MDR1 haplotypes significantly minimize intracellular uptake and transcellular P‐gp substrate transport in recombinant LLC‐PK1 cells

To date, research on the effect of single nucleotide polymorphisms (SNPs) on P‐glycoprotein (P‐gp) expression and functionality has rendered inconsistent results. This study systematically evaluates the impact of MDR1 haplotypes (1236/2677, 1236/3435, 2677/3435, 1236/2677/3435) on P‐gp functionality...

Full description

Saved in:
Bibliographic Details
Published in:Journal of pharmaceutical sciences 2006-10, Vol.95 (10), p.2293-2308
Main Authors: Salama, Noha N., Yang, Ziping, Bui, T.o.t., Ho, Rodney J.Y.
Format: Article
Language:English
Subjects:
Animals
ATP-Binding Cassette, Sub-Family B, Member 1 - metabolism
Biological and medical sciences
Biological Transport
drug transport
efflux pumps
Fluorescent Dyes - metabolism
Gene Expression
General pharmacology
Genes, MDR - genetics
Haplotypes
LLC-PK1 Cells
Medical sciences
P-glycoprotein
Pharmaceutical technology. Pharmaceutical industry
Pharmacology. Drug treatments
polymorphism
Polymorphism, Single Nucleotide
Rhodamine 123 - metabolism
single nucleotide polymorphism
Swine
Transfection
Vinblastine - metabolism
Vincristine - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:To date, research on the effect of single nucleotide polymorphisms (SNPs) on P‐glycoprotein (P‐gp) expression and functionality has rendered inconsistent results. This study systematically evaluates the impact of MDR1 haplotypes (1236/2677, 1236/3435, 2677/3435, 1236/2677/3435) on P‐gp functionality compared to individual SNPs (1236, 2677, and 3435) in validated stable recombinant epithelial cells. Recombinant LLC‐PK1 cells expressing MDR1wt or its variants were developed and validated for this purpose. Intracellular accumulation and time‐dependant efflux of a P‐gp substrate, Rhodamine 123 (R123, 5 µM) were evaluated in control and recombinant cells. Additionally, the transepithelial transport of R123 (1 µM) and Vinca alkaloids (5 µM) was evaluated. Except for MDR12677T and MDR11236T/2677T/3435T, cells expressing MDR1 variants displayed intermediate R123 intracellular accumulation (1.5–2‐fold higher) and lower effluxed R123 (10–20% vs. 52%) compared to those expressing MDR1wt. Efflux ratios across MDR1wt expressing cells were significantly larger for R123 (3.95 ± 1.1), Vinblastine (3.75 ± 0.26), and Vincristine (2.8 ± 0.29). Recombinant cells expressing MDR1 variants displayed 0%–22.7% P‐gp activity (∼80%–100% efflux loss). Results suggest that MDR1 polymorphisms at the 1236, 2677, and/or 3435 positions significantly minimize P‐gp functionality in vitro, the extent of which appears to be substrate dependant.
ISSN:0022-3549
1520-6017
DOI:10.1002/jps.20717