MicroRNA-127 is a tumor suppressor in human esophageal squamous cell carcinoma through the regulation of oncogene FMNL3

In this study, we investigated the expression patterns and functional roles of microRNA 127 (miR-127) and its target gene Formin-Like 3 (FMNL3) in human esophageal squamous cell carcinoma (ESCC). Quantitative RT-PCR (qRT-PCR) was used to compare miR-127 expression between ESCC cell lines and normal esophageal epithelium cell line, as well as paired ESCC tumors and adjacent normal esophageal tissues in 33 patients. We found miR-127 was aberrantly downregulated in both ESCC cell lines and human ESCC tumors. In ESCC cell lines TE-1 and ECA109 cells, lentiviral-induced miR-127 upregulation markedly inhibited cancer proliferation and migration in vitro, and tumorigenicity in vivo. Through dual-luciferase assay and qRT-PCR, FMNL3 was confirmed to be the downstream target gene of miR-127 in ESCC. Finally, FMNL3 was downregulated by siRNA in TE-1 and ECA109 cells. And we discovered that SiRNA-induced FMNL3 downregulation had tumor suppressive effect in ESCC, inhibiting cancer proliferation, migration in vitro, and tumorigenicity in vivo. These results suggest that miR-127 is downregulated and acting as tumor suppressor in ESCC. Inversely, FMNL3, the target gene of miR-127, is upregulated and acting as an oncogene in ESCC.