Zhang Ya-Long, Li Xue-Bing, Hou Yan-Xu, Fang Nian-Zhen, You Jia-Cong, Zhou Qing-Hua
Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenviroment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin 300052, China.
Binzhou Medical University Hospital, Binzhou 256603, China.
Acta Pharmacol Sin. 2017 Mar;38(3):371-381. doi: 10.1038/aps.2016.133. Epub 2017 Jan 9.
Long non-coding RNAs (lncRNAs) are associated with the occurrence, development and prognoses of non-small cell lung cancer (NSCLC). In the present study, we investigated the functional mechanisms of the lncRNA XIST in two human NSCLC cell lines, A549 and NCI-H1299. In all the 5 NSCLC cell lines (NL9980, NCI-H1299, NCI-H460, SPC-A-1 and A549) tested, the expression levels of XIST were significantly elevated, as compared with those in normal human bronchial epithelial cell line BEAS-2B. In A549 and NCI-H1299 cells, knockdown of XIST by siRNA significantly inhibited the cell proliferation, migration and invasion, and promoted cell apoptosis. Furthermore, XIST knockdown elevated the expression of E-cadherin, and suppressed the expression of Bcl-2. Moreover, knockdown of XIST significantly suppressed the tumor growth in NSCLC A549 xenograft mouse model. Bioinformatic analysis and luciferase reporter assays revealed that XIST was negatively regulated by miR-449a. We further identified reciprocal repression between XIST and miR-449a, which eventually influenced the expression of Bcl-2: XIST functioned as a miRNA sponge of miR-449a, which was a negative regulator of Bcl-2. These data show that expression of the lncRNA XIST is associated with an increased growth rate and metastatic potential in NSCLC A549 and NCI-H1299 cells partially through miR-449a, and suggest that XIST may be a potential prognostic factor and therapeutic target for patients with NSCLC.
长链非编码RNA（lncRNAs）与非小细胞肺癌（NSCLC）的发生、发展及预后相关。在本研究中，我们调查了lncRNA XIST在两种人NSCLC细胞系A549和NCI-H1299中的功能机制。在所检测的所有5种NSCLC细胞系（NL9980、NCI-H1299、NCI-H460、SPC-A-1和A549）中，与正常人支气管上皮细胞系BEAS-2B相比，XIST的表达水平显著升高。在A549和NCI-H1299细胞中，通过siRNA敲低XIST可显著抑制细胞增殖、迁移和侵袭，并促进细胞凋亡。此外，敲低XIST可提高E-钙黏蛋白的表达，并抑制Bcl-2的表达。而且，敲低XIST可显著抑制NSCLC A549异种移植小鼠模型中的肿瘤生长。生物信息学分析和荧光素酶报告基因检测显示，XIST受miR-449a负调控。我们进一步确定了XIST与miR-449a之间的相互抑制关系，这最终影响了Bcl-2的表达：XIST作为miR-449a的miRNA海绵发挥作用，而miR-449a是Bcl-2的负调控因子。这些数据表明，lncRNA XIST的表达与NSCLC A549和NCI-H1299细胞中生长速率增加和转移潜能增加相关，部分是通过miR-449a实现的，并提示XIST可能是NSCLC患者的潜在预后因素和治疗靶点。
