Up-regulation of miR-221 in early-stage esophageal squamous cell cancer and its promotion effect on proliferation, migration and invasion of EC109 cells

Objective: To investigate the expression of microRNA (miRNA, miR)-221 in early esophageal squamous cell cancer tissues and the effect of miR-221 on the abilities of proliferation, migration and invasion of esophageal squamous cell cancer EC109 cells.Methods: The expressions of miR-221 in 42 specimens of early-stage esophageal squamous cell cancer tissues and the corresponding para-cancerous tissues as well as in esophageal squamous cell cancer EC109 cells and esophageal epithelial HET-1A cells were detected by real-time fluorescent quantitative PCR. After transfection with miR-221 mimics, mimics negative control (mimics NC), miR-221 inhibitor or inhibitor negative control (inhibitor NC), respectively, the expression level of miR-221 in EC109 cells was detected by real-time fluorescent quantitative PCR. The abilities of cell proliferation, migration and invasion of EC109 cells were determined by CCK-8, wound healing and Transwell assay, respectively.Results: The expression level of miR-221 in early-stage esophageal squamous cell cancer tissues was significantly higher than that in the corresponding para-cancerous tissues (P < 0.01). The expression level of miR-221 in EC109 cells was higher than that in HET-1A cells (P < 0.05). The expression level of miR-221 and abilities of cell proliferation, migration and invasion of EC109 cells after transfection with miR-221 mimics were significantly higher than those of EC109 cells transfected with mimics NC or without any transfection (as a blank control) (P < 0.01, P < 0.05, P < 0.01, P < 0.01, respectively). However, the expression level of miR-221 and the abilities of cell proliferation, migration and invasion of EC109 cells after transfection with miR-221 inhibitor were significantly lower than those in EC109 cells transfected with inhibitor NC or without any transfection (P < 0.01, P < 0.05, P < 0.01, P < 0.01, respectively).Conclusion: miR-221 is highly expressed in early-stage esophageal squamous cell cancer tissues, and it can promote the abilities of proliferation, migration and invasion of EC109 cells in vitro. DOI:10.3781/j.issn.1000-7431.2016.33.865