MicroRNA-363-3p is downregulated in hepatocellular carcinoma and inhibits tumorigenesis by directly targeting specificity protein 1

microRNAs exhibit important regulatory roles in tumorigenesis and tumor development, such as in hepatocellular carcinoma (HCC). The present study aimed to investigate the expression and functional roles of microRNA (miR)-363-3p in HCC. miR-363-3p expression levels in a number of HCC tissues and cell lines were measured by reverse transcription-quantitative PCR (RT-qPCR). The effects of miR-363-3p expression on HCC cell proliferation, migration and invasion were examined by MTT assay, Transwell migration and invasion assay, respectively. The effects of miR-363-3p on its downstream target gene, specificity protein 1 (SP1), were examined by bioinformatics analysis, luciferase reporter assay, RT-qPCR and western blotting. An SP1 overexpression vector was subsequently transfected into HCC cells to assess any selective effects on miR-363-3p in modulating HCC. The results revealed that miR-363-3p expression levels were downregulated in both HCC tissues and cell lines, and this low expression level was correlated with tumor size, tumor-node-metastasis stage and venous infiltration in patients with HCC. Upregulation of miR-363-3p inhibited cell proliferation, migration and invasion in HCC cell cultures. In HCC cells transfected with an SP1 expression vector the miR-363-3p-induced tumor suppressive roles on cell proliferation, migration and invasion were reversed. In conclusion, results from the present study indicated that miR-363-3p is a tumor suppressor in HCC and functions through a mechanism involving SP1, suggesting that miR-363-3p may be a potential new therapeutic target for the treatment of HCC.