NCI/ADR-RES is actually an Ovarian tumor cell line (OVCAR-8). If you want to develop resistant cell line against doxorubicin,you have to first calculate IC50 of doxorubicin, after that starting giving doses from IC50 of doxorubicin and after few months,when cell proliferation takes place in maintaining dose, then you have to increase its dose accordingly for 6-8 months,after that you will calculate IC50 of that cell line and surely PGP expression will be higher when compared with wild type. I had made few resistant cell lines Like HEPG2, K562, and MCF-7 against various anticancer drug. After that i have checked out PGP expression through western blot and by functional assay. I am already working on NCI-RES cell.