Nuclear EGFRvIII resists hypoxic microenvironment induced apoptosis via recruiting ERK1/2 nuclear translocation

Abstract

Glioblastoma (GBM) is the most aggressive type of primary brain tumor. Its interaction with the tumor microenvironment promotes tumor progression. Furthermore, GBM bearing expression of EGFRvIII displays more adaptation to tumor microenvironment related stress. But the mechanisms were poorly understood. Here, we presented evidence that in the human U87MG glioblastoma tumor model, EGFRvIII overexpression led aberrant kinase activation and nuclear translocation of EGFRvIII/ERK1/2 under hypoxia, which induced growth advantage by resisting apoptosis. Additionally, EGFRvIII defective in nuclear entry impaired this capacity in hypoxia adaptation, and partially interrupted ERK1/2 nuclear translocation. Pharmacology or genetic interference ERK1/2 decreased hypoxia resistance triggered by EGFRvIII expression, but not EGFRvIII nuclear translocation. In summary, this study identified a novel role for EGFRvIII in hypoxia tolerance, supporting an important link between hypoxia and subcellular localization alterations of the receptor.

Keywords: EGFRvIII; ERK1/2; Glioblastoma; Hypoxia; Nuclear translocation.