Supplementary Fig. S6  Effect of digoxin on PI3K kinase activity. PI3K was reacted with PI(4,5)P2 in the presence and absence of digoxin for 2 h and PI(3,4,5)P3 production was measured with a competitive ELISA. Data were expressed as mean ± SD, and the results were representative of three independent experiments. Significant differences were indicated as ***P < 0.001 vs. control group.