Research career advancement: Role of the SIRT1 deacetylase in maintenance of FLT3

研究职业发展：SIRT1 脱乙酰酶在维持 FLT3 中的作用

• 批准号: 8679747
• 负责人: LING LI
• 金额: $ 14.03万
• 依托单位: BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-20 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8679747
• 关键词: Acetylation; Acute Myelocytic Leukemia; Adult; Aftercare; Biology; Cell Aging; Cell Maintenance; Cells; Child; Chronic Myeloid Leukemia; Cities; Clinical; Clinical Trials; Deacetylase; Disease; Disease Reservoirs; Drug resistance; Elements; Environment; Event; Faculty; Future; Genetic; Goals; Growth; Hand; Health; Hematologic Neoplasms; Human; Knock-out; Knockout Mice; Laboratories; Laboratory Finding; Lead; MLL-AF9; Maintenance; Mediating; Mentors; Mentorship; Modeling; Molecular; Molecular Abnormality; Mus; Mutation; NCI-Designated Cancer Center; Normal Cell; Outcome; Patients; Phase; Phosphotransferases; Play; Population; Positioning Attribute; Protein Tyrosine Kinase; Regulation; Regulatory Pathway; Relapse; Research; Research Personnel; Resistance; Risk; Role; Scientist; Signal Transduction; Source; Stem cells; Testing; Therapeutic; Training; Translating; Translational Research; Transplantation; Tyrosine Kinase Inhibitor; Up-Regulation; Work; Xenograft Model; base; career; career development; cell age; cell growth; drug discovery; effective therapy; fetal liver kinase-2; high risk; improved; in vivo; inhibitor/antagonist; innovation; insight; leukemia; leukemic stem cell; mouse model; new therapeutic target; novel; novel therapeutics; overexpression; pre-clinical; progenitor; prognostic; response; skills; stem cell biology; success; therapeutic target; transcription factor

DESCRIPTION (provided by applicant): Every year, approximately 200,000 children and adults around the world die from leukemia. The most common leukemia -acute myeloid leukemia (AML) is propagated by small population of leukemia stem cells (LSC). The FMS-like tyrosine kinase-3 (FLT3) Internal tandem duplication (ITD) represents the most frequent mutation seen in AML patients with high risk of relapse. The FLT3-ITD mutation results in constitutive FLT3 tyrosine kinase (TK) activation. Persistent FLT3-ITD+ AML LSCs represent a reservoir of disease and source of relapse after treatment. However, FLT3 TK inhibitors (TKI) only modestly inhibit primary AML FLT3-ITD+ LSC growth and fail to demonstrate effective, long-term clinical activity. Therefore, additional therapeutic strategies are required to improve outcomes for FLT3-ITD+ AML patients. In preliminary studies I have found that the SIRT1 deacetylase is overexpressed in FLT3-ITD+ AML LSC, and SIRT1 inhibition significantly reduces growth and survival of AML LSC compared to normal stem cells. The studies also suggest that p53 acetylation and activation may play an important role in mediating the effects of SIRT1 inhibition on AML progenitors. In addition, the studies suggest that SIRT1 inhibition significantly further enhances inhibition of AML LSC growth by FLT3 TKI. Therefore, I hypothesize that SIRT1 activation with suppression of p53 activity is required for FLT3-ITD+ LSC maintenance; and that SIRT1 inhibition in combination with TKI could lead to elimination of FLT3-ITD+ AML LSC. Here I propose to determine the role of SIRT1 and p53 in regulating growth of FLT3/ITD+ AML LSCs in vivo (Aim1) in the mentored phase, and with this information in hand, I will then investigate mechanisms underlying SIRT1 upregulation in FLT3-ITD+ AML cells and evaluate whether SIRT1 inhibition can enhance elimination of AML LSCs in combination with TKI (Aim2) in the independent phase. In Aim1, I will use a well-characterized FLT3-ITD+ murine transduction and transplantation AML model to test the effect of genetic deletion of SIRT1 on FLT3/ITD+ AML LSC. I will use a conditional p53 expression mouse model to determine the role of p53 activation, as opposed to other SIRT1 targets, in mediating pro-survival effects of SIRT1. In Aim2, I will investigate SIRT1 regulatory pathway especially FLT3 kinase independent factors which would provide molecular rationale to combine SIRT1 and FLT3 inhibitors together to target FLT3- ITD AML LSC. Then I will directly test whether the combination of SIRT1 inhibition with FLT3 TKI can effectively target AML LSC in murine AML model as well as primary human AML xenograft model. The proposed studies will determine whether SIRT1 is a valid therapeutic target in AML LSC, and evaluate whether the combination of TKI and SIRT1 inhibitors represents an innovative and safe approach to effectively target FLT3-ITD+ AML LSC. I am motivated by a lifelong goal to create novel targeted therapeutics for leukemia. The short-term career goal is to establish a translational laboratory that provides an interface between basic biology and drug discovery. Both scientific and career developments are essential components to achieve this aim. Dr. Bhatia's lab at City of Hope (COH) provides such an environment to support the candidate's objectives of understanding the disease mechanisms and developing clinical relevant models to identify possible treatments. Also important elements such as mentorship from an established committee, advanced training in translational research, and incurring relevant scientific management skills would be utilized for the overall career development. All those components will ultimately help me to procure a faculty position in an environment supportive of translational research. COH, a NCI-designated Cancer Center is well known for its success in performing innovative investigator-initiated clinical trials for hematological malignancy that translate findings from laboratory into the clini. Working in this environment I have already made the important findings in chronic myeloid leukemia (CML) stem cells. Recently I turned my focus to AML, because in contrast to CML, the outcomes for AML treatment still remain very poor. Without understanding of mechanisms of maintenance and drug resistance of AML LSC, scientists can't develop any effective approaches to achieve potential cure of AML. Hence, it is evident that working on AML LSC biology would be an excellent focus for my future career development. Therefore, the present project will allow me to establish my independent expertise separate from my mentor's expertise in CML.

