Role of NF-kB in hematopoietic stem cells and leukemia-initiating cell formation

NF-kB 在造血干细胞和白血病起始细胞形成中的作用

• 批准号: 8607152
• 负责人: CHRISTOPHER KLUG
• 金额: $ 28.6万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-09 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8607152
• 关键词: 1-Phosphatidylinositol 3-Kinase; AML1-ETO fusion protein; Acute Myelocytic Leukemia; Address; Affect; Alleles; American; Apoptosis; Biological Response Modifiers; Blast Cell; Bone Development; Bone Marrow; British; CD34 gene; Cell Lineage; Cell Maintenance; Cell Proliferation; Cell division; Cell physiology; Cells; Chromosome abnormality; Chronic; Complex; Cytoplasm; DNA Binding; Development; Disease; Etiology; Event; Family; Genetic Transcription; Goals; Growth Factor; HOXA9 gene; Hematopoietic; Hematopoietic Stem Cell Mobilization; Hematopoietic stem cells; Homo; Human; Immune; In Vitro; Inflammation; Inhibition of Apoptosis; Malignant Neoplasms; Mediating; Mus; Mutation; Myelogenous; Myeloproliferative disease; NF-kappa B; NUP98 gene; Normal Cell; Nuclear Translocation; Oncogenic; PTEN gene; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Proto-Oncogene Protein c-kit; Proto-Oncogene Proteins c-akt; Recurrence; Regulation; Retroviral Vector; Role; Sampling; Secondary to; Signal Pathway; Signal Transduction; Spleen; Splenomegaly; Staging; Stem cells; Stimulus; Stress; TNFRSF5 gene; Testing; Transcriptional Regulation; base; chemokine; cytokine; defined contribution; dimer; in vivo; inhibitor/antagonist; leukemia; leukemic stem cell; leukemogenesis; member; monocyte; multicatalytic endopeptidase complex; novel; p65; progenitor; public health relevance; reconstitution; response; self-renewal; stem; stem cell differentiation; tumor

DESCRIPTION (provided by applicant): Constitutive activation of the classical NF-?B pathway, which principally involves RelA/p65, c-Rel, and p50, has been observed in human acute myeloid leukemia (AML) where constitutive NF-?B DNA-binding activity has been detected in myeloid blasts and in CD34? hematopoietic progenitor cells in 47-100% of all cases. In AML, constitutive NF-?B activity could be a direct downstream consequence of activating mutations affecting the PI3 kinase pathway, which is also constitutively active in the majority of AML cases and induces NF-?B through Akt signaling. In mice, constitutive activation of Akt through inducible deletion of the Akt regulatory phosphatase, PTEN, results in rapid hematopoietic stem cell (HSC) loss from bone marrow and development of a transplantable, lethal myeloproliferative disease (MPD) and AML. These studies and others have shown that constitutive activation of Akt and NF-?B distinguishes leukemia-initiating cells (LIC) from normal HSC in bone marrow. To address whether NF-?B activation in HSC is sufficient to induce LIC formation and promote MPD/AML, we expressed a constitutively active allele of I?B kinase beta (Ikk?SS/EE) in normal HSC using a retroviral vector. Analysis of mice reconstituted with Ikk?SS/EE -expressing cells showed that constitutive NF-?B activity promoted relatively rapid HSC loss from bone marrow that, unlike activated Akt, was not accompanied by the development of MPD/AML. NF-?B-mediated HSC loss was likely due to differentiation and loss of HSC self-renewal potential since there was not evidence of increased HSC apoptosis or mobilization to the spleen. Furthermore, blocking NF-?B activation in HSC by conditional deletion of the Ikk regulatory subunit, NEMO, resulted in a substantial decrease in one of the earliest multipotential progenitor subsets (c-Kit?Sca-1? cells) and an increase in absolute numbers of more primitive c-Kit?Sca-1? (KLSF) cells. NEMO loss also completely blocked proliferation of KLSF cells in vitro, which further supports an essential role for NF-?B in promoting the earliest HSC differentiation event. Together, these results demonstrate that constitutive activation of the classical NF-?B pathway, as an initiating event in AML, is not sufficient to maintain HSC or to promote development of LIC associated with AML. The primary goal of this proposal will be to test the central hypothesis that NF-?B functions in normal HSC to couple proliferation and differentiation associated with the first HSC cell division and to maintain viability of LIC subsequent to other oncogenic changes that preserve HSC self-renewal in the presence of activated NF-?B. To test this hypothesis, we will pursue the following specific aims: (1), Determine the function of NF-?B in the regulation of normal HSC maintenance, proliferation, and differentiation (2), Define the contribution of NF-?B to Akt-stimulated leukemogenesis, LT-HSC loss from bone marrow, and to leukemia-initiating cell formation and (3), Characterize whether recurrent cytogenetic abnormalities found in AML, including the translocations AML1-ETO, inv(16), or NUP98-HOXA9, can preserve HSC self-renewal in the presence of activated Akt or NF-?B.

