The calcium channel blockers, 1,4-dihydropyridines, are substrates of the multidrug resistance-linked ABC drug transporter, ABCG2
The calcium channel blockers, 1,4-dihydropyridines, are substrates of the multidrug resistance-linked ABC drug transporter, ABCG2
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DOI：
10.1021/bi060552f
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发表时间：
2006-07-25
期刊：
影响因子：
2.9
通讯作者：
Ambudkar, Suresh V.
中科院分区：
文献类型：
--
作者：
Shukla, Suneet;Robey, Robert W.;Ambudkar, Suresh V.
人类 ATP 结合盒转运蛋白 ABCG2 赋予多种化疗药物耐药性，并且还会影响不同药物的生物利用度。本研究中使用[I-125]碘芳基叠氮哌唑嗪 (IAAP) 和[H-3]叠氮平对 ABCG2 进行光亲和标记。我们在这里首次表明，这两种光亲和类似物都是 ABCG2 的转运底物，并且 [H-3] 叠氮平也可用于光标记野生型 R482-ABCG2 和突变体 T482-ABCG2。我们进一步使用这些测定法来筛选ABCG2的潜在底物或调节剂，并观察到临床上用作抗高血压药物的1,4-二氢吡啶类药物如尼卡地平和硝苯地平抑制ABCG2与[I-125] IAAP和[H-3]叠氮平的光标记以及ABCG2对这些光亲和类似物的转运。此外，[H-3]尼群地平和 bodipy-F1-二氢吡啶累积测定表明这些化合物由 ABCG2 转运。这些二氢吡啶还抑制已知的 ABCG2 底物米托蒽醌和脱镁叶绿酸-a 从 ABCG2 过表达细胞中流出，尼卡地平在抑制这种转运方面更有效。尼卡地平和硝苯地平均刺激 ABCG2 的 ATP 酶活性，而硝苯地平刺激的活性被夫米特莫金 C 抑制，表明这些药物可能在转运蛋白的同一位点相互作用。此外，无毒浓度的二氢吡啶使ABCG2表达细胞对米托蒽醌的敏感性增加了3-5倍。总的来说，使用 [I-125] IAAP 和 [H-3] 叠氮平的光亲和标记和外排测定结果表明，1,4-二氢吡啶是 ABCG2 的底物，并且这些光标记可用于筛选该转运蛋白的新底物和/或抑制剂。
The human ATP-binding cassette transporter, ABCG2, confers resistance to multiple chemotherapeutic agents and also affects the bioavailability of different drugs. [I-125]Iodoarylazidoprazosin (IAAP) and [H-3] azidopine were used for photoaffinity labeling of ABCG2 in this study. We show here for the first time that both of these photoaffinity analogues are transport substrates for ABCG2 and that [H-3] azidopine can also be used to photolabel both wild-type R482-ABCG2 and mutant T482-ABCG2. We further used these assays to screen for potential substrates or modulators of ABCG2 and observed that 1,4-dihydropyridines such as nicardipine and nifedipine, which are clinically used as antihypertensive agents, inhibited the photolabeling of ABCG2 with [I-125] IAAP and [H-3] azidopine as well as the transport of these photoaffinity analogues by ABCG2. Furthermore, [H-3] nitrendipine and bodipy-F1-dihydropyridine accumulation assays showed that these compounds are transported by ABCG2. These dihydropyridines also inhibited the efflux of the known ABCG2 substrates, mitoxantrone and pheophorbide-a, from ABCG2-overexpressing cells, and nicardipine was more potent in inhibiting this transport. Both nicardipine and nifedipine stimulated the ATPase activity of ABCG2, and the nifedipine-stimulated activity was inhibited by fumitremorgin C, suggesting that these agents might interact at the same site on the transporter. In addition, nontoxic concentrations of dihydropyridines increased the sensitivity of ABCG2-expressing cells to mitoxantrone by 3-5-fold. In aggregate, results from the photoaffinity labeling and efflux assays using [I-125] IAAP and [H-3] azidopine demonstrate that 1,4-dihydropyridines are substrates of ABCG2 and that these photolabels can be used to screen new substrates and/or inhibitors of this transporter.