Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany.
Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
Neuropathol Appl Neurobiol. 2019 Aug;45(5):441-458. doi: 10.1111/nan.12532. Epub 2019 Feb 19.
Aberrant expression of microRNAs (miRNAs) is frequent in various cancers including gliomas. We aimed to characterize the role of miR-16-5p as a candidate tumour suppressor miRNA in gliomas.
Real-time PCR-based approaches were used for miRNA and mRNA expression profiling of glioma and non-neoplastic brain tissues as well as glioma cell lines. Protein levels were determined by Western blotting. In vitro analyses were performed following overexpression of miR-16-5p, trichostatin A (TSA) treatment, and siRNA-mediated knock-down of HDAC3 in glioma cells. Effects of miR-16-5p on glioma cell viability, apoptosis and response to irradiation and temozolomide (TMZ) were assessed.
Expression of miR-16-5p was reduced relative to control brain tissue in isocitrate dehydrogenase (IDH)-mutant astrocytomas of World Health Organization (WHO) grades II, III and IV, and a subset of IDH-wildtype glioblastomas WHO grade IV. MiR-16-5p expression was lower in IDH-mutant than in IDH-wildtype gliomas, and down-regulated in IDH-wildtype glioma lines. MiR-16-5p overexpression reduced expression of important cell cycle and apoptosis regulators in glioma cells, including CDK6, CDC25A, CCND3, CCNE1, WEE1, CHEK1, BCL2 and MCL1. In line, CDK6, WEE1, CHEK1, BCL2 and MCL1 transcript levels were increased in WHO grade III or IV gliomas. TSA treatment and HDAC3 knockdown in glioma cells induced miR-16-5p up-regulation and reduced expression of its targets. Moreover, miR-16-5p overexpression inhibited proliferation and induced apoptosis in various glioma cell lines and increased sensitivity of A172 glioma cells to irradiation and TMZ.
Reduced expression of miR-16-5p contributes to glioma cell proliferation, survival and resistance to cytotoxic therapy.
微小 RNA（miRNA）的异常表达在包括神经胶质瘤在内的各种癌症中很常见。我们旨在将 miR-16-5p 鉴定为神经胶质瘤中的候选肿瘤抑制 miRNA。
使用实时 PCR 方法对神经胶质瘤和非神经组织以及神经胶质瘤细胞系进行 miRNA 和 mRNA 表达谱分析。通过 Western blot 确定蛋白水平。在神经胶质瘤细胞中转染 miR-16-5p、曲古抑菌素 A（TSA）处理和 HDAC3 siRNA 敲低后进行体外分析。评估 miR-16-5p 对神经胶质瘤细胞活力、凋亡以及对辐射和替莫唑胺（TMZ）的反应的影响。
与对照脑组织相比，异柠檬酸脱氢酶（IDH）突变型星形细胞瘤的 WHO 分级 II、III 和 IV 级以及部分 IDH 野生型胶质母细胞瘤 WHO 分级 IV 级的 miR-16-5p 表达降低。IDH 突变型神经胶质瘤中的 miR-16-5p 表达低于 IDH 野生型神经胶质瘤，且 IDH 野生型神经胶质瘤系中的 miR-16-5p 表达下调。miR-16-5p 的过表达降低了神经胶质瘤细胞中重要的细胞周期和凋亡调节因子的表达，包括 CDK6、CDC25A、CCND3、CCNE1、WEE1、CHEK1、BCL2 和 MCL1。同样，WHO 分级 III 或 IV 级神经胶质瘤中 CDK6、WEE1、CHEK1、BCL2 和 MCL1 的转录水平升高。TSA 处理和 HDAC3 在神经胶质瘤细胞中的敲低诱导 miR-16-5p 的上调并降低其靶标表达。此外，miR-16-5p 的过表达抑制了各种神经胶质瘤细胞系的增殖并诱导了凋亡，并增加了 A172 神经胶质瘤细胞对辐射和 TMZ 的敏感性。
miR-16-5p 的表达降低有助于神经胶质瘤细胞的增殖、存活和对细胞毒性治疗的耐药性。
