[Effects of TGF beta 1 on the cell cycle of irradiated human lung fibroblasts and its signal transduction mechanism].
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.
Li
Yang
Y
Institute of Radiation Medicine, Academy of Military Medicine Sciences, Beijing 100850, China. leeyoung33@vip.sina.com
Wang
De-wen
DW
Song
Liang-wen
LW
Peng
Rui-yun
RY
Cui
Xue-mei
XM
Gao
Ya-bin
YB
Gu
Qing-yang
QY
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
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