Abstract
Recombinant nucleotide-binding domains (NBDs) from human multidrug resistance protein MRP1 were overexpressed in bacteria and purified to measure their direct interaction with high-affinity flavonoids, and to evaluate a potential correlation with inhibition of MRP1-mediated transport activity and reversion of cellular multidrug resistance. Among different classes of flavonoids, dehydrosilybin exhibited the highest affinity for both NBDs, the binding to N-terminal NBD1 being prevented by ATP. Dehydrosilybin increased vanadate-induced 8-N3-[α-32P]ADP trapping, indicating stimulation of ATPase activity. In contrast, dehydrosilybin strongly inhibited leukotriene C4 (LTC4) transport by membrane vesicles from MRP1-transfected cells, independently of reduced glutathione, and chemosensitized cell growth to vincristine. Hydrophobic C-isoprenylation of dehydrosilybin increased the binding affinity for NBD1, but outsite the ATP site, lowered the increase in vanadate-induced 8-N3-[α- 32P]ADP trapping, weakened inhibition of LTC4 transport which became glutathione dependent, and induced some cross-resistance. The overall results indicate multiple binding sites for dehydrosilybin and its derivatives, on both cytosolic and transmembrane domains of MRP1.
Original language | English (US) |
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Pages (from-to) | 2164-2177 |
Number of pages | 14 |
Journal | Cellular and Molecular Life Sciences |
Volume | 60 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2003 |
Keywords
- ABC transporter
- Chemosensitization
- Drug-binding site
- Flavonoid
- Multidrug resistance (MDR)
- Multidrug resistance protein 1 (MRP1)
- Nucleotide-binding domain (NBD)
ASJC Scopus subject areas
- Molecular Medicine
- Molecular Biology
- Pharmacology
- Cellular and Molecular Neuroscience
- Cell Biology