Cell Death and Clonal Survival in Myelodysplastic Syndr*

描述(由申请人提供)： 骨髓增生异常综合征(MDS)主要是一种年龄较大的疾病，随着人口老龄化，预计病例会增加。我们的建议旨在提高我们对MDS病理生理学的理解，并确定适合于新的治疗策略的细胞或分子靶点。MDS是一种造血干细胞的克隆性疾病；然而，有证据表明，微环境中的因素有助于疾病的传播。因此，我们建议描述骨髓微环境和造血祖细胞之间的相互作用，并确定决定细胞程序性死亡(凋亡)和克隆性存活的信号通路。具体地说，我们将1)定义影响MDS骨髓克隆性和非克隆性造血祖细胞存活/扩张的基质依赖性活动。在使用髓系细胞系和原代MDS细胞的体外系统中，我们将研究肿瘤坏死因子(TNF)α诱导的间质基因表达变化与克隆或非克隆性造血祖细胞(MDS上调TNFpha)的功能相关性。在异种体内模型中，我们将确定人类基质对移植到小鼠体内的MDS来源克隆的存活所起的作用。我们将2)描述MDS骨髓中的凋亡和增殖事件，并将其与疾病进展相关联。我们将定义由TNFpha启动的控制细胞凋亡和增殖的信号之间的相互作用，特别是NFkappaB和抗凋亡分子FliP的作用。初步的体外数据显示，FliP的过表达提高了细胞的存活率。我们现在将在体内确定对移植到免疫缺陷小鼠的MDS细胞中翻转表达的遗传修改是否会影响存活并允许克隆的扩张。在追求我们的目标所涉及的技术包括在体外培养系统中的造血、细胞凋亡和增殖的体外分析。体外发现的相关性将在免疫缺陷小鼠的细胞系和原代MDS细胞的异种移植模型中得到体内验证，在该模型中，正常细胞和克隆细胞的繁殖将得到表征。通过使用阻断相关信号的干预措施或对发挥关键作用的分子进行基因修饰，我们将确定新治疗策略的潜在靶点。人类人口正在老龄化，MDS的发病率随着年龄的增长而增加。需要新的治疗方法，让老年人能够忍受，希望不会干扰他们的生活质量。为了实现这些目标，我们必须更好地了解MDS的潜在机制，从而确定可以阻止疾病进程、防止病情发展并有望治愈疾病的方法。

DESCRIPTION (provided by applicant): The Myelodysplastic Syndrome (MDS) is predominantly a disease of older age, and with the aging of the population, an increase in cases is expected. Our proposal is aimed at improving our understanding of the pathophysiology of MDS, and to identify cellular or molecular targets suitable for novel treatment strategies. MDS is a clonal disorder of hematopoietic stem cells; however, there is evidence that factors in the microenvironment contribute to the propagation of the disease. Thus, we propose to characterize interactions between the marrow microenvironment and hematopoietic precursors and identify signaling pathways that determine programmed cell death (apoptosis) and clonal survival. Specifically, we will 1) define stroma-dependent activities that affect survival/expansion of clonal and non-clonal hematopoietic precursors from MDS marrow. In an in vitro system using myeloid cell lines and primary MDS cells, we will characterize the functional relevance of tumor necrosis factor (TNF)alpha-induced alterations in gene expression in stroma for the support of clonal or non-clonal hematopoietic precursors (TNFalpha is upregulated in MDS). In a xenogeneic in vivo model we will determine the role of human stroma for the survival of MDS-derived clones transplanted into mice. We will 2) characterize apoptotic and proliferative events in MDS marrow and correlate these with disease progression. We will define interactions of TNFalpha-initiated signals that control apoptosis and proliferation, in particular, the roles of NFkappaB and the anti-apoptotic molecule, FLIP. Preliminary in vitro data show that overexpression of FLIP enhances cell survival. We will now determine in vivo whether genetic modification of FLIP expression in MDS cells transplanted in immunodeficient mice affects survival and allows for expansion of the clone. The techniques involved in pursuit of our objectives include in vitro assays of hematopoiesis, apoptosis, and proliferation in in vitro culture systems. The relevance of in vitro findings will be validated in vivo in a xenogeneic transplant model of cell lines and primary MDS cells in immunodeficient mice in which propagation of normal and clonal cells will be characterized. By using interventions that block relevant signals or by genetically modifying molecules that play pivotal roles, we will identify potential targets for novel therapeutic strategies. The human population is aging, and the incidence of MDS increases with age. Novel treatment approaches are needed that are tolerated by older individuals and, hopefully, will not interfere with their quality of life. To achieve these objectives, we must better understand the underlying mechanisms of MDS and thereby identify ways by which the disease process can be arrested, progression prevented, and the disease hopefully be cured.