Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China.
Department of Laboratory Medicine, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China.
PLoS One. 2021 Jul 1;16(7):e0253522. doi: 10.1371/journal.pone.0253522. eCollection 2021.
Glioma is the most common and lethal form of brain cancer. It is highly malignant and is often characterized by chemoresistance and radioresistance, which are thought to mainly result from hypoxic microenvironments. Various tumour-promoting and tumour-suppressing microRNAs (miRNAs) have been identified in gliomas; however, it is still largely unknown how miRNAs are modified by hypoxia and subsequently affect glioma. In this study, we examined the expression of miR-210-3p, a well-characterized miRNA that responds to hypoxia in glioma cell lines.
The expressions of miR-9 and miR-210-3p were analysed by using qPCR. Cell viability was measured by performing CCK-8 after eechinomycin treatment or introduction of miR-210 for 24 or 48 h. The correlation of HIF-1α expression with TGF-β were analysed using the REMBRANDT database. The biomarkers of EMT, including E-cadherin, N-cadherin and Vimentin, were detected by western blot. Apoptotic cell death was measured by performing Annexin V-FITC/PI double staining followed by flow cytometry.
We found that miR-210-3p was induced by a mechanism dependent on the hypoxia-induced transcriptional activity of HIF-1α. Then we established a positive association between the HIF-1α and TGF-β expression levels, and miR-210-3p upregulation induced TGF-β expression, indicating that hypoxia-induced HIF-1α activity upregulated TGF-β via miR-210-3p upregulation. Hypoxia-induced miR-210-3p activity was found to promote EMT by upregulating TGF-β, which subsequently enhanced the invasive ability in U87-MG cells. We further confirmed that miR-210-3p induced chemoresistance to TMZ in U87-MG cells via TGF-β upregulation under hypoxic conditions.
These results help to reveal the potential regulatory mechanisms of hypoxia-induced miR-210-3p expression that affect malignant behaviors and chemoresistance via TGF-β upregulation in glioma cells.
脑胶质瘤是最常见和最致命的脑癌形式。它高度恶性，通常表现出化学抗性和放射抗性，这主要被认为是由于缺氧微环境造成的。在脑胶质瘤中已经鉴定出各种促进肿瘤和抑制肿瘤的 microRNAs（miRNAs）；然而，miRNAs 如何受到缺氧的修饰以及随后如何影响脑胶质瘤仍然很大程度上未知。在这项研究中，我们检查了 miR-210-3p 的表达，miR-210-3p 是一种在脑胶质瘤细胞系中对缺氧有反应的特征明确的 miRNA。
通过 qPCR 分析 miR-9 和 miR-210-3p 的表达。在用 echimomycin 处理或转染 miR-210 24 或 48 小时后，通过 CCK-8 测量细胞活力。使用 REMBRANDT 数据库分析 HIF-1α 表达与 TGF-β 的相关性。通过 Western blot 检测 EMT 的生物标志物，包括 E-cadherin、N-cadherin 和 Vimentin。通过 Annexin V-FITC/PI 双重染色后进行流式细胞术测量凋亡细胞死亡。
我们发现 miR-210-3p 的诱导是一种依赖于 HIF-1α 缺氧诱导的转录活性的机制。然后，我们建立了 HIF-1α 和 TGF-β 表达水平之间的正相关关系，并且 miR-210-3p 的上调诱导了 TGF-β 的表达，表明缺氧诱导的 HIF-1α 活性通过 miR-210-3p 的上调上调了 TGF-β 的表达。发现缺氧诱导的 miR-210-3p 活性通过上调 TGF-β 促进 EMT，从而增强 U87-MG 细胞的侵袭能力。我们进一步证实，在缺氧条件下，miR-210-3p 通过上调 TGF-β 诱导 U87-MG 细胞对 TMZ 的化学抗性。
这些结果有助于揭示缺氧诱导的 miR-210-3p 表达影响恶性行为和化学抗性的潜在调节机制，该机制通过 TGF-β 在脑胶质瘤细胞中的上调。
