Circular RNA hsa_circ_103809 suppresses hepatocellular carcinoma proliferation and invasion by sponging miR-620.

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, particularly in China. In recent years, numerous studies have investigated the roles of circular RNAs (circRNAs) in tumour development because circRNAs generally act as microRNA (miRNA) sponges to regulate gene expression. However, whether circRNAs are also involved in HCC progression remains largely unknown.

MATERIALS AND METHODS: In the present study, we identified a novel circRNA (hsa_circ_103809) and determined its expression in HCC tissues and cell lines by qRT-PCR assays. CCK8, colony formation, wound-healing and transwell assays were performed to assess the effects of hsa_circ_103809 and miR-620 on HCC cell proliferation, migration and invasion. Bioinformatics analysis and luciferase reporter assays were used to explore the correlation between hsa_circ_103809 and miR-620 in HCC cells.

RESULTS: The results showed that hsa_circ_103809 expression was significantly down- regulated in HCC tissues and cell lines. The ectopic expression of hsa_circ_103809 inhibited HCC cell proliferation, migration and invasion. In addition, we found that miR-620 expression was significantly up-regulated in HCC tissues and was negatively correlated with hsa_circ_103809 expression in HCC tissues. Furthermore, we found that hsa_circ_103809 could bind to miR-620 and that hsa_circ_103809 negatively regulates miR-620 expression. We also showed that hsa_circ_103809 inhibited the proliferation and invasion abilities of HCC cells by sponging miR-620.

CONCLUSIONS: Hsa_circ_103809 acts by binding to miR-620 and inhibiting the tumourigenicity of HCC. Thus, this circRNA may serve as a potential biomarker and novel therapeutic target of HCC.