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: 10599230
• 负责人: JENNIFER H ELISSEEFF
• 金额: $ 50.13万
• 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 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10599230
• 关键词: Adverse drug effect; Affect; Aging; Antineoplastic Agents; Apoptosis; Apoptotic; BCL1 Oncogene; 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; Elderly; Evaluation; Event; Exposure to; Hematopoietic System; Hematopoietic stem cells; Human; Immune system; In Vitro; Individual; Lead; Ligand Binding; Ligands; Link; Mediating; Molecular; Mus; Pathologic; Pharmacology; Play; Predisposition; Protac; Protein Family; Proteins; Rejuvenation; Role; Safety; Series; Systemic Therapy; Technology; Thrombocytopenia; Tissues; Toxic effect; Translating; Treatment Efficacy; Ubiquitination; age related; aged; anti aging; 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.

项目总结/摘要 最近发现，衰老细胞（SnCs）在衰老和许多与年龄相关的疾病中起着致病作用， 表明细胞衰老是衰老的基本机制。用α-Al_2O_3选择性消除SnC 小分子，被称为senolytic，已成为一种新的“抗衰老”策略，有可能扩大 通过预防和治疗与年龄有关的疾病来维持人类健康。虽然有几个老年人 鉴定和表征，迄今发现的大多数senolytics是再利用的抗癌剂 因为SnCs使用一些与癌细胞相同的分子机制来逃避凋亡。这些 衰老清除剂通常具有各种靶向和/或脱靶毒性，这可能妨碍其临床应用 因为老年人比年轻人更容易受到药物不良反应的影响 对药物毒性的耐受性不如癌症患者。ABT 263是一种选择性BCL-2和BCL-xL抑制剂， 迄今为止发现的最有效和最广谱的再利用senolytics。我们和其他人发现， 许多不同类型的SnCs依赖于抗凋亡BCL-2家族蛋白的存活，特别是BCL-2家族蛋白。 xL。ABT 263可以有效地杀死细胞培养物中的各种SnC，并有效地清除各种小鼠组织中的SnC。 用ABT 263清除SnC还可以使老化的造血干细胞（HSC）和衰老的造血干细胞（HSC）恢复活力。 造血系统，并改善一些病理性 与衰老有关的疾病然而，其血小板减少症的靶向毒性阻碍了其临床应用 即使是癌症患者，因为血小板也依赖于BCL-xL生存。我们假设这是- 通过将ABT 263和其它BCL-xL抑制剂转化为血小板保留BCL-xL 蛋白水解靶向嵌合体（PROTAC），其将BCL-XL靶向血小板中表达较差的E3连接酶， 泛素化和降解。这一假设得到了我们的初步发现的支持，BCL-xL PROTAC 在体外，与ABT 263相比，对SnCs的作用更强，但对非SnCs和血小板的毒性更小，并且可以清除SnCs 在正常年龄小鼠中与ABT 263一样有效，而不会引起血小板减少。我们认为， 将ABT 263转化为血小板保留BCL-xL PROTAC也可以减少全身药物暴露，以降低脱靶 ABT 263的毒性，因为PROTAC在与靶点结合后可以消除其靶蛋白（事件- 驱动的药理学），并介导多轮的目标降解（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有率 （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 1）设计和合成具有最佳生物相容性的保留血小板的BCL-xL PROTAC， 作为衰老清除剂的安全性、效力和体内功效; 2）选择用于治疗衰老的领先的保留血小板的BCL-xL PROTAC。 评估它们对清除SnC和使老化HSC再生以及衰老HSC再生的治疗效果。 造血和免疫系统（HIS）;和3）确定用铅血小板- 保留BCL-xLPROTAC可用于有效治疗老年小鼠的骨关节炎（OA）， 局部UBX 101突触融合治疗。我们预计，拟议的研究将导致发现更安全， 更有效的衰老清除剂，更有可能转化为临床用途，以预防和治疗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 可用于将其它有毒的再利用的衰老清除剂转化为更安全和更有效的抗衰老剂。