Long noncoding RNA RP11-766N7.4 functions as a tumor suppressor by regulating epithelial-mesenchymal transition in esophageal squamous cell carcinoma.

Background: Numerous studies have proved that long non-coding RNAs participate in the initiation and metastasis of various cancers including esophageal squamous cell carcinoma (ESCC). Recently, a novel long non-coding RNA RP11-766N7.4 was discovered in a variety of human tissues. However, its role in oncogenesis and tumor metastasis remains unknown. Methods: To investigate the function of long noncoding RNA RP11-766N7.4 in ESCC, RT-qPCR was used to monitor the expression level of long non-coding RNA RP11-766N7.4 in ESCC cell lines and 50 paired ESCC tissues. Moreover, the association between long non-coding RNA RP11-766N7.4 expression level and clinicopathological characteristics as well as 5-year survival rate of ESCC patients was evaluated. Furthermore, function assays containing cell proliferation assay, flow cytometry, Colony Formation, wound healing assay and Transwell assays were conducted to investigate the role of long noncoding RNA RP11-766N7.4 in ESCC. Western blotting assay were used to explore the regulation mechanism. Results: In this study, we found that long noncoding RNA RP11-766N7.4 was downregulated in ESCC tissues and cell lines and correlated with lymph node metastasis, tumor stage and survival rate. Results also revealed that long noncoding RNA RP11-766N7.4 had no significant effect on cell proliferation, cell cycle or cell apoptosis of ESCC cells. In addition, long noncoding RNA RP11-766N7.4 knockdown promoted cellular migration and invasion via inducing EMT process, and overexpression of long noncoding RNA RP11-766N7.4 inhibited cellular migration and invasion by suppressing EMT process. Conclusion: Our study suggested that long noncoding RNA RP11-766N7.4 acts as a tumor suppressor in ESCC carcinogenesis and metastasis, and may be a potential prognostic mark and a therapeutic target for ESCC. (C) 2017 Elsevier Masson SAS. All rights reserved.