Transforming growth factor-beta expression in mouse lung carcinogenesis

Exp Lung Res. 1998 Jul-Aug;24(4):579-93. doi: 10.3109/01902149809087387.

Abstract

Transforming growth factor-beta (TGF-beta) is a multifunctional growth modulator that inhibits the proliferation of many epithelial cells while stimulating the proliferation of most fibroblasts. To examine the role of TGF-beta in mouse lung chemically induced tumorigenesis, expression of the TGF-beta 1, -beta 2, and -beta 3 proteins was examined in A/J mice treated with the carcinogen urethane to induce lung adenomas using immunohistochemical staining analysis. Immunostaining for the TGF-beta ligands was detected in the epithelium of the bronchioles of untreated A/J mice with immunostaining being more intense for TGF-beta 1 than for TGF-beta 2 and TGF-beta 3; immunostaining for each TGF-beta ligand was also detected in the bronchiolar epithelium of urethane-treated A/J mice at levels similar to untreated mice. Immunostaining for the TGF-beta ligands was also detected in adenomas by 2 months; staining for TGF-beta 1, -beta 2, and -beta 3 in adenomas was detected at levels comparable with bronchioles. Following treatment with urethane for 8 months, immunostaining for TGF-beta s 1, 2, and 3 in bronchioles persisted at levels comparable to that in normal bronchioles and also persisted in adenomas, with staining for the TGF-beta ligands being very prominent on the edge of the tumor. Expression of TGF-beta 1 mRNA was examined in urethane-treated mouse lung tissue using Northern blot hybridization; here, expression of TGF-beta 1 mRNA increased 2-fold in 3-month urethane-treated lung tissue and an additional 2.5-fold by 8 months following urethane administration. Expression of TGF-beta 1 mRNA was also examined in nontumorigenic and tumorigenic mouse lung cells; in these cells, expression of TGF-beta 1 mRNA was higher in the tumorigenic cells than in the nontumorigenic cell line. These data show that there is an increase in expression of TGF-beta 1 during tumorigenesis and suggest that TGF-beta may play an important role in mouse lung carcinogenesis induced by urethane.

MeSH terms

  • Adenoma / chemically induced
  • Adenoma / metabolism*
  • Adenoma / pathology
  • Animals
  • Blotting, Northern
  • Bronchi / cytology
  • Bronchi / metabolism
  • Carcinogens / toxicity
  • DNA Primers / chemistry
  • Disease Progression
  • Epithelial Cells / metabolism
  • Female
  • Immunoenzyme Techniques
  • Ligands
  • Lung / cytology
  • Lung / metabolism
  • Lung Neoplasms / chemically induced
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology
  • Mice
  • Mice, Inbred A
  • Polymerase Chain Reaction
  • RNA, Messenger / biosynthesis
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*
  • Tumor Cells, Cultured
  • Urethane / toxicity

Substances

  • Carcinogens
  • DNA Primers
  • Ligands
  • RNA, Messenger
  • Transforming Growth Factor beta
  • Urethane