Exploring the role of Nrf2 signaling in glioblastoma multiforme

Abstract

Glioblastoma multiforme (GBM) is one of the most aggressive glial cell tumors in adults. Although current treatment options for GBM offer some therapeutic benefit, median survival remains poor and does not generally exceed 14 months. Several genes, such as isocitrate dehydrogenase (IDH) enzyme and O6-methylguanine-DNA methyltransferase (MGMT), have been implicated in pathogenesis of the disease. Treatment is often adapted based on the presence of IDH mutations and MGMT promoter methylation status. Recent GBM cell line studies have associated Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) expression with high-grade tumors. Increased Nrf2 expression is often found in tumors with IDH-1 mutations. Nrf2 is an important transcription factor with anti-apoptotic, antioxidative, anti-inflammatory, and proliferative properties due to its complex interactions with multiple regulatory pathways. In addition, evidence suggests that Nrf2 promotes GBM cell survival in hypoxic environment,by up-regulating hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Downregulation of Nrf2 has been shown to improve GBM sensitivity to chemotherapy drugs such as Temozolomide. Thus, Nrf2 could be a key regulator of GBM pathways and potential therapeutic target. Further research efforts exploring an interplay between Nrf2 and major molecular signaling mechanisms could offer novel GBM drug candidates with a potential to significantly improve patients prognosis.

Keywords: Glioblastoma; JAK–STAT; MAP/ERK; Molecular signaling pathways; Nrf-2 expression; Temozolomide; c-Myc.

Fig. 1

An overview of the molecular and genetic influences of Nrf2 on GBM formation. (Created with BioRender.com)

Fig. 2

A general overview of the Nrf2 pathway in basal conditions vs. oxidative stress and how it influences the pathogenesis of GBM. (Created with biorender.com)

Fig. 3

Schematic showing potential targets for GBM therapy related to Nrf2 signaling and expression. (Created with BioRender.com)