GF120918, at 250 ng/ml, increased the sensitivity of a P-glycoprotein (P-gp)-mediated multidrug resistant (MDR) small cell lung cancer cell line (H69/LX4) to the P-gp substrates, paclitaxel, taxotere, vinblastine, vinorelbine, daunorubicin and etoposide to levels which were either greater ...