Molecular mechanisms of drug transports via amino acid transporters

通过氨基酸转运蛋白转运药物的分子机制

基本信息

批准号：
12670095
负责人：
KANAI Yoshikatsu
金额：
$ 2.56万
依托单位：
Kyorin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The purpose of this study is to reveal the mechanisms of drug transports via amino acid transporters. In this study, system L transporters LAT1 and LAT2 were investigated using Xenopus oocyte expression system, T24 human bladder carcinoma cells expressing high-level of LAT1 and mouse S2 cell-lines stably transfecting human LAT 1 and LAT2. It was demonstrated that LAT1 transports aromatic-amino-acid derivatives including L-dopa, α-methyldopa, α- methyltyrosine, gabapentin, thyroid hormones such as triiodothyronine and thyroxine, and anti-cancer drug melphalan. Based on the experimental and semi-empirical computational analyses, it is proposed that, in order for an aromatic amino acid to be a LAT1 substrate, it must have a free carboxyl and an amino group. In addition, the hydrophobic interaction between the substrate side chain and the substrate binding site of LAT1 seems to be crucial for the substrate binding. Because of this multispecific property, LAT1 has been established as a drug … More transporter.LAT1 has been demonstrated to be upregulated in cancer cells and its inhibition results in the inhibition of cancer cell growth. Based on the pharmacological properties of LAT1, we have designed and generated new compounds (KYT0193, KYT0206 and KYT0213) with high affinity to LATI, which can be candidates for anti-cancer agents.It has been proposed that the amino acid transporters are the major routes for methylmercury mobilization. In the present study it was found that LAT1 and LAT2 transport methylmercury as a cysteine-conjugate. We have further found that a classical system L inhibitor BCH rescued T24 human bladder carcinoma cells expressing LAT1 form the toxicity of methylmercury-cysteine conjugate, indicating that the cytotoxicity of methylmercury is mediated by system L transporters.In addition, we have identified novel aromatic amino acid transporter TAT1 (T-type amino acid transporter 1) and two members of heterodimeric amino acid transporters Asc-2 and AGT 1 proposed to be associated with unknown heavy chains. Less

本研究的目的是揭示通过氨基酸转运蛋白的药物转运机制。本研究使用非洲爪蟾卵母细胞表达系统、表达高水平 LAT1 的 T24 人膀胱癌细胞和小鼠 S2 来研究系统 L 转运蛋白 LAT1 和 LAT2。稳定转染人 LAT 1 和 LAT2 的细胞系已证明 LAT1 转运芳香族氨基酸衍生物，包括 L-多巴、α-甲基多巴、α-。甲基酪氨酸、加巴喷丁、三碘甲状腺原氨酸和甲状腺素等甲状腺激素以及抗癌药物美法仑基于实验和半经验计算分析，提出芳香族氨基酸必须成为LAT1底物。此外，LAT1 的底物侧链和底物结合位点之间的疏水相互作用似乎对于底物结合至关重要。由于这种多特异性特性，LAT1 已被确立为一种药物转运蛋白。LAT1 已被证明在癌细胞中上调，并且其抑制会导致癌细胞生长的抑制。根据 LAT1 的药理学特性，我们设计了 LAT1。并生成了与 LATI 具有高亲和力的新化合物（KYT0193、KYT0206 和 KYT0213），这些化合物可作为抗癌药物的候选药物。有人提出，氨基酸转运蛋白是在本研究中，我们发现 LAT1 和 LAT2 以半胱氨酸缀合物的形式转运甲基汞，我们进一步发现经典的 L 系统抑制剂 BCH 可以挽救表达 LAT1 的 T24 人膀胱癌细胞免遭甲基汞的毒性。半胱氨酸缀合物，表明甲基汞的细胞毒性是由L系统转运蛋白介导的。此外，我们还鉴定了新型芳香族氨基酸转运蛋白TAT1（T 型氨基酸转运蛋白 1）和异二聚氨基酸转运蛋白 Asc-2 和 AGT 1 的两个成员被认为与未知重链 Less 相关。