PGP and prostate cancer: To this aim, experiments similar to those reported in Fig 2 were performed with the prostate cancer cell line, DU145 [20], that does not over-express P-glycoprotein [21] (Fig 6A) and with a relatively normal human lung fibroblast cell line, HFL-1[22] (Fig 6B), which also does not over-express P-gp.