Small molecule CXCR4 modulators as molecular probes for studying AML

 描述（由申请人提供）：趋化因子CXCL 12（SDF-1）及其同源受体CXCR 4参与多种生理和病理过程，如HIV感染、炎症、肿瘤发生、干细胞迁移和自身免疫性疾病。尽管CXCR 4受体及其独特的配体SDF-1已被广泛研究，但SDF-1/CXCR 4轴的所有小分子调节剂都是拮抗剂。缺乏可用的小分子激动剂构成了探测CXCR 4生物学能力的巨大差距。使用新的计算机筛选策略，我们最近发现了第一系列小分子CXCR 4激动剂，并在各种生物环境中证明了它们的独特行为。值得注意的是，我们的小分子引起CXCR 4受体的内化，强烈的趋化反应和肿瘤细胞系的化学增敏。这些小分子激动剂和结构上相关的拮抗剂的发展将提供一个独特的和强大的手段来研究CXCR 4受体的功能，以及如何与疾病的过程。急性髓性白血病（AML）是一组髓性白血病，如果不治疗，具有非常侵袭性和致命的病程。骨髓（BM）微环境提供了对化疗的重要保护作用，这种相互作用的破坏使AML细胞在体外和体内对化疗敏感。SDF-1/CXCR 4轴在调节干细胞动员和运输中起关键作用，并且其表达已被证明与许多癌症的预后呈负相关。我们的先导激动剂显著增强了多种白血病细胞系对几种化疗药物的敏感性，这表明CXCR 4激动剂可能为治疗AML提供一种新的治疗方法。该项目的总体目标是优化小分子CXCR 4激动剂探针，并在体外和体内表征其对CXCR 4受体和AML的活性。我们独特的小分子CXCR 4激动剂和拮抗剂为我们提供了一套独特的分子工具，以了解CXCR 4受体药理学如何影响AML。在目标1中，我们将使用合理的药物化学来优化我们的先导化合物系列的效价和药物样性质，将计算机设计和稳健的生物学测试纳入迭代过程。我们将通过评估其对许多体外系统的行为，包括钙动员，受体结合，受体内化，趋化性和通过各种途径的信号传导，来表征目标2中的新CXCR 4调节剂。目的3将使用白血病细胞系和原代人肿瘤细胞以及使用患者来源的AML异种移植物模型在体内评估CXCR 4调节对AML的影响。拟议的研究将产生新的分子探针，以研究CXCR 4的药理学，并了解这种重要的受体如何参与AML。这些结果将为AML提供新的见解，并可能为治疗开发开辟新的途径。

 DESCRIPTION (provided by applicant): The chemokine CXCL12 (SDF-1) and its cognate receptor CXCR4 are involved in diverse physiological and pathological processes such as HIV infectivity, inflammation, tumorigenesis, stem cell migration, and autoimmune diseases. Although the CXCR4 receptor and its unique ligand SDF-1 have been widely studied, all small molecule modulators of the SDF-1/CXCR4 axis have been antagonists. The lack of available small molecule agonists constitutes a substantial gap in the ability to probe the biology of CXCR4. Using new in silico screening strategies, we have recently discovered the first series of small molecule CXCR4 agonists and have demonstrated their unique behavior in a variety of biological settings. Notably, our small molecules cause internalization of the CXCR4 receptor, a strong chemotactic response, and chemosensitization of tumor cell lines. Development of these small molecule agonists and structurally related antagonists will provide a unique and powerful means to study the function of the CXCR4 receptor and how this relates to disease processes. Acute myeloid leukemia (AML) is a group of myeloid leukemias with a very aggressive and fatal course if left untreated. The bone marrow (BM) microenvironment provides an important protective effect against chemotherapy and disruption of this interaction renders AML cells sensitive to chemotherapy in vitro and in vivo. The SDF-1/CXCR4 axis plays a key role in regulating stem cell mobilization and trafficking and its expression has been shown to negatively correlate to the prognosis of many cancers. Our lead agonist significantly enhances chemosensitivity of multiple leukemic cell lines to several chemotherapies, suggesting that CXCR4 agonists may provide a novel therapeutic approach for the treatment of AML. The overall goal of this project is to optimize small molecule CXCR4 agonist probes and characterize their activity against the CXCR4 receptor and AML in vitro and in vivo. Our unique small molecule CXCR4 agonists and antagonists give us a set of unique molecular tools to understand how CXCR4 receptor pharmacology impacts AML. In Aim 1 we will use rational medicinal chemistry to optimize our lead series for potency and drug-like properties, incorporating in silico design and robust biological testing into an iterative process. We will characterize new CXCR4 modulators in Aim 2 by evaluating their behavior against a number of in vitro systems including calcium mobilization, receptor binding, receptor internalization, chemotaxis, and signaling through various pathways. Aim 3 will evaluate the effects of CXCR4 modulation on AML using leukemia cell lines and primary human tumor cells as well as in vivo using patient-derived xenografts models of AML. The proposed studies will generate new molecular probes to investigate the pharmacology of CXCR4 and understand how this important receptor is involved in AML. These results will provide new insights into AML and potentially open up new avenues for therapeutic development.