Figure 5. EM-E-11-4 inhibited the P-gp ATPase activity. (A) A549/Tax cells were treated with EM-E-11-4 (2.5, 5, and 10 μM) for 48 h, and P-gp was determined by Western blot analysis. (B) A luminescent assay for P-gp ATPase activity was performed according to the Pgp-GloTM Assay System instructions. ATP consumption in the presence EM-E-11-4 (2, 10, and 50 μM) combined with or without paclitaxel. Con: control; Vrp: verapamil. Columns represent the means±SD values for the luminescent change obtained from three individual experiments * p<0.05 and ** p<0.01 vs. control (10μM EM-E-11-4).