Knockdown of circHIPK3 Facilitates Temozolomide Sensitivity in Glioma by Regulating Cellular Behaviors Through miR-524-5p/KIF2A-Mediated PI3K/AKT Pathway.

Abstract

Background: Temozolomide (TMZ) resistance is a serious hindrance in clinical chemotherapy for glioma. Circular RNA homeodomain interacting protein kinase 3 (circHIPK3) can be involved in regulating the progression of glioma, but the molecular mechanism of circHIPK3 in TMZ-resistant-glioma is completely unclear. Materials and Methods: The levels of circRNA, miRNA, and mRNA were examined using quantitative real-time polymerase chain reaction. 3-(4,5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide assay was used for assessing the half inhibitory concentration (IC50) of TMZ and cell proliferation. Cell apoptosis and metastasis (migration and invasion) were detected by flow cytometry and transwell assay, respectively. Western blot and dual-luciferase reporter assay were performed several times to analyze the expression levels of associated proteins and the targeted relation. Results: The upregulation of circHIPK3 was found in TMZ-resistant glioma tissues and cells. Both circHIPK3 knockdown and kinesin family member 2A (KIF2A) inhibition could facilitate TMZ sensitivity and apoptosis but repress proliferation and metastasis in TMZ-resistant glioma cells. CircHIPK3 targeted microRNA-524-5p (miR-524-5p) and KIF2A functioned as a downstream target of miR-524-5p. Decrease of miR-524-5p relieved the effects of si-circHIPK3 on TMZ-resistant glioma cells by upregulating KIF2A. Downregulation of circHIPK3 refrained the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signal pathway partly through miR-524-5p/KIF2A axis. Conclusions: Knockdown of circHIPK3 promoted TMZ sensitivity in glioma by modulating proliferation, metastasis, and apoptosis through miR-524-5p/KIF2A-mediated PI3K/AKT pathway. CircHIPK3 may be the potential target for the diagnosis and therapy of TMZ-resistant glioma.