Fig. 8. MAPK/ERK1/2 inhibition reverses the effect of EGF on TGFβ1-mediated N-cadherin expression. Serum-starved OKF4 and OKF6 cells were pre-treated with DMSO (as vehicle control), or MEK1/2 inhibitor U0126 (10 µM) for 30 minutes prior to treatment with EGF (20 ng/ml). The samples were then treated 30 minutes later with TGFβ1 (10 ng/ml) for an additional 24 hours. (A) E- and N-cadherin protein levels were determined by western blot analysis. (B) N-cadherin and GAPDH mRNA levels were determined in OKF6 cells using real-time PCR, and normalized to DMSO,EGF(–),TGF-b1(–) samples arbitrarily set at 1.0. The results are representative of four independent experiments.