title: Dyes providing increased sensitivity in flow-cytometric dye-efflux assays for multidrug resistance.
abstract: In an effort to improve detection of P-glycoprotein-mediated multidrug resistance (mdr), several dyes were compared to rhodamine 123 (R123) in efflux assays. Two dyes (SY-38 and SY-3150) were found that provided better sensitivity. These dyes were effluxed by a cell line known to be mdr-positive (P388/R84) but not by an mdr-negative cell line (P388). Efflux was blocked by both verapamil and cyclosporine A. Efflux from KG1a cells was less than from P388/R84, just as has been seen with R123 and daunomycin. In further experiments, a model system was used to demonstrate two-color immunofluorescence plus efflux measurements. This was done using a sequential staining method. A procedure was devised that, at least for this model system, allowed single-step staining with both dye and antibody. The sensitivity of the efflux measurement was slightly compromised by using this one-step staining method.
authors.affiliation: Becton Dickinson Immunocytometry System, San Jose, California 95131, USA.
authors.forename: T
authors.initials: T
authors.lastname: Frey
authors.forename: S
authors.initials: S
authors.lastname: Yue
authors.forename: R P
authors.initials: RP
authors.lastname: Haugland
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis / Q000378:metabolism; D000818:Animals; D002051:Burkitt Lymphoma; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004396:Coloring Agents; D018432:Drug Resistance, Multiple; D005434:Flow Cytometry / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D006801:Humans; D007941:Leukemia P388; D015473:Leukemia, Promyelocytic, Acute; D015459:Leukemia-Lymphoma, Adult T-Cell; D051379:Mice; D020112:Rhodamine 123; D012235:Rhodamines; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002121:Calcium Channel Blockers; D004396:Coloring Agents; D005456:Fluorescent Dyes; D012235:Rhodamines; D020112:Rhodamine 123; D014700:Verapamil; D016650:Fluorescein-5-isothiocyanate