Role of hepatic transporters in the detoxification

肝脏转运蛋白在解毒中的作用

• 批准号: 09044267
• 负责人: SUGIYAMA Yuichi
• 金额: $ 4.8万
• 依托单位: Graduate School of Pharmaceutical Sciences, The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044267/
• 关键词: ABC transporter; cMOAT; MRP; MLP; multidrug resistance; biliary excretion; ABC輸送担

It is established that many organic anions including glucuronide and glutathione conjugates are excreted into the bile across the canalicular membrane via a primary active transporter referred to as canalicular multispecific organic anion transporter (cMOAT). In the present study, we clarified the substrate specificity of cMOAT by comparing the transport properties in normal and mutant rats (Eisai hyperbilirubinemic rats ; EHBR) whose cMOAT function is hereditarily defective. Since it has been established that the substrate specificity of cMOAT resembles that of multidrug resistance associated protein (MRP), we examined the substrate specificity of cMOAT,particularly focusing on the transport of antitumor reagents. We found that cMOAT accepts the following compounds ; methotrexate, carboxylate forms of CPT-11 (a topoisomerase inhibitor) and its reactive metabolite (SN-38), along with the glucuronide conjugate of SN-38. These results suggest that the tumor cells overexpressing cMOAT/MRP should acquire resistance against these chemotherapeutic reagents. Moreover, we had examined the function of cloned cMOAT cDNA by preparing the stable transfectant. ATP-dependent uptake of 2,4-dinitrophenyI-S-glutathione, a typical substrate for cMOAT,into membrane vesicles isolated from NIH/3T3 cells was stimulated by transfection of rat cMOAT cDNA This is the first direct demonstration that the cloned cMOAT cDNA has a function to transport organic anions. These results indicate that the membrane vesicles from the transfectant should be an excellent tool for the screening of chemotherapeutic reagents which cannot be the substrate for cMOAT/MRP.

已证实，许多有机阴离子，包括葡萄糖醛酸和谷胱甘肽结合物，是通过一种主要的活性转运体，即小管多特异性有机阴离子转运体(CMOAT)，通过小管膜排泄到胆汁中的。在本研究中，我们通过比较cMOAT功能遗传缺陷的正常大鼠和突变大鼠(卫材高胆红素血症大鼠；EHBR)的转运特性，阐明了cMOAT的底物特异性。由于已经确定cMOAT的底物专一性类似于多药耐药相关蛋白(MRP)，我们研究了cMOAT的底物专一性，尤其是抗肿瘤药物的转运。我们发现cMOAT可以接受以下化合物：甲氨蝶呤、羧酸盐形式的CPT-11(一种拓扑异构酶抑制剂)及其反应性代谢产物(SN-38)，以及SN-38的葡萄糖醛酸化物结合物。这些结果表明，过表达cMOAT/MRP的肿瘤细胞应该对这些化疗药物产生耐药性。此外，我们还通过制备稳定的转染体来检测克隆的cMOAT基因的功能。CMOAT的典型底物2，4-二硝基苯基-S-谷胱甘肽在NIH/3T3细胞膜泡中的摄取依赖于ATP。这是首次直接证明克隆的cMOAT具有运输有机阴离子的功能。这些结果表明，转染体中的膜泡是筛选化疗药物的良好工具，而不能作为cMOAT/MRP的底物。

项目成果

X. Y. Chu: "Multiplicity of biliary excretion mechanisms for irinotecan, CPT-11, and its metabolites in rats" Cancer Res.57. 1934-1938 (1997)

X. Y. Chu：“大鼠体内伊立替康、CPT-11 及其代谢物的胆汁排泄机制的多样性”Cancer Res.57。

X.Y.Chu: "Multiplicity of biliary excretion mechanisms for irinotecan,CPT-11,and its metabolites in rats" Cancer Res.57. 1934-1938 (1997)

X.Y.Chu：“大鼠体内伊立替康、CPT-11 及其代谢物的胆汁排泄机制的多样性”Cancer Res.57。

K. Niinuma: "Kinetic analysis of the primary active transport of conjugated metabolites across the bile canalicular membrae : Comparative study between DNP-SG (S-(2, 4-dinitrophenyl) -glutathione) and E3040-glucuronide" J. Pharmacol. Exp. Ther.282. 866-87

K. Niinuma：“结合代谢物穿过胆小管膜的主要主动转运的动力学分析：DNP-SG（S-（2, 4-二硝基苯基）-谷胱甘肽）和 E3040-葡萄糖醛酸之间的比较研究”J. Pharmacol。

K.Niinuma: "Kinetic analysis of the primaryactive transport of conjugated metabolites across the bile canalicular membrane:Comparative study between DNP-SG(S-(2,4-dinitrophenyl)-glutathione)and E3040-glucuronide" J.Pharmacol.Exp.Ther.282. 866-872 (1997)

K.Niinuma：“结合代谢物穿过胆小管膜的主要活性转运的动力学分析：DNP-SG（S-（2,4-二硝基苯基）-谷胱甘肽）和 E3040-葡萄糖醛酸苷之间的比较研究”J.Pharmacol.Exp。

H.C.Shin: "Hepatobiliary transport mechanism for the cyclopentapeptide endothelin antagonistBQ-123" Am.J.Physiol.272. G976-G986 (1997)

H.C.Shin：“环五肽内皮素拮抗剂 BQ-123 的肝胆转运机制”Am.J.Physiol.272。