Abstract: Objective · To detect the effects of miR-760 on proliferation, apoptosis, migration and invasion of human esophageal squamous cell carcinoma (ESCC) TE-10 cells and to analyse the underlying mechanism. Methods · The mRNA and protein levels of miR-760 and c-Myc in five ESCC cell lines (normal esophageal epithelial cells as control) and 14 pieces of ESCC tissue specimens (paracancerous tissues as control) were detectedusing reverse transcription quantitative PCR (RT-qPCR) and Western blotting. TE-10 cells were transfected with miR-760 mimics, miR-760 inhibitor (miR-mimics/miR-inhibitor group) and corresponding negative controls (mimics-NC/inhibitor-NC group), in which the over and inhibition efficiency of miR-760 and the of c-Myc were verifiedRT-qPCR. The effect of miR-760 on the proliferation of TE-10 cells was assessedCCK-8 and colony formation assay. Changes of cell cycle distribution and proportion of apoptotic cells were measuredflow cytometry. Expression levels of cell cycle-, apoptosis-, migration-, and invasion-associated proteins as well as c-Myc were analyzedWestern blotting. The targeting relationship between miR-760 and c-Myc was verifiedusing the dual luciferase reporter assay. Results · The s of miR-760 were down-regulated and the s of c-Myc mRNA and protein were up-regulated in five ESCC cell lines compared with those in the normal esophageal epithelial cells. In 14 cases of ESCC tissue specimens, the s of miR-760 were down-regulated but the s of c-Myc were up-regulated compared with those in the cancer-adjacent tissues. The proliferation ability of TE-10 cells in the miR-mimics group was markedly attenuated, and colony numbers were also decreased. Flow cytometry assay showed that the proportion of cells in G1 phase was notably augmented, and the proportion of apoptotic cells was also increased. The miR-mimics group cells had weaker migration and invasion potential compared with mimics-NC group. Western blotting analysis conformed that levels of cyclin D1, B cell lymphoma 2, matrix metalloproteinase 2 and vimentin were decreased, but levels of cleaved-caspase3, E-cadherin and β-catenin were elevated. The miR-inhibitor group showed opposite results compared with the miR-mimics group. The dual luciferase reporter assay validated the direct targeted binding of miR-760 to the 3UTR of c-Myc. Conclusion · miR-760 can suppress proliferation, migration and invasion, and induce apoptosis of TE-10 cellsdirectly targeting c-Myc.

Key words: miR-760, esophageal squamous cell carcinoma, c-Myc, target gene