Develop BCL-xL proteolysis targeting chimeras as safer and better senolytics

开发针对嵌合体的 BCL-xL 蛋白水解作为更安全、更好的 senolytics

• 批准号: 10375406
• 负责人: JENNIFER H ELISSEEFF
• 金额: $ 50.36万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10375406
• 关键词: Adverse drug effect; Affect; Aging; Antineoplastic Agents; Apoptosis; Apoptotic; BCL2 gene; BCL2L1 gene; Binding; Binding Sites; Blood Platelets; Cancer Patient; Cell Aging; Cell Culture Techniques; Cells; Clinic; Clinical; Data; Degenerative polyarthritis; Development; Disease; Dose-Limiting; Drug Exposure; Drug toxicity; Evaluation; Event; Exposure to; Hematopoietic System; Hematopoietic stem cells; Human; Immune system; In Vitro; Individual; Lead; Ligand Binding; Ligands; Link; Mediating; Molecular; Mus; Pathologic; Persons; Pharmacology; Play; Protac; Protein Family; Proteins; Rejuvenation; Role; Safety; Series; Systemic Therapy; Technology; Thrombocytopenia; Tissues; Toxic effect; Translating; Treatment Efficacy; Ubiquitination; age related; aged; anti aging; base; cancer cell; design; healthspan; in vivo; inhibitor; link protein; multicatalytic endopeptidase complex; new therapeutic target; novel; premature; prevent; protein function; recruit; senescence; small molecule; ubiquitin-protein ligase

PROJECT SUMMARY / ABSTRACT The recent discovery that senescent cells (SnCs) play a causative role in aging and in many age-related diseases suggests that cellular senescence is a fundamental mechanism of aging. Selective elimination of SnCs with a small molecule, termed senolytic, has become a new “anti-aging” strategy that has the potential to extend human healthspan by preventing and treating age-related diseases. Although a few senolytics have been identified and characterized, the majority of the senolytics discovered to date are repurposed anticancer agents because SnCs use some of the same molecular mechanisms to evade apoptosis as cancer cells. These senolytics usually possess various on-target and/or off-target toxicities, which could preclude their clinical use as anti-aging agents because old people are more susceptible to adverse drug effects than young individuals and tolerate drug toxicity less well than cancer patients. ABT263, a selective BCL-2 and BCL-xL inhibitor, is one of the most potent and broad-spectrum repurposed senolytics discovered to date. We and others found that many different types of SnCs depend on the anti-apoptotic BCL-2 family proteins for survival, particularly BCL- xL. ABT263 can potently kill a variety of SnCs in cell culture and effectively clear SnCs in various murine tissues. Clearance of SnCs with ABT263 can also rejuvenate aged hematopoietic stem cells (HSCs) and the senescent hematopoietic system in both prematurely and naturally aged mice, and ameliorate several pathological conditions associated with aging. However, its on-target toxicity of thrombocytopenia prevents its clinical use even for cancer patients, because platelets also depend on BCL-xL for survival. We hypothesize that this on- target toxicity can be averted by converting ABT263 and other BCL-xl inhibitors into platelet-sparing BCL-xL proteolysis targeting chimeras (PROTACs) that target BCL-XL to an E3 ligase poorly expressed in platelets for ubiquitination and degradation. This hypothesis is supported by our preliminary findings that BCL-xL PROTACs are more potent against SnCs but less toxic to non-SnCs and platelets than ABT263 in vitro, and can clear SnCs as effectively as ABT263 in normally aged mice without causing thrombocytopenia. We expect that converting ABT263 into platelet-sparing BCL-xL PROTACs can also reduce systemic drug exposure to lower off-target toxicities of ABT263 because PROTACs can eliminate their target proteins upon binding to the targets (event- driven pharmacology) and mediate multiple rounds of target degradation (sub-stoichiometric activity), whereas the activity of an inhibitor depends on occupancy of a binding site that directly affects protein function (occupancy-driven pharmacology and stoichiometric activity). Based on these exciting preliminary data, we plan to pursue the following specific aims: 1) design and synthesize platelet-sparing BCL-xL PROTACs with optimal safety, potency, and in vivo efficacy as senolytic agents; 2) select lead platelet-sparing BCL-xL PROTACs for evaluation of their therapeutic efficacy for clearance of SnC and rejuvenation of aged HSCs and the senescent hematopoietic and immune system (HIS) in mice; and 3) determine whether systemic therapy with lead platelet- sparing BCL-xL PROTACs can be used to effectively treat osteoarthritis (OA) in aged mice when combined with local UBX101 synolytic treatment. We anticipate that the proposed studies will lead to the discovery of safer and more potent senolytic agents that are more likely to translate into clinical use to prevent and treat OA and other age-related diseases. Furthermore, our preliminary data provide proof-of-concept that PROTAC technology may be useful to convert other toxic repurposed senolytic agents into safer and more effective anti-aging agents.

