Arecoline alters the expression of apoptosis-related proteins and caspase activity in HA22T/VGH cells. (A) HA22T/VGH cells were treated with 0, 30, or 100 μg/ml of arecoline for 24 h, then the cells were harvested and proteins extracted and used for Western blotting for Bcl-2, Bcl-XL, Bax, cytochrome c, or procaspase-9. β-actin was used as the internal control. The values shown are the quantitative density analysis expressed as the relative density compared to that in untreated cells (control), taken as 100%. The results are expressed as the mean ± S.D. for three separate experiments. (B) Caspase-3 activity was detected using RPE-conjugated anti-active caspase-3 antibody by flow cytometric analysis. The values shown are the percentage of cells with active caspase-3 and are the mean ± S.D. of three independent experiments. The red filled area is the untreated control and the black lines the treated groups. *: p < 0.05 as compared to the untreated control.