Figure 5.

ZD6474 stimulates P-gp ATPase activity, but does not affect P-gp expression. (A) MCF-7/ADR cells were exposed to ZD6474 for 3 h. (B) MCF7/ADR cells were treated with ZD6474 for different periods of time. Cell lysates were resolved by SDS–PAGE and immunoblotted with antibodies specific for P-gp. Data shown are representatives of at least three independent experiments. (C) P-gp-expressing membranes were obtained from MCF-7/ADR cells and the ATPase activity was determined as described in the ‘Materials and methods’ section. Each point represents the mean±s.d. for three experiments. ^*P<0.05 vs control by Student's t-test.