Detection of murine S180 cells expressing a multidrug resistance phenotype using different in vitro test systems and a monoclonal antibody.

Doxorubicin (adriamycin) preconditioned S180 cells were more resistant to doxorubicin. The resistance was detected by three different methods (short-term test, colony assay, tissue culture assay). The doxorubicin-resistant S180 cells express the pleitrop drug resistance phenotype. There exists a multidrug resistance to doxorubicin, dactinomycin (actinomycin D), vincristine and colchicine. In addition, collateral sensitivity was found to fluorouracil (5-fluorouracil) and methotrexate. This multidrug phenotype is in accordance with the pleiotropic phenotype of colchicine-resistant CHO cells. Resistant S180 cells express a glycoprotein of Mr 170 kd determined by indirect immunofluorescence using a monoclonal antibody (Mab 265/F4) to the P-glycoprotein of colchicine-resistant CHO-cells. The P-glycoprotein could be an important prognostic factors for tumors with multidrug resistance.