Development and Testing of ERE-Targeting Molecules for Breast Cancer Therapy

描述（由申请人提供）：雌激素受体（ER）靶向内分泌治疗干扰雌激素信号已成为乳腺癌的标准治疗方法。这些治疗包括直接内质网结合剂（如他莫昔芬）或降低乳腺组织雌激素水平的芳香化酶抑制剂（如来曲唑）。尽管对于表达er的乳腺癌是一种有效的治疗方法，但目前的治疗方法在固有或获得性耐药方面存在显著的局限性。我们最近的工作描述了一种dna插入剂（命名为XR5944），它通过一种新的作用机制具有抗癌特性；通过直接结合关键DNA调控位点抑制基因转录。我们已经证明了XR5944通过特异性抑制ER与雌激素反应元件（ERE）的结合而具有强大的抗雌激素活性。由于这些研究的结果，我们假设专门针对ERE的小分子可能是治疗乳腺癌的有希望的候选药物，并且可以有效地克服当前抗雌激素治疗的耐药性。以XR5944为原型，我们的总体目标是利用最先进的分子和硅技术开发这种化合物。目的1将表征ERE作为XR5944在乳腺癌细胞中作用的分子靶点的性质和特异性。作为这一目标的一部分，我们将对受XR5944影响的ER的dna结合位点进行全基因组鉴定，并以此确定受XR5944- dna相互作用影响的靶基因和下游分子途径。利用核磁共振（NMR）技术，aim 2将确定XR5944-ERE复合物的详细结构，并利用这些信息，以及计算机分子建模研究，作为设计更好的ERE抑制剂的基础。一旦发现有希望的新化合物，将对它们进行合成，并对有希望的候选化合物进行进一步的生物活性和作用机制测试。促进ERE结合和随后的ER抑制的结构特征将用于指导进一步的药物改进。最后，目的3将在两种体内小鼠模型中评估ERE-插入化合物阻断雌激素信号的特异性和治疗效果；一个芳香化酶转基因模型产生雌激素依赖型乳腺肿瘤，以及一个野生型Sencar（癌变敏感性）小鼠模型，用于确定化合物对雌激素依赖型癌症的特异性和作用。公共卫生相关性：乳腺癌是一个重大的公共卫生问题，大约九分之一的妇女在其一生中的某个时候会受到影响。由于目前对er阳性肿瘤的内分泌治疗有局限性，迫切需要新的治疗方式。这些研究除了为开发新的抗雌激素化合物提供基本框架外，还将建立抑制DNA/转录因子与小分子DNA结合物相互作用的新概念。

DESCRIPTION (provided by applicant): Estrogen receptor (ER)-targeting endocrine therapies that interfere with estrogen signaling have become a standard treatment for breast cancer. These treatments involve either direct ER binders (e.g. tamoxifen) or aromatase inhibitors that reduce mammary tissue estrogen levels (e.g. letrozole). Despite being an effective treatment for ER-expressing breast cancer, current therapies have significant limitations related to inherent or acquired resistance. Our recent work has characterized a DNA-intercalating agent (designated XR5944) which possess anticancer properties through a novel mechanism of action; inhibition of gene transcription via direct binding at critical DNA regulatory sites. We have demonstrated potent antiestrogenic activity of XR5944 through specific inhibition of the binding of ER with estrogen response elements (ERE). As a result of these studies, we hypothesis that small molecules which specifically target ERE can be promising drug candidates for the treatment of breast cancer and would be effective in overcoming the resistance to current antiestrogen therapies. Using XR5944 as a prototype, it is our overall goal to develop such compounds using state-of-the- art molecular and in silico techniques. Aim 1 will characterize the nature and specificity of ERE as the molecular target of XR5944 action in breast cancer cells. As part of this aim, we will perform a genome-wide identification of the DNA-binding sites for ER which are affected by XR5944 and, in so doing, determine the target genes and downstream molecular pathways that are affected by XR5944-DNA interactions. Using nuclear magnetic resonance (NMR) technology, aim 2 will determine the detailed structure of the XR5944-ERE complex, and use this information, along with computer molecular modeling studies, as a basis for designing better ERE inhibitors. Upon identification of promising new compounds, they will be synthesized and promising candidates further tested for biological activity and mechanisms of action. Structural features that promote ERE binding and subsequent ER inhibition will be utilized to guide further drug improvement. Finally, aim 3 will evaluate the specificity and therapeutic consequences of blocking estrogen signaling by the ERE- intercalating compounds in two in vivo mouse models; an aromatase transgenic model which gives rise to estrogen-dependent breast tumors, and a wild-type Sencar (SENsitivity to CARcinogenesis) mouse model with which to determine the specificity and effects of the compounds on estrogen-independent cancers. PUBLIC HEALTH RELEVANCE: Breast cancer is a major public health issue that will affect approximately one of nine women sometime during her life. Since current endocrine therapies for ER-positive tumors have limitations, new treatment modalities are desperately needed. In addition to providing a basic framework for the development of new antiestrogen compounds, these studies will establish a new concept of inhibiting DNA/transcription factor interactions with small molecule DNA binders.