Circular RNA-encoded oncogenic E-cadherin variant promotes glioblastoma tumorigenicity through activation of EGFR–STAT3 signalling

Menée à l'aide de modèles murins de glioblastome, cette étude met en évidence un mécanisme par lequel une variante oncogène de la E-cadhérine codée par un ARN circulaire favorise le caractère tumorigène des cellules souches de gliome via l'activation de la signalisation EGFR–STAT3

Résumé en anglais

Activated EGFR signalling drives tumorigenicity in 50% of glioblastoma (GBM). However, EGFR-targeting therapy has proven ineffective in treating patients with GBM, indicating that there is redundant EGFR activation. Circular RNAs are covalently closed RNA transcripts that are involved in various physiological and pathological processes. Herein, we report an additional activation mechanism of EGFR signalling in GBM by an undescribed secretory E-cadherin protein variant (C-E-Cad) encoded by a circular E-cadherin (circ-E-Cad) RNA through multiple-round open reading frame translation. C-E-Cad is overexpressed in GBM and promotes glioma stem cell tumorigenicity. C-E-Cad activates EGFR independent of EGF through association with the EGFR CR2 domain using a unique 14-amino-acid carboxy terminus, thereby maintaining glioma stem cell tumorigenicity. Notably, inhibition of C-E-Cad markedly enhances the antitumour activity of therapeutic anti-EGFR strategies in GBM. Our results uncover a critical role of C-E-Cad in stimulating EGFR signalling and provide a promising approach for treating EGFR-driven GBM.