Atovaquone specifically and rapidly downregulates cell-surface expression of gp130. (A) U266 cells were treated with atovaquone (20 μM), JAK inhibitor 1 (1 μM), or brefeldin A (3 μg/mL) for 2.5 hours, then analyzed by flow cytometry for cell-surface expression of gp130 and IL-6 receptor (CD126). Data are representative of 3 independent experiments. (B) U266 cells were treated with atovaquone at 20 μM for the indicated time periods, and then cells were assayed by western blot or flow cytometry from the same experimental treatment. Data are representative of 2 independent experiments.