Novel HDAC Class III Specific Radiotracers for PET Imaging.

用于 PET 成像的新型 HDAC III 类特异性放射性示踪剂。

• 批准号: 8641825
• 负责人: Juri George Gelovani
• 金额: $ 36.61万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8641825
• 关键词: Novel; HDAC; Class; III; Specific

DESCRIPTION (provided by applicant): The availability of novel HDAC class- and isoform-specific PET radiotracers will have a significant positive impact on the pace or research in the field of epigenetics. SIRTs-specific PET imaging agents will enable non- invasive and repetitive in vivo imaging of SIRTs expression and activity in the brain and different organs and tissues (including cancer) and help to understand the mechanisms of SIRTs involvement in normal physiology and in the mechanisms of different diseases, enable non-invasive monitoring of pharmacodynamics and therapeutic efficacy of novel SIRTs-specific inhibitors (or activators) in experimental animals and in humans, and facilitate their translation into clinic. Therefore, the overall aim of this grant application is to conduct a series of comprehensive in vivo imaging studies in rodents and non-human primates to further assess the efficacy of 18F-PhFAHA for non-invasive imaging of SIRTs in the brain and other organs and tissues. To further improve substrate selectivity and binding to SIRTs, we will synthesize and evaluate 42 potential SIRTs-specific substrates different 18F-labeled acyl "leaving" groups and two different side chains in the "cap" region. The substrate efficiency of compounds in the focused library will be in a panel of recombinant HDACs 1-11 and SIRTs 1-7. Three best substrates will be radiolabeled with F-18 and evaluated further in vitro and in vivo. Then, In vitro radiotracer accumulation studies will be performed with 18F-PhAHA and three novel 18F-labeled radiotracers in tumor cell lines with high, moderate, and low levels of SIRT1 expression; we will determine the radiolabeled metabolites in the primary cultures of human hepatocytes. By conducting these in vitro studies we will select three best novel radiotracers for subsequent microPET/CT imaging and autoradiography studies in mice to assess their efficacy and specificity for imaging SIRTs expression-activity. We will perform in situ immunohistochemical comparative studies to validate PET/CT imaging results. Also, PET/CT imaging studies will be performed in tumor-bearing mice at: a) baseline; b) pre-treatment with resveratrol (SIRTs activator); c) pre-treatment with sirtinol (SIRTs inhibitor) to assess the feasibility of pharmacodynamic imaging. The best radiotracer will be selected for subsequent studies in non-human primates to assess: a) the time-course of biodistribution, uptake, retention, and efflux from different organs and tissues; b) whole body and individual organ radiation dosimetry; and d) the time-course of 18F-labeled metabolites in blood. Also, we will assess the feasibility of PET/CT/MRI with the selected novel radiotracer (or 18F-PhAHA) for monitoring pharmacodynamic (PD) effects of SIRTs activators and inhibitors (resveratrol and sirtinol) in the same animals. Through the proposed studies we will select SIRTs-specific 18F-labeled radiotracer with optimal pharmacokinetic and radiation dosimetry characteristics and sensitivity for PET/CT/MRI imaging of SIRTs expression-activity in vivo. PUBLIC HEALTH RELEVANCE: Program Director/Principal Investigator (Last, First, Middle): Gelovani, Juri G. With the recent advances in epigenetic research and improvement in our understanding of various epigenetic mechanisms histone deacetylase (HDAC) Class III enzymes or Sirtuins (Sirts) have emerged as important regulators of development and life span, normal physiology. In this grant application we propose series of comprehensive imaging studies in rodents and non-human primates to assess the efficacy of novel radiolabeled agents non-invasive PET imaging of Class-III histone deacetylase enzymes called sirtuins (SIRTs) in the brain and other organs and tissues. The availability of novel HDAC class- and isoform-specific PET radiotracers will have a significant positive impact on the pace or research in the field of epigenetics. SIRTs-specific PET imaging agents will enable non-invasive and repetitive in vivo imaging of SIRTs expression and activity in the brain and different organs and tissues (including cancer) and help to understand the mechanisms of SIRTs involvement in normal physiology and in the mechanisms of different diseases. The utilization of invasive biopsies of normal tissues (i.e., brain, heart, etc.) is prohibitive in humans due to obvious reasons of traumatism and morbidity. Therefore, PET/CT(MR) imaging using SIRTs-specific substrate-type radiotracers should enable non-invasive monitoring of pharmacodynamics and therapeutic efficacy of novel SIRTs-specific inhibitors (or activators) in experimental animals and in humans, and facilitate their translation into clinic. Therefore, the overall aim of this grant application is to conduct a series of comprehensive in vivo imaging studies in rodents and non-human primates to further assess the efficacy of 18F-PhFAHA for non- invasive imaging of SIRTs in the brain and other organs and tissues. Also, we propose to continue developing potentially even more selective and sensitive substrate-type radiotracers for PET imaging of SIRTs activity in vivo.

