Figure 5.

Smad4 does not mediate TGF-β induction of glucocorticoid insensitivity. Smad4 targeted siRNA reduces Smad4 expression (A), Smad-dependent gene expression and the activity of the Smad-dependent promoter of SM22 (B), but does not alter the level of impairment of GC-inducible gene activity by TGF-β (C). BEAS-2B cells were transfected with scrambled control or Smad4-targeted siRNA, then incubated with TGF-β (40 pM) for 24 h, followed by stimulation with Dex (30 nM) for 4 h. Data are presented as mean and SEM for n = 4 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001.