G-quadruplexes formed in human oncogene promoters and their drug complexes

描述（由申请人提供）：四种癌基因，c-MYC, bcl-2， VEGF和HIF-1a，在其转录激活的关键启动子区域均含有polyG/polyC束。在这四种癌基因的启动子区域，DNA g -四重体二级结构的出现已被证明是一种转录调节剂。虽然DNA g -四重体是很有希望的新药物靶点，但评估其作为癌症治疗靶点的潜力取决于对生物学相关g -四重体结构的理解。我们的初步研究已经使我们确定了c-MYC、bcl-2、VEGF和HIF-1a启动子区域的主要g -四联体形式，它们似乎代表了三种不同的基本g -四联体结构，VEGF/HIF-1a的g -四联体是相同的基本类型。启动子g -四联体的不同分子结构使这些结构成为通路特异性药物设计的有吸引力的靶点。在本提案中，我们打算定义每个g-四重体及其药物复合物的特定分子结构。所获得的结构信息将与生物学数据相关联，以了解有效的基因调控。深入了解启动子g -四联体及其药物配合物的结构将为基于结构的合理药物设计提供重要依据。我们将验证我们的假设，即每个启动子g -四重体可以被不同的小分子药物化合物特异性靶向。除了可以通过与不同g -四重体核心结构的相互作用来实现选择性的原理外，我们还期望通过产生结合口袋的外部环和盖层结构之间的相互作用来实现选择性。在这方面，证明原则是很重要的。我们将结合核磁共振、CD、分子建模和微量热测量数据，并结合适当的突变启动子元件。我们的主要方法，高场核磁共振波谱，代表了一个主要的工具，以确定生物相关的g -四重化合物的结构，由于这种结构的结晶困难。我们的最终目标是使用基于结构的方法来合理设计小分子g -四重体相互作用化合物，这些化合物专门针对每个启动子特有的g -四重体结构并调节基因转录。具体来说，我们计划1)确定在c-MYC启动子区域形成的生物学相关g -四重体的分子结构及其药物相互作用；2)确定bcl-2启动子区形成的生物学相关g -四重体的分子结构及其药物相互作用；3)确定在VEGF/HIF-1a启动子区形成的具有生物学意义的g -四重体的分子结构及其药物相互作用。

DESCRIPTION (provided by applicant): The four oncogenes, c-MYC, bcl-2, VEGF, and HIF-1a, all contain polyG/polyC tracts in their promoter regions critical for transcriptional activation. The occurrence of DNA G-quadruplex secondary structures has been demonstrated in the promoter regions of these four oncogenes and has been shown to be a transcriptional modulator. While the DNA G-quadruplexes are promising new drug targets, the evaluation of their potential as cancer therapeutic targets depends on the understanding of biologically relevant G-quadruplex structures. Our preliminary studies have allowed us to identify the predominant forms of G-quadruplexes in the promoter regions of c-MYC, bcl-2, VEGF, and HIF-1a, which appear to represent three different basic G-quadruplex structures with VEGF/HIF-1a G-quadruplexes being the same basic type. The different molecular structures of the promoter G-quadruplexes make these structures attractive targets for pathway-specific drug design. In this proposal we intend to define the specific molecular structure of each G-quadruplex and its drug-complex(es). The structural information obtained will be correlated with the biological data to understand the effective gene modulation. Insight into the structures of the promoter G-quadruplexes and their drug complexes will provide an important basis for structure-based rational drug design. We will test our hypothesis that each promoter G-quadruplex can be specifically targeted by different small molecule drug compounds. In addition to the principle that selectivity can be achieved by interactions with different G-quadruplex core structures, we expect that selectivity can also be achieved by interactions within the external loops and capping structures in which binding pockets are generated. Proof of principle will be important in this regard. We will use a combination of NMR, CD, molecular modeling, and microcalorimetry data in concert with appropriate mutant promoter elements. Our primary approach, high field NMR spectroscopy, represents a major tool for structure determination of biologically relevant G-quadruplexes, due to the difficulty of crystallization of such structures. Our ultimate objective is to use a structure-based approach to rationally design small molecule G-quadruplex-interactive compounds that specifically target the G-quadruplex structure unique to each promoter and modulate gene transcription. Specifically, we plan to 1) determine the molecular structure of the biologically relevant G-quadruplex formed in the promoter region of c-MYC and its drug interactions; 2) determine the molecular structure of the biologically relevant G-quadruplex formed in the promoter region of bcl-2 and its drug interactions; and 3) determine the molecular structure of the biologically relevant G-quadruplex formed in the promoter region of VEGF/HIF-1a and its drug interactions.