Department of Pain Care, Southwest Hospital, Army Medical University, Chongqing, PR China.
Eur Rev Med Pharmacol Sci. 2020 Mar;24(6):3204-3214. doi: 10.26355/eurrev_202003_20687.
Glioma is one of the most common and invasive brain tumors worldwide. Long non-coding RNAs (LncRNAs) play an important role in the development of glioma. However, the regulatory mechanism of LncRNAs in glioma has not been fully elucidated. This study aimed to explore the interaction of lncRNA maternally expressed gene 3 (MEG3) and aberrant histone modification in glioma.
The expression levels of MEG3 and miR-21-3p in glioma cells were measured by quantitative polymerase chain reaction (qPCR). EZH2 (enhancer of zeste homolog 2) and H3K27me3 expression in glioma cells were detected by Western Blot (WB). The binding site of the promoter of MEG3 by H3K27me3 was confirmed by ChIP-Real-time PCR. The direct target of MEG3 and miR-21-3p in glioma cells was measured by a luciferase reporter assay. Cell proliferation was detected by Cell Counting Kit-8 (CCK8), and cell invasion and migration were measured by Transwell assays.
EZH2 and miR-21-3p were upregulated and MEG3 was downregulated in glioma cells. Silencing of EZH2 inhibited cell proliferation, migration, and invasion in U87 and U251 cells. Meanwhile, the expression of H3K27me3 could be significantly inhibited by EZH2 interference. H3K27me3 protein can bind to MEG3 promoter directly. EZH2 inhibition and MEG3 down-expression in U87 cells reversed the effects of silencing of EZH2 on glioma cell growth and metastasis. However, EZH2 inhibition and MEG3 overexpression in U251 cells restricted cell proliferation, migration, and invasion. Furthermore, miR-21-3p was verified to interact with MEG3 by direct binding. Inhibition of MEG3 promoted U87 cell growth and metastasis, which was further strengthened following the co-transfection of si-MEG3 and miR-21-3p. Overexpressed MEG3 inhibited U251 cell growth and metastasis and a complete reversal of the results observed in the co-transfection of LV-MEG3 and miR-21-3p.
EZH2 was highly expressed in glioma cells and EZH2-mediated H3K27me3 enrichment on the MEG3 promoter regulated the growth and metastasis of glioma cells by targeting miR-21-3p. It potentially provided a new therapeutic marker targeting glioma.
神经胶质瘤是全世界最常见和最具侵袭性的脑肿瘤之一。长链非编码 RNA（lncRNA）在神经胶质瘤的发生发展中发挥着重要作用。然而，lncRNA 在神经胶质瘤中的调控机制尚未完全阐明。本研究旨在探讨 lncRNA 母系表达基因 3（MEG3）与神经胶质瘤中异常组蛋白修饰的相互作用。
采用实时定量聚合酶链反应（qPCR）检测神经胶质瘤细胞中 MEG3 和 miR-21-3p 的表达水平。采用 Western blot（WB）检测神经胶质瘤细胞中 EZH2（增强子的锌指蛋白 2）和 H3K27me3 的表达。采用染色质免疫沉淀-实时 PCR（ChIP-Real-time PCR）验证 MEG3 启动子与 H3K27me3 的结合位点。采用荧光素酶报告基因检测验证 MEG3 和 miR-21-3p 在神经胶质瘤细胞中的直接靶标。采用细胞计数试剂盒-8（CCK8）检测细胞增殖，Transwell 检测细胞侵袭和迁移。
EZH2 和 miR-21-3p 在神经胶质瘤细胞中上调，而 MEG3 下调。沉默 EZH2 可抑制 U87 和 U251 细胞的增殖、迁移和侵袭。同时，EZH2 干扰可显著抑制 H3K27me3 的表达。H3K27me3 蛋白可直接结合 MEG3 启动子。EZH2 抑制和 MEG3 在 U87 细胞中的下调逆转了 EZH2 对神经胶质瘤细胞生长和转移的抑制作用。然而，EZH2 抑制和 MEG3 在 U251 细胞中的过表达限制了细胞的增殖、迁移和侵袭。此外，miR-21-3p 被证实可通过直接结合与 MEG3 相互作用。沉默 MEG3 可促进 U87 细胞的生长和转移，而 si-MEG3 与 miR-21-3p 的共转染则进一步增强了这种作用。过表达 MEG3 可抑制 U251 细胞的生长和转移，并且完全逆转了 LV-MEG3 与 miR-21-3p 共转染时观察到的结果。
EZH2 在神经胶质瘤细胞中高表达，EZH2 介导的 H3K27me3 富集在 MEG3 启动子上，通过靶向 miR-21-3p 调节神经胶质瘤细胞的生长和转移。这为神经胶质瘤的治疗提供了新的靶点。
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