Abstract
Long non-coding RNAs (lncRNAs) are involved in governing fundamental biological processes, and, in many lncRNAs, the expression level is altered and likely to have a functional role in tumorigenesis, including apoptosis, migration and invasion. The lncRNA‑Low Expression in Tumor (LET), a recently identified lncRNA, was demonstrated to be downregulated in hepatocellular and gallbladder cancer. However, its role in esophageal squamous cell carcinoma (ESCC) requires investigation. The expression level of lncRNA‑LET mRNA in primary ESCC and matched healthy tissues (48 cases) was determined by reverse transcription‑quantitative polymerase chain reaction. In addition, the effects of lncRNA-LET on cell apoptosis were evaluated by flow cytometric analysis, the regulatory effect of lncRNA‑LET on migration was detected using a wound healing assay and cellular invasion was analyzed by Matrigel‑coated transwell assay. Furthermore, the effect of lncRNA‑LET on cell proliferation was investigated by 5‑ethynyl‑2'-deoxyuridine cell proliferation assay and protein levels of lncRNA-LET targets were analyzed by western blotting. lncRNA-LET expression was decreased in primary ESCC tissues when compared with paired healthy tissues, and was identified to be associated with the clinical features. Overexpression of lncRNA‑LET was observed to inhibit the migration and invasion of ESCC cells, and modulate p53 expression levels in human ESCC cell lines in vitro. These results establish that lncRNA-LET is significant in the regulation of tumor progression and metastasis, and serves as a tumor suppressor in, and therefore has therapeutic potential for, the treatment of human ESCC.