Sal B attenuated TGF-β1-induced TβR-I and Smad2/3 phosphorylation and up-regulated Smad7 expression in HK-2 cells. HK-2 cells were incubated with serum-free medium or treated with (1) 2.5 ng/ml TGF-β1, (2) 2.5 ng/ml TGF-β1 plus 1 μM of Sal B, (3) 2.5 ng/ml TGF-β1 plus 10 μM of Sal B, (4) 2.5 ng/ml TGF-β1 plus 10 μM of SB-431542 for 24 h. The expression of TβR-I, Smad2, Smad3, p-Smad2/3 and Smad7 was detected by Western Blot. There was no significant change between each group in Smad2/3, but the expression of phosphorylated Smad2/3 and TβR-I was significantly increased. Smad7 expression was decreased after incubation with TGF-β1. Treatment with 1 μM and 10 μM Sal B and SB-431542 significantly attenuated the TGF-β1-induced up-regulation of p-Smad2/3 and TβR-I and increased Smad7 expression. The values are represented as the density of p-Smad2/3, TβR-I or Smad7 vs. GAPDH (%). **P < 0.01 vs. control; #P < 0.05 vs. TGF-β1, # #P < 0.01 vs. TGF-β1.
Wang et al. BMC Cell Biology 2010 11:31 doi:10.1186/1471-2121-11-31