Background: MicroRNAs have been reported to play regulatory functions in various cancers, including esophageal cancer. The aim of this study was to investigate the effects of miR-140 on the progression of esophageal cancer and the underlying regulatory mechanism.
Methods: The levels of miR-140 and zinc finger E-box-binding homeobox 2 (ZEB2) messenger RNA in esophageal cancer tissues and cell lines were measured by quantitative real-time polymerase chain reaction. The protein levels of ZEB2, β-catenin, c-Myc, and cyclinD1 were determined by Western blot. Cell proliferation and apoptosis were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and flow cytometry, respectively. Cell migration and invasion were assessed by transwell assay. In addition, the relationship between miR-140 and ZEB2 was predicted by TargetScan online database and confirmed by dual-luciferase reporter assay. The tumor xenograft model was used to verify the role of miR-140 in esophageal cancer progression in vivo.
Results: The expression of miR-140 was downregulated whereas ZEB2 expression was upregulated in esophageal cancer tissues compared with paracancerous normal tissues. Functionally, both miR-140 overexpression and ZEB2 knockdown inhibited proliferation, migration, and invasion and induced apoptosis in esophageal cancer cells. ZEB2 overexpression reversed the effects of miR-140 on proliferation, apoptosis, migration, and invasion of esophageal cancer cells. Mechanistically, ZEB2 was identified as a target of miR-140. Furthermore, miR-140 suppressed Wnt/β-catenin pathway by regulating ZEB2 expression in esophageal cancer cells. MiR-140 inhibited tumor growth of esophageal cancer through repressing ZEB2 expression in vivo.
Conclusions: Our results demonstrated that miR-140 inhibited esophageal cancer development by targeting ZEB2 through inactivating Wnt/β-catenin pathway.
Keywords: Esophageal cancer; Wnt/β-catenin pathway; ZEB2; miR-140.
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