Control of the cellular pharmacology of the platinum-containing drugs by CTR1

CTR1 控制含铂药物的细胞药理学

• 批准号: 8257984
• 负责人: STEPHEN B HOWELL
• 金额: $ 30.49万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-18 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8257984
• 关键词: Address; Alleles; Binding; Bortezomib; Carboplatin; Cell membrane; Cells; Cisplatin; Code; Copper; Defect; Dissection; Drug Exposure; Drug resistance; Effectiveness; Endocytosis; Exposure to; Extracellular Domain; Goals; Homeostasis; Knock-out; Malignant Neoplasms; Mammalian Cell; Mediating; Molecular; Molecular Chaperones; Molecular Models; Mutation; Pathway interactions; Pharmaceutical Preparations; Pharmacology; Phase I Clinical Trials; Phosphorylation; Phosphorylation Site; Platinum; Recovery; Resistance; Route; Site; Technology; Testing; Therapeutic Index; Ubiquitination; Variant; Xenograft Model; cell killing; chemotherapeutic agent; cytotoxic; cytotoxicity; drug efficacy; drug sensitivity; glycosylation; improved; in vitro testing; in vivo; innovation; molecular modeling; neoplastic cell; novel strategies; oxaliplatin; public health relevance; response; trafficking; tumor; uptake

DESCRIPTION (provided by applicant): Multiple lines of evidence indicate that the platinum (Pt)-containing drugs can enter cells, be distributed to various subcellular compartments and exported from cells via transporters that evolved to manage copper (Cu) homeostasis. We and others have shown that the major Cu influx transporter CTR1 mediates the import of cisplatin (DDP), carboplatin and oxaliplatin into mammalian tumor cells. Knockout of both alleles of CTR1 impairs Pt drug accumulation and results in resistance when tested in vitro; it also renders tumors completely unresponsive to DDP treatment in vivo in a xenograft model. Thus, irrespective of what other Pt drug influx mechanisms might exist, CTR1 is a key determinant of the sensitivity of tumors to these drugs. Like Cu, the Pt drugs trigger the rapid endocytosis and degradation of CTR1 and thus these drugs limit their own uptake. It is the overall goal of this project to identify novel strategies for selectively enhancing Pt drug accumulation in tumors. It is our hypothesis that this can be achieved by determining the mechanism by which CTR1 transports the Pt-containing drugs and identifying the factors that modulate CTR1 trafficking, endocytosis and degradation in response to Pt drug exposure. The specific aims are to: 1) determine the mechanism by which CTR1 transports the Pt-containing drugs including whether the Pt drugs enter tumor cells by transiting the pore formed by CTR1 or by endocytosis after binding to the extracellular domain, and if they enter by both routes, whether they make different contributions to cytotoxicity; b) determine the mechanism that controls the trafficking of CTR1 within the cell and its endocytosis and subsequent degradation following exposure to the Pt drugs including the motifs in CTR1 that mediate its delivery to and recovery from the plasma membrane, its phosphorylation and ubiquitination and the mechanism by which the Cu chaperone ATOX1 controls Pt drug- induced degradation of CTR1; c) determine what is wrong with CTR1 function in cells with acquired Pt drug resistance including whether there is a defect in glycosylation that disables the transport function or defects in the pathways that control trafficking of CTR1 in resistant cells that result in inadequate delivery to the plasma membrane. The Pt-containing drugs remain one of the most important and widely used class of chemotherapeutic agents. We have already succeeded in using the results of detailed studies of the interaction of DDP with the Cu influx transporter CTR1 to identify a strategy for improving the therapeutic index of these agents that is currently entering a Phase I clinical trial. This proposal is innovative in that it challenges dogma in the field, introduces new concepts regarding how the Pt drugs enter cells, and brings state-of-the-art technology to a careful dissection of the mechanism by which CTR1 mediates the transport of DDP that can be expected to identify strategies for further increasing the efficacy and selectivity of the Pt containing drugs. PUBLIC HEALTH RELEVANCE: The platinum-containing drugs are important cancer chemotherapeutic agents that get into tumor cells using a transporter (CTR1) that evolved to permit cells to take up copper. The goal of this project is to improve the effectiveness of these drugs by determining the molecular mechanism by which CTR1 transports the platinum- containing drugs and identifying the factors that regulate the amount of CTR1 in the cell.

描述（由申请人提供）：多个证据表明，含有铂（PT）的药物可以进入细胞，分配到各种亚细胞区室，并通过转运蛋白从细胞中导出，这些转运蛋白会进化为管理铜（CU）稳态。我们和其他人表明，主要的Cu涌入转运蛋白CTR1介导顺铂（DDP），卡铂和奥沙利铂的进口到哺乳动物肿瘤细胞中。 CTR1的两个等位基因的敲除损害PT药物的积累，并在体外测试时会导致耐药性；它还使肿瘤完全没有反应，可在异种移植模型中在体内进行DDP治疗。因此，无论其他PT药物涌入机制是否存在，CTR1都是肿瘤对这些药物敏感性的关键决定因素。像铜一样，PT药物会引发CTR1的快速内吞作用和降解，因此这些药物限制了它们自己的摄取。该项目的总体目标是确定有选择地增强肿瘤中PT药物积累的新型策略。我们的假设是，这可以通过确定CTR1传输含PT的药物的机制来实现，并确定调节CTR1运输，内吞作用和降解以应对PT药物暴露的因素。具体目的是：1）确定CTR1传输含PT的药物的机制，包括PT药物是通过转移Ctr1形成的孔还是通过结合细胞外结构域的内吞作用来进入肿瘤细胞，以及是否通过两种途径进入两种途径，对它们是否对细胞毒性产生不同的贡献； b) determine the mechanism that controls the trafficking of CTR1 within the cell and its endocytosis and subsequent degradation following exposure to the Pt drugs including the motifs in CTR1 that mediate its delivery to and recovery from the plasma membrane, its phosphorylation and ubiquitination and the mechanism by which the Cu chaperone ATOX1 controls Pt drug- induced degradation of CTR1; c）确定在获得PT耐药性的细胞中CTR1功能的问题，包括是否存在糖基化缺陷，该缺陷会禁用控制CTR1在抗性细胞中运输的途径中的传输功能或缺陷，从而导致递送到Plasmammbrane中。含PT的药物仍然是最重要，最广泛使用的化学治疗剂之一。我们已经成功地使用了DDP与CU涌入转运蛋白CTR1相互作用的详细研究的结果来确定改善这些药物的治疗指数的策略，该指数当前正在进入I期临床试验。该提案具有创新性，因为它挑战了该领域的教条，引入了有关PT药物如何进入细胞的新概念，并将最先进的技术带来了对CTR1介导DDP传输的机制的仔细解剖，该机制可以预期，该机制可以预期识别策略，以进一步提高含有PT药物的PT的功效和选择性。 公共卫生相关性：含铂的药物是重要的癌症化学治疗剂，使用转运蛋白（CTR1）进入肿瘤细胞，以允许细胞吸收铜。该项目的目的是通过确定CTR1传输含有铂的药物并确定调节细胞中CTR1量的因子的分子机制来提高这些药物的有效性。