miR-877-3p as a Potential Tumour Suppressor of Oesophageal Squamous Cell Carcinoma

Background/Aim: MicroRNAs (miRNAs) are abnormally expressed and involved in the pathogenesis of various carcinomas. The present study aimed to identify novel miRNA genes associated with the pathogenesis and prognosis of οesophageal squamous cell carcinoma (ESCC). Materials and Methods: The miRNA profiling of 873 genes was performed using surgically resected οesophageal tissues from 35 patients with ESCC to identify candidate miRNAs. To examine the biological activities of candidate miRNAs, their proliferative, invasive, and migratory abilities were evaluated in ESCC cells subjected to miRNA mimic-mediated over-expression. The miRNA expression levels of the selected candidate miRNAs were analysed in the resected οesophageal tissues of 76 patients with ESCC from the two cohorts and correlated with the clinicopathological parameters. Results: Among the four candidate miRNAs identified by miRNA profiling, miR-877-3p was selected for subsequent analyses. In vitro analyses showed that the over-expression of miR-877-3p significantly suppressed the proliferation, invasion, and migration of ESCC cell lines compared with those of control cells. In the analyses of clinical specimens, the expression of miR-877-3p was down-regulated in ESCC tissues compared with that in adjacent normal οesophageal tissues. The down-regulation of miR-877-3p expression in ESCC tissues was significantly associated with advanced local progression and lymphatic involvement. The miR-877-3p down-regulation was also significantly associated with poor disease-free and disease-specific survival. Conclusion: miR-877-3p acts as a tumour suppressor gene in ESCC cells, and its down-regulation in ESCC tissues is associated with a poor prognosis. Thus, miR-877-3p may serve as a novel prognostic marker and promising therapeutic target.