Identification and validation long non-coding RNAs of oral squamous cell carcinoma by bioinformatics method

Gene markers of oral squamous cell carcinoma (OSCC) have great significance on early diagnosis and treatment of clinical oral cancer. In this study, we used RNA-Seq data from OSCC patients and filtered differentially-expressed long non-coding RNA (lncRNA) to further clarify the molecular mechanism. Firstly, we downloaded datasets of OSCC from National Center for Biotechnology Information(NCBI), which were predicted and analyzed by cufflinks and tophat. Then, differentially expressed lncRNA enrichment was performed with The Database for Annotation, Visualization and Integrated Discovery (DAVID). Finally, we verified the gene expression via in vitro assays. Results showed that 52 lncRNAs were significantly differentially expressed compared to those in normal oral tissues, three highly expressed genes (XLOC_002599, XLOC_002634 and XLOC_132858) were verified by RT-PCR, which was consistent with the prediction. XLOC_002634 (GAS5) transcript levels were reduced both in vivo and in vitro assays, which confirmed that the expression of GAS5 was comparatively low in OSCC. Over-expression of GAS5 in cancer cells inhibited cell proliferation. Moreover, the migration and invasion potential of cancer cells were inhibited compared to control groups. All in all, the study indicated that the decrease in GAS5 expression may contribute to OSCC tumor pathogenesis and serve as a potential target for cancer therapy.