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 exa-mined 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.

Abstract. The expression, function and underlying mechanisms of microRNA-139 (miR-139) in gastric cancer were investigated in the present study. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect miR-139 expression in gastric cancer tissues and cell lines. The effects of miR-139 overexpression on gastric cancer cell proliferation, migration and invasion were evaluated. ρ-associated protein kinase 1 (ROCK1) was predicted as a downstream target of miR-139 and its role in gastric cancer was assessed by bioinformatics analysis, luciferase reporter assay, RT-qPCR and western blot analysis. ROCK1 overexpression was established to investigate if the effects of miR-139 on gastric cancer cells may be attenuated. The results indicated that miR-139 was aberrantly downregulated in gastric cancer tissues and cell lines. Increased miR-139 expression reduced gastric cancer cell proliferation, migration and invasion. ROCK1 was demonstrated to be a direct target of miR-139 in gastric cancer and ROCK1 overexpression reversed the suppressive effects on gastric cancer cell proliferation, migration and invasion induced by miR-139 overexpression. The present study provides clear evidence demonstrating the anti-oncogenic activity of miR-139 in human gastric cancer, as mediated by the targeted downregulation of ROCK1.