Targeting the Metabolic Regulator SIRT5 in Acute Myeloid Leukemia

靶向急性髓系白血病的代谢调节因子 SIRT5

• 批准号: 10523086
• 负责人: Michael W. Deininger
• 金额: $ 32.47万
• 依托单位: VERSITI WISCONSIN, INC.
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10523086
• 关键词: Targeting; Metabolic; Regulator; SIRT5; Acute

PROJECT SUMMARY TARGETING THE METABOLIC REGULATOR SIRT5 IN ACUTE MYELOID LEUKEMIA. AML is an aggressive hematologic malignancy with <30% long-term survival. The current therapy standard, chemotherapy alone or combined with allogeneic stem cell transplant, has not changed for decades. Despite initial responses, most patients eventually relapse, suggesting persistence of leukemia initiating cells in protective niches. Inhibitors of FLT3 or mutant isocitrate dehydrogenase 1/2 (IDH1/2) have expanded therapy options and validated the paradigm of genotype-directed therapy. However, even with these new drugs, relapse is common and frequently due to selection of subclones with resistance mutations in the drug target. Unlike FLT3 and IDH1/2 inhibitors, the BCL2 inhibitor venetoclax is active in multiple AML genotypes, indicating that targeting shared vulnerabilities in a genotype-agnostic manner can be effective. Unfortunately many venetoclax-induced responses are not durable as leukemia cells adapt by activating alternative anti-apoptosis mechanisms or by reprogramming mitochondrial metabolism. Microenvironmental protection, intra-tumoral heterogeneity and metabolic flexibility limit the utility of current AML therapies. To identify new therapy targets in AML, we adapted an shRNA screen for testing primary AML cells under bone marrow microenvironment-like conditions. We discovered that many AML patient samples are highly dependent on SIRT5, while normal CD34+ cells are not. SIRT5 is a lysine deacylase implicated in the regulation of energy metabolic pathways, including oxidative phosphorylation (OXPHOS), fatty acid β-oxidation and glycolysis. SIRT5 knockdown (KD) reduces growth and increases apoptosis in most AML cell lines, with consistent results upon disruption of SIRT5 using CRISPR/Cas9 or NRD167, a novel cell-permeable SIRT5 inhibitor. Genetic absence of Sirt5 impairs in vitro transformation of mouse hematopoietic cells by several myeloid oncogenes, including MLL-AF9, and attenuates leukemogenesis in vivo. At a biochemical level, SIRT5 KD or inhibition with NRD167 is associated with reduced OXPHOS, reduced glutathione levels and increased mitochondrial superoxide, suggesting that AML cells depend on SIRT5 to maintain redox homeostasis. Sirt5-/- mice are viable with minor metabolic abnormalities, suggesting that in vivo inhibition of SIRT5 would be tolerated. We hypothesize that SIRT5 is a therapy target in AML and will test this in three Specific Aims: (1) Identify and validate SIRT5-regulated metabolic pathways in normal and AML stem and progenitor cells. (2) Identify biomarkers of sensitivity to SIRT5 inhibition in primary AML cells. (3) Identify a potent, selective, and bioavailable SIRT5 inhibitor, starting from the NRD167 tool compound. Our work will rigorously test whether SIRT5 is a therapy target in AML, clarify the mechanisms underlying SIRT5 dependence, and identify potent and selective SIRT5 inhibitors for future clinical development.

项目摘要 针对急性髓样白血病中的代谢调节剂SIRT5。 AML是一个侵略性 长期生存率<30％的血液系统恶性肿瘤。当前的治疗标准，单独化疗或 结合同种异体干细胞移植，数十年来一直没有变化。尽管有初步的回应，但大多数 患者最终中继，表明白血病在受保护的壁ni中引发了细胞。抑制剂 FLT3或突变体异氯酸盐脱氢酶1/2（IDH1/2）已扩大治疗方案，并验证了 基因型定向治疗的范式。但是，即使使用这些新药，退休也很普遍，而且经常 由于在药物靶标中选择了具有抗性突变的亚克隆。与FLT3和IDH1/2抑制剂不同， BCL2抑制剂Venetoclax在多种AML基因型中活跃，表明靶向共享漏洞 以基因型 - 不合稳定方式可以有效。不幸的是，许多Venetoclax引起的响应不是 通过激活替代性抗凋亡机制或重新编程来适应白血病细胞的耐用性白血病细胞 线粒体代谢。微环境保护，肿瘤内异质性和代谢灵活性 限制当前AML疗法的效用。为了确定AML中的新疗法靶标，我们改编了shRNA屏幕 用于测试骨髓微环境样条件下的原代AML细胞。我们发现很多 AML患者样品高度依赖于SIRT5，而正常的CD34+细胞不依赖。 SIRT5是赖氨酸 与能量代谢途径的调节有关的脱酰基酶，包括氧化物磷酸化 （Oxphos），脂肪酸β氧化和糖酵解。 SIRT5敲低（KD）减少了增长并增加 大多数AML细胞系的凋亡，使用CRISPR/CAS9或 NRD167，一种新型的细胞可渗透SIRT5抑制剂。 SIRT5的遗传缺失会损害体外转化的体外转化 小鼠造血细胞由几种髓样癌基因（包括MLL-AF9），并减弱白血病发生 体内。在生化水平上，NRD167的SIRT5 KD或抑制与OXPHOS减少有关 谷胱甘肽水平降低并增加线粒体超氧化物，表明AML细胞依赖于SIRT5 维持氧化还原稳态。 SIRT5 - / - 小鼠可行，且较小的代谢异常，这表明 体内抑制SIRT5将被耐受。我们假设SIRT5是AML的疗法靶标，将测试 这在三个具体目的中：（1）在正常和 AML茎和祖细胞。 （2）确定对初级AML中SIRT5抑制敏感性的生物标志物 细胞。 （3）从NRD167工具开始，确定潜在，选择性和生物利用的SIRT5抑制剂 化合物。我们的工作将严格测试SIRT5是否是AML中的治疗靶标，澄清机制 SIRT5依赖性的基础，并确定未来临床开发的潜在和选择性SIRT5抑制剂。