描述（由申请人提供）：每年，世界各地约有200,000名儿童和成人死于白血病。最常见的白血病 - 纯髓性白血病（AML）是由小群白血病干细胞（LSC）传播的。 FMS样酪氨酸激酶-3（FLT3）内部串联重复（ITD）代表了高复发风险高的AML患者中最常见的突变。 FLT3-ITD突变导致组成型FLT3酪氨酸激酶（TK）激活。持续的FLT3-ITD+ AML LSC代表了疾病的储层和治疗后复发的来源。但是，FLT3 TK抑制剂（TKI）仅适度抑制原发性AML FLT3-ITD+ LSC的生长，并且无法证明有效的长期临床活性。因此，需要其他治疗策略来改善FLT3-ITD+ AML患者的预后。在初步研究中，我发现SIRT1脱乙酰基酶在FLT3-ITD+ AML LSC中过表达，而SIRT1抑制显着降低了与正常干细胞相比，AML LSC的生长和存活率。研究还表明，p53乙酰化和激活可能在介导SIRT1抑制对AML祖细胞的影响中起重要作用。此外，研究表明，SIRT1抑制作用显着进一步增强了FLT3 TKI对AML LSC生长的抑制作用。因此，我假设SIRT1激活抑制p53活性是FLT3-ITD+ LSC维护所必需的； SIRT1抑制与TKI结合可能导致消除FLT3-ITD+ AML LSC。 Here I propose to determine the role of SIRT1 and p53 in regulating growth of FLT3/ITD+ AML LSCs in vivo (Aim1) in the mentored phase, and with this information in hand, I will then investigate mechanisms underlying SIRT1 upregulation in FLT3-ITD+ AML cells and evaluate whether SIRT1 inhibition can enhance elimination of AML LSCs in combination with TKI (Aim2) in the independent 阶段。在AIM1中，我将使用良好的FLT3-ITD+鼠转导和移植AML模型来测试SIRT1遗传缺失对FLT3/ITD+ AML LSC的影响。我将使用条件p53表达小鼠模型来确定p53激活的作用，而不是其他SIRT1靶标，在介导SIRT1的促生存效应中。在AIM2中，我将研究SIRT1调节途径，尤其是FLT3激酶独立因素，这些因素将提供分子原理，以将SIRT1和FLT3抑制剂组合在一起，以靶向FLT3- ITD AML LSC。然后，我将直接测试SIRT1抑制与FLT3 TKI的组合是否可以有效地靶向鼠AML模型中的AML LSC以及原代人AML异种移植模型。拟议的研究将确定SIRT1是否是AML LSC中的有效治疗靶标，并评估TKI和SIRT1抑制剂的组合是否代表了有效靶向FLT3-ITD+ AML LSC的创新且安全的方法。我的动机是一个终生的目标，是为白血病创造新颖的靶向治疗剂。短期职业目标是建立一个翻译实验室，该实验室提供基本生物学和药物发现之间的接口。科学和职业发展都是实现这一目标的重要组成部分。 Bhatia博士在希望之城（COH）的实验室提供了这样一个环境，以支持候选人了解疾病机制和开发临床相关模型以识别可能治疗的目标。同样重要的要素，例如既定委员会的指导，转化研究的高级培训以及招致相关科学管理技能的培训，也将用于整体职业发展。所有这些组件最终都将帮助我在支持转化研究的环境中获得教师职位。 COH是一个NCI指定的癌症中心，以其在创新研究者引发的血液恶性肿瘤临床试验方面的成功而闻名，该试验将实验室的发现转化为临床。在这种环境中工作，我已经在慢性髓样白血病（CML）干细胞中提出了重要发现。最近，我将重点放在AML上，因为与CML相比，AML治疗的结果仍然非常差。在不了解AML LSC的维持和耐药性机制的情况下，科学家无法开发任何有效的方法来实现AML的潜在治疗方法。因此，很明显，从事AML LSC生物学工作将是我未来职业发展的绝佳重点。因此，本项目将使我能够建立与导师在CML中的专业知识分开的独立专业知识。