NMDA Receptor Signaling Mediates cFos Expression via Top2β-Induced DSBs in Glioblastoma Cells

Area of Science:

• Neuroscience
• Oncology
• Molecular Biology

Background:

• N-methyl-D-aspartic acid (NMDA) receptor channels (NMDARs) are vital for neuronal function but are also implicated in cancer progression.
• NMDAR-mediated signaling enhances tumor growth and invasiveness, suggesting potential as a therapeutic target in cancer.
• DNA double-strand breaks (DSBs) are critical signaling intermediates in neurons, facilitating gene expression.

Purpose of the Study:

• To investigate NMDAR-induced DNA double-strand breaks (DSBs) in glioblastoma multiforme (GBM) cells.
• To elucidate the role of topoisomerase IIβ (Top2β) in NMDAR signaling within glioma cells.
• To evaluate the therapeutic potential of targeting NMDAR and related pathways in GBM.

Main Methods:

• Utilized LN229 and U-87MG glioblastoma cell lines.
• Employed immunofluorescence staining (53BP1) to detect DSBs.
• Performed Western blot analysis for protein expression (cFos, CREB, Top2β) and siRNA-mediated knockdown of Top2β.

Main Results:

• NMDAR activation induced DSBs in a subpopulation of glioma cells, dependent on topoisomerase IIβ (Top2β) activity.
• Inhibition of NMDARs, CREB, and Top2β decreased cFos expression.
• Top2β knockdown reduced cFos expression and increased radiosensitivity in LN229 cells, with similar effects observed in a primary GBM cell line.

Conclusions:

• NMDAR signaling contributes to DNA damage in glioma cells, analogous to its role in neurons.
• The pathway involving NMDAR, Top2β, and cFos is active in GBM cells.
• Targeting NMDAR signaling proteins presents a promising therapeutic strategy for glioblastoma multiforme.