MiR-124 governs glioma growth and angiogenesis and enhances chemosensitivity by targeting R-Ras and N-Ras
MiR-124 governs glioma growth and angiogenesis and enhances chemosensitivity by targeting R-Ras and N-Ras
复制标题
MiR-124 控制神经胶质瘤生长和血管生成，并通过靶向 R-Ras 和 N-Ras 增强化疗敏感性。
DOI：
10.1093/neuonc/nou084
复制
发表时间：
2014-10-01
期刊：
影响因子：
15.9
通讯作者：
Jiang, Bing-Hua
中科院分区：
文献类型：
--
作者：
Shi, Zhumei;Chen, Qiudan;Jiang, Bing-Hua
背景。胶质瘤是最具侵袭性和致命性的人类脑肿瘤之一。越来越多的证据表明，microrna在包括神经胶质瘤在内的癌症中发挥着重要作用。先前的研究报道了在胶质瘤标本中miR-124水平下调。在这里，我们进一步研究了miR-124在胶质瘤中的潜在作用。通过定量逆转录酶PCR检测miR-124在胶质瘤标本中的表达水平。通过生物信息学分析鉴定miR-124的直接靶点，并通过免疫印迹和荧光素酶报告基因试验进一步验证。通过cell - counting Kit 8分析miR-124对胶质瘤细胞增殖和替莫唑胺化学敏感性的影响。荧光活化细胞分选法检测细胞凋亡。采用异种移植瘤模型研究miR-124对肿瘤生长和血管生成的影响。在胶质瘤标本中，miR-124的表达水平显著下调。相关Ras病毒癌基因同源物（R-Ras）和神经母细胞瘤Ras病毒癌基因同源物（N-Ras）被确定为miR-124的直接靶点。MiR-124通过负调控Ras家族及其下游信号通路：磷脂酰肌醇-3激酶/Akt和Raf/细胞外信号调节激酶1/2，抑制胶质瘤细胞的生长、侵袭、血管生成和肿瘤生长，并增加对替唑胺治疗的化学敏感性。此外，R-Ras的过表达恢复了miR-124的抑制作用。同时，R-Ras和N-Ras的过表达恢复了mir -124抑制的血管内皮生长因子（VEGF）转录激活。在临床胶质瘤标本中，R-Ras和N-Ras蛋白水平上调，并与miR-124表达水平呈负相关。综上所述，这些结果揭示了肿瘤组织中miR-124水平与胶质瘤的发生、血管生成和化疗耐药相关，miR-124可能在未来作为胶质瘤新的诊断标志物和治疗靶点。
Background. Glioma is one of the most aggressive and lethal human brain tumors. Accumulating evidence shows that microRNAs play important roles in cancers, including glioma. Previous studies reported that miR-124 levels were downregulated in glioma specimens. Here, we further investigate the potential role of miR-124 in glioma.Methods. The expression levels of miR-124 were detected in glioma specimens by quantitative reverse transcriptase PCR. The direct targets of miR-124 were identified by bioinformatics analysis and were further validated by immunoblotting and luciferase reporter assay. The effects of miR-124 on glioma cell proliferation and chemosensitivity to temozolomide were analyzed by Cell-Counting Kit 8 assay. Apoptosis was evaluated by fluorescence activated cell sorting analysis. A xenograft model was used to study the effect of miR-124 on tumor growth and angiogenesis.Results. Expression levels of miR-124 were greatly downregulated in glioma specimens. related Ras viral oncogene homolog (R-Ras) and neuroblastoma Ras viral oncogene homolog (N-Ras) were identified as direct targets of miR-124. MiR-124 inhibited glioma cell growth, invasion, angiogenesis, and tumor growth and increased chemosensitivity to temozolomide treatment by negatively regulating the Ras family and its downstream signaling pathways: phosphatidylinositol-3 kinase/Akt and Raf/extracellular signal-regulated kinase 1/2. Furthermore, overexpression of R-Ras rescued the inhibitory effects of miR-124. Meanwhile, overexpression of R-Ras and N-Ras restored miR-124-inhibited vascular endothelial growth factor (VEGF) transcription activation. In clinical glioma specimens, protein levels of R-Ras and N-Ras were upregulated and inversely correlated with miR-124 expression levels.Conclusions. Taken together, these results revealed that miR-124 levels in tumor tissues are associated with glioma occurrence, angiogenesis, and chemoresistance and that miR-124 may be used as a new diagnostic marker and therapeutic target for glioma in the future.