The role of m6A‐modified CircEPHB4 in glioma pathogenesis: Insights into cancer stemness metastasis

Abstract

ObjectiveWhile existing literature has provided insights into involvement of circEPHB4, SOX2 in glioma, their precise molecular mechanisms and synergistic implications in glioma pathogenesis still dim. This study aims to investigate significance and underlying mechanism of m6A‐modified circEPHB4 in regulating SOX2/PHLDB2 axis in gliomas.MethodsThe mRNA and protein expression were tested by qRT‐PCR and Western blot, respectively. ChIP assay was performed to detect SOX2 enrichment on the PHLDB2 promoter. Cell sphere‐forming assay to detect self‐renewal ability, flow cytometry to determine positivity of CD133 expressions, Malignant behavior of glioma cells were detected by CCK‐8, plate colony formation, scratch, and transwell assays. Glioma xenograft models were constructed to investigate effects of CircEPHB4 in tumor development in vivo.ResultsMethyltransferase MELLT3 upregulated m6A modification of CircEPHB4, and YTHDC1 promoted cytoplasmic localization of m6A‐modified CircEPHB4. Overexpression of wild‐type CircEPHB4 enhanced glioma cells' stemness, metastasis, and proliferation. Cytoplasmic CircEPHB4 increased SOX2 mRNA stability by binding to IGF2BP2, and the effects observed by SOX2 knockdown were reversed by CircEPHB4 in glioma cells. SOX2 promoted transcriptional expression of PHLDB2 by enriching the PHLDB2 promoter region. SOX2 reversed the inhibition of PHLDB2 knockdown on stemness of glioma, cell proliferation, and metastasis. In vivo experiments also revealed that CircEPHB4 upregulated PHLDB2 expression by stabilizing SOX2 mRNA, which promoted in vivo tumor growth and accelerated stemness of glioma cells and metastasis.ConclusionThis study reveals functional interaction and molecular mechanisms of m6A‐modified circEPHB4 in regulating SOX2/PHLDB2 axis, highlighting their importance in glioma pathogenesis and potential as therapeutic targets.

Emerging Roles and Mechanisms of RNA Modifications in Neurodegenerative Diseases and Glioma

“…This localization facilitates the stabilization of SOX2 mRNA, promoting the transcription of PHLDB2, a molecule associated with epithelial–mesenchymal transformation in various cancers. This mechanism underscores the role of YTHDC1 in enhancing stemness in glioma spheres, as evidenced by the increased expression of stemness marker proteins and the promotion of cell proliferation, invasion, and migration [ 170 , 171 , 172 ]. Additionally, YTHDC1 influences glioma cell proliferation through its impact on VPS25, a protein upregulated in gliomas.…”