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: 8876619
• 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 2015-09-25
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8876619
• 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; collaborative environment; drug discovery; effective therapy; fetal liver kinase-2; high risk; improved; in vivo; inhibitor/antagonist; innovation; insight; leukemia; leukemia treatment; leukemic stem cell; mouse model; new therapeutic target; novel; novel therapeutics; overexpression; pre-clinical; progenitor; prognostic; response; skills; stem cell biology; success; targeted treatment; 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.

简介（由申请人提供）：全球每年约有20万儿童和成人死于白血病。最常见的白血病——急性髓系白血病（AML）是由少量白血病干细胞（LSC）传播的。fms样酪氨酸激酶-3 （FLT3）内部串联重复（ITD）是复发风险高的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。持续性FLT3-ITD+ AML LSCs是疾病的储存库和治疗后复发的来源。然而，FLT3 TK抑制剂（TKI）只能适度抑制原发性AML FLT3- itd + LSC的生长，并不能显示出有效的、长期的临床活性。因此，需要额外的治疗策略来改善FLT3-ITD+ AML患者的预后。在前期研究中，我发现SIRT1去乙酰化酶在FLT3-ITD+ AML LSC中过表达，与正常干细胞相比，SIRT1抑制显著降低AML LSC的生长和存活。这些研究还表明，p53乙酰化和激活可能在介导SIRT1抑制AML祖细胞的作用中起重要作用。此外，研究表明SIRT1抑制进一步显著增强FLT3 TKI对AML LSC生长的抑制作用。因此，我假设SIRT1激活并抑制p53活性是FLT3-ITD+ LSC维持所必需的；SIRT1抑制联合TKI可导致FLT3-ITD+ AML LSC的消除。在这里，我建议确定SIRT1和p53在指导期调节FLT3/ITD+ AML LSCs （Aim1）生长中的作用，并掌握这些信息，然后我将研究FLT3-ITD+ AML细胞中SIRT1上调的机制，并评估SIRT1抑制是否可以在独立期联合TKI （Aim2）增强AML LSCs的消除。在Aim1中，我将使用具有良好特征的FLT3-ITD+小鼠转导和移植AML模型来测试SIRT1基因缺失对FLT3/ITD+ AML LSC的影响。我将使用条件p53表达小鼠模型来确定p53激活在介导SIRT1促生存作用中的作用，而不是其他SIRT1靶点。在Aim2中，我将研究SIRT1调控途径，特别是FLT3激酶独立因子，这将为SIRT1和FLT3抑制剂联合靶向FLT3- ITD AML LSC提供分子基础。然后，我将直接测试SIRT1抑制与FLT3 TKI联合是否可以有效靶向小鼠AML模型和人类原发AML异种移植模型中的AML LSC。拟议的研究将确定SIRT1是否是AML LSC的有效治疗靶点，并评估TKI和SIRT1抑制剂的联合是否代表一种创新和安全的方法来有效靶向FLT3-ITD+ AML LSC。我的毕生目标是为白血病创造新的靶向治疗方法。短期职业目标是建立一个转化实验室，提供基础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City of Hope （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确定可能的治疗方法的目标。此外，一些重要因素，如来自一个既定委员会的指导、转译研究方面的高级培训和获得有关的科学管理技能，也将用于全面的职业发展。所有这些因素最终将帮助我在一个支持转化研究的环境中获得一个教职。COH是nci指定的癌症中心，以其在执行创新的研究者发起的血液恶性肿瘤临床试验方面的成功而闻名，这些临床试验将实验室的发现转化为临床。在这种环境下工作，我已经在慢性髓性白血病（CML）干细胞中取得了重要的发现。最近我把注意力转向了AML，因为与CML相比，AML的治疗效果仍然很差。在不了解AML LSC维持和耐药机制的情况下，科学家无法开发出任何有效的方法来实现AML的潜在治愈。因此，很明显，AML LSC生物学研究将是我未来职业发展的一个极好的重点。因此，目前的项目将使我能够在导师的CML专业知识之外建立自己的独立专业知识。