描述(申请人提供)：在人类急性髓系白血病(AML)中观察到经典的NF-B途径的结构性激活，主要涉及RelA/p65、c-Rel和p50，其中髓系母细胞和CD34？造血祖细胞占全部病例的47-100%。在AML中，结构性的NF-B活性可能是影响PI3激酶通路的突变激活的直接下游结果，该通路在大多数AML病例中也是结构性活跃的，并通过Akt信号诱导NF-？B。在小鼠中，通过可诱导的Akt调节磷酸酶PTEN的缺失，Akt的结构性激活会导致骨髓中的造血干细胞(HSC)迅速丧失，并发展为可移植的、致命的骨髓增生性疾病(MPD)和急性髓细胞白血病(AML)。这些研究和其他研究表明，Akt和NF-β的结构性激活将骨髓中的白血病启动细胞(LIC)与正常的HSC区分开来。为了探讨HSC中核因子B的激活是否足以诱导LIC的形成和促进MPD/AML，我们利用逆转录病毒载体在正常HSC中表达了I B激酶β的结构性活性等位基因(ikk SS/EE)。对重组了IKK、SS/EE表达细胞的小鼠的分析表明，结构性的NF-B活性促进了骨髓中相对较快的HSC丢失，与激活的Akt不同，它不伴随MPD/AML的发展。NFB介导的HSC丢失可能是由于HSC的分化和自我更新能力的丧失，因为没有证据表明HSC的凋亡或对脾的动员增加。此外，通过条件性缺失IKK调节亚基NEMO来阻断HSC中NF-βB的激活，导致最早的多潜能祖细胞亚群之一(c-Kit、Sca-1、Sca-1)显著减少。细胞)和更原始的c-Kit、Sca-1、Sca-1的绝对数量增加。(KLSF)细胞。NEMO的丢失也完全阻断了KLSF细胞的体外增殖，这进一步支持了NF-β在促进最早的HSC分化事件中的重要作用。综上所述，这些结果表明，作为AML的启动事件，经典的NF-β途径的结构性激活不足以维持HSC或促进与AML相关的LIC的发展。这项提议的主要目的是检验中心假设，即在正常的HSC中，核因子-βB的功能是与第一次HSC分裂相关的增殖和分化的耦合，并在其他致癌变化后维持LIC的活性，从而在激活的核因子-βB的存在下保持HSC的自我更新。为了检验这一假说，我们将追求以下具体目标：(1)确定核因子-β在调节正常的HSC维持、增殖和分化中的作用(2)确定核因子-β在Akt刺激的白血病发生中的作用，以及LT-HSC从骨髓中丢失，和白血病启动细胞的形成和(3)，表征在AML中发现的反复细胞遗传学异常，包括易位AML1-ETO、inv(16)或NUP98-HOXA9，是否能够在激活的Akt或NF-？B存在的情况下保持HSC的自我更新。