项目概要/摘要 最近发现衰老细胞 (SnC) 在衰老和许多与年龄相关的疾病中发挥着致病作用 表明细胞衰老是衰老的基本机制。选择性消除 SnCs 小分子，称为 senolytic，已成为一种新的“抗衰老”策略，有可能扩展 通过预防和治疗与年龄相关的疾病来延长人类的健康寿命。尽管已经有一些 senolytics 经过鉴定和表征，迄今为止发现的大多数 senolytics 都是重新利用的抗癌药物 因为 SnC 使用一些与癌细胞相同的分子机制来逃避细胞凋亡。这些 senolytics 通常具有各种靶向和/或脱靶毒性，这可能妨碍其临床使用 作为抗衰老剂，因为老年人比年轻人更容易受到药物不良反应的影响 与癌症患者相比，其对药物毒性的耐受性较差。 ABT263 是一种选择性 BCL-2 和 BCL-xL 抑制剂， 迄今为止发现的最有效、最广谱的重新利用的衰老剂。我们和其他人发现 许多不同类型的 SnC 的生存依赖于抗凋亡 BCL-2 家族蛋白，特别是 BCL- xL。 ABT263可以有效杀死细胞培养物中的多种SnCs，并有效清除多种小鼠组织中的SnCs。 用 ABT263 清除 SnC 还可以使老化的造血干细胞 (HSC) 和衰老的细胞恢复活力。 早产和自然衰老小鼠的造血系统，并改善多种病理学 与衰老相关的条件。然而，其血小板减少症的靶向毒性阻碍了其临床应用 即使对于癌症患者，因为血小板也依赖于 BCL-xL 的生存。我们假设这对 通过将 ABT263 和其他 BCL-xl 抑制剂转化为血小板保留 BCL-xL 可以避免目标毒性 蛋白水解靶向嵌合体 (PROTAC) 将 BCL-XL 靶向血小板中表达不佳的 E3 连接酶 泛素化和降解。我们的初步发现支持了这一假设，即 BCL-xL PROTAC 在体外，与 ABT263 相比，抗 SnC 更有效，但对非 SnC 和血小板的毒性更小，并且可以清除 SnC 对正常衰老小鼠的疗效与 ABT263 一样，且不会引起血小板减少症。我们期望转换 ABT263 进入血小板保留 BCL-xL PROTAC 还可以减少全身药物暴露，降低脱靶率 ABT263 的毒性，因为 PROTAC 可以在与靶标结合后消除其靶蛋白（事件- 驱动药理学）并介导多轮目标降解（亚化学计量活性），而 抑制剂的活性取决于直接影响蛋白质功能的结合位点的占据 （占用驱动的药理学和化学计量活性）。根据这些令人兴奋的初步数据，我们计划 追求以下具体目标：1）设计和合成具有最佳性能的保留血小板的 BCL-xL PROTAC 作为抗衰老药物的安全性、效力和体内功效； 2) 选择领先的血小板保留 BCL-xL PROTAC 评估其清除 SnC 和恢复衰老 HSC 和衰老细胞的疗效 小鼠的造血和免疫系统（HIS）； 3) 确定是否采用铅血小板进行全身治疗 保留 BCL-xL PROTAC 与以下药物联合使用可有效治疗老年小鼠的骨关节炎 (OA) 局部UBX101溶酶治疗。我们预计拟议的研究将导致发现更安全和 更有效的 senolytics 药物更有可能转化为临床用途，用于预防和治疗 OA 和其他疾病 与年龄有关的疾病。此外，我们的初步数据提供了 PROTAC 技术可以 可用于将其他有毒的重新利用的抗衰老剂转化为更安全、更有效的抗衰老剂。