ROS-generating NADPH oxidase NOX4 is a critical mediator in oncogenic H-Ras-induced DNA damage and subsequent senescence

Oncogene. 2012 Mar 1;31(9):1117-29. doi: 10.1038/onc.2011.327. Epub 2011 Aug 15.

Abstract

Activated Ras oncogene induces DNA-damage response by triggering reactive oxygen species (ROS) production and this is critical for oncogene-induced senescence. Until now, little connections between oncogene expression, ROS-generating NADPH oxidases and DNA-damage response have emerged from different studies. Here we report that H-RasV12 positively regulates the NADPH oxidase system NOX4-p22(phox) that produces H(2)O(2). Knocking down the NADPH oxidase with small interference RNA decreases H-RasV12-induced DNA-damage response detected by γ-H2A.X foci analysis. Using HyPer, a specific probe for H(2)O(2), we detected an increase in H(2)O(2) in the nucleus correlated with NOX4-p22(phox) perinuclear localization. DNA damage response can be caused not only by H-RasV12-driven accumulation of ROS but also by a replicative stress due to a sustained oncogenic signal. Interestingly, NOX4 downregulation by siRNA abrogated H-RasV12 regulation of CDC6 expression, an essential regulator of DNA replication. Moreover, senescence markers, such as senescence-associated heterochromatin foci, PML bodies, HP1β foci and p21 expression, induced under H-RasV12 activation were decreased with NOX4 inactivation. Taken together, our data indicate that NADPH oxidase NOX4 is a critical mediator in oncogenic H-RasV12-induced DNA-damage response and subsequent senescence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Checkpoints / genetics
  • Cellular Senescence / genetics*
  • DNA Damage*
  • Humans
  • Hydrogen Peroxide / metabolism
  • NADPH Oxidase 4
  • NADPH Oxidases / antagonists & inhibitors
  • NADPH Oxidases / genetics*
  • NADPH Oxidases / metabolism*
  • Oxidation-Reduction
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • Reactive Oxygen Species / metabolism*

Substances

  • Reactive Oxygen Species
  • Hydrogen Peroxide
  • NADPH Oxidase 4
  • NADPH Oxidases
  • NOX4 protein, human
  • Proto-Oncogene Proteins p21(ras)