Abstract:

Objective To evaluate the effects of decitabine on the proliferation of keloid fibroblasts and the expression of proteins relevant to TGF-β/Smad signal pathways. Methods CCK8 assay was adopted to detect the effects of decitabine of different concentrations on the proliferation of keloid fibroblasts. The expressions of transforming growth factor-β1 (TGF-β1), phosphorylated p-Smad2/3 (p-Smad2/3), Smad4, collagen type I alpha 1 (COL1A1), and COL3A1 of keloid fibroblasts before and after being intervened by decitabine were detected by the Western blotting. Immunoprecipitation assay and Smad4 siRNA transfection were adopted to explore the role of p-Smad2/3-Smad4 complex during the formation of keloid. Real-time PCR was used to detect the expression of downstream transcriptional factors. Results The results of CCK8 assay showed that the growth inhibition rate of fibroblasts increased with the concentration of decitabine after being intervened for 48 h. IC50 concentration of decitabine of 4.38 μmol/L was selected as the intervention concentration of ear lobe keloid fibroblasts. After being intervened by decitabine, expressions of TGF-β1, p-Smad2/3, COL1A1, and COL3A1 of keloid fibroblasts and the formation of p-Smad2/3-Smad4 complex significantly decreased. The expression of COL1A1 of keloid fibroblasts decreased and mRNA expressions of transcriptional factors c-jun, runx2, and irf-7 were down-regulated after Smad4 was silenced. Conclusion Decitabine can inhibit the proliferation of keloid fibroblasts and the synthesis of collagens. The mechanism may be relevant to the inhibition of phosphorylation of Smad2/3 and the formation of p-Smad2/3-Smad4 protein complex.

Key words: decitabine, keloid fibroblasts, TGF-β/Smad signal pathway, p-Smad2/3-Smad4 protein complex