Pathologic Signaling Pathways in AML Cells

摘要：急性髓细胞白血病（AML）是一种严重的血液肿瘤， 退伍军人和其他人。多项研究表明， 信号通路是白血病细胞转化的必要步骤。但 FLT 3野生型AML中激活信号传导的机制描述不多。我们 假设PI 3激酶途径组成性激活导致一种 一种名为哺乳动物雷帕霉素靶蛋白2（mTORC 2）的复合物， 平衡AML细胞中细胞生长和存活的途径。在本提案中，我们将 定义这些信号通路，并确定是否单独或联合抑制mTORC 2， 与其他药物联合将提高AML临床前模型的生存率 从而为这种具有挑战性的疾病带来新的治疗方法。 1.目的：研究提案的总体目标是确定 AML细胞中激活的细胞信号传导机制，决定了 AML细胞中mTORC 2调节的通路，并确定mTORC 2的抑制是否 可以增加AML患者的生存率。 2.研究设计：我们提出了三个具体目标。具体目标1）确认 4 EBP 1是人AML样品中MTORC 2而不是MTORC 1的靶标，并定义了 MTORC 2是否调节细胞存活或细胞生长。具体目标2）确定是否 mTORC 2调节AML细胞中的FOXO 3磷酸化以调节细胞存活。 3）确定MTORC 1/MTORC 2的组合抑制是否在 联合化疗或Bcl 2抑制剂可抑制AML细胞生长， 临床模型 3.方法学：具体目标1将主要使用人AML细胞， 培养的人AML细胞。具体目标2将使用类似的方法，但也评估 使用染色质免疫沉淀的FOXO与DNA结合。具体目标3将重点 在我们实验室开发的AML异种移植模型中的研究。 4.研究结果：我们预期确认mTORC 2实际上是一个主调节因子， AML细胞中的信号传导。特别是，我们预计mTORC 2调节4 EBP 1， 调节蛋白质翻译。我们还预期mTORC 2调节FOXO蛋白， 调节c-Myc表达。最后，我们预计mTORC 2抑制将起作用， 单独或与其它疗法组合以抑制体内AML细胞存活。 5.临床关系：这些研究将使用来自患者的主要材料， 急性髓细胞白血病和将用于开发一种新的方法来治疗这种疾病。

Abstract: Acute myeloid leukemia (AML) is a serious blood cancer that affects United States Veterans and other individuals. Multiple studies have demonstrated that active signaling pathways are a necessary step to leukemic cell transformation. However, the mechanism(s) of activated signaling in FLT3 wild type AML are poorly described. We hypothesize that constitutive activation of the PI3 kinase pathway leads to activation of a complex called mammalian target of rapamycin 2 (mTORC2) which regulates diverse pathways to balance cell growth and survival in AML cells. In this proposal, we will define these signaling pathways and determine if inhibition of mTORC2 alone or in combination with other drugs will enhance survival in pre-clinical models of AML leading to new therapies for this challenging disease. 1. Objective(s): The overall objective of the research proposal is to define the mechanisms of activated cell signaling in AML cells, determine the biochemical pathways regulated by mTORC2 in AML cells and determine if inhibition of mTORC2 in pre-clinical models can increase survival of individuals with AML. 2. Research Design: We propose three Specific Aims. Specific Aim 1) Confirm that 4EBP1 is a target of MTORC2 and not MTORC1 in human AML samples and define whether MTORC2 regulates cell survival or cell growth. Specific Aim 2) Determine if mTORC2 Regulates FOXO 3 phosphorylation in AML cells to Regulate Cell Survival. Specific Aim 3) Determine if combinatorial MTORC1/MTORC2 inhibition in combination with chemotherapy or Bcl2 inhibition suppresses AML cell growth in pre- clinical models. 3. Methodology: Specific Aim 1 will primary use human AML cells and primary human AML cells in culture. Specific Aim 2 will use similar methods but also assess FOXO binding to DNA using chromatin immunoprecipitation. Specific Aim 3 will focus on studies in a xenotransplantation model of AML developed by our laboratory. 4. Findings: We anticipate confirming that mTORC2 is actually a master regulator of signaling in AML cells. In particular, we anticipate that mTORC2 regulates 4EBP1 to regulate protein translation. We also anticipate that mTORC2 regulates FOXO proteins to regulate c-Myc expression. Finally, we anticipate that mTORC2 inhibition will work alone or in combination with other therapies to inhibit AML cell survival in vivo. 5. Clinical Relationships: These studies will use primary material from patients with AML and will be used to develop a new approach to therapy of the disease.