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）：全世界每年约有 200,000 名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) 由少量白血病干细胞 (LSC) 传播。 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 FLT3 酪氨酸激酶 (TK) 组成型激活。持续性 FLT3-ITD+ AML LSC 代表疾病库和治疗后复发的来源。然而，FLT3 TK 抑制剂 (TKI) 仅适度抑制原发性 AML FLT3-ITD+ LSC 生长，未能表现出有效的长期临床活性。因此，需要额外的治疗策略来改善 FLT3-ITD+ AML 患者的预后。在初步研究中，我发现 SIRT1 脱乙酰酶在 FLT3-ITD+ AML LSC 中过度表达，与正常干细胞相比，SIRT1 抑制显着降低 AML LSC 的生长和存活。研究还表明，p53 乙酰化和激活可能在介导 SIRT1 抑制对 AML 祖细胞的影响中发挥重要作用。此外，研究表明，SIRT1 抑制显着进一步增强 FLT3 TKI 对 AML LSC 生长的抑制作用。因此，我推测 SIRT1 激活并抑制 p53 活性是 FLT3-ITD+ LSC 维持所必需的； SIRT1 抑制与 TKI 联合使用可消除 FLT3-ITD+ AML LSC。在这里，我建议在指导阶段确定 SIRT1 和 p53 在调节 FLT3/ITD+ AML LSC 体内生长 (Aim1) 中的作用，有了这些信息，我将研究 FLT3-ITD+ AML 中 SIRT1 上调的潜在机制细胞并评估 SIRT1 抑制是否可以在独立阶段与 TKI (Aim2) 联合增强 AML LSC 的消除。在 Aim1 中，我将使用一个充分表征的 FLT3-ITD+ 小鼠转导和移植 AML 模型来测试 SIRT1 基因删除对 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（相对于其他 SIRT1 靶标）在介导 SIRT1 促生存效应中的作用。在 Aim2 中，我将研究 SIRT1 调控途径，尤其是 FLT3 激酶独立因素，这将为将 SIRT1 和 FLT3 抑制剂联合起来以靶向 FLT3-ITD AML LSC 提供分子原理。然后我将直接测试SIRT1抑制与FLT3 TKI的组合是否可以在小鼠AML模型以及原发性人类AML异种移植模型中有效靶向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 抑制剂的组合是否代表了有效靶向 FLT3-ITD+ AML LSC 的创新且安全的方法。创造针对白血病的新型靶向疗法是我一生的目标。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 博士位于希望之城 (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确定可能的治疗方法的目标。此外，诸如来自既定委员会的指导、转化研究的高级培训以及相关科学管理技能等重要元素也将用于整体职业发展。所有这些组成部分最终将帮助我在支持转化研究的环境中获得教职。 COH 是 NCI 指定的癌症中心，因其成功开展由研究者发起的血液恶性肿瘤创新临床试验而闻名，这些试验将实验室的研究结果转化为临床。在这种环境下工作，我已经在慢性粒细胞白血病 (CML) 干细胞方面取得了重要发现。最近我把注意力转向了AML，因为与CML相比，AML治疗的效果仍然很差。如果不了解 AML LSC 的维持和耐药机制，科学家就无法开发任何有效的方法来实现 AML 的潜在治愈。因此，很明显，从事 AML LSC 生物学工作将是我未来职业发展的一个很好的重点。因此，当前的项目将使我能够建立独立于我导师在 CML 方面的专业知识的专业知识。