NMDA Receptor-Mediated Signaling Pathways Enhance Radiation Resistance, Survival and Migration in Glioblastoma Cells-A Potential Target for Adjuvant Radiotherapy

• Published in: Cancers Vol. 11; no. 4; p. 503
• Main Authors: Müller-Längle, Adriana, Lutz, Henrik, Hehlgans, Stephanie, Rödel, Franz, Rau, Kerstin, Laube, Bodo
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09-04-2019; MDPI
• Subjects: Antagonists; Brain cancer; Brain tumors; Calcium permeability; Cell activation; Cell adhesion & migration; Cell migration; Cell survival; Cyclic AMP response element-binding protein; DNA damage; DNA repair; Double-strand break repair; Glioblastoma; Glioblastoma cells; Glutamatergic transmission; Glutamic acid receptors; Glutamic acid receptors (ionotropic); Ionizing radiation; Localization; Malignancy; Medical prognosis; Memantine; Morphology; N-Methyl-D-aspartic acid receptors; Physiology; Radiation therapy; Radioresistance; Therapeutic applications; CREB inhibitor; U-87MG; ifenprodil; ionotropic glutamate receptors; LN229; NMDAR subunit GluN2B; memantine; radiotherapy; sulfasalazine; DNA repair
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers11040503

Glioblastoma is one of the most aggressive malignant brain tumors, with a survival time less than 15 months and characterized by a high radioresistance and the property of infiltrating the brain. Recent data indicate that the malignancy of glioblastomas depends on glutamatergic signaling via ionotropic glutamate receptors. In this study we revealed functional expression of Ca
-permeable NMDARs in three glioblastoma cell lines. Therefore, we investigated the impact of this receptor on cell survival, migration and DNA double-strand break (DSB) repair in the presence of both, glutamate and NMDAR antagonists, and after clinically relevant doses of ionizing radiation. Our results indicate that treatment with NMDAR antagonists slowed the growth and migration of glutamate-releasing LN229 cells, suggesting that activation of NMDARs facilitate tumor expansion. Furthermore, we found that DSB-repair upon radiation was more effective in the presence of glutamate. In contrast, antagonizing the NMDAR or the Ca
-dependent transcription factor CREB impaired DSB-repair similarly and resulted in a radiosensitizing effect in LN229 and U-87MG cells, indicating a common link between NMDAR signaling and CREB activity in glioblastoma. Since the FDA-approved NMDAR antagonists memantine and ifenprodil showed differential radiosensitizing effects, these compounds may constitute novel optimizations for therapeutic interventions in glioblastoma.