Nicotine induced ERA/MAPK activation in NPC cells.

<p><b>(A, B),</b> Human CNE1 cells were treated with nicotine at the concentration of 10 µM for 15–120 minutes. The expression of the phosphorylated or total protein of ERK1/2, JNK and P38 <b>(A)</b> were detected by Western blotting. β-Actin was used as a control for sample loading. The relative densities of ERK1/2, JNK and p38 proteins to β-Actin <b>(B)</b> were analyzed. <b>(C),</b> Human CNE1 cells were treated with the ERK-selective inhibitor U0126 (25 and 50 µM), JNK inhibitor SB203580 (300 and 600 nM) or p38 inhibitor SP600125 (25 and 50 nM), respectively, for 4 hours, and then treated with nicotine at 10 µM. At 72 hours after treatment, cell viability <b>(C)</b> was determined by MTT analysis. The percent cell viability in each treatment group was calculated relative to cells treated with the vehicle control. The data are presented as the mean ± SD of three separate experiments. *, <i>P</i><0.05, significant differences between treatment groups and control groups.