描述（由申请人提供）： 新型HDAC类和同工型特异性PET放射性示例的可用性将对表观遗传学领域的速度或研究产生重大积极影响。 SIRTS特定的PET成像剂将使SIRTS表达和活性在大脑以及不同的器官和组织中的表达和活性（包括癌症）（包括癌症）（包括癌症），并有助于了解SIRT在正常生理学中的机制以及在不同疾病中的机制中的机制，并有效地监测药物疾病的机制，并有助于了解药物学的机制，并有助于了解药物学的机制，并有助于了解药物学的机制，并有助于了解药物学的机理（或激活剂）在实验动物和人类中，并促进其转化为诊所。因此，该赠款应用的总体目的是在啮齿动物和非人类灵长类动物中进行一系列全面的体内成像研究，以进一步评估18F-PHFAHA对大脑和其他器官和其他器官和其他组织中SIRT的非侵入性成像的疗效。为了进一步提高底物的选择性并与SIRT结合，我们将合成和评估42个潜在的SIRTS特异性底物不同的18F标记的酰基“离开”基团和“ CAP”区域中的两个不同的侧链。重点库中化合物的底物效率将在重组HDAC 1-11和SIRT 1-7的小组中。三个最佳底物将用F-18进行放射性标记，并在体外和体内进行进一步评估。然后，将使用18F-PHAHA和三个新型的18F标记放射性示例在肿瘤细胞系中进行体外放射性示例积累研究，具有高，中度和低水平的SIRT1表达。我们将确定人肝细胞主要培养物中的放射性标记代谢产物。通过进行这些体外研究，我们将在小鼠中选择三种最佳新型放射性示踪剂，用于随后的MicroPET/CT成像和放射自显影研究，以评估其成像SIRT SIRTS表达活性的功效和特异性。我们将进行原位免疫组织化学比较研究，以验证PET/CT成像结果。同样，在肿瘤小鼠中，将在以下基线中进行PET/CT成像研究； b）用白藜芦醇（SIRTS激活剂）进行预处理； c）用Sirtinol（SIRTS抑制剂）预处理以评估药效成像的可行性。最好的放射性示感将被选中进行非人类灵长类动物的后续研究以评估：a）不同器官和组织的生物分布，摄取，保留和外排的时间顺序； b）全身和单个器官辐射剂量测定法； d）血液中18F标记的代谢产物的时间顺序。此外，我们将使用所选的新型放射性示踪剂（或18F-PHAHA）评估PET/CT/MRI的可行性，以监测同一动物中SIRTS激活剂和抑制剂（白藜芦醇和SIRTOL）的药效学（PD）效应。通过拟议的研究，我们将选择具有最佳药代动力学和放射剂量测定特征的SIRTS特异性18F标记的放射性示例，以及对体内SIRTS表达活性的PET/CT/MRI成像的灵敏度。 公共卫生相关性： 计划总监/首席研究员（最后，第一，中间）：Gelovani，JuriG。随着我们对各种表观遗传机制组蛋白脱乙酰基酶（HDAC）III酶或SIRTUINS（SIRTS）（SIRTS）（SIRTS）（SIRTS）的最新进步和改善的进步，已经成为了重要的开发和生活范围的重要调节剂。在此赠款应用中，我们提出了一系列在啮齿动物和非人类灵长类动物中的综合成像研究，以评估新型放射性标记剂的疗效，非侵入性PET成像III III组脱乙酰酶酶（称为SIRT）在大脑以及其他器官和组织中的功效。新型HDAC类和同工型特异性PET放射性示例的可用性将对表观遗传学领域的速度或研究产生重大积极影响。 SIRTS特异性的PET成像剂将使SIRTS表达和活性在大脑以及不同的器官和组织（包括癌症）的体内成像中，并有助于了解SIRT参与正常生理学的机制以及不同疾病的机制。由于创伤和发病率的明显原因，人类的侵入性活检（即大脑，心脏等）的利用是过时的。因此，使用SIRTS特异性底物型放射性示例剂的PET/CT（MR）成像应对实验动物和人类中新型SIRTS特异性抑制剂（或激活剂）的药效学和治疗功效进行非侵入性监测，并促进其转化为临床。因此，该赠款应用的总体目的是在啮齿动物和非人类灵长类动物中进行一系列全面的体内成像研究，以进一步评估18F-PHFAHA对大脑以及其他器官和其他器官和组织中SIRT的非侵入性成像的疗效。另外，我们建议继续开发潜在的更具选择性和敏感的底物型放射性示例，以用于体内SIRTS活性的PET成像。