Cigarette smoke-induced oxidative stress and TGF-beta1 increase p21waf1/cip1 expression in alveolar epithelial cells

Ann N Y Acad Sci. 2002 Nov;973:278-83. doi: 10.1111/j.1749-6632.2002.tb04649.x.


Sustained oxidative stress caused by cigarette smoking induces a chronic inflammatory response, resulting in the destruction of the alveolar cell wall characteristic of emphysema. The loss of tissue may involve the progressive depletion of epithelial cells through inhibition of proliferation leading to cell death. The cell cycle regulator p21(waf1/cip1) acts as a G(1)/S and G(2)/M phase checkpoint regulator. We hypothesize that cigarette smoke-induced oxidative stress and transforming growth factor beta 1 (TGF-beta(1)) may inhibit cellular proliferation by p21(waf1/cip1) in type II alveolar epithelial cells (A549). A significant increase was observed in p21(waf1/cip1) mRNA expression in A549 cells by cigarette smoke condensate, H(2)O(2), and TGF-beta(1). In conclusion, cigarette smoke-induced oxidative stress and TGF-beta(1) modulate expression of the cell cycle inhibitor p21(waf1/cip1). This may be important in the growth arrest and cell survival of alveolar type II cells in the G(1) phase.

MeSH terms

  • Base Sequence
  • Cell Cycle / drug effects
  • Cell Cycle / physiology*
  • Cell Division / drug effects
  • Cell Line
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / genetics*
  • DNA Primers
  • Gene Expression Regulation
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Kinetics
  • Oxidative Stress / physiology*
  • Polymerase Chain Reaction
  • Pulmonary Alveoli / physiology*
  • Respiratory Mucosa / physiology*
  • Smoke / adverse effects*
  • Smoking / physiopathology*
  • Transforming Growth Factor beta / pharmacology*
  • Transforming Growth Factor beta1


  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • DNA Primers
  • Smoke
  • TGFB1 protein, human
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • Hydrogen Peroxide