Accumulated evidence suggests that miR-106b played a key role in the promotion of the metastases of cancer; however, little is known about miR-106b in esophageal squamous cell carcinoma (ESCC). To investigate expression level of miR-106b in ESCC tissues, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-106b expression in 35 Kazakh's ESCC and paired normal adjacent tissues (NATs). To evaluate the role mediated by miR-106b in the proliferation, migration, and invasion, MTT, wound healing, and transwell assays were employed, respectively. Luciferase reporter assay was used to identify the downstream target through miR-106b. To understand the regulation between miR-106b and Smad 7, qRT-PCR and western blot were performed. The present study showed that miR-106b was pronouncedly upregulated in ESCC relative to paired NAT and that upregulated miR-106b was significantly associated with lymph node metastases. MiR-106b was found to be able to promote proliferation, migration, and invasion of ESCC cells in vitro. Smad 7 was confirmed as a downstream target of miR-106b in our experimental setting. Smad 7 was remarkably downregulated in ESCC compared with paired NAT. In addition, upregulation of miR-106b can promote epithelial mesenchymal transition (EMT) in ESCC cell in vitro. Our results indicated that miR-106b can promote migration and invasion of ESCC cells through enhancing EMT process via downregulation of Smad 7, suggesting that miR-106b can be a potential molecular phenotype in ESCC metastases.
Keywords: Epithelial mesenchymal transition; Invasion; MiR-106b; Migration; Smad 7.