Circular RNA circFANCL motivates the glioma progression via the action on the miR-337-3p/HMGB1 signal axis

BACKGROUND Circular RNAs (circRNAs) are significant modulatory molecules in the developing process of glioma. Our study will emphasize on exploring the function of circRNA Fanconi anemia group L protein (circFANCL) and the specific mechanism in glioma. METHODS The quantitative real-time polymerase chain reaction (qRT-PCR) was implemented for detecting circFANCL, microRNA-337-3p (miR-337-3p) and high mobility group box-1 (HMGB1). Cell proliferation analysis was assessed using Cell Counting Kit-8 (CCK-8) and colony formation assays. Flow cytometry was applied to determine cell cycle and apoptosis. All protein detection was completed by western blot. Animal experiment was performed to investigate the role of circFANCL in vivo. Dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays were collectively conducted for analyzing the targeted combination. RESULTS CircFANCL was signally increased in glioma tissues and cells, and the up-regulated circFANCL could predict poor prognosis in clinical glioma patients. Down-regulated circFANCL induced the proliferation inhibition, cell cycle arrest and apoptosis promotion of glioma cells in vitro, and inhibited tumor growth in vivo. Regarding the mechanism, circFANCL served as a sponge of miR-337-3p that was a tumor suppressor in glioma and circFANCL targeted miR-337-3p to regulate HMGB1 that was a target gene of miR-337-3p. Furthermore, HMGB1 down-regulation was responsible for the repression of glioma progression caused by knockdown of circFANCL. CONCLUSIONS Through the illustration of oncogenic function of circFANCL in glioma by the miR-337-3p/HMGB1 axis, we believed that circFANCL might be a great target in the early diagnosis and late treatment of glioma.