The Role of the Stem Cell Niche in ALL

干细胞生态位在 ALL 中的作用

• 批准号: 8010156
• 负责人: Laura F. Gibson
• 金额: $ 29.49万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8010156
• 关键词: Acute Lymphocytic Leukemia; Apoptosis; Blood Vessels; Bone Marrow; Cancer Relapse; Cell Communication; Cell Fate Control; Cell Line; Cell Survival; Cell model; Cells; Cellular Structures; Characteristics; Child; Clinical; Coculture Techniques; Cues; Data; Disease; Disease Progression; Equilibrium; Goals; Health; Hematologic Neoplasms; Hematopoiesis; Hematopoietic Neoplasms; Human; Hypoxia; Hypoxia Inducible Factor; Imatinib; In Vitro; Investigation; Kinetics; Leukemic Cell; Maintenance; Mammary Neoplasms; Modeling; Mus; NOD/SCID mouse; National Cancer Institute; Neuroepithelial, Perineurial, and Schwann Cell Neoplasm; Nuclear; Pathway interactions; Patients; Phenotype; Population; Pre-B Acute Lymphoblastic Leukemia; Prostatic Neoplasms; Proteins; Regulation; Relapse; Relative (related person); Reporting; Resistance; Role; Sampling; Signal Pathway; Signal Transduction; Solid; Solid Neoplasm; Source; Stem cells; Stromal Cells; Structure; Target Populations; Testing; Tumor Biology; Tumor Stem Cells; Tumor-Derived; Ubiquitination; Work; angiogenesis; bHLH-PAS factor HLF; base; cadherin 5; cancer diagnosis; chemotherapy; design; high risk; in vivo; leukemia; mRNA Expression; mimicry; neoplastic cell; novel; outcome forecast; reconstitution; research study; self-renewal; stem cell niche; three dimensional structure; treatment strategy; tumor

DESCRIPTION (provided by applicant): The contribution of tumor stem cells to progression and relapse of cancer is recognized as a significant clinical challenge in both solid and hematologic malignancies. Critical to understanding the mechanisms of tumor stem cell survival and self-renewal is investigation of their support by the microenvironments in which they thrive. Somewhat unique to hematopoietic malignancies, and subsequently leukemic stem cells (LSC), is an established appreciation of the contribution of the bone marrow microenvironment to regulation of cell fate. In the current study we investigate the interaction of LSC with bone marrow stromal cells (BMSC) and the mechanisms by which BMSC contribute to maintenance of the LSC phenotype. We utilize a unique population of Bcr;Abl+ (Ph+) ALL SUP-B15 cells that co-express a panel of stem cell markers, VE-cadherin, and proteins associated with commitment to the B-lineage. Following long-term co- culture (LTCC) with BMSC, SUP-B15 tumor cells demonstrate tri-lineage hematopoiesis, formed anatomically distinct three dimensional chemo-resistant hemospheres, had increased expression of the stem cell marker Oct-4, and had sustained, high levels of hypoxia inducible factor-2a (HIF-2a). SUP-B15 cells also reconstituted leukemia in NOD/SCID mice, as well as demonstrating differentiation in vivo. Destabilization of VE-cadherin increased chemotherapy-induced apoptosis of LSCs suggesting an important role for it in this novel setting. These studies are supplemented by inclusion of primary, human derived, de-identified pro/pre-B ALL cells that, consistent with the Ph+ SUP-B15 cell line utilized in our studies, express high levels of VE- cadherin, Oct-4 and HIF-2a. Using a model of LTCC of bone marrow stroma with SUP-B15 tumor cells and patient-derived samples we will test the working hypothesis that a LSC phenotype in ALL is supported by bone marrow microenvironment regulation of VE-cadherin and Oct-4 expression and stability. Our hypothesis will be tested by completion of the following specific aims: (1) To determine the contribution of VE-cadherin to LSC phenotype and the mechanism by which VE-cadherin is modulated in LSC, (2) To determine the mechanisms by which stromal cells regulate expression and activity of tumor cell Oct-4, and (3) To develop a murine model to identify the critical factors involved in initiating leukemia from sub-populations of Ph+ cells with a LSC phenotype. Our long-term goal is to identify pathways that are essential to bone marrow niche support of leukemic stem cells that are amenable to disruption, either through targeting the tumor itself, or the niche. Consequently, existing therapies may have enhanced efficacy in targeting the stem cell component of aggressive Ph+ leukemia. PUBLIC HEALTH RELEVANCE: The National Cancer Institute reports that acute lymphoblastic leukemia (ALL) is the most common cancer diagnosed in children and represents 23% of cancer diagnoses among children younger than 15 years. Within ALL there are sub-types of tumors that are characteristic of high risk for relapse and poor prognosis (Ph+ ALL) in which it is particularly urgent to understand the contribution of sub-populations of cells, characterized by a stem cell phenotype, to disease progression. Understanding the mechanisms by which the Ph+ leukemic stem cell is protected by the bone marrow microenvironment will increase our ability to design novel treatment strategies that are more effective in targeting this population.

