miR-145-5p Suppresses Tumor Cell Migration, Invasion and Epithelial to Mesenchymal Transition by Regulating the Sp1/NF-κB Signaling Pathway in Esophageal Squamous Cell Carcinoma.

MicroRNAs (miRNAs) play important roles in the progression of human cancer. Although previous reports have shown that miR-145-5p is down-regulated in esophageal squamous cell carcinoma (ESCC), the roles and mechanisms of down-regulation of miR-145-5p in ESCC are still largely unknown. Using microRNA microarray and Gene Expression Omnibus (GEO) datasets, we confirmed that miR-145-5p was down-regulated in ESCC tissues. In vitro assays revealed that ectopic miR-145-5p expression repressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT). miR-145-5p also reduced the expressions of cell cycle genes including cyclin A2 (), cyclin D1 () and cyclin E1 (), the EMT-associated transcription factor Slug, and matrix metalloproteinases (MMPs) including , and . Furthermore, miR-145-5p mimics reduced candidate target gene specificity protein 1 () and nuclear factor κ B () () both in mRNA and protein levels. Knockdown of phenocopied the effects of miR-145-5p overexpression on cell cycle regulators, EMT and the expression of (). Importantly, inhibition of the signaling pathway or knockdown of () phenocopied the effects of miR-145-5p on the migration, invasion and EMT of ESCC cells. In conclusion, our results suggested that miR-145-5p plays tumor-suppressive roles by inhibiting esophageal cancer cell migration, invasion and EMT through regulating the signaling pathway.