Oligosaccharyltransferase inhibition reduces receptor tyrosine kinase activation and enhances glioma radiosensitivity

• Autores: Barontini, Marta Beatriz; López Sambrooks, Cecilia; Quijano, Amanda; Mark Saltzman, W.; Contessa, Joseph
• Año de publicación: 2019
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: RTK; Radiosensitization; Oligosaccharyltransferase; N-glycosylation; Glioma
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Purpose: Parallel signaling reduces the effects of receptor tyrosine kinase (RTK)–targeted therapies in glioma. We hypothesized that inhibition of protein N-linked glycosylation, an endoplasmic reticulum co- and posttranslational modification crucial for RTK maturation and activation, could provide a new therapeutic approach for glioma radiosensitization. Experimental Design: We investigated the effects of a small-molecule inhibitor of the oligosaccharyltransferase (NGI-1) on EGFR family receptors, MET, PDGFR, and FGFR1. The influence of glycosylation state on tumor cell radiosensitivity, chemotherapy-induced cell toxicity, DNA damage, and cell-cycle arrest were determined and correlated with glioma cell receptor expression profiles. The effects of NGI-1 on xenograft tumor growth were tested using a nanoparticle formulation validated by in vivo molecular imaging. A mechanistic role for RTK signaling was evaluated through the expression of a glycosylation-independent CD8-EGFR chimera. Results: NGI-1 reduced glycosylation, protein levels, and activation of most RTKs. NGI-1 also enhanced the radiosensitivity and cytotoxic effects of chemotherapy in those glioma cells with elevated ErbB family activation, but not in cells without high levels of RTK activation. NGI-1 radiosensitization was associated with increases in both DNA damage and G 1 cell-cycle arrest. Combined treatment of glioma xenografts with fractionated radiotherapy and NGI-1 significantly reduced tumor growth compared with controls. Expression of the CD8-EGFR eliminated the effects of NGI-1 on G 1 arrest, DNA damage, and cellular radiosensitivity, identifying RTK inhibition as the principal mechanism for the NGI-1 effect. Conclusions: This study suggests that oligosaccharyltransferase inhibition with NGI-1 is a novel approach to radio-sensitize malignant gliomas with enhanced RTK signaling.
Fil: Barontini, Marta Beatriz. University of Yale; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: López Sambrooks, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentina. University of Yale; Estados Unidos
Fil: Quijano, Amanda. University of Yale; Estados Unidos
Fil: Mark Saltzman, W.. University of Yale; Estados Unidos
Fil: Contessa, Joseph. University of Yale. School of Medicine; Estados Unidos