title: Fluorescent dye rhodamine 6G as a molecular probe to study drug resistance of C6 rat glioma cells.
abstract: A study was made of the membrane transport of cytoplasm and mitochondria stained fluorescence dye Rhodamine 6G (R6G). In rat glioma C6 cells and 1-(4-amino-2-methyl-5-pyrymidinyl)-methyl-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU) and vincristine (VCR) resistant cell lines (C6/ACNU, C6/VCR), the rate of uptake of R6G decreased in C6/VCR cells, but verapamil increased the intracellular accumulation of R6G in C6/VCR. The intracellular accumulation of R6G of C6/ACNU cells was essentially the same as that of wild-type cells. C6/ACNU cells did not show cross resistance and were sensitive to VCR and cisplatin. C6/VCR cells showed cross resistance to ACNU and CDDP, but C6/VCR cells in the presence of verapamil were more sensitive to drugs than C6/VCR cells in the absence of verapamil. We conclude that the reduction of R6G fluorescence staining intensity in C6/VCR cells compared to wild-type cells may be associated with the mechanism of multidrug resistance (MDR) but does not reflect the mechanism of resistance to ACNU. Verapamil increased the accumulation of R6G in C6/VCR cells and overcame MDR, suggesting that there is a correlation between the MDR overcoming effect and enhancement of R6G accumulation, and that this correlation validates the use of the R6G staining test for clinical and laboratory investigation of MDR.
authors.affiliation: Department of Neurological Surgery, Kagawa Medical School, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: N
authors.initials: N
authors.lastname: Sasaoka
authors.forename: T
authors.initials: T
authors.lastname: Tsuchida
authors.forename: T
authors.initials: T
authors.lastname: Fujiwara
authors.forename: S
authors.initials: S
authors.lastname: Nagao
authors.forename: T
authors.initials: T
authors.lastname: Ohmoto
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D004351:Drug Resistance / Q000502:physiology; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D005910:Glioma / Q000188:drug therapy*; D015335:Molecular Probes; D051381:Rats; D012235:Rhodamines; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D015335:Molecular Probes; D012235:Rhodamines; C026188:rhodamine 6G