title: [Effects of TGF beta 1 on the cell cycle of irradiated human lung fibroblasts and its signal transduction mechanism].
abstract: OBJECTIVE
  To investigate the effects of TGF beta 1 on the proliferative activity and cell cycle of normal and gamma ray-irradiated human lung fibroblasts (HLFs).
  
  
  METHODS
  HLFs were cultured and irradiated with 3Gy gamma rays and then stimulated by TGF beta 1 at 0.01, 0.1, 1 and 10 microg/L. The proliferative activity and cell cycle were detected by MTT colorimetry and FACS. Furthermore, the expressions of signal proteins Smad3/4 in HLFs were observed by immunohistochemical staining and FACS.
  
  
  RESULTS
  TGF beta 1 of 10 microg/L could promote the proliferation of HLFs, with the number of cells in S phase increased. It also could enhance the expression of Smad3 protein and promote the nuclear translocation of Smad4 protein.
  
  
  CONCLUSIONS
  A given dose of TGF beta 1 can promote the proliferation of gamma rays-irradiated HLFs by regulating their cell cycle in which the activation of Smad pathway may play a role.
authors.affiliation: Institute of Radiation Medicine, Academy of Military Medicine Sciences, Beijing 100850, China. leeyoung33@vip.sina.com
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: De-wen
authors.initials: DW
authors.lastname: Wang
authors.forename: Liang-wen
authors.initials: LW
authors.lastname: Song
authors.forename: Rui-yun
authors.initials: RY
authors.lastname: Peng
authors.forename: Xue-mei
authors.initials: XM
authors.lastname: Cui
authors.forename: Ya-bin
authors.initials: YB
authors.lastname: Gao
authors.forename: Qing-yang
authors.initials: QY
authors.lastname: Gu
mesh_terms: D002453:Cell Cycle; D003037:Cobalt Radioisotopes; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D008168:Lung / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects; D015398:Signal Transduction; D051900:Smad3 Protein; D051901:Smad4 Protein; D015534:Trans-Activators / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
chemical_list: D003037:Cobalt Radioisotopes; D004268:DNA-Binding Proteins; C497790:SMAD3 protein, human; C497796:SMAD4 protein, human; D051900:Smad3 Protein; D051901:Smad4 Protein; C508960:TGFB1 protein, human; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1