Stem Cell Selection & Expansion Via HOX Gene Activation

干细胞选择

• 批准号: 6724878
• 负责人: STEPHEN G EMERSON
• 金额: $ 29.6万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-16 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6724878
• 关键词: SCID mouse; gene induction /repression; genetic promoter element; genetically modified animals; homeobox genes; stem cells; transcription factor

DESCRIPTION: (Applicant's Abstract) Stem cell therapies play a major and increasing role in cancer therapies. If we were able to isolate repopulating stem cells, expand them in vitro and genetically manipulate them prior to reinfusion, we would be able to explore many avenues of protective therapies, including expansion of stem cells for multi-cycle chemotherapy, protection of stem cells with chemotherapy resistance genes, and improvement in stem cell quality with DNA repair genes. Published studies indicate that the homeobox gene HOXB4 is expressed in primitive hematopoietic cells, and that its enforced expression induces stem cell symmetric cycling. Our preliminary data indicates that we have isolated the human HOXB4 gene and its promoter, and that we have isolated at least two transcription factors that activate this promoter in both leukemic cells and normal CD34+ cells. In addition, we have found that CD34+ cells activating a HOXB4 expression construct are substantially enriched in long term culture initiating cells (LTCIC). This proposal seeks to identify and stimulate the fraction of stem cells that are capable of self-renewal, as illustrated by their ability to transcribe the homeobox gene HOXB4. In particular, we propose to: 1) Test the Ability of the Activated HOXB4 Promoter to NOD/SCID Repopulating Cells following Xenotransplantation; 2) Identify the Transcription Factors Activating the HOXB4 Promoter at the HxRE-1 (NF-1) Site; and 3) Identify Additional More Distant Genetic Elements That Enhance the Activity of the HOXB4 Promoter In Vivo. Integrated together, these aims will define a new paradigm for the molecular identification and manipulation of stem cells for hematopoietic support and genetic modification. If successful, this model should be directly translatable to clinical practice in the future.

描述：(申请者摘要)干细胞疗法发挥着重要的作用 在癌症治疗中发挥越来越大的作用。如果我们能够分离出重新繁殖 干细胞，在体外扩增，并在基因操作之前 重新输血，我们将能够探索许多保护性治疗的途径， 包括扩增用于多周期化疗的干细胞，保护 携带化疗耐药基因的干细胞及其改良 具有DNA修复基因的高质量。已发表的研究表明，同源异型盒 HOXB4基因在原始造血细胞中表达，并强制 表达诱导干细胞对称周期。我们的初步数据显示 我们已经分离了人类HOXB4基因及其启动子，我们有 分离出至少两个激活这一启动子的转录因子 白血病细胞和正常CD34+细胞。此外，我们还发现CD34+ 激活HOXB4表达构建体的细胞实质上富含 长期培养启动细胞(LTCIC)。这项提案旨在确定和 刺激部分具有自我更新能力的干细胞，如 它们转录同源异型盒基因HOXB4的能力说明了这一点。在……里面 具体地说，我们建议：1)检测激活的HOXB4启动子的能力 异种移植后NOD/SCID细胞的再填充；2)鉴定 转录因子激活HxRE-1(NF-1)位点的HOXB4启动子； 以及3)确定额外的更远距离的遗传元素，这些基因元素可以增强 HOXB4启动子在体内的活性综合起来，这些目标将 为茎的分子鉴定和操作定义一个新的范式 用于造血支持和基因改造的细胞。如果成功，这将是 模型在未来应该可以直接翻译到临床实践中。