Numerous circular RNAs (circRNAs) have been recognized as vital modulators of human malignancies, including glioma. Whereas, the functional role of circRNA Pituitary Homeo Box 1 (circPITX1) in the radioresistance of glioma cells remains largely uncertain. Quantitative real-time PCR (qRT-PCR) or western blot analysis was employed to examine the expression of circPITX1, microRNA (miR)-329-3p and NIMA-related kinase 2 (NEK2). 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to determine cell viability. Glycolysis was assessed by commercial kits and western blot analysis. Colony formation assay was conducted to analyze cell survival and clonogenicity capacity. The relationship among circPITX1, miR-329-3p and NEK2 was confirmed via dual-luciferase reporter assay. The in vivo function of circPITX1 was evaluated by tumor xenograft assay. Expression of circPITX1 and NEK2 was up-regulated in glioma tissues and cells, while miR-329-3p exhibited reverse trend. CircPITX1 knockdown repressed viability, glycolysis and colony formation, but promoted radiosensitivity of glioma cells, as well as inhibited tumor growth in vivo. MiR-329-3p was a target miRNA of circPITX1 and miR-329-3p deficiency reversed knockdown of circPITX1-mediated glycolysis inhibition and radioresistance reduction. MiR-329-3p exerted inhibitory effects on glycolysis and radioresistance of glioma cells by targeting NEK2. CircPITX1 facilitated NEK2 expression by sponging miR-329-3p. Glycolytic inhibitor 2-deoxy-d-glucose (2-DG) disposition weakened the promoted impact on glycolysis caused by circPITX1. CircPITX1 knockdown reduced glycolysis to contribute to radiosensitivity in glioma through miR-329-3p/NEK2 axis, providing a possible mechanism of circPITX1 in the development of glioma.

中文翻译：

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环状 RNA circPITX1 敲低通过 miR-329-3p/NEK2 轴抑制糖酵解以增强胶质瘤细胞的放射敏感性

许多环状 RNA (circRNA) 已被认为是人类恶性肿瘤（包括神经胶质瘤）的重要调节剂。然而，circRNA Pituitary Homeo Box 1 (circPITX1) 在胶质瘤细胞的放射抗性中的功能作用仍然很大程度上不确定。采用定量实时 PCR (qRT-PCR) 或蛋白质印迹分析来检查 circPITX1、microRNA (miR)-329-3p 和 NIMA 相关激酶 2 (NEK2) 的表达。3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) 测定用于确定细胞活力。通过商业试剂盒和蛋白质印迹分析评估糖酵解。进行集落形成测定以分析细胞存活和克隆形成能力。通过双荧光素酶报告基因分析证实了 circPITX1、miR-329-3p 和 NEK2 之间的关系。通过肿瘤异种移植试验评估circPITX1的体内功能。circPITX1和NEK2在胶质瘤组织和细胞中表达上调，而miR-329-3p则呈相反趋势。CircPITX1 敲低抑制了活力、糖酵解和集落形成，但促进了胶质瘤细胞的放射敏感性，并抑制了体内肿瘤的生长。MiR-329-3p 是 circPITX1 的靶 miRNA，miR-329-3p 缺陷逆转了 circPITX1 介导的糖酵解抑制和放射抗性降低的敲低。MiR-329-3p 通过靶向 NEK2 对胶质瘤细胞的糖酵解和放射抗性发挥抑制作用。CircPITX1 通过海绵化 miR-329-3p 促进 NEK2 的表达。糖酵解抑制剂 2-脱氧-d-葡萄糖 (2-DG) 的分布减弱了 circPITX1 对糖酵解的促进作用。