[Effect of the methylation enzyme inhibitors of 5-aza-2-deoxycytidine on the TGF-beta/smad signal transduction pathway in human keloid fibroblasts].
OBJECTIVE
To investigate the effect of 5-aza-2-deoxycytidine on the TGF-beta/smad signal transduction pathway in human keloid fibroblasts (KFSs).


METHODS
Firstly, immunohistochemical method was used to detect the positive expression rate of phospho-smad2 and phospho-smad3 in the specimens of 15 cases of keloid and 15 cases of normal skin. The keloid fibroblasts were cultured in vitro with 5-aza-2-deoxycytidine(experimental group) or with DMEM (control group). The effect of 5-aza-2-deoxycytidine on the cell cycle and apoptosis of fibroblasts was analysed with flow cytometry ( FCM). Transforming growth factor (TGF)-beta1, Smad7, phospho-smad2 and phospho-smad3 were analyzed by Western Blot, and Immunofluorescence.


RESULTS
It was found that the positive expression of phospho-smad2 and phospho-smad3 in keloid were higher than those in normal skin. The FCM showed that the proportion of cells in G0/G1 stage was increased, and so does the proportion of apoptosis cells in keloid fibroblasts intervened by 5-aza-2-deoxycytidine. The expression of TGF-beta1, phospho-smad2 and phospho-smad3 protein were significantly suppressed while the expression of smad7 protein increased in keloid fibroblasts with 5-aza-2-deoxycytidine. In addition, 5-aza-2-deoxycytidine reversed phosphorylation and nuclear translocation of smad2 and smad3.


CONCLUSIONS
5-aza-2-deoxycytidine, methylase inhibitors, inhibits cell proliferation and promotes apoptosis of KFSs, which may be associated with the suppression of TGF-beta/smad signal pathway.
Department of Plastic and Burning Surgery,The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
Qi-Pa
QP
Zou
E
E
Yang
Heng-Shu
HS
Zhang
D017209:Apoptosis / Q000187:drug effects; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007627:Keloid / Q000378:metabolism* / Q000473:pathology; D008297:Male; D015398:Signal Transduction / Q000187:drug effects*; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D051906:Smad7 Protein / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism
D004791:Enzyme Inhibitors; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; C497806:SMAD7 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein; D051906:Smad7 Protein; D016212:Transforming Growth Factor beta; D000077209:Decitabine; D001374:Azacitidine