Downregulation of microRNA-1 in esophageal squamous cell carcinoma correlates with an advanced clinical stage and its overexpression inhibits cell migration and invasion.

Esophageal squamous cell carcinoma (ESCC) is one of most common and fatal forms of cancer worldwide. Recent studies have suggested that an aberrant microRNA (miRNA or miR) expression signature exists in ESCC. In the present study, in order to determine the involvement of miRNA in the development and progression of ESCC, the expression profiles of miRNA in 8 paired ESCC tissues and corresponding normal esophageal tissues were analyzed by miRNA microarray. A total of 43 differentially expressed miRNAs, including 27 downregulated and 16 upregulated miRNAs were found in the ESCC tissue samples. Among these miRNAs, we found that miR-1 was significantly downregulated. Subsequently, the expression of miR-1 was validated in 64 pairs of primary ESCC samples by RT-qPCR. The expression level of miR-1 was found to be frequently decreased, and significantly correlated with tumor invasion and an advanced clinical stage (P = 0.022 and P = 0.028, respectively). In addition, functional assays revealed that miR-1 inhibited cell proliferation, clonogenicity, cell invasion and migration. Bioinformatics analyses identified the major biological processes that were targeted by miR-1. These results suggest that miR-1 has a tumor-suppressive effect on the development and progression of ESCC. The findings of this study may contribute to the further understanding of the functions of miR-1 in ESCC.