Inhibition or evasion of P-glycoprotein-mediated drug transport

该项目的总体目标是获得对P-糖蛋白（Pgp）的深入的分子水平的了解。 介导的药物转运和外排抑制。Pgp属于一类非常重要的ATP结合盒 (ABC)利用ATP水解的能量将底物转运出细胞的转运蛋白。一个真正的 Pgp的显著特征是其异常广泛的多特异性。Pgp的功能就像一个疏水真空 更清洁，运输不同的分子，包括许多临床上有用的药物，分配到脂质双层。 众所周知，Pgp是药物生物利用度、药代动力学和临床疗效的关键决定因素， 人类Pgp也会引起细胞的多药耐药性，阻碍许多疾病的治疗。因为 Pgp外排对药物的潜在不良影响，美国食品和药物管理局要求 记录药物与Pgp的相互作用，以批准任何新药。逃避或抑制Pgp， 降低治疗效果一直是制药工业的主要目标，然而， 由于缺乏对多特异性Pgp-药物相互作用的基本理解，这一研究受到严重阻碍。我们 研究Pgp/药物相互作用的长期目标是促进新药的开发和发现， 抑制或逃避Pgp外排。为此，我们提出了三个独立但相关的具体目标， 该项目的研究，每一个解决一个关键问题密切相关的药物开发。目标1： 将发现真正的Pgp拮抗剂进行机制研究。我们注意到许多广泛研究的Pgp抑制剂 与药物竞争Pgp转运。我们设想发现新的非底物Pgp拮抗剂 显示出与已知抑制剂不同的性质，这对Pgp抑制机制研究至关重要， 用于开发更好的抑制Pgp的药物。在目标2中，我们将探讨Pgp如何区分转运 底物和抑制剂。我们提出了一个新的假设，即Pgp的两个半体可能发挥不同的作用， Pgp转运和抑制中的作用。我们将对此进行进一步调查 通过将配体共价连接到Pgp中的不同结合位点，然后表征Pgp结构， and activity活动to find correlations相关.在目标3中，我们建议合理化化学策略，以修改药物， Pgp转运。我们将对Pgp结构的特异性配体进行系统的化学修饰， 活性关系研究，以了解Pgp-药物相互作用的基本化学原理。我们的目标 对Pgp的研究结合了新的化学设计，并辅以深入的活性和结构研究。 我们已经收集了强有力的初步数据，以证明每个目标研究的可行性和新奇。我们 这种方法非常独特，将为药物与Pgp的复杂相互作用提供前所未有的见解， 因此对药物发现具有显著影响。

The overarching goal of this project is to obtain a deep, molecular-level understanding of P-glycoprotein (Pgp)- mediated drug transport and efflux inhibition. Pgp belongs to a very important class of ATP-binding cassette (ABC) transporters that transport substrates out of cells using the energy of ATP hydrolysis. One of the truly remarkable features of Pgp is its unusually broad polyspecificity. Pgp functions like a hydrophobic vacuum cleaner, transporting diverse molecules including many clinically useful drugs that partition into the lipid bilayer. Pgp is known to be a key determinant of the bioavailability, pharmacokinetics, and clinical efficacy of drugs in humans. Pgp also causes cellular multidrug resistance, hindering the treatment of many diseases. Because of the potential adverse effects of Pgp efflux on drugs, the US Food and Drug Administration mandates documentation of drug interactions with Pgp for approval of any new drug. Evasion or inhibition of Pgp without compromising therapeutic efficacy has been a major goal of the pharmaceutical industry, which, however, is seriously hindered by the lack in the fundamental understanding of the polyspecific Pgp-drug interactions. Our long-term goal in studying Pgp/drug interactions is to facilitate the development and discovery of new drugs that either inhibit or evade Pgp efflux. Towards this end, we propose three independent but related specific aim studies for this project, with each addressing a key question closely related to drug development. In Aim 1, we will discover bona fide Pgp antagonists for mechanistic studies. We note that many widely studied Pgp inhibitors compete with drugs for Pgp transport. We envision the discovery of novel, nonsubstrate Pgp antagonists displaying distinct properties from the known inhibitors, which is crucial to Pgp inhibition mechanistic studies and for the development of better drugs to inhibit Pgp. In Aim 2, we will interrogate how Pgp discriminates transport substrates and inhibitors. We have formulated a novel hypothesis that the two halves of Pgp may play different roles in Pgp transport and inhibition, based on several preliminary studies. We will further investigate this hypothesis by covalently attaching ligands to different binding sites in Pgp and then characterizing Pgp structure and activity to find correlations. In Aim 3, we propose to rationalize chemical strategies to modify drugs to evade Pgp transport. We will carry out systematic chemical modifications on specific ligands for Pgp structural and activity relationship studies to learn the basic chemical principles underlying Pgp-drug interactions. Our aim studies for Pgp incorporate novel chemical designs complemented by in-depth activity and structural studies. We have collected strong preliminary data to demonstrate the feasibility and novelty of each Aim study. Our approach is quite unique and will offer unprecedented insights into the complex interactions of drugs with Pgp, thus having a significant impact on drug discovery.