DISCOVERY OF SMALL MOLECULAR ACTIVATORS OF NR4A ORPHAN NUCLEAR RECEPTORS

NR4A 孤儿核受体小分子激活剂的发现

• 批准号: 8891381
• 负责人: ORLA M. CONNEELY
• 金额: $ 32.47万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-10 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8891381
• 关键词: Acute; Acute Myelocytic Leukemia; Animal Model; Behavior; Blast Cell; Cell Line; Cell Proliferation; Cells; Chemicals; Chromatin; Clinical Trials; Computer Simulation; Cytogenetics; Data; Development; Disease; Disease Progression; Disease-Free Survival; Family; Gene Expression; Gene Targeting; Genes; Genetic; Genomics; Hematopoietic stem cells; Heterogeneity; Homeostasis; Human; Informatics; Lead; Malignant Neoplasms; Mediator of activation protein; Molecular; Molecular Analysis; Mus; Myeloid Cells; NR4A1 gene; Nuclear Orphan Receptor; Nuclear Receptors; Orphan; Outcome Study; Pathway Analysis; Patients; Pharmaceutical Preparations; Population; Property; Public Health; Radio; Resistance; Signal Pathway; Staging; Stem cells; Testing; Therapeutic; Therapeutic Intervention; Transcriptional Regulation; Tumor Suppressor Proteins; Warburg Effect; Xenograft procedure; aerobic glycolysis; antileukemic agent; base; cdc Genes; drug discovery; drug efficacy; efficacy testing; in vitro testing; member; mouse model; new therapeutic target; novel; postnatal; prevent; progenitor; protein expression; restoration; screening; self-renewal; small molecule; stem; transcription factor

DESCRIPTION (provided by applicant): The overall objective of this proposal is to identify novel antileukemic drugs for treatment of acute myeloid leukemias (AMLs) via activation of the NR4A subclass of orphan nuclear receptors. AMLs are primarily diseases of corruption of normal transcriptional control of myeloid cell development leading to accumulation of immature blasts and emergence of a transformed leukemic initiating cell (LIC) population with long term self renewal properties capable of sustaining leukemic expansion. NR4A1 and NR4A3 are potent tumor suppressors of AML. They are silenced in all human AML LICs irrespective of patient cytogenetics. Deletions in mice lead to extremely rapid postnatal AML due to disruption of hematopoietic stem cell (HSC) homeostasis and the emergence of a transformed radio-resistant LIC. Further, acute rescue of NR4A1 or NR4A3 in human AML cells inhibits their proliferation and reprograms a subset of gene signatures that distinguish all primary human LICs from normal HSCs regardless of cytogenetics. We hypothesize that NR4A silencing is an obligate step in AML development and that strategies directed toward their reactivation may be of general therapeutic benefit in treatment of AMLs. By intersection of our NR4A target based genomics data with in silico chemical genomics screening, we have employed a novel integrative strategy to successfully identify small molecules that reactivate NR4As in AML cells and that can be used to disclose mechanisms of NR4A silencing. Our specific aims in this proposal are: 1) to further validate NR4As as novel therapeutic targets for treatment of human AMLs by analysis of the cellular and molecular consequences of NR4A reactivation in human AML cells, 2) to test the anti-leukemic properties of small molecule activators of NR4As in human AML cells by analysis of their efficacy in elimination of LICs using AML cell lines, primary cells from AML patients and animal models of human AML and by interrogation of their AML selectivity by comparison of their effects on normal human HSCs, and 3) to disclose mechanisms of silencing and reactivation of NR4As in AML cells. In this aim, we will combine informatics pathway analysis of small molecule activators with molecular analysis of the chromatin landscape of the NR4A genes to identify marks and mediators of NR4A silencing in AML and to disclose signaling pathways involved in their reactivation. Given the widespread silencing of NR4As in AML patients and the sufficiency of their inactivation in causing AML, we believe that a successful outcome from these studies in terms of new drug discovery will quickly result in new clinical trials that will have major impact on treatment of AML patients.

描述（由申请方提供）：本提案的总体目标是通过激活孤儿核受体的NR4A亚类来鉴定用于治疗急性髓性白血病（AML）的新型抗白血病药物。AML主要是骨髓细胞发育的正常转录控制破坏的疾病，导致未成熟胚细胞的积累和具有能够维持白血病扩增的长期自我更新特性的转化的白血病起始细胞（LIC）群体的出现。NR4A1和NR4A3是AML的有效肿瘤抑制剂。它们在所有人类AML LIC中均沉默，与患者的细胞遗传学无关。在小鼠中，由于造血干细胞（HSC）稳态的破坏和转化的放射抗性LIC的出现，缺失导致出生后AML非常迅速。此外，人AML细胞中NR4A1或NR4A3的急性拯救抑制其增殖并重新编程基因特征的子集，所述基因特征将所有原代人LIC与正常HSC区分开，而不管细胞遗传学如何。我们假设NR4A沉默是AML发展中的一个必要步骤，并且针对其重新激活的策略可能在AML治疗中具有一般治疗益处。通过我们基于NR4A靶标的基因组学数据与计算机化学基因组学筛选的交叉，我们采用了一种新的整合策略来成功鉴定在AML细胞中重新激活NR4A的小分子，并且可以用于揭示NR4A沉默的机制。我们在这项建议中的具体目标是：1）通过分析人AML细胞中NR4A再活化的细胞和分子后果，进一步验证NR4A作为治疗人AML的新治疗靶点，2）通过分析NR4A的小分子活化剂在使用AML细胞系消除LIC中的功效，测试NR4A的小分子活化剂在人AML细胞中的抗白血病性质，来自AML患者和人AML动物模型的原代细胞，并通过比较它们对正常人HSC的作用来询问它们的AML选择性，和3）揭示AML细胞中NR4A沉默和再活化的机制。在这个目标中，我们将结合联合收割机信息学途径分析的小分子激活剂与分子分析的染色质景观的NR4A基因，以确定标志物和介质的NR4A沉默在AML中，并披露参与其重新激活的信号通路。鉴于AML患者中NR4A的广泛沉默及其失活足以导致AML，我们相信这些研究在新药发现方面的成功结果将很快导致新的临床试验，这将对AML患者的治疗产生重大影响。