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中的重大临床挑战。了解肿瘤干细胞存活和自我更新机制的关键是研究它们赖以生存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）的独特之处在于对骨髓微环境对细胞命运调节的贡献的既定认识。在当前的研究中，我们研究了 LSC 与骨髓基质细胞 (BMSC) 的相互作用以及 BMSC 有助于维持 LSC 表型的机制。我们利用独特的 Bcr;Abl+ (Ph+) ALL SUP-B15 细胞群，这些细胞共同表达一组干细胞标记物、VE-钙粘蛋白和与 B 谱系相关的蛋白质。与 BMSC 长期共培养 (LTCC) 后，SUP-B15 肿瘤细胞表现出三系造血作用，形成解剖学上独特的三维化疗抗性血球，干细胞标记物 Oct-4 的表达增加，并持续，高水平的缺氧诱导因子-2a (HIF-2a)。 SUP-B15 细胞还在 NOD/SCID 小鼠中重建了白血病，并在体内表现出分化。 VE-钙粘蛋白的不稳定增加了化疗诱导的 LSC 细胞凋亡，表明它在这种新环境中发挥着重要作用。这些研究还补充了原代、人源性、去鉴定的 pro/pre-B ALL 细胞，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。使用具有 SUP-B15 肿瘤细胞和患者来源样本的骨髓基质 LTCC 模型，我们将测试以下工作假设：ALL 中的 LSC 表型受到 VE-钙粘蛋白和 Oct-4 表达和稳定性的骨髓微环境调节的支持。我们的假设将通过完成以下具体目标进行检验：（1）确定 VE-钙粘蛋白对 LSC 表型的贡献以及 VE-钙粘蛋白在 LSC 中的调节机制，（2）确定基质细胞调节肿瘤细胞 Oct-4 的表达和活性，以及​​ (3) 开发小鼠模型，以鉴定具有 LSC 的 Ph+ 细胞亚群引发白血病的关键因素表型。我们的长期目标是确定对白血病干细胞的骨髓生态位支持至关重要的途径，这些途径可以通过靶向肿瘤本身或生态位来破坏。因此，现有疗法可能会增强针对侵袭性 Ph+ 白血病干细胞成分的疗效。公共健康相关性：美国国家癌症研究所报告称，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%。 ALL 中存在一些具有高复发风险和预后不良 (Ph+ ALL) 特征的肿瘤亚型，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的贡献进展。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治疗策略的能力，从而更有效地针对该人群。