Comparative studies on resistance to anthracycline derivatives between doxorubicin-resistant mouse lymphoblastoma L5178Y cells and mouse leukemia P388 cells.

When tumor cells are chronically treated with antitumor drugs such as vinca alkaloids or anthracyclines, they often acquire resistance not only to the same drugs but also to other antitumor drugs1~3). Although the mechanism of this pleiotropic drug resistance is not fully understood, decreased uptake and retention of doxorubicin ( = adriamycin, ADM) and daunorubicin ( = daunomycin, DNR) in drug resistant cell lines induced by ADMin mouseleukemia P388 cells and mouse lymphoblastoma L5178Y cells have been reported4'5). Inaba et al.5) observed the enhanced