ROS-generating oxidases Nox1 and Nox4 contribute to oncogenic Ras-induced premature senescence

Genes Cells. 2013 Jan;18(1):32-41. doi: 10.1111/gtc.12015. Epub 2012 Dec 6.


Activated oncogenes induce premature cellular senescence, a permanent state of proliferative arrest in primary rodent and human fibroblasts. Recent studies suggest that generation of reactive oxygen species (ROS) is involved in oncogenic Ras-induced premature senescence. However, the signaling mechanism controlling this oxidant-mediated irreversible growth arrest is not fully understood. Here, we show that through the Ras/MEK pathway, Ras oncogene up-regulated the expression of superoxide-generating oxidases, Nox1 in rat REF52 cells and Nox4 in primary human lung TIG-3 cells, leading to an increase in intracellular level of ROS. Ablation of Nox1 and Nox4 by small interfering RNAs (siRNAs) blocked the RasV12 senescent phenotype including β-galactosidase activity, growth arrest and accumulation of tumor suppressors such as p53 and p16Ink4a. This suggests that Nox-generated ROS transduce senescence signals by activating the p53 and p16Ink4a pathway. Furthermore, Nox1 and Nox4 siRNAs inhibited both Ras-induced DNA damage response and p38MAPK activation, whereas overexpression of Nox1 and Nox4 alone was able to induce senescence. The involvement of Nox1 in Ras-induced senescence was also confirmed with embryonic fibroblasts derived from Nox1 knockout mice. Together, these findings suggest that Nox1- and Nox4-generated ROS play an important role in Ras-induced premature senescence, which may involve DNA damage response and p38MAPK signaling pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Cycle
  • Cell Line
  • Cellular Senescence*
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism
  • DNA Damage
  • Fibroblasts / cytology
  • Fibroblasts / enzymology
  • Humans
  • Mice
  • NADH, NADPH Oxidoreductases / genetics
  • NADH, NADPH Oxidoreductases / metabolism*
  • NADPH Oxidase 1
  • NADPH Oxidase 4
  • NADPH Oxidases / genetics
  • NADPH Oxidases / metabolism*
  • Oncogene Protein p21(ras) / metabolism*
  • RNA, Small Interfering
  • Reactive Oxygen Species / metabolism*
  • Signal Transduction
  • Tumor Suppressor Protein p53 / metabolism
  • Up-Regulation
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Cyclin-Dependent Kinase Inhibitor p16
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Tumor Suppressor Protein p53
  • NADH, NADPH Oxidoreductases
  • NADPH Oxidase 1
  • NADPH Oxidase 4
  • NADPH Oxidases
  • NOX1 protein, mouse
  • NOX1 protein, rat
  • Nox4 protein, mouse
  • p38 Mitogen-Activated Protein Kinases
  • Oncogene Protein p21(ras)