Zhu Guiquan, Wang Shaoxin, Chen Jin, Wang Zhaohui, Liang Xinhua, Wang Xiaoyi, Jiang Jian, Lang Jinyi, Li Ling
Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Mol Carcinog. 2017 Oct;56(10):2210-2222. doi: 10.1002/mc.22674. Epub 2017 Jun 7.
A hypoxic microenvironment plays important roles in the progression of solid tumors, including oral squamous cell carcinoma (OSCC). Long noncoding RNAs (lncRNAs) have gained much attention in the past few years. However, it is not clear whether lncRNAs can regulate hypoxia adaptation of OSCC or which lncRNAs participate in this process. Using a lncRNA microarray, we analyzed the aberrant lncRNA expression profiles in OSCC tissues compared with paired normal oral mucosa and in hypoxic OSCC cells compared with normoxic OSCC cells. The top 10 lncRNAs that had more than threefold increase with P-value <0.01 in both microarray data were validated by qRT-PCR. Among the top 10 lncRNAs, hyaluronan synthase 2 antisense 1 (HAS2-AS1) was the only one that has a hypoxia-responsive element (HRE) on its promoter region and has been validated to increase in OSCC tissues and in cells cultured under hypoxia. Tumor HAS2-AS1 levels were closely associated with lymph node metastasis and hypoxic tumor status in patients with OSCC. Moreover, the hypoxia-induced HAS2-AS1 expression is dependent on HIF-1α which directly binds to and activates the transcription of HAS2-AS1. In addition, HAS2-AS1 mediates hypoxia-induced epithelial mesenchymal transition of OSCC cells via stabilizing HAS2. In conclusion, our results suggest that hypoxia would induce an overexpression of HAS2-AS1 in an HIF-1α dependent manner. The increase of HAS2-AS1 plays important roles mediating the hypoxia-regulated EMT and invasiveness of OSCC.
缺氧微环境在实体瘤进展中发挥重要作用，包括口腔鳞状细胞癌（OSCC）。长链非编码RNA（lncRNA）在过去几年中备受关注。然而，尚不清楚lncRNA是否能调节OSCC的缺氧适应性，以及哪些lncRNA参与这一过程。我们使用lncRNA芯片，分析了OSCC组织与其配对的正常口腔黏膜相比以及缺氧的OSCC细胞与常氧的OSCC细胞相比时异常的lncRNA表达谱。通过qRT-PCR验证了在两个芯片数据中上调超过三倍且P值<0.01的前10个lncRNA。在前10个lncRNA中，透明质酸合酶2反义1（HAS2-AS1）是唯一在其启动子区域具有缺氧反应元件（HRE）且已被证实在OSCC组织和缺氧培养的细胞中表达增加的lncRNA。OSCC患者肿瘤组织中的HAS2-AS1水平与淋巴结转移和肿瘤缺氧状态密切相关。此外，缺氧诱导的HAS2-AS1表达依赖于HIF-1α，HIF-1α直接结合并激活HAS2-AS1的转录。此外，HAS2-AS1通过稳定HAS2介导缺氧诱导的OSCC细胞上皮-间质转化。总之，我们的结果表明缺氧以HIF-1α依赖的方式诱导HAS2-AS1的过表达。HAS2-AS1的增加在介导缺氧调节的OSCC细胞上皮-间质转化和侵袭中发挥重要作用。
