Project 5: Targeting Oxidative Phosphorylation in AML

项目概要/摘要 急性髓性白血病（AML）包括一组遗传和临床异质性的白血病， 恶性血液病尽管AML的分子表征取得了进展， 大多数病人会复发并死于疾病。在AML中，氧化磷酸化（OxPhos） 产生细胞内能量和代谢中间体，促进生长和支持 生存与正常造血干细胞不同，AML和白血病干细胞（LCS）过度表达抗- 凋亡线粒体蛋白Bcl-2依赖于OxPhos，当细胞凋亡时不能利用糖酵解。 线粒体呼吸被抑制，表明线粒体功能的维持是 对AML生存至关重要。 我们已经鉴定了一种新的有效的OxPhos（OxPhosi）纳摩尔抑制剂IACS-010759， 从不同结构类别的1,000多种化合物中选出。IACS-010759 已发现抑制OxPhos呼吸链的复合物I并阻断氧消耗。我们的数据 证明了该药物在AML细胞系中具有显著的生长抑制和促凋亡作用， 在低nM浓度下，对原代AML细胞具有最小的对正常BM细胞的毒性。反过来， OxPhos抑制剂和Bcl-2抑制剂venetoclax的组合在AML中是协同的。每日给药 IACS-010759在小鼠中耐受性良好，在体内异种移植研究中表现出较强的疗效 利用人AML患者来源的异种移植物（PDX）和减少的表型定义的LSC 通过新的质谱技术，CyTOF测量的组分。OxPhosi给药， 标准化疗延长了原发性AML PDX模型的生存期。IACS的I期临床试验- 010759治疗复发性/难治性AML的研究最近在MDACC启动。 我们建议测试OxPhos抑制构成一种新的治疗方法的假设， 针对AML独特的代谢脆弱性的方法;以及联合阻断 OxPhos和Bcl-2抑制剂的线粒体呼吸将消除白血病起始细胞， 做出客观的回应。我们将在体外建立对OxPhosi反应的生物标志物，包括RNA 和代谢组学特征，在一个大系列的原发性AML与已知的遗传谱，并验证 这些在体内AML PDX模型中。我们将进一步确定AML细胞协同作用的机制， 当用维奈托克阻断Bcl-2引发OxPhos抑制时死亡，并表征抗AML 以及这种组合的抗LSC功效。我们将进一步代谢分析存活的AML细胞， 标准化疗，并测试OxPhosi将减少或消除残留存活的假设 AML细胞。这些概念将转化为标准化疗和Bcl-2的I/II期研究。 2抑制剂维奈托克联合IACS-010759治疗复发性/难治性AML患者。

PROJECT SUMMARY/ABSTRACT Acute myeloid leukemia (AML) comprises a genetically and clinically heterogeneous group of aggressive hematological malignancies. Despite advances in molecular characterization of AML, the majority of patients will relapse and die of their disease. In AML, oxidative phosphorylation (OxPhos) generates intracellular energy and metabolic intermediates necessary to promote growth and support survival. Unlike normal hematopoietic stem cells, AML and leukemia stem cells (LCS) overexpress anti- apoptotic mitochondrial protein Bcl-2, rely on OxPhos and are unable to utilize glycolysis when mitochondrial respiration is inhibited, indicating that the maintenance of mitochondrial function is essential for AML survival. We have identified a novel potent nanomolar inhibitor of OxPhos (OxPhosi) IACS-010759, selected from the series of more than 1,000 compounds across distinct structural classes. IACS-010759 has been found to inhibit complex I of OxPhos respiratory chain and block oxygen consumption. Our data demonstrated profound growth-inhibitory and pro-apoptotic effects of this agent in AML cell lines and primary AML cells at low nM concentrations, with minimal toxicity against normal BM cells. In turn, combination of OxPhos inhibitors and Bcl-2 inhibitor venetoclax is synergistic in AML. Daily dosing of IACS-010759 was well tolerated in mice, demonstrated strong efficacy in the in vivo xenograft studies utilizing the human AML patient-derived xenografts (PDX) and reduced phenotypically defined LSC fractions measured by novel technique of mass cytometry, CyTOF. Administration of OxPhosi following standard chemotherapy extended survival in primary AML PDX model. A Phase I clinical trial of IACS- 010759 in relapsed/refractory AML was recently launched at MDACC. We propose to test the hypothesis that OxPhos inhibition constitutes a novel therapeutic approach that targets a unique metabolic vulnerability of AML; and that combined blockade of mitochondrial respiration by OxPhos and Bcl-2 inhibitors will eliminate leukemia-initiating cells and produce objective responses. We will establish biomarkers of response to OxPhosi in vitro including RNA and metabolomics signatures, in a large series of primary AML with known genetic profiling, and validate these in the in vivo AML PDX models. We will further determine mechanisms of synergistic AML cell death when OxPhos inhibition is primed by Bcl-2 blockade with venetoclax, and characterize anti-AML and anti-LSC efficacy of such combination. We will further metabolically profile AML cells surviving standard chemotherapy, and test the hypothesis that OxPhosi will reduce or eliminate residual surviving AML cells. These concepts will be translated into Phase 1/2 study of standard chemotherapy and of Bcl- 2 inhibitor Venetoclax combined with IACS-010759 in patients with relapsed/refractory AML.