The purpose of our study was aimed to determine the functional role of microRNA (miR)-182 in clear cell renal cell carcinoma (ccRCC) and try to clarify its underlying molecular mechanism. Expression of miR-182 in both cancer and peripheral blood samples was analyzed by quantitative real-time PCR (qRT-PCR). Human RCC line Caki-1 cells were transfected with miR-182 mimic, miR-182 inhibitor, or negative controls, and then the cell viability, colony-formation ability, migration, and invasion assay

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... ere determined. Luciferase reporter assay, qRT-PCR and Western blotting were used to determine whether insulin-like growth factor 1 receptor (IGF1R) was a target of miR-182. Further, small interfering RNA (siRNA) against IGF1R was co-transfected with miR-182 inhibitor into cells, and then the effects on migration and invasion were assessed. MiR-182 was down-regulated in both cancer and blood samples compared to the matched non-tumor adjacent tissues and healthy volunteers, respectively (both P<0.05). Compared to the control group, cell viability, colony-forming ability, and numbers of migrated and invaded cells were significantly decreased by transfection with miR-182 mimic but were markedly increased by miR-182 inhibitor (all P < 0.05). Luciferase reporter assay confirmed that IGF1R was a target gene of miR-182, and IGF1R was negatively regulated by miR-182. Co-transfection of miR-182 inhibitor with si-IGF1R reversed the effect of miR-182 inhibitor on the migration and invasion of the cells. MiR-182 functions as an anti-oncogene in ccRCC, and miR-182-mediated inhibition of cell migration and invasion might be through directly targeting IGF1R.