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MDR‐1 gene expression is a minor factor in determining the multidrug resistance phenotype of MCF7/ADR and KB‐V1 cells
Author(s) -
Kim Hwan Mook,
Oh Goo Taeg,
Hong Dong Ho,
Kim Moon Soon,
Kang Jong Seong,
Park Sun Mi,
Han Sang Bae
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00777-1
Subject(s) - efflux , multiple drug resistance , p glycoprotein , drug resistance , biology , drug , gene expression , pharmacology , gene , verapamil , microbiology and biotechnology , chemistry , biochemistry , genetics , organic chemistry , calcium
The relevance of MDR‐1 gene expression to the multidrug resistance phenotype was investigated. Drug‐resistant cells, KB‐V1 and MCF7/ADR, constantly expressed mRNA of the MDR‐1 gene and were more resistant to vinblastine and adriamycin than drug‐sensitive cells, KB‐3–1 and MCF7. The drug efflux rate of KB‐V1 was the same as KB‐3–1 although the MDR‐1 gene was expressed in only the resistant cell. The higher intracellular drug concentration of KB‐3–1 than KB‐V1 was due to the large drug influx. In the case of MCF7 and MCF7/ADR, the influx and efflux of the drug had nearly the same pattern and drug efflux was not affected by verapamil. The amount of ATP, cofactor of drug pumping activity of P‐glycoprotein, was not changed by the resistance. These observations suggested that drug efflux mediated by MDR‐1 gene expression was not a major determining factor of drug resistance in the present cell systems, and that the drug resistance could be derived from the change in drug uptake and other mechanisms.