Probing membrane alterations associated with anthracycline resistance using fluorescent dyes.
Properties of membranes of intact P388 murine lymphoblastic leukemia and a sub-line selected for resistance to adriamycin (P388/ADR) were examined using two fluorescent probes: diphenylhexatriene (DPH) and trimethylammonium diphenylhexatriene (T-DPH). Time-dependent changes in dye accumulation, fluorescence anisotropy, and lifetimes were measured. Accumulation of DPH, which eventually labels all cellular lipids, increased with time. Uptake of T-DPH, a more membrane-specific probe, reached a maximum in less than 1 min. No alteration could be detected in fluorescence anisotropy or lifetime of either dye associated with anthracycline resistance or anthracycline treatment. The rate of uptake of the T-DPH was not different in P388 versus P388/ADR cell lines, suggesting no differences in membrane "traffic". Calcium-channel antagonists could partially reverse anthracycline resistance in P388/ADR, but this was not accompanied by alterations in fluorescence parameters.
Kessel
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Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201.
D000818:Animals; D004161:Diphenylhexatriene / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004317:Doxorubicin / Q000494:pharmacology*; D004351:Drug Resistance; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D007941:Leukemia P388 / Q000473:pathology*; D007942:Leukemia, Experimental / Q000473:pathology*
D005456:Fluorescent Dyes; D004161:Diphenylhexatriene; C033628:1-(4-(trimethylamino)phenyl)-6-phenylhexa-1,3,5-triene; D004317:Doxorubicin