Establishing a molecular system for drug targeting of transcriptional control

描述（由申请人提供）：我们已经确定了一类新的分子受体，可用于药物靶向调节基因表达。基因表达的调节在分子治疗中有广泛的应用，包括癌症、心脏病、炎症、神经变性、内分泌学、哮喘和糖尿病。受这一发现影响的科学界非常广泛，包括基础科学家和转化科学家。这些分子靶标包括二级DNA结构（G-四重体和i-motif），这些结构经常在多种基因的启动子元件中发现，包括c-Myc、Bcl-2、VEGF、Hif-1a、PDGF-A和RET。原理证明，这些二级DNA结构的小分子稳定性导致细胞中基因表达的抑制，这种抑制依赖于启动子区域完整的G-四重体。Quarfloxin是一种来自PI实验室的药物，是一种一流的g -四重体相互作用药物，靶向核糖体DNA中的g -四重体，目前正在进行II期临床试验。在临床试验中，选择性和相应的没有任何严重毒性部分取决于癌细胞对核仁的选择性摄取，以及四氟辛对rDNA中平行型g -四重体的选择性比双工DNA高400倍。本提案的目的是提供结构上的洞察，包括一个G-四重基序和i-motif在一个双工区域，对应于消声器元件。这是一个挑战，因为i基序通常只在质粒超卷曲状态下的负超螺旋下产生，或者作为转录径流的结果。我们已经提出了一个解决这个问题的方法，以及提供基于结构的方法和开发高通量分析来筛选与该复合结构相互作用的化合物的技术。在双相分子内形成复合i-motif/ g -四重结构的能力将使我们能够识别具有增强目标选择性的小分子。在这个提议中提出的挑战是设计一个系统，在这个系统中我们可以从外部控制细胞中基因的产生。这项技术如果成功，将应用于癌症、心脏病和阿尔茨海默病的治疗。

DESCRIPTION (provided by applicant): We have identified a new class of molecular receptors amenable to drug targeting to modulate gene expression. Modulation of gene expression has broad applications in molecular therapeutics, including cancer, heart disease, inflammation, neurodegeneration, endocrinology, asthma, and diabetes. The scientific community affected by this discovery is very broad and includes basic as well as translational scientists. These molecular targets comprise secondary DNA structures (G- quadruplexes and i-motifs) found frequently in the promoter elements of a wide variety of genes including c-Myc, Bcl-2, VEGF, Hif-1a, PDGF-A, and RET. Proof of principle exists that stabilization of these secondary DNA structures with small molecules results in repression of gene expression in cells and this repression is dependent on an intact G-quadruplex in the promoter region. Quarfloxin, a drug originating from the PI's laboratory, is a first-in-class G-quadruplex-interactive drug that targets G-quadruplexes in ribosomal DNA and is in phase II clinical trials. The selectivity and corresponding lack of any serious toxicity in the clinical trials is partially dependent on the selective uptake into the nucleolus of cancer cells along with the 400-fold selectivity of Quarfloxin for the parallel-type G-quadruplex found in rDNA over duplex DNA. The objective of this proposal is to provide structural insight into silencer elements consisting of a G- quadruplex and i-motif within a duplex region that corresponds to the silencer elements. Herein lies the challenge because the i-motif is only normally generated under the negative superhelicity found in a plasmid supercoiled state or as a consequence of transcriptional runoff. We have proposed a solution to this problem along with techniques to provide a structure-based approach and development of a high-throughput assay for screening for compounds that interact with this composite structure. The ability to form the composite i-motif/G-quadruplex structure within a duplex molecule will permit us to identify small molecules that have enhanced target selectivity. The challenge addressed in this proposal is to design a system in which we can externally control the production of genes in cells. This technology, if successful, will have applications in the treatment of cancer, heart disease, and Alzheimer's disease.