Nox 4 knockdown and a antioxidant compound suppress cycling hypoxia-induced ROS levels in glioblastoma xenografts.

<p>(A) Regulation of Nox4 by Dox-inducible shRNA. GBM8401-Luc cells were infected with Tet-regulable lentiviral vectors encoding Nox4 shRNAs. The infected cells were treated with or without Dox for 24 h and harvested for western blot analysis. (B) Immunohistochemical analysis of Nox4 in GBM8401-Luc xenografts with or without conditional knockdown of Nox4 under cycling hypoxic stress. Original magnification, ×200. Bar, 100 µm. (C) <i>In vivo</i> optical imaging of GBM-bearing mice injected with L-012. (D) Quantitative data obtained from <i>in vivo</i> optical imaging of ROS levels in GBM xenografts with or without Dox or Tempol following <i>in vivo</i> cycling hypoxic stress. * p<0.01 compared to normoxia. # p<0.01 compared to cycling hypoxia.