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D(GPG) IN CRUCIFORM LOOPS AS TARGETS FOR CISPLATIN

十字形环中的 D(GPG) 作为顺铂的靶标

基本信息

批准号：
2329083
负责人：
PUI S HO
金额：
$ 10万
依托单位：
OREGON STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1996
资助国家：
美国
起止时间：
1996-09-15 至 1998-09-14
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2329083
关键词：
DNA chemical binding cis platinum compound drug receptors gel electrophoresis neoplasm /cancer chemotherapy nucleic acid structure

项目摘要

THIS IS A SHANNON AWARD PROVIDING PARTIAL SUPPORT FOR THE RESEARCH PROJECTS THAT FALL SHORT OF THE ASSIGNED INSTITUTE'S FUNDING RANGE BUT ARE IN THE MARGIN OF EXCELLENCE. THE SHANNON AWARD IS INTENDED TO PROVIDE SUPPORT TO TEST THE FEASIBILITY OF THE APPROACH; DEVELOP FURTHER TESTS AND REFINE RESEARCH TECHNIQUES; PERFORM SECONDARY ANALYSIS OF AVAILABLE DATA SETS; OR CONDUCT DISCRETE PROJECTS THAT CAN DEMONSTRATE THE PI'S RESEARCH CAPABILITIES OR LEAD ADDITIONAL WEIGHT TO AN ALREADY MERITORIOUS APPLICATION. THE APPLICATION BELOW IS TAKEN FROM THE ORIGINAL DOCUMENT SUBMITTED BY THE PRINCIPAL INVESTIGATOR. Here, we propose that distorted DNA structures, specifically the loops of cruciforms, may render certain d(GpG) dinucleotides more susceptible as targets for modification by the antitumor drug cis- diamminedichloroplatinum (II) (cis-DDP, or cisplatin). This is a radical departure from the standard paradigm that cis-DDP binds to d(GpG) dinucleotides in linear DNA and subsequently distorts the DNA duplex. Our model was derived from preliminary studies which show that cis-DDP, but not its clinically inactive trans-isomer, can shift the dynamic equilibrium between duplex DNA and a cruciform, and a recent NMR structure of a platinated DNA hairpin. The role of these structural perturbations may he to provide greater specificity to the drug by setting up the stereochemical environment that is more amenable to the structure of the cross-linked adduct. We estimate that the number of d(GpG) sites in a human genome that lie in cruciform forming sequences (about 5,000) is similar to the number of drug molecules found in a cell during treatment (about 1,000). The proteins that recognize platinum adducts in DNA (particularly the high mobility group or HMG classes of proteins) may actually be recognizing a cis-DDP stabilized cruciforms. These proteins have been shown to bind to synthetic four-way junctions, which form at the base of cruciforms. In this application, we propose studies to provide further support of this new model. We propose to: i) determine whether d(GpG) sites in cruciform loops are significantly more susceptible to cis-DDP binding compared to the same sites in linear duplex DNA by comparing the rate of platinum reaction at a d(GpG) site in linear versus extruded cruciform DNAs; ii) determine the degree to which cis-DDP helps to stabilize the extruded cruciform by two-dimensional gel analysis of topoisomers of cruciform containing plasmids; and iii) determine whether HMG-I--a protein which is elevated in certain cancerous cells--recognizes and binds to cis-DDP stabilized cruciforms by comparing the binding of this protein to d(GpG) sites in cruciform and linear DNAs.

这是一个香农奖提供部分支持的研究项目不属于指定机构的资助范围，但在优秀的边缘。香农奖旨在提供支持测试方法的可行性;支持进一步测试和完善研究技术;对现有的数据集;或进行离散项目，以证明PI 研究能力或导致额外的重量已经优秀应用程序.下面的应用程序是从原始文件由主要经销商提交。在这里，我们提出，扭曲的DNA结构，特别是环可能使某些d（GpG）二核苷酸更容易作为抗肿瘤药物顺式- 二氨二氯铂（II）（顺式-DDP或顺铂）。这是一个激进偏离了顺式DDP与d（GpG）结合的标准范例线性DNA中的双核苷酸，随后扭曲DNA双链体。我们模型来自初步研究，表明顺式DDP，但而不是其临床上无活性的反式异构体，双链DNA和十字形之间的平衡，以及最近的NMR 铂化DNA发夹结构。这些结构的作用扰动可以通过以下方式为药物提供更大的特异性：建立立体化学环境，交联加合物的结构。我们估计，人类基因组中位于十字形形成序列中的d（GpG）位点（约5,000个）类似于一个细胞中发现的药物分子数量治疗期间（约1,000人）。识别铂的蛋白质 DNA中的加合物（特别是高迁移率基团或HMG类，蛋白质）实际上可能识别顺式DDP稳定的十字形。这些蛋白质已被证明与合成的四向连接点结合，形成于十字形的底部在本申请中，我们建议进行研究，以进一步支持这个新模型。我们建议：i）确定d（GpG）位点是否在十字形环对顺式DDP结合明显更敏感与线性双链体DNA中的相同位点相比，线性与挤出十字形中d（GpG）位点处的铂反应 ii）确定顺式-DDP有助于稳定DNA的程度，挤出十字形的拓扑异构体的二维凝胶分析含有十字形的质粒;和iii）确定HMG-I-a 在某些癌细胞中含量升高的蛋白质--识别并通过比较这种结合，与顺式-DDP稳定的十字形结合在十字形和线性DNA中，蛋白质与d（GpG）位点连接。