title: Construction of a model cell line for the assay of MDR1 (multi drug resistance gene-1) substrates/inhibitors using HeLa cells.
abstract: Cancer cells often become resistant to chemotherapy, and induction of the ABC transporter Multi-drug Resistance gene-1 (MDR1) is a major cause. We established a tool for high-throughput screening of substrates and inhibitors of MDR1, using transformed HeLa cells that over-express MDR1. The cDNA for human MDR1 was subcloned into the eukaryotic expression vector pBK-CMV to produce an MDR1 expression vector, pBK-CMV/MDR1. HeLa cells were transfected with pBK-CMV/MDR1 or the empty vector pBK-CMV. Transfection of the vector sequence for MDR1 and its expression were evaluated by genomic PCR and western blotting, respectively. The efficiency of the MDR1 transporter for pumping a substrate out of the transformed cells was evaluated using rhodamine123 (R-123), a mitochondrial dye that is also an MDR1 substrate. After treatment of the MDR1-expressing HeLa cells with MDR1 substrate vinblastin or inhibitors cyclosporin A and verapamil, the amount of R-123 retained in the cells was increased to 2 to 2.3 times the level in untreated MDR1-expressing HeLa cells. The transfection of empty pBK-CMV had no effect on the R-123 retention in HeLa cells, regardless of drug treatment. In conclusion, we have established a model human carcinoma cell line that expresses functional MDR1 and can be used to screen for substrates and inhibitors of MDR1.
authors.affiliation: Department of Biopharmaceutics1, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo, Japan. jfkugawa@huhs.ac.jp
authors.forename: F
authors.initials: F
authors.lastname: Kugawa
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Miyata
authors.forename: K
authors.initials: K
authors.lastname: Tomono
authors.forename: F
authors.initials: F
authors.lastname: Tamanoi
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics*; D002460:Cell Line; D005456:Fluorescent Dyes; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D008957:Models, Genetic; D020112:Rhodamine 123; D014162:Transfection
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005456:Fluorescent Dyes; D020112:Rhodamine 123