FIG. 2.

Effects of CAM (10 μg/ml) on pERK. Growth factors were withdrawn from the culture medium at 24 h before CAM exposure. NHBE cells were exposed to CAM for 30, 60, and 90 min. ERK phosphorylation was measured by Western blotting. The baseline pERK1/2 level or the ratio of pERK to tERK was set at 100%. These experiments were repeated three times, and results are shown as means ± SEMs. (A) pERK expression decreased in CAM-exposed cells compared with that of controls at 30, 60, and 90 min. (B) There was a decrease in the ratio of pERK1/2 to tERK1/2 at 60 min. *, P < 0.05; **, P < 0.01; ****, P < 0.0001 compared with the control (Cont).