Autophagy by MicroRNA-17-5p Enhanced the Radiosensitivity of Glioma Cells.
Inhibition of Beclin-1-Mediated Autophagy by MicroRNA-17-5p Enhanced the Radiosensitivity of Glioma Cells.
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DOI：
10.3727/096504016x14719078133285
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发表时间：
2017-01-02
影响因子：
3.1
通讯作者：
Zhang S
中科院分区：
文献类型：
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作者：
Hou W;Song L;Zhao Y;Liu Q;Zhang S
mirna在胶质瘤细胞放射敏感性中的作用及其潜在机制尚不清楚。在本研究中，我们通过miRNA面板PCR检测到放疗后血清中与放疗前配对血清样本相比，有6个下调的miRNA和7个上调的miRNA。其中，miR-17-5p高度降低（倍数变化=−4.21）。此外，我们用qRT-PCR验证了所有血清样本中miR-17-5p的水平。此外，统计分析表明miR-17-5P水平的降低与胶质瘤的临床分期、复发发生率和肿瘤分化呈正相关。此外，我们提供的证据表明，在胶质瘤细胞系中，辐照显著激活自噬并降低miR-17-5p。此外，我们证明辐照诱导的自噬激活是由beclin-1介导的，通过siRNA下调beclin-1可显著消除辐照激活的自噬。有趣的是，我们通过荧光素酶基因报告实验证明了miR-17-5p可以直接靶向beclin-1。体外表达miRNA-17-5p可降低自噬活性。在裸鼠中，miRNA-17-5p上调使异种移植肿瘤对辐照敏感，并抑制辐照诱导的自噬。最后，药物抑制自噬可显著增强辐照对RR-U87细胞的细胞毒性。
The role of miRNAs in the radiosensitivity of glioma cells and the underlying mechanism is still far from clear. In the present study, we detected six downregulated and seven upregulated miRNAs in the serum after radiotherapy compared with paired serum samples before radiotherapy via miRNA panel PCR. Among these, miR-17-5p was highly reduced (fold change = −4.21). Further, we validated the levels of miR-17-5p in all serum samples with qRT-PCR. In addition, statistical analysis suggested that a reduced miR-17-5P level was positively associated with advanced clinical stage of glioma, incidence of relapse, and tumor differentiation. Moreover, we provided evidence that irradiation markedly activated autophagy and decreased miR-17-5p in the glioma cell line. Further, we demonstrated that irradiation-induced autophagy activation was mediated by beclin-1, and downregulation of beclin-1 via siRNA significantly abolished the irradiation-activated autophagy. Interestingly, we demonstrated that miR-17-5p could directly target beclin-1 via luciferase gene reporter assay. Exotic expression of miRNA-17-5p decreased autophagy activity in vitro. In nude mice, miRNA-17-5p upregulation sensitized the xenograft tumor to irradiation and suppressed irradiation-induced autophagy. Finally, pharmacal inhibition of autophagy markedly enhanced the cytotoxicity of irradiation in RR-U87 cells.