Liao Yuxiang, Liu Jingping, Liu Bo, Fei Xiyun, Jin Chen
Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha 410008, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2025 May 20;45(5):942-953. doi: 10.12122/j.issn.1673-4254.2025.05.06.
To investigate the mechanism by which circ_EPHB4 regulates temozolomide (TMZ) sensitivity of glioma cells through the miR-424-5p/Wnt3 signal axis.
We detected the expression levels of circ_EPHB4, miR-424-5p and Wnt3 mRNA in glioma specimens from 25 patients with primary glioma and 25 patients experiencing relapse following temozolomide-based chemotherapy and in TMZ-sensitive and -resistant glioma A172 and SHG44 cells with circ_EPHB4 knockdown using qRT-PCR, and Wnt3 protein expression level was detected with Western blotting. Cell viability, colony-forming ability, and apoptosis of the cells with circ_EPHB4 knockdown were assessed, and the targeted regulation relationship between circ_EPHB4, miR-424-5p, and Wnt3 was verified by dual luciferase reporter assay and RNA immunoprecipitation (RIP) experiments. The effect of circ_EPHB4 knockdown on tumorigenesis of glioma cells was evaluated in subcutaneous tumor-bearing nude mouse models.
The expression of circ_EPHB4 was significantly increased in glioma tissues and cells as compared with normal neural tissues and astrocytes (=0.014). In TMZ-resistant glioma cells, circ_EPHB4 knockdown resulted in an obvious reduction of IC50 value of TMZ, inhibited cell colony formation, and promoted cell apoptosis, and these effects were reversed by miR-424-5p knockdown. The expressions of miR-424-5p and circ_EPHB4 were negatively correlated in glioma tissues (=0.011). MiR-424-5p knockdown also attenuated the effect of circ_EPHB4 knockdown on expressions of PCNA, P-gp, MRP1 and bax.
Circ_EPHB4 regulates Wnt3 expression through "sponge adsorption" of miR-424-5p, thereby modulating TMZ-resistant glioblastoma cell clonogenesis, apoptosis, and TMZ sensitivity, suggesting the potential of circ_EPHB4 as a therapeutic target for reversing drug resistance of gliomas.
探讨环状EPHB4（circ_EPHB4）通过微小RNA-424-5p（miR-424-5p）/Wnt3信号轴调节胶质瘤细胞对替莫唑胺（TMZ）敏感性的机制。
采用qRT-PCR检测25例原发性胶质瘤患者和25例替莫唑胺化疗后复发患者的胶质瘤标本以及circ_EPHB4基因敲低的TMZ敏感和耐药胶质瘤A172及SHG44细胞中circ_EPHB4、miR-424-5p和Wnt3 mRNA的表达水平，采用蛋白质免疫印迹法检测Wnt3蛋白表达水平。评估circ_EPHB4基因敲低细胞的活力、集落形成能力和凋亡情况，并通过双荧光素酶报告基因检测和RNA免疫沉淀（RIP）实验验证circ_EPHB4、miR-424-5p和Wnt3之间的靶向调控关系。在皮下荷瘤裸鼠模型中评估circ_EPHB4基因敲低对胶质瘤细胞致瘤性的影响。
与正常神经组织和星形胶质细胞相比，circ_EPHB4在胶质瘤组织和细胞中的表达显著升高（P=0.014）。在TMZ耐药胶质瘤细胞中，circ_EPHB4基因敲低导致TMZ的半数抑制浓度（IC50）值明显降低，抑制细胞集落形成，并促进细胞凋亡，而miR-424-5p基因敲低可逆转这些作用。在胶质瘤组织中，miR-424-5p与circ_EPHB4的表达呈负相关（P=0.011）。miR-424-5p基因敲低还减弱了circ_EPHB4基因敲低对增殖细胞核抗原（PCNA）、P-糖蛋白（P-gp）、多药耐药相关蛋白1（MRP1）和bax表达的影响。
Circ_EPHB4通过“海绵吸附”miR-424-5p调节Wnt3表达，从而调节TMZ耐药胶质母细胞瘤细胞的克隆形成、凋亡及对TMZ的敏感性，提示circ_EPHB4作为逆转胶质瘤耐药治疗靶点的潜力。
