FIGURE 9.

Pgp protein expression (A and B) and function (C) in a panel of cervical, breast, and colorectal carcinoma cell lines. The cervical carcinoma cell lines KB31 (−Pgp) and KBV1 (+Pgp; 1 μg/ml vinblastine), the breast cancer cell lines, MCF7 and MDA-MB-231, and the colorectal carcinoma cell line, HCT-15, were assessed for Pgp protein expression by Western blotting (A), cell plasma membrane-Pgp expression measured by flow cytometry at 4 °C (B), and Pgp function analysis by flow cytometric measurement of the intracellular retention of Rh123 for 30 min/37 °C (C). Data are the mean ± S.D. of three independent experiments. ***, p < 0.001 is relative to KBV1 cells; *, p < 0.05, relative to MCF-7 cells. a.u., arbitrary units.