Expression changes of EMT-related markers in A549 cells. (A) A549 cells were incubated with up to 10 ng/ml of TGF-β1 in the absence of serum for up to 72 h. Expression of the epithelial marker E-cadherin is down-regulated by TGF-β1 stimulation in a concentration-and time-dependent manner. Expression of Fn-EDA, which is a mesenchymal marker, is up-regulated by TGF-β1 in parallel with the down regulation in the epithelial marker. The same amounts of total protein are loaded in each lane. (B) Densitometric analysis of band intensities for each EMT related marker was performed at 48 h. Each bar represents mean ± SD of three independent experiments. * P < 0.05 and ** P < 0.01.