Long noncoding RNAs (lncRNAs) are a type of noncoding RNA transcript that are characterized by lack of protein-coding capacity. The vital role of lncRNAs in tongue squamous cell carcinoma (TSCC) is attracting increasing attention. In the present study, we identify a key lncRNA regulating TSCC metastasis and investigated the underlying mechanism. Our results indicate that the lncRNA ADAMTS9-AS2 is most significantly upregulated in TSCC tissues from patients with lymph node metastasis and is closely associated with poor prognosis. Furthermore, ADAMTS9-AS2 knockdown in TSCC cells leads to a inhibition of cell migration and invasion and reverses TGF-β1 induced EMT. ADAMTS9-AS2 knockdown also inhibits TSCC cell growth in vitro and in vivo. In addition, we show that ADAMTS9-AS2 is a cytoplasmic lncRNA that shares the miRNA response elements (MREs) of miR-600 with EZH2, which is confirmed by a luciferase reporter assay and AGO2-dependent RNA immunoprecipitation (RIP). In summary, our results demonstrate an explicit oncogenic role of ADAMTS9-AS2 in TSCC tumorigenesis via competition with miR-600, suggesting a new regulatory mechanism of ADAMTS9-AS2 and providing a potential therapeutic target for TSCC patients.
KEYWORDS: ADAMTS9-AS2, EZH2, Tongue squamous cell carcinoma, lncRNA, miR-600