MiR-181 c modulates the proliferation , migration , and invasion of neuroblastoma cells by targeting Smad 7

MicroRNAs (miRNAs) function as key regulators of gene expression in various cancers. In this study, the aim is to explore the roles and regulation mechanism of miR-181c in neuroblastoma (NB) cells. We found that miR-181c was downregulated in metastatic NB tissues, compared with primary NB tissues. Then functional studies indicated that miR-181c overexpression inhibited NB cell proliferation, migration, and invasion, while miR-181c inhibition increased cell proliferation, migration, and invasion. EGFP reporter assay, real-time polymerase chain reaction and western blot analysis validated that Smad7 was a direct target of miR181c. MiR-181c reduced Smad7 expression at both mRNA and protein levels. Finally, functional assays showed that the effect of Smad7 knockdown on cells was similar to that of miR-181c overexpression. Importantly, Smad7 overexpression could restore the antitumor effects that were induced by miR-181c. In conclusion, our results demonstrated that miR181c inhibits NB cell growth and metastasis-related traits through the suppression of Smad7, functioning as a tumor suppressor. Moreover, our results suggested that miR-181c may serve as an important therapeutic target for NB patients.