Department of Neurosurgery, First Affiliated Hospital of China Medical University, Shenyang, 110001, Liaoning, China.
Department of Cardiac Surgery, First Affiliated Hospital of China Medical University, Shenyang, 110001, Liaoning, China.
J Exp Clin Cancer Res. 2019 Aug 16;38(1):358. doi: 10.1186/s13046-019-1370-1.
MicroRNAs (miRNAs) play crucial roles in tumor initiation and development. Previously, we indicated that miR-504 is downregulated and suppresses tumor proliferation in glioblastoma (GBM). However, the regulation and relevant mechanism of miR-504 in GBM mesenchymal (ME) transition remain unclear.
Transcriptome and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. The potential functions of miR-504 were predicted using gene ontology analysis. GBM cell migration and invasion were examined using wound healing and Transwell assays. Epithelial-mesenchymal transition (EMT) progression in GBM cell lines was detected with immunofluorescence and western blotting. The stemness activity of glioma stem-like cells (GSCs) was assessed by sphere formation assay and tumor xenograft model. miR-504 binding to the FZD7 (frizzled class receptor 7) 3' untranslated region (3'UTR) was validated using dual luciferase reporter assay. TOP/FOP Flash assays were conducted to determine the effects of miR-504 on Wnt/β-catenin signaling.
Analysis of TCGA transcriptomic data showed that low miR-504 expression correlated with ME subtype transition and poor survival in patients with GBM. Functional experiments showed that miR-504 overexpression suppressed malignant behaviors of GBM cells, such as migration, invasion, EMT, and stemness activity. Furthermore, miR-504 was a negative regulator of the Wnt-β-catenin pathway by directly repressing FZD7 expression, and FZD7 overexpression reversed the EMT inhibition caused by miR-504. Moreover, the low miR-504/FZD7 expression ratio was a ME subtype marker and could serve as a significant prognostic indicator and predict the clinical outcome of chemotherapy and radiotherapy for patients with GBM in TCGA dataset.
Our results suggest that miR-504 suppresses the aggressive biological processes associated with the ME phenotype of GBM and could be a potential candidate for therapeutic applications in these malignant brain tumors.
MicroRNAs（miRNAs）在肿瘤的发生和发展中起着至关重要的作用。此前，我们表明 miR-504 下调并抑制胶质母细胞瘤（GBM）中的肿瘤增殖。然而，miR-504 在 GBM 间质（ME）转化中的调控及其相关机制尚不清楚。
从 The Cancer Genome Atlas（TCGA）数据库中获取转录组和临床数据。使用基因本体分析预测 miR-504 的潜在功能。通过划痕愈合和 Transwell 测定检查 GBM 细胞迁移和侵袭。使用免疫荧光和 Western blot 检测 GBM 细胞系中的上皮-间质转化（EMT）进展。通过球体形成测定和肿瘤异种移植模型评估神经胶质瘤干细胞（GSCs）的干性活性。使用双荧光素酶报告基因测定验证 miR-504 与 FZD7（卷曲受体 7）3'非翻译区（3'UTR）的结合。进行 TOP/FOP Flash 测定以确定 miR-504 对 Wnt/β-catenin 信号的影响。
TCGA 转录组数据分析表明，miR-504 表达水平低与 GBM 中的 ME 亚型转化和不良预后相关。功能实验表明，miR-504 过表达抑制了 GBM 细胞的恶性行为，如迁移、侵袭、EMT 和干性活性。此外，miR-504 通过直接抑制 FZD7 表达成为 Wnt-β-catenin 通路的负调节剂，而 FZD7 过表达逆转了 miR-504 引起的 EMT 抑制。此外，miR-504/FZD7 表达比值低是 ME 亚型标志物，可作为 TCGA 数据集 GBM 患者化疗和放疗临床结局的显著预后指标和预测因子。
我们的研究结果表明，miR-504 抑制与 GBM 的 ME 表型相关的侵袭性生物学过程，可能成为这些恶性脑肿瘤治疗应用的潜在候选物。
