title: Mitotracker green is a P-glycoprotein substrate.
abstract: P-glycoprotein has a widespread expression on normal tissues. The protein has also been strongly associated with the multidrug resistance phenotype (MDR) on tumor cells. The employment of flow cytometry and confocal microscopy has contributed to the discovery and application of new particular fluorescent dyes. Nevertheless, several studies are being performed in different cellular types neglecting the expression/activity of MDR proteins. Because many fluorochromes have been reported as P-glycoprotein substrates, an especial attention must be given to the properties of new dyes in the presence of MDR proteins. Flow cytometric analyzes of Mitotracker Green (MTG) fluorescence profile were performed in a human erythroleukemic cell line and its resistant counterpart. In this report we demonstrated that MTG, a probe used to evaluate the mitochondrial mass, is a P-glycoprotein substrate and its staining profile is dependent on the activity of this protein. In vitro studies on a human erythroleukemic cell line and its resistant counterpart revealed that MDR modulators (Cyclosporin A, Verapamil, and Trifluoperazine) alter the MTG fluorescence pattern on a resistant cell line. The findings suggest that attention should be given to the expression of P-glycoprotein when performing an evaluation of mitochondria properties with MTG.
authors.affiliation: Laboratório de Imunologia Tumoral, Departamento de Bioquímica Médica--ICB, Universidade Federal do Rio de Janeiro,Brazil. lfmarques@bioqmed.ufrj.br
authors.forename: Luis F
authors.initials: LF
authors.lastname: Marques-Santos
authors.forename: José G P
authors.initials: JG
authors.lastname: Oliveira
authors.forename: Raquel C
authors.initials: RC
authors.lastname: Maia
authors.forename: Vivian M
authors.initials: VM
authors.lastname: Rumjanek
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000447:Aldehydes / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D048429:Cell Size; D016572:Cyclosporine / Q000494:pharmacology; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005434:Flow Cytometry / Q000379:methods; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D020014:K562 Cells; D008928:Mitochondria / Q000378:metabolism; D020112:Rhodamine 123 / Q000494:pharmacology; D013997:Time Factors; D014268:Trifluoperazine / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000447:Aldehydes; D005456:Fluorescent Dyes; C111472:mitotracker green FM; D020112:Rhodamine 123; D014268:Trifluoperazine; D016572:Cyclosporine; D014700:Verapamil