Effects of new 4-aryl-1,4-dihydropyridines and 4-arylpyridines on drug efflux mediated by multidrug resistance-associated protein 1
✍ Scribed by Xiao-fei Zhou; Robert A. Coburn; Marilyn E. Morris
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 164 KB
- Volume
- 94
- Category
- Article
- ISSN
- 0022-3549
No coin nor oath required. For personal study only.
✦ Synopsis
The purpose of this study is to evaluate the effects of newly synthesized 4aryl-1,4-dihydropyridine and pyridines on drug efflux mediated by multidrug resistanceassociated protein 1 (MRP1, ABCC1). These compounds were designed to maximize inhibition of P-glycoprotein and minimize calcium channel binding activity, based on structure modifications of niguldipine. A [ 3 H]vinblastine accumulation study was conducted in human small cell lung cancer H69AR (overexpressing MRP1) and wild type H69 cells. Five out of 16 dihydropyridines and 6 out of 9 pyridines were found to significantly increase the intracellular accumulation of vinblastine in resistant H69AR cells (p < 0.01) at a concentration of 2.5 mM. Daunomycin accumulation studies, determined using a flow cytometric assay, were also performed in H69AR and human pancreatic adenocarcinoma Panc-1 cells and the results were highly correlated with those obtained from the [ 3 H]vinblastine accumulation studies. Four compounds, which significantly increased vinblastine accumulation, were tested for their effect on daunomycin cytotoxicity in H69AR cells and found to significantly decrease the IC 50 of daunomycin, confirming the accumulation study results. Compounds were also tested for their effect on intracellular glutathione (GSH) concentrations, a cosubstrate for MRP1mediated efflux in H69AR and Panc-1 cells. No significant changes in the intracellular GSH level were observed in H69AR cells after treatment with these test compounds. However, following a 2-hr and 24-hr incubation with a dihydropyridine compound, I m , and its pyridine derivative II m , there was a small ($20%) but statistically significant decrease in intracellular GSH in Panc-1 cells. Our results indicate that some dihydropyridine and pyridine compounds in our series could inhibit MRP1-mediated transport and that GSH modulation plays a minor, if any, role in this effect.