Abstract
Breast cancer resistance protein (BCRP/ABCG2) is a novel member of ATP-binding cassette transporters, which induce multidrug resistance in cancer cells. We previously reported that a high level of BCRP expression in CD4 + T cells conferred cellular resistance to nucleoside reverse transcriptase inhibitors (NRTIs) of human immunodeficiency virus type 1 (HIV-1). However, this BCRP was found to have a mutation of Arg to Met at position 482 (BCRPR482M). The present study demonstrated that the wild-type BCRP (BCRPWT) also conferred cellular resistance to NRTIs. MT-4 cells (a CD4+ T-cell line) highly expressing BCRPWT (MT-4/BCRP) were generated and the expression of BCRPWT was confirmed by genotypic and phenotypic analyses. Compared to the parental MT-4 cells, MT-4/BCRP cells displayed resistance to zidovudine (AZT) in terms of antiviral activity as well as drug cytotoxicity. In addition, other NRTIs were also less inhibitory to HIV-1 replication in MT-4/BCRP cells than in MT-4 cells. Significant reduction of intracellular AZT accumulation was observed in MT-4/BCRP cells. An analysis for intracellular metabolism of AZT suggested that the resistance was attributed to the increased efflux of AZT and its metabolites in MT-4/BCRP cells. Furthermore, the BCRP-specific inhibitor fumitremorgin C completely restored the reduction of AZT in MT-4/BCRP cells. These results indicate that, like BCRPR482M, BCRPWT also plays an important role in cellular resistance to NRTIs.
Original language | English |
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Pages (from-to) | 1363-1370 |
Number of pages | 8 |
Journal | Biochemical Pharmacology |
Volume | 68 |
Issue number | 7 |
DOIs | |
Publication status | Published - 2004 Oct 1 |
Externally published | Yes |
Keywords
- ABC
- ATP-binding cassette
- AZT
- CNS
- HAART
- HIV-1
- MRP
- NRTI
- P-glycoprotein
- P-gp
- PI
- central nervous system
- highly active antiretroviral therapy
- human immunodeficiency virus type 1
- multidrug resistance protein
- protease inhibitor
- zidovudine
ASJC Scopus subject areas
- Biochemistry
- Pharmacology