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）主要是一种老年疾病，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，并确定适合新治疗策略的细胞或分子靶点。MDS是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，我们建议表征骨髓微环境和造血前体之间的相互作用，并确定信号通路，决定程序性细胞死亡（凋亡）和克隆存活。具体而言，我们将1）定义影响来自MDS骨髓的克隆和非克隆造血前体的存活/扩增的基质依赖性活性。在使用骨髓细胞系和原代MDS细胞的体外系统中，我们将表征肿瘤坏死因子（TNF）α诱导的基质中基因表达改变的功能相关性，以支持克隆或非克隆造血前体（TNF α在MDS中上调）。在异种体内模型中，我们将确定人基质对移植到小鼠中的MDS衍生克隆的存活的作用。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TNF α启动的信号，控制细胞凋亡和增殖的相互作用，特别是NF κ B和抗凋亡分子，FLIP的作用。 初步的体外数据显示，FLIP的过表达增强了细胞存活。我们现在将在体内确定移植到免疫缺陷小鼠中的MDS细胞中FLIP表达的遗传修饰是否影响存活并允许克隆的扩增。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测定。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体内验证体外结果的相关性，其中将表征正常和克隆细胞的繁殖。通过使用阻断相关信号的干预措施或通过遗传修饰起关键作用的分子，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，这些方法可以被老年人耐受，并且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，防止疾病进展，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.