Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Department of Thoracic Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Int J Oncol. 2019 Sep;55(3):745-754. doi: 10.3892/ijo.2019.4841. Epub 2019 Jul 15.
The long non‑coding RNA nuclear enriched abundant transcript 1 (NEAT1) has important roles in the regulation of multiple cell functions, such as proliferation, apoptosis and migration. However, the mechanism by which NEAT1 regulates breast cancer progression is not well elucidated. In the present study, NEAT1 and microRNA‑124 (miR‑124) levels were detected by reverse transcription‑quantitative PCR in breast cancer tissues and cell lines. STAT3 protein levels were detected by western blot analysis. Cell proliferation and cell cycle distribution were determined using MTT and colony formation assays, and flow cytometry, respectively. The results demonstrated that NEAT1 and STAT3 expression levels were increased in breast cancer tissues compared with normal breast tissues, whereas miR‑124 expression was significantly decreased. Functional analyses revealed that NEAT1 promoted cell proliferation and cell cycle progression in breast cancer cells. Additionally, NEAT1 and STAT3 expression levels were negatively correlated with miR‑124 levels in breast cancer tissues. A direct interaction between miR‑124, and NEAT1 and STAT3, was predicted by bioinformatics analysis and confirmed using a luciferase activity assay. NEAT1 overexpression markedly increased STAT3 protein expression levels, and this effect was reversed by miR‑124 overexpression in breast cancer cells. Furthermore, miR‑124 overexpression partially attenuated the effects of NEAT1 on breast cancer cell proliferation and cell cycle progression. The inhibitory effects of miR‑124 overexpression on the proliferation rate and cell cycle progression were abolished by STAT3 overexpression. In turn, STAT3 silencing inhibited NEAT1 transcription in breast cancer cells. In summary, the present findings revealed that NEAT1 and STAT3 formed a feedback loop via sponging miR‑124 to promote breast cancer progression.
长链非编码 RNA 核丰富丰富转录物 1（NEAT1）在调节多种细胞功能（如增殖、凋亡和迁移）方面发挥着重要作用。然而，NEAT1 调节乳腺癌进展的机制尚未阐明。在本研究中，通过逆转录-定量 PCR 检测乳腺癌组织和细胞系中的 NEAT1 和 microRNA-124（miR-124）水平。通过 Western blot 分析检测 STAT3 蛋白水平。通过 MTT 和集落形成测定法分别检测细胞增殖和细胞周期分布，通过流式细胞术检测细胞周期分布。结果表明，与正常乳腺组织相比，乳腺癌组织中 NEAT1 和 STAT3 的表达水平升高，而 miR-124 的表达水平显著降低。功能分析表明，NEAT1 促进乳腺癌细胞的增殖和细胞周期进程。此外，乳腺癌组织中 NEAT1 和 STAT3 的表达水平与 miR-124 的水平呈负相关。通过生物信息学分析预测了 miR-124 与 NEAT1 和 STAT3 之间的直接相互作用，并通过荧光素酶活性测定进行了验证。NEAT1 过表达显著增加 STAT3 蛋白表达水平，而在乳腺癌细胞中过表达 miR-124 可逆转此作用。此外，miR-124 过表达部分减弱了 NEAT1 对乳腺癌细胞增殖和细胞周期进程的影响。miR-124 过表达对增殖率和细胞周期进程的抑制作用被 STAT3 过表达所消除。反过来，STAT3 沉默抑制乳腺癌细胞中 NEAT1 的转录。综上所述，本研究结果表明，NEAT1 和 STAT3 通过海绵吸附 miR-124 形成反馈回路，促进乳腺癌的进展。
