LRH-1 Antagonism: Impact on Estrogen-dependent Breast Cancer

LRH-1 拮抗剂：对雌激素依赖性乳腺癌的影响

• 批准号: 8597538
• 负责人: MARCIA I. DAWSON
• 金额: $ 39.25万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-12 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8597538
• 关键词: Ablation; Adipose tissue; Adjuvant; Adjuvant Therapy; Adrenal Glands; Adverse effects; Adverse event; Androgens; Androstenedione; Aromatase; Aromatase Inhibitors; Attenuated; Binding; Biological Assay; Breast; Breast Cancer Cell; Cancer Patient; Cancer cell line; Cancerous; Cell Line; Cell Proliferation; Cellular biology; Computer Analysis; Coupled; Cyclin D1; Diagnosis; Disease; Elements; Engineering; Enzymes; Estrogen Antagonists; Estrogen Nuclear Receptor; Estrogen Receptors; Estrogens; Genes; Genetic Transcription; Human; Immunodeficient Mouse; In Vitro; Indium; Lead; Ligand Binding; Ligand Binding Domain; Ligands; Malignant Neoplasms; Mammary Gland Parenchyma; Memory Loss; Menopause; Methods; Molecular Biology; Mus; Mutagenesis; Nuclear Orphan Receptor; Nuclear Receptor Gene; Ovary; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacology; Postmenopause; Production; Proteins; Recurrence; Relapse; Reporter; Reporter Genes; Resistance; Role; Signal Pathway; Spectrometry; Synthesis Chemistry; Therapeutic; Tissues; Validation; Woman; Xenograft Model; base; bone loss; cancer cell; computer studies; design; human NR5A2 protein; improved; in vivo; interdisciplinary approach; malignant breast neoplasm; multidisciplinary; overexpression; pharmacophore; prevent; promoter; scaffold; small heterodimer partner protein; small molecule; transcription factor; treatment duration

DESCRIPTION (provided by applicant): Using NMR spectrometry and reporter assays we identified liver receptor homolog 1 (LRH-1) transcriptional antagonists. We hypothesize that LRH-1-selective antagonists would be useful for treating or preventing recurrence of estrogen-dependent breast cancer in postmenopausal women. We base this hypothesis on the following findings: After menopause, estrogen is produced locally in breast tissue rather than coming from the ovary. In the postmenopausal cancerous breast, expression of the enzyme synthesizing estrogen (aromatase) becomes elevated, as do estrogen and the estrogen nuclear receptor (ER). Moreover, compared to other tissues, aromatase is expressed by activation of a different promoter that is responsive to binding by LRH-1, an orphan nuclear receptor. LRH-1 is also overexpressed in the postmenopausal cancerous breast. There, the major producer of estrogen is the preadipocyte followed by the cancer cell. Thus, treatment with an LRH-1 antagonist would locally reduce estrogen levels compared to adjuvant therapeutics such as estrogen antagonists and aromatase inhibitors and, thereby, attenuate the adverse systemic effects caused by whole-body estrogen ablation. Use of a dual therapeutic approach may also extend the treatment period for adjuvant therapy until relapse occurs. LRH-1 also activates the ER gene promoter to induce the expression of the ER, which in the presence of estrogen is activated to drive breast cancer cell proliferation. LRH-1 also has independent roles in cell proliferation and invasion that are related to its ability to induce the expression of other genes such as cyclin D1 and c-Myc. Therefore, treatment with an LRH-1 antagonist could block estrogen-dependent breast cancer cell proliferation and invasion. We propose a three-year multidisciplinary project involving three Specific Aims: (1) LRH-1 antagonist design and synthesis based on direct design and SAR approaches. The lead antagonist was first found to interact with another orphan nuclear receptor, small heterodimer partner. On the basis of computational analysis, we hypothesize that appropriate scaffold substitutions will selectively enhance interaction with the LRH-1 ligand-binding domain and improve antagonism of transcriptional activity. (2) Bioevaluation in preadipocyte and estrogen-dependent cell lines coupled with mutagenesis studies will enable us to identify an LRH-1 pharmacophore and ligand-binding pose in the human LRH-1 ligand-binding pocket to optimize activity. The antagonists will also permit us to investigate LRH-1 signaling pathways in breast cancer cells and preadipocytes. (3) In vivo validation in an estrogen-dependent breast cancer xenograft model in ovariectomized immunodeficient mice inoculated with engineered cancer cells stably expressing LRH-1 and treated with the estrogen precursor androstenedione.

描述（由申请人提供）： 使用NMR光谱和报告基因分析，我们确定了肝受体同源物1（LRH-1）的转录拮抗剂。我们假设LRH-1选择性拮抗剂可用于治疗或预防绝经后女性雌激素依赖性乳腺癌复发。我们的假设基于以下发现：绝经后，雌激素是在乳腺组织局部产生的，而不是来自卵巢。在绝经后乳腺癌中，合成雌激素的酶（芳香酶）的表达升高，雌激素和雌激素核受体（ER）也升高。此外，与其他组织相比，芳香酶通过激活不同的启动子来表达，该启动子响应于LRH-1（孤儿核受体）的结合。LRH-1在绝经后乳腺癌中也过表达。在那里，雌激素的主要生产者是前脂肪细胞，其次是癌细胞。因此，与辅助治疗剂如雌激素拮抗剂和芳香酶抑制剂相比，用LRH-1拮抗剂治疗将局部降低雌激素水平，从而减弱由全身雌激素消融引起的不良全身作用。使用双重治疗方法也可以延长辅助治疗的治疗期，直至复发。LRH-1还激活ER基因启动子以诱导ER的表达，ER在雌激素存在下被激活以驱动乳腺癌细胞增殖。LRH-1在细胞增殖和侵袭中也具有独立的作用，这与其诱导其他基因如细胞周期蛋白D1和c-Myc表达的能力有关。因此，使用LRH-1拮抗剂治疗可以阻断雌激素依赖性乳腺癌细胞的增殖和侵袭。我们提出了一个为期三年的多学科项目，涉及三个具体目标：（1）基于直接设计和SAR方法的LRH-1拮抗剂的设计和合成。先导拮抗剂首先被发现与另一个孤儿核受体，小异源二聚体伴侣相互作用。在计算分析的基础上，我们假设适当的支架取代将选择性地增强与LRH-1配体结合结构域的相互作用，并提高转录活性的拮抗作用。(2)在前脂肪细胞和雌激素依赖性细胞系中的生物评价加上诱变研究将使我们能够确定LRH-1药效团和人LRH-1配体结合口袋中的配体结合姿势，以优化活性。拮抗剂也将使我们能够研究乳腺癌细胞和前脂肪细胞中的LRH-1信号通路。(3)雌激素依赖性乳腺癌异种移植模型中的体内验证：卵巢切除的免疫缺陷小鼠接种稳定表达LRH-1的工程化癌细胞，并用雌激素前体雄烯二酮治疗。