Circ_EPHB4 regulates temozolomide sensitivity in glioma cells through the miR-424-5p/Wnt3 axis

LIAO Yuxiang; LIU Jingping; LIU Bo; FEI Xiyun; JIN Chen

doi:10.12122/j.issn.1673-4254.2025.05.06

Abstract：Objective To investigate the mechanism by which circ_EPHB4 regulates temozolomide(TMZ)sensitivity of glioma cells through the miR-424-5p/Wnt3 signal axis.Methods 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.Results The expression of circ_EPHB4 was significantly increased in glioma tissues and cells as compared with normal neural tissues and astrocytes(P=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(P=0.011).MiR-424-5p knockdown also attenuated the effect of circ_EPHB4 knockdown on expressions of PCNA,P-gp,MRP1 and bax.Conclusion 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.