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: 8462119
• 负责人: STEPHEN B HOWELL
• 金额: $ 28.59万
• 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/8462119
• 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.

描述（由申请人提供）：多种证据表明，含铂 (Pt) 的药物可以进入细胞，分布到各个亚细胞区室，并通过转运蛋白从细胞中输出，转运蛋白进化为管理铜 (Cu) 稳态。我们和其他人已经证明，主要的铜流入转运蛋白 CTR1 介导顺铂 (DDP)、卡铂和奥沙利铂进入哺乳动物肿瘤细胞。 CTR1 的两个等位基因的敲除会损害 Pt 药物的积累，并在体外测试时导致耐药性；它还使异种移植模型中的肿瘤对体内 DDP 治疗完全没有反应。因此，无论可能存在什么其他 Pt 药物流入机制，CTR1 都是肿瘤对这些药物敏感性的关键决定因素。与 Cu 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身的摄取。该项目的总体目标是确定选择性增强肿瘤中 Pt 药物积累的新策略。我们的假设是，这可以通过确定 CTR1 转运含 Pt 药物的机制并确定调节 CTR1 运输、内吞作用和响应 Pt 药物暴露而降解的因素来实现。具体目的是：1）确定CTR1转运含Pt药物的机制，包括Pt药物是通过CTR1形成的孔道进入肿瘤细胞还是通过与胞外结构域结合后的内吞作用进入肿瘤细胞，如果两种途径进入，它们对细胞毒性的贡献是否不同； b) 确定控制 CTR1 在细胞内运输及其内吞作用和随后接触 Pt 药物后降解的机制，包括 CTR1 中介导其递送至质膜和从质膜恢复的基序、其磷酸化和泛素化以及 Cu 伴侣 ATOX1 控制 Pt 药物诱导的 CTR1 降解的机制； c) 确定具有获得性 Pt 耐药性的细胞中 CTR1 功能的问题，包括是否存在导致转运功能失效的糖基化缺陷，或控制耐药细胞中 CTR1 运输的途径是否存在缺陷，导致无法充分递送到质膜。含铂药物仍然是最重要和最广泛使用的化疗药物之一。我们已经成功地利用 DDP 与 Cu 流入转运蛋白 CTR1 相互作用的详细研究结果来确定提高这些药物治疗指数的策略，该策略目前正在进入 I 期临床试验。该提案的创新之处在于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，并采用最先进的技术仔细剖析 CTR1 介导 DDP 转运的机制，有望确定进一步提高含 Pt 药物的功效和选择性的策略。