Abstract

Objective To investigate the role of hsa_circ_0008934 in osteosarcoma and the molecular mechanism involved in the regulation of the occurrence and development of osteosarcoma Methods Differentially expressed circRNAs in the osteosarcoma cell lines SaOS2 and MG63 and in the normal human osteoblast cell line hFOB1.19 were identified via next-generation RNA sequencing . The expression and circular morphology of hsa_circ_0008934 were analyzed via quantitative real-time polymerase chain reaction (qRT-PCR) and RT-PCR analysis, respectively. Proliferation, apoptosis, cell cycle progression , migration, and invasion of SaOS2 and MG63 cells with hsa_circ_0008934 silencing or overexpression were assessed using the MTS method, colony formation assay, flow cytometry, and the transwell system, respectively. The subcellular distribution of hsa_circ_0008934 was revealed via fluorescence in situ hybridization . The binding of hsa_circ_0008934 with microRNAs was confirmed using the dual-luciferase reporter assay. The oncogenic roles of hsa_circ_0008934 in osteosarcoma were determined using an in vivo tumorigenesis assay with nude mice . qRT-PCR, western blotting , TUNEL assay , and immunohistochemistry (IHC) were used to detect the tumorigenicity of hsa_circ_0008934 in osteosarcoma cells. Results Many circRNAs were differentially expressed in SaOS2 and MG63 cells than in hFOB1.19 cells. Hsa_circ_0008934 expression was significantly elevated in SaOS2 and MG63 cells. Hsa_circ_0008934 silencing significantly reduced proliferation, enhanced apoptosis, blocked cell cycle progression, and impaired migration and invasion capacities of SaOS2 cells. Opposite cellular alterations were achieved by overexpressing hsa_circ_0008934 in MG63 cells. Hsa_circ_0008934 was mainly distributed in the cytosol and positively regulated E2F3 expression in osteosarcoma cells. In addition, it directly bound with miR-145−5p to repress E2F3 expression and enhanced the tumorigenesis of MG63 cells i