描述（由申请人提供）：肿瘤干细胞对癌症进展和复发的贡献被认为是实体瘤和血液恶性肿瘤的重大临床挑战。了解肿瘤干细胞存活和自我更新机制的关键是研究它们生长的微环境对它们的支持。造血系统恶性肿瘤以及随后的白血病干细胞（LSC）的独特之处在于，骨髓微环境对细胞命运调控的贡献已得到公认。在目前的研究中，我们调查LSC与骨髓基质细胞（BMSC）的相互作用和BMSC有助于维持LSC表型的机制。我们利用了一个独特的Bcr;Abl+（Ph+）ALL SUP-B15细胞群，该细胞群共表达一组干细胞标志物、VE-钙粘蛋白和与B系定型相关的蛋白质。在与BMSC长期共培养（LTCC）后，SUP-B15肿瘤细胞显示三系造血，形成解剖学上不同的三维化学抗性血球，具有干细胞标志物Oct-4的增加的表达，并且具有持续的高水平的缺氧诱导因子-2a（HIF-2a）。SUP-B15细胞还在NOD/SCID小鼠中重建白血病，并在体内表现出分化。VE-钙粘蛋白的去稳定化增加了化疗诱导的LSC凋亡，这表明它在这种新的环境中发挥了重要作用。这些研究通过纳入原代、人源性、去识别的pro/pre-B ALL细胞进行补充，这些细胞与我们研究中使用的Ph+ SUP-B15细胞系一致，表达高水平的VE-钙粘蛋白、Oct-4和HIF-2a。使用骨髓基质的LTCC模型与SUP-B15肿瘤细胞和患者来源的样品，我们将测试工作假设，即ALL中的LSC表型由VE-钙粘蛋白和Oct-4表达和稳定性的骨髓微环境调节支持。我们的假设将通过完成以下具体目标来检验：（1）确定VE-钙粘蛋白对LSC表型的贡献以及VE-钙粘蛋白在LSC中调节的机制，（2）确定基质细胞调节肿瘤细胞Oct-4的表达和活性的机制，（3）建立一种小鼠模型，以鉴定具有LSC表型的Ph+细胞亚群引发白血病的关键因素。我们的长期目标是确定对白血病干细胞的骨髓小生境支持至关重要的途径，这些途径可以通过靶向肿瘤本身或小生境来破坏。因此，现有的疗法可能在靶向侵袭性Ph+白血病的干细胞组分方面具有增强的功效。公共卫生关系：美国国家癌症研究所报告说，急性淋巴细胞白血病（ALL）是儿童中最常见的癌症，占15岁以下儿童癌症诊断的23%。在ALL中，存在具有复发高风险和预后不良特征的肿瘤亚型（Ph+ ALL），其中特别迫切需要了解以干细胞表型为特征的细胞亚群对疾病进展的贡献。了解骨髓微环境保护Ph+白血病干细胞的机制将提高我们设计新的治疗策略的能力，这些策略在针对这一人群方面更有效。