Molecular mechanisms of drug resistance and disease progression in acute myeloid leukemia.

急性髓系白血病耐药和疾病进展的分子机制。

• 批准号: 10698907
• 负责人: Elizabeth Ann Eklund
• 金额: --
• 依托单位: JESSE BROWN VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10698907
• 关键词: AML/MDS; Acceleration; Acute Myelocytic Leukemia; Amino Acids; Anti-Inflammatory Agents; Bone Marrow; Bone Marrow Transplantation; CD34 gene; Cell Cycle Progression; Cell Death; Cells; Chimeric Proteins; Chromosomes; Clinical; Clinical Research; DNA Damage; Defect; Development; Disease; Disease Progression; Drug resistance; Dysmyelopoietic Syndromes; Emergency Situation; Event; FLT3 gene; Fusion Oncogene Proteins; Genes; Genetic Transcription; Goals; Granulopoiesis; Hematopoietic stem cells; Human; Impairment; Inflammasome; Inflammation; Inflammation Mediators; Inflammatory; Innate Immune Response; MLL gene; Mediating; Messenger RNA; Metabolic; Modeling; Molecular; Mus; Mutagenesis; Mutation; Myeloid Cells; Myeloid Leukemia; Myeloproliferative disease; Oncoproteins; Pathway interactions; Patients; Phosphorylation; Physiological; Polyribosomes; Process; Production; Prognosis; Proliferating; Protein Biosynthesis; Proteins; Proteomics; RNA metabolism; Receptor Protein-Tyrosine Kinases; Regulation; Repression; Ribosomes; Role; Site; Stress; Time; Transfer RNA; Translations; Transplantation; Twin Multiple Birth; Twin Studies; Tyrosine Phosphorylation; Ubiquitin; Xenograft procedure; adverse outcome; biological adaptation to stress; comparison control; density; exhaustion; exome sequencing; granulocyte; homeodomain; human subject; immunoregulation; knock-down; leukemia; leukemogenesis; mRNA Translation; molecular marker; molecular subtypes; mouse model; overexpression; peripheral blood; prevent; protein expression; protein metabolism; response; stem; stem cells; therapeutic target; transcription factor; transcriptome sequencing; translatome; transplant model; ubiquitin-protein ligase

Aberrant activation of the innate immune response is hypothesized to contribute to leukemogenesis in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Patients with MDS were described with mutations that constitutively activated such pathways. Our studies suggested that mutations which impair termination of emergency (stress) granulopoiesis (EG) are also a possible mechanism. EG is the process for rapid, episodic granulocyte (PMN) production during infectious challenge and a key component of the innate immune response. We previously determined that Triad1, an E3 ubiquitin (Ub) ligase, was essential for EG- termination. Consistent with a role for a sustained EG response in leukemogenesis, we found Triad1 functioned as a leukemia suppressor for AML with increased expression of homeodomain transcription factors. An adverse prognosis subset of clonal myeloid malignancies, including MDS/AML with MLL1/KMT2A rearrangements, is characterized by overexpression of a group of these proteins (e.g HoxB3, B4, A9-11, Cdx1 and 2, Meis1). Mice transplanted with bone marrow expressing leukemia-associated Mll1-fusion proteins develop AML after a lag time of months; suggesting leukemogenesis requires accumulation of mutations in addition to those involving MLL1/KMT2A-rearrangement. We found Triad1 expression decreased during leukemogenesis in a mice with expression of an Mll1-fusion protein in the bone marrow. We also found that either Triad1 knockdown or EG episodes accelerated AML development in such mice. We demonstrated HoxA10 enhanced, but HoxA9 repressed, Triad1 gene transcription. And, Triad1 re-expression rescued EG termination in Hoxa10-/- mice. We performed a screen to identify proteins with Triad1-dependent Ub. In addition to inflammatory mediators and RTKs, we identified proteins involved in the integrated stress response (ISR; Gcn1, eIF2B4 and eIF4G1). The ISR prevents metabolic exhaustion and cell death during sustained inflammation by modulating translation to correct metabolic defects and enhance proliferation once defects are corrected. Gcn1 functions as a primary regulator of this process by activating Gcn2/eIF2B4. We found Triad1-knockdown in myeloid cells altered the profile of mRNAs undergoing translation. However, combined knockdown of Triad1 and Gcn1 in these cells reversed abnormalities in translation of mRNAs involved in cellular response to stress, cellular response to DNA damage, cell cycle progression, translation, protein metabolism and ISR termination with Triad1 knockdown alone. We found Gcn1 knockdown delayed AML development in mice transplanted with bone marrow expressing an Mll1-fusion oncoprotein, and reversed the effect of Triad1-knockdown on accelerating leukemogenesis. We hypothesize that inhibition of the ISR by Triad1 facilitates emergency granulopoiesis (EG)-termination and suppresses leukemogenesis in disorders with increased Hox expression. This will be pursued by 3 Aims. Aim 1: Define the role of ISR inhibition by HoxA10/Triad1 in terminating emergency granulopoiesis. Murine models of emergency granulopoiesis (EG) will be studied for the role of HoxA10/Triad1-mediated Ub of Gcn1 in EG termination, the modulation of the translatome, and downstream pathways relevant to this process. Aim 2: Identify the influence of ISR regulation by Hox/Triad1 on mutagenesis and leukemogenesis. Using the murine models of MLL1/KMT2A rearranged, adverse prognosis AML, we will study the impact of HoxA10/Triad1-mediated Ub of Gcn1 on the translatome and accumulation of mutations during leukemogenesis. Aim 3: Determine the impact of Hox/Triad1 on inflammatory pathways and leukemogenesis in human MDS/AML. Bone marrow and peripheral blood CD34+ cells from human subjects with MDS/AML will be studied for association of Hox/Triad1 expression with inflammatory pathway activation and adverse outcomes. Molecular mechanisms will be investigated by RNA-Seq, whole exome sequencing and in murine xenografts. The goal is to identify a molecular subset of human MDS/AML with Triad1/ISR related events as molecular markers and possible therapeutic targets for sustained inflammation and mutagenesis in myeloid leukemia.

