Antizyme-mediated inhibition of polyamine transport

抗酶介导的多胺转运抑制

• 批准号: 7115633
• 负责人: JOHN L A MITCHELL
• 金额: $ 0.69万
• 依托单位: NORTHERN ILLINOIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7115633
• 关键词: CHO cells; biofeedback; biological transport; enzyme inhibitors; isozymes; membrane transport proteins; neoplastic cell; polyamines; protease inhibitor; protein protein interaction; protein structure function

DESCRIPTION (provided by applicant): The long-term goal of this project is to clarify the role of antizyme (AZ) in feedback regulation of cellular polyamine transport. It has been well established that cancer cell growth and metastatic potential are closely associated with abnormal polyamine accumulation. The enhanced activity of polyamine transport into cancer cells provides an ideal system for targeting cytotoxic drugs specifically to tumors. Accordingly, many polyamine-based anticancer compounds are being tested and some have progressed to clinical trials. Recent studies have shown that most of these polyamine analogs also stimulate the production of AZ, a regulatory protein that prevents excessive accumulation of polyamines by inhibiting the polyamine transporter. This AZ-mediated limitation of the uptake of potentially useful drugs obviously presents a serious potential problem to the pharmacological use of this transport system. Unfortunately, the mechanisms and even the most basic characteristics of this feedback system are not known. The four investigations in this project are designed to explore fundamental aspects of AZ's involvement in blocking this transporter. The investigations will benefit from the recent discovery that a short N-terminal sequence, present only on the minor, full-length AZ isoform, is critical for maximal transport inhibition. Specifically these studies will (a) establish the relative effects of the two AZ isoforms on both inhibiting polyamine uptake and stimulating export; (b) determine the effectiveness of antizyme inhibitor (AZI) in reversing feedback inhibition of polyamine transport by each of the AZ isoforms; (c) explore possible differences in the interactions of the AZ isoforms with the potential transport intermediate sorting nexin-5; and (d) identify the N-terminal sequences that are important for this feedback activity. The transport inhibition studies will be conducted using CHO clones that have been stably transfected for controlled expression of the distinct AZ isoforms, AZ inhibitor and sorting nexin-5. By elucidating AZ's involvement in controlling this uptake system, this investigation will improve efforts to design and utilize compounds exploiting this useful transporter.

描述（由申请人提供）：本项目的长期目标是阐明抗酶（AZ）在细胞多胺转运反馈调节中的作用。已经确定癌细胞生长和转移潜能与异常多胺积累密切相关。多胺转运到癌细胞中的增强的活性为特异性靶向肿瘤的细胞毒性药物提供了理想的系统。因此，许多基于多胺的抗癌化合物正在被测试，并且一些已经进展到临床试验。最近的研究表明，大多数这些多胺类似物也刺激AZ的产生，AZ是一种调节蛋白，通过抑制多胺转运蛋白来防止多胺的过度积累。这种AZ介导的对潜在有用药物摄取的限制显然对这种转运系统的药理学应用提出了严重的潜在问题。不幸的是，这个反馈系统的机制甚至最基本的特征都不为人所知。本项目的四项调查旨在探索AZ参与阻断这种转运蛋白的基本方面。调查将受益于最近的发现，一个短的N-末端序列，目前只对较小的，全长AZ亚型，是至关重要的最大的运输抑制。具体地说，这些研究将（a）确定两种AZ同种型对抑制多胺摄取和刺激输出的相对作用;（B）确定抗酶抑制剂（AZI）在逆转每种AZ同种型对多胺转运的反馈抑制中的有效性;（c）探索AZ同种型与潜在转运中间体分选连接蛋白-5相互作用的可能差异;和（d）鉴定对该反馈活性重要的N-末端序列。将使用稳定转染的CHO克隆进行转运抑制研究，以控制不同AZ亚型、AZ抑制剂和分选连接蛋白-5的表达。通过阐明AZ的参与控制这一摄取系统，这项调查将改善努力，设计和利用利用这种有用的转运蛋白的化合物。