Figure 4

The inhibition of extracellular signal regulated kinase (ERK)1/2 phosphorylation prevents transforming growth factor β1 (TGFβ1)-stimulated cell proliferation. Serum-deprived cells in 96-well plates were treated with 5 or 20 ng/mL TGFβ1 (abbreviated to T) with or without 10, 20, 30 μM PD98059. Cell proliferation was evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on day 3 after treatment. Five replicates per experimental condition were made. Data are normalized to values obtained for untreated cells cultured in 0.5% serum containing medium and represented as mean ± standard error of the mean (SEM) (*p < 0.05, **p < 0.01 when compared with control, #p < 0.01 when as compared with TGFβ1-treated group).