The Role of HIF1A-DNMT3A axis in AML1/ETO-Driven Acute MyelogenousLeukemia

由t（8;21）易位产生的融合蛋白AML 1/ETO （AE）是一种白血病启动转录因子，通常与急性髓性白血病（AML）相关。尽管被定义为AML的“有利”亚型，但许多AE阳性（AE+）患者复发并死亡，原因大多未知。AE如何介导疾病可预测的DNA甲基化特征也尚不清楚。长期目标是进一步阐明AE+ AML白血病发生机制，发现新的治疗靶点，开发有效的靶向治疗方法。该提案的目的是探索AE+ AML中疾病可预测的DNA甲基化特征的分子基础，重点关注缺氧非依赖性HIF1alpha-DNMT3a信号轴激活的影响。这一建议的基本原理是缺氧无关的HIF1alpha信号激活是癌症的新标志。与本项目相关，高活性的HIF1alpha信号可能是AE+ AML的疾病促进因子和表观遗传介质。HIF1alpha与AE形成前馈回路，并激活另一个AE+ AML预后标志物DNMT3a。抑制hif1α抑制AML细胞生长。然而，HIF1alpha信号与AE AML发病机制和疾病复发之间的详细机制和生化联系尚不清楚。核心假设是HIF1alpha通过增强AE转录活性和调节AML细胞中AE控制的DNA甲基化景观来促进AE的白血病发生；因此，在AE+ AML中，HIF1alpha可能是一个易感的可药物靶点。这一假设将通过追求三个具体目标来检验：剖析HIF1alpha如何对ae驱动的白血病发生至关重要的机制细节；2)确定HIF1alpha在ae依赖性DNA甲基化中的作用；3)试验靶向HIF1alpha作为AE+ AML的治疗选择。为了实现我们的目标，我们将使用生物技术与独特的转基因和患者来源的异种移植（POX）小鼠模型的创新组合，以及异常HIF1alpha信号和表观遗传学的创新整合来理解和治疗AE+ AML。这项研究具有重要意义，因为它将揭示AE白血病发生所必需的新基因/机制途径，确定治疗性生物标志物，并发现AE+ AML的新药物。此外，它将深入研究HIF1alpha在癌症中的表观遗传和致癌作用。近期的预期结果是证明HIF1alpha-表观遗传学串扰在确定ae启动的转录调控和白血病发病机制方面的作用，并确定使用HIF1alpha抑制剂提高现有治疗方案的治疗指标的可行性。这些结果将具有重要的影响，因为它们将促进我们对AE+ AML分子病理学、白血病的异常表观遗传学以及缺氧非依赖性HIF1alpha信号在癌症中的致癌功能的理解。这些发现也将为开发更好地靶向AE+ AML的新策略奠定基础。

The fusion protein AML 1/ETO (AE), resulting from the t(8;21) translocation, is a leukemia-initiating transcription factor that is frequently associated with acute myeloid leukemia (AML). Despite being defined as a "favorable" subtype of AML, many AE positive (AE+) patients relapse and die with largely unknown causes. It is also unclear how AE mediates a disease-predictable DNA methylation signature. The long-term goals are to elucidate further the mechanisms of AE+ AML leukemogenesis, discover new therapeutic targets and develop effective targeted therapies. The objective of this proposal is to explore the molecular basis of a disease-predictable DNA methylation signature underlying AE+ AML with a focus on the impact of hypoxia-independent HIF1alpha-DNMT3a signaling axis activation. The rationale underlying this proposal is that the hypoxia-independent HIF1alpha signaling activation is a new hallmark of cancer. In relation to this project, the hyperactive HIF1alpha signaling may be a disease-promoting factor and an epigenetic mediator in AE+ AML. HIF1alpha forms a feedforward loop with AE and transactivates DNMT3a, another prognostic marker in AE+ AML. HIF1alpha inhibition suppresses AML cell growth. However, the detailed mechanistic and biochemical links between HIF1alpha signaling and AE AML pathogenesis and disease recurrence are poorly defined. The central hypothesis is that HIF1alpha promotes AE leukemogenicity through enhancing AE transcriptional activities and modulating the AE-governed DNA methylation landscape in AML cells; therefore HIF1alpha may be a vulnerable and druggable target in AE+ AML. This hypothesis will be tested by pursuing three specific aims: 1.) Dissect the mechanistic details of how HIF1alpha is critical for AE-driven leukemogenesis; 2) Determine the role of HIF1alpha in AE-dependent DNA methylation; 3) Test pharmacological targeting of HIF1alpha as a therapeutic option for AE+ AML. To pursue our aims, we will use innovative combinations of biological techniques with unique transgenic and patient-derived xenograft (POX) mouse models, as well as innovative integration of aberrant HIF1alpha signaling and epigenetics in understanding and treating AE+ AML. The proposed research is significant, because it will disclose new genes/mechanistic pathways that are necessary for AE leukemogenicity, identify the therapeutic biomarkers, and discover new medicinal agents for AE+ AML. Further, it will thoroughly investigate the epigenetic and oncogenic role of HIF1alpha in cancer. The proximate expected outcomes are to demonstrate HIF1alpha-epigenetics crosstalk in defining AE-initiated transcriptional regulation and leukemia pathogenesis, and to establish the feasibility of using HIF1alpha inhibitors to enhance the therapeutic index of the existing treatment regimens. The results will have an important impact because they will advance our understanding of AE+ AML molecular pathology, aberrant epigenetics in leukemia and the oncogenic functions of hypoxia-independent HIF1alpha signaling in cancers. The findings will also lay the groundwork to develop newer strategies to better target AE+ AML.