Addition of IL-6 does not alter the effects of arecoline. HA22T/VGH cells were left untreated (C) or were incubated with 100 μg/ml of arecoline for 24 h (A100), with 100 ng/ml of IL-6 for 25 h (IL-6), or with IL-6 for 1 h, then with arecoline in the continued presence of IL-6 for 24 h (IL-6+A100). The cells were then harvested and proteins extracted and used for Western blotting for phospho-Tyr705-STAT3 (STAT3-Tyr-p), Bcl-2, phospho-Tyr (Tyr-p) p190RhoGAP, phospho-Tyr (Tyr-p) SHP2, and Rock-1, as described in the legend to Fig. 3. 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. *: p < 0.05 as compared to the untreated control.