Exploring multidrug resistance using rhodamine 123.
Accumulation of the dye rhodamine 123 was characterized by fluorescence in murine leukemia P388 cells and the Adriamycin-resistant subline, P388/ADR. Dye uptake by P388 cells was a slow, temperature-sensitive process, and involved binding at relatively hydrophobic and heterogeneous loci. Dye uptake by P388/ADR cells was temperature-insensitive, a steady state was quickly achieved, and the fluorescence emission spectrum suggested a relatively hydrophilic dye-binding site. Treatment of P388/ADR cells with verapamil resulted in enhanced accumulation of dye at hydrophobic loci. The fluorescence studies suggest that this dye may not reach the cytoplasm of P388/ADR cells, a result which may have implications with regard to the mechanism of multidrug resistance.
Kessel
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Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201.
D000818:Animals; D003630:Daunorubicin / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology*; D004351:Drug Resistance; D005456:Fluorescent Dyes; D007700:Kinetics; D007941:Leukemia P388 / Q000378:metabolism*; D007942:Leukemia, Experimental / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence; D020112:Rhodamine 123; D012235:Rhodamines; D013050:Spectrometry, Fluorescence; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000378:metabolism
D005456:Fluorescent Dyes; D012235:Rhodamines; D020112:Rhodamine 123; D004317:Doxorubicin; D003630:Daunorubicin