MicroRNA-486 inhibits cell proliferation, invasion and migration via down-regulating the TENM1 expressions and affecting ERK and Akt signaling pathways and epithelial-to-mesenchymal transition in papillary thyroid carcinoma.

OBJECTIVE: Papillary thyroid carcinoma (PTC) is one of the general thyroid malignancies. Recently, microRNAs (miRNAs) have identified as pivotal gene regulators in PTC tumorigenesis. The aim of this study was to investigate the role of miR-486 in PTC and its underlying mechanism. PATIENTS AND METHODS: Fifty-six pairs of PTC tissue and matched normal tissue samples were collected from PTC patients who underwent surgery at our hospital from March 2015 to September 2017. Human thyroid epithelial cell line Nthy-ori3-1and PTC cell lines (BCPAP, K1, HTH83, and TPC-1) were cultured. The mRNA and protein expression level were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot, respectively. Additionally, the proliferation and migration abilities were checked by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method and transwell assay, respectively. Furthermore, dual-luciferase reporter assay was performed to confirm the combination of miR-486 and TENM1. Xenograft Model experiments were performed to assess the effects of miR-486 on tumor growth in vivo. RESULTS: MiR-486 expression was significantly reduced in PTC, which was associated with the poorer clinicopathologic characteristics and overall survival (OS) of PTC patients. Moreover, miR-486 restoration in PTC cells was confirmed to markedly inhibit proliferation, invasion, and migration via the regulation of extracellular-signal-regulated kinase (ERK) and protein kinase B (Akt) signaling pathways and epithelial-mesenchymal transition (EMT). In the meantime, teneurin transmembrane protein 1 (TENM1) was identified as a direct functional target for miR-486 in PTC cells on the basis of bioinformatic analysis and luciferase reporter assays. Additionally, we also verified that miR-486 restoration could prominently repress the PTC growth in vivo. CONCLUSIONS: MiR-486 exerted anti-tumor functions in PTC progression and served as promising biomarkers for the PTC treatment.