先天免疫反应的异常激活被认为与白血病的发生有关 骨髓增生异常综合征(MDS)和急性髓系白血病(AML)。MDS患者被描述为 结构性地激活这些途径的突变。我们的研究表明，损害人类健康的突变 终止紧急(应激)粒细胞生成(EG)也是一种可能的机制。Eg是指 感染攻击时快速、间歇性的粒细胞(PMN)产生，是先天免疫的关键成分 免疫反应。我们先前确定了Triad1，一种E3泛素(Ub)连接酶，对EG- 终止。与持续的EG反应在白血病发生中的作用一致，我们发现Triad1起作用 作为AML的白血病抑制因子，同源结构域转录因子的表达增加。不利的一面 克隆性髓系恶性肿瘤的预后亚群，包括伴有MLL1/KMT2A重排的MDS/AML 以一组这些蛋白(如Hoxb3、B4、A9-11、CDX1和2、Meis1)的过度表达为特征。 将表达白血病相关MLL1融合蛋白的骨髓移植到小鼠体内后，小鼠会发生AML 几个月的滞后时间；这表明白血病的发生需要在这些突变之外积累突变 涉及MLL1/KMT2A-重排。我们发现Triad1在白血病发生过程中表达下降 骨髓中表达mll1融合蛋白的小鼠。我们还发现，要么是Triad1击倒 或EG发作加速了这类小鼠的AML发展。我们演示了HoxA10增强版，但HoxA9 抑制，Triad1基因转录。并且，Triad1的重新表达挽救了Hoxa10-/-小鼠的EG终止。 我们进行了一次筛选，以确定具有Triad1依赖的Ub的蛋白质。除了炎性介质 和RTK，我们鉴定了参与整合应激反应的蛋白质(ISR；Gcn1，eIF2B4和eIF4G1)。 ISR通过调节翻译来防止持续炎症期间的代谢衰竭和细胞死亡 以纠正代谢缺陷，并在缺陷被纠正后促进增殖。Gcn1充当主服务器 通过激活GCN2/eIF2B4调节这一过程。我们发现髓系细胞中的Triad1基因敲除改变了 正在翻译的mRNAs的概况。然而，Triad1和Gcn1在这些细胞中的联合敲除 逆转参与细胞应激反应、细胞对DNA反应的mRNAs翻译异常 Triad1基因敲除后的损伤、细胞周期进程、翻译、蛋白质代谢和ISR终止 独自一人。我们发现Gcn1基因敲除延缓了骨髓移植小鼠AML的发展 M111融合癌蛋白，并逆转Triad1基因敲除加速白血病发生的作用。 我们假设Triad1抑制ISR有助于紧急粒细胞生成终止 并在HOX表达增加的疾病中抑制白血病的发生。这将通过三个目标来实现。 目的1：明确HoxA10/Triad1抑制ISR在终止急性粒细胞生成中的作用。 将研究HoxA10/Triad1介导的Ub在急性粒细胞生成(EG)小鼠模型中的作用。 Gcn1在EG终止中的作用，翻译体的调节，以及与这一过程相关的下游通路。 目的2：确定HOX/Triad1对ISR的调节对诱变和白血病发生的影响。 利用MLL1/KMT2A重排、预后不良的AML小鼠模型，我们将研究其对AML的影响 HoxA10/Triad1介导的Gcn1 Ub在白血病发生过程中对翻译组和突变积累的影响 目的3：确定HOX/Triad1在人类炎症途径和白血病发生中的作用 MDS/AML。将研究MDS/AML患者的骨髓和外周血CD34+细胞 研究HOX/Triad1的表达与炎症途径激活和不良结局的关系。分子 机制将通过RNA-Seq、整个外显子组测序和小鼠异种移植进行研究。 目标是确定与Triad1/ISR相关事件为分子的人类MDS/AML的分子子集 髓系白血病持续炎症和突变的标志物和可能的治疗靶点。