Circular RNA circ_0001588 sponges miR‐211‐5p to facilitate the progression of glioblastoma via up‐regulating YY1 expression

As the most common and detrimental brain tumor with high invasiveness and poor prognosis, glioblastoma (GBM) has severely threatened people's health globally. Therefore, it is of great importance and necessary to identify the molecular mechanisms involved in tumorigenesis and development, thus contributing to potential therapeutic targets and strategies.The level of circ_0001588 was detected in 68 pairs of GBM tissues and adjacent normal tissues and human glioma cell lines via a real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Then, the effect of circ_0001588 on the proliferation, migration and invasion of glioma cells was evaluated. In addition, potential downstream targets of circ_0001588 were forecasted by circBANK and Starbase. Their interaction was confirmed by introducing luciferase reporter assays. Moreover, sh-circ_0001588 transfected U251 cells were used to form tumors in vivo. Finally, the functional mechanism of circ_0001588 was identified by qRT-PCR, western blotting, xenograft and immunohistochemistry (IHC) assays.The expression of circ_0001588 is markedly up-regulated in GBM tissues and human gliomas cells. Additionally, increased expression of circ_0001588 is positively relevant with poor survival in GBM patients. The down-regulation of circ_0001588 distinctly inhibits the proliferation, migration and invasion of GBM in vitro, as well as tumor growth in vivo. Moreover, knockdown of circ_0001588 reduces the tumor volume and weight, enhances the relative IHC staining index of E-cadherin and decreases the relative IHC staining index of Ki-67, Yin Yang 1 (YY1) and vinmentin in vivo. Mechanistically, circ_0001588 locates in the cytoplasm, which is directly bound with miR-211-5p. Furthermore, circ_0001588 can positively regulate YY1 via sponging miR-211-5p. Moreover, circ_0001588 accelerates the proliferation, migration and invasion of GBM by modulating miR-211-5p/YY1 signaling.These results illustrate a new circ_0001588/miR-211-5p/YY1 regulatory signaling axis in GBM.