951 Molecular Studies of Mechanisms of Drug Resistance in Malignant Cells With Focus on Lymphomas

Results:In comparison to control MCF7 cells, jadomycins G, DNV, B and N were equally toxic to ABCB1-overexpressing MCF7 cells; jadomycins DNV, SPhG and N were equally toxic ABCC1-overexpressing MCF7 cells; and only jadomycin N was equally toxic to ABCG2-overexpressing MCF7 cells.None of the jadomycin analogues inhibited the efflux of ABCB1, ABCC1 or ABCG2 probe substrates in transport assays. Conclusion:The ability of jadomycins to retain cytotoxic activity in the corresponding drug resistant MCF7 cells stems from their ability to circumvent interactions with the ABCB1, ABCC1 and ABCG2 drug efflux transporters.