Yan Kai, Tian Jie, Shi Wenzheng, Xia Hao, Zhu Yuanfang
Department of Gastrointestinal Surgery, Clinical Medical College of Yangzhou University (Northern Jiangsu People's Hospital), Yangzhou, China.
Department of Pathology, Clinical Medical College of Yangzhou University (Northern Jiangsu People's Hospital), Yangzhou, China.
Cell Physiol Biochem. 2017;42(3):999-1012. doi: 10.1159/000478682. Epub 2017 Jun 27.
Background/Amis: Long non-coding RNAs (lncRNAs), a novel class of transcripts, have been shown to play critical roles in diverse cellular biological processes, including tumorigenesis. Small nucleolar RNA host gene 6 (SNHG6) regulates various biological processes in cancer cells. However, the biological role of SNHG6 in gastric cancer still remains to be explored. The aim of this study is to investigate the characteristic of the SNHG6 in gastric cancer.
Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of SNHG6 in gastric cancer tissues and cell lines. MTT assays, colony formation assays were used to determine the impact of SNHG6 on tumorigenesis . Flow cytometric analysis of cell cycle and apoptosis was performed to measure the effect of SNHG6 on cell cycle and apoptosis rate. Transwell assay was performed to measure the effect of SNHG6 on cell migration. Western blotting and immunofuorescence were utilized to examine the effect of SNHG6 on epithelial-mesenchymal transition (EMT) of GC cells. Chromatin immunoprecipitation (ChIP), RNA immunoprecipitation (RIP), RNA-pulldown and luciferase reporter assays were employed to dissect molecular mechanisms.
In this study, we revealed that SNHG6 was overexpressed in gastric cancer tissues and cell lines. High expression levels of SNHG6 wereassociated with invasion depth, lymph node metastasis, distant metastasis and tumor/node/metastasis (TNM) stage, and predicted poor prognosis. Loss-of-function assays revealed that silenced SNHG6 obviously inhibited gastric cancer cell growth, weakened cell migration capacity and suppressed the EMT processes of gastric cancer cells. Additionally, ChIP, RIP, RNA-pulldown and luciferase reporter assays evidenced that SNHG6 could epigenetically silenced p27 and could competitively sponging miR-101-3p thereby regulating zinc finger E-box-binding homeobox 1 (ZEB1).
In summary, our findings demonstrated that SNHG6 acted as an oncogene in gastric cancer cells through regulating miR-101-3p/ZEB1 at a post-transcriptional level and silencing expression at a transcriptional level by recruiting enhancer of zeste homolog 2 (EZH2) to the promoter of p27. SNHG6 might serve as a candidate prognostic biomarker and a target for novel therapies of gastric cancer patients.
背景/目的：长链非编码RNA（lncRNAs）是一类新的转录本，已被证明在包括肿瘤发生在内的多种细胞生物学过程中发挥关键作用。小核仁RNA宿主基因6（SNHG6）调节癌细胞中的各种生物学过程。然而，SNHG6在胃癌中的生物学作用仍有待探索。本研究的目的是探讨SNHG6在胃癌中的特征。
采用定量实时聚合酶链反应（qRT-PCR）检测胃癌组织和细胞系中SNHG6的表达。采用MTT法、集落形成试验测定SNHG6对肿瘤发生的影响。进行细胞周期和凋亡的流式细胞术分析，以测定SNHG6对细胞周期和凋亡率的影响。采用Transwell试验测定SNHG6对细胞迁移的影响。利用蛋白质免疫印迹法和免疫荧光法检测SNHG6对胃癌细胞上皮-间质转化（EMT）的影响。采用染色质免疫沉淀（ChIP）、RNA免疫沉淀（RIP）、RNA下拉和荧光素酶报告基因试验来剖析分子机制。
在本研究中，我们发现SNHG6在胃癌组织和细胞系中过表达。SNHG6的高表达水平与浸润深度、淋巴结转移、远处转移和肿瘤/淋巴结/转移（TNM）分期相关，并预示预后不良。功能丧失试验表明，沉默SNHG6明显抑制胃癌细胞生长，减弱细胞迁移能力，抑制胃癌细胞的EMT过程。此外，ChIP、RIP、RNA下拉和荧光素酶报告基因试验证明，SNHG6可以在表观遗传上使p27沉默，并能竞争性结合miR-101-3p，从而调节锌指E盒结合同源框1（ZEB1）。
总之，我们的研究结果表明，SNHG6在胃癌细胞中通过在转录后水平调节miR-101-3p/ZEB1，并通过将zeste同源物2（EZH2）增强子募集到p27启动子上在转录水平沉默表达，从而作为一种癌基因发挥作用。SNHG6可能作为胃癌患者的候选预后生物标志物和新治疗靶点。
