Improving targeted therapy in FLT3-mutated AML

项目摘要 本申请描述了我对急性髓系白血病（AML）细胞信号传导的研究， 5年职业发展规划的指导。我的最终目标是成为一个独立的 在实验室为基础的学术血液学/肿瘤学领域的医生-科学家。在我的指导下， 主要的研究导师，马丁卡罗尔博士，在宾夕法尼亚大学（UPENN），我已经制定了一个 结构化的培训计划，包括密集的实验室研究，教学法，并由经验丰富的监督 教师顾问委员会。拟议的研究将集中在对FLT 3靶向的耐药机制上。 根据在宾夕法尼亚大学进行的这些药物的临床试验的关键见解，早期 第二代FLT 3抑制剂（FLT 3 i）由于靶点特异性差和有限的 生物利用度最近已经开发了具有改善的针对FLT 3和临床应用的活性的较新的药剂。 通过白血病母细胞的清除证明了疗效。然而，这些药剂不是治愈性的，并且许多 患者的反应是分化而不是根除白血病克隆。这引起了重要的 关于FLT 3如何调节白血病细胞分化状态的问题。在初步研究中，我发现 FLT 3抑制下游导致组蛋白快速下调的新途径 甲基转移酶，EZH 2。EZH 2是PRC 2转录抑制子的催化组分。本研究 代表FLT 3调控表观遗传修饰剂的第一个证明。EZH 2活性的丧失已被证实是 与髓系分化增加和白血病发生减少有关，使其成为一个有吸引力的研究目标 作为FLT 3 i诱导分化的潜在机制。该提案旨在证明PRC 2是 FLT 3-ITD白血病发生所必需（目的1），证明FLT 3 i功能性抑制PRC 2活性（目的 2），并确定FLT 3抑制后EZH 2下调的机制（目的3）。这些发现将 提供对FLT 3信号传导生物学的深入了解，并确定诱导终末 FLT 3-ITD白血病细胞的分化。在进行拟议的研究和培训计划时，我将制定 建立翻译研究独立职业所需的技能和专业知识。

PROJECT SUMMARY This application describes my research on cell signaling in acute myeloid leukemia (AML) to be performed within the context of a 5-year mentored career development plan. My ultimate goal is to become an independent physician-scientist in the area of laboratory-based academic Hematology/Oncology. Under the guidance of my primary research mentor, Dr. Martin Carroll, at the University of Pennsylvania (UPENN), I have developed a structured training plan consisting of intensive laboratory research, didactics, and oversight by an experienced faculty advisory committee. The proposed research will focus on mechanisms of resistance to FLT3 targeted therapy in AML based on key insights from the clinical trials of these agents conducted at UPENN. Early generation FLT3 inhibitors (FLT3i) were met with lukewarm enthusiasm due to poor target specificity and limited bioavailability. Newer agents have recently been developed with improved activity against FLT3 and clinical efficacy as evidenced by clearance of leukemic blast cells. However, these agents are not curative and many patients respond with differentiation rather than eradication of the leukemic clone. This raises important questions about how FLT3 regulates the differentiation state of leukemia cells. In preliminary studies, I identified a novel pathway downstream of FLT3 inhibition that leads to rapid downregulation of the histone methyltransferase, EZH2. EZH2 is the catalytic component of the PRC2 transcriptional repressor. This research represents the first demonstration of FLT3 regulation of an epigenetic modifier. Loss of EZH2 activity has been linked to increased myeloid differentiation and decreased leukemogenicity, making it an attractive target to study as a potential mechanism for FLT3i-induced differentiation. This proposal aims to demonstrate that PRC2 is necessary for FLT3-ITD leukemogenesis (Aim 1), demonstrate that FLT3i functionally inhibit PRC2 activity (Aim 2), and determine the mechanism of EZH2 downregulation after FLT3 inhibition (Aim 3). These findings will provide insight into the biology of FLT3 signaling and identify improved approaches to induce terminal differentiation of FLT3-ITD leukemia cells. In undertaking the proposed studies and training plan, I will develop the skills and expertise necessary to establish an independent career in translational research.