Hsa_circ_0008092 Contributes to Cell Proliferation and Metastasis in Hepatocellular Carcinoma via the miR-502-5p/CCND1 Axis

Background: The present study was targeted at investigating the effects of hsa_circRNA_0008092 (circ_0008092) on hepatocellular carcinoma (HCC) cell proliferation, migration, invasion and apoptosis, and its related mechanism. Methods: The gene expression profiles of GSE166678 were downloaded from the Gene Expression Omnibus database, and differentially expressed circRNAs in human HCC were screened out. Besides, circ_0008092, microRNA-502-5p (miR-502-5p) and cyclin D1 (CCND1) expressions in HCC tissues and cell lines were detected by quantitative real-time polymerase chain reaction (qRTPCR). Cell countering kit-8 (CCK-8), Transwell and flow cytometry assays were used to detect the proliferation, migration, invasion and apoptosis of HCC cells. Bioinformatics was utilized to predict the targeted relationships between miR-502-5p and circ_0008092, as well as miR-502-5p and CCND1 mRNA 3'-untranslated region (3’UTR). Western blot assay was applied to detect CCND1 protein expression in HCC cells. Results: Circ_0008092 was highly expressed in HCC tissues and cells, which was associated with a shorter survival time in patients with HCC. Circ_0008092 overexpression promoted proliferation, migration and invasion, and inhibited apoptosis of HCC cells; circ_0008092 knockdown worked oppositely. Circ_0008092 directly targeted miR-502-5p and negatively modulated miR-502-5p expression. CCND1 was a target gene of miR-502-5p, and was positively and indirectly modulated by circ_0008092. Conclusion: Our data suggest that circ_0008092 promotes HCC progression by regulating the miR- 502-5p/CCND1 axis.