Stem Cell Selection & Expansion Via HOX Gene Activation

干细胞选择

• 批准号: 6515018
• 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/6515018
• 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：（申请人的摘要）干细胞疗法发挥主要作用， 在癌症治疗中发挥越来越大的作用。如果我们能够分离出 干细胞，在体外扩增它们，并在 再输注，我们将能够探索许多保护性治疗的途径， 包括用于多周期化疗的干细胞扩增， 具有化疗抗性基因干细胞，以及干细胞 DNA修复基因。已发表的研究表明，同源盒 基因HOXB 4在原始造血细胞中表达，并且其增强了 表达诱导干细胞对称循环。我们的初步数据显示 我们已经分离出人类HOXB 4基因及其启动子， 分离至少两个转录因子，激活这两个启动子， 白血病细胞和正常CD 34+细胞。此外，我们还发现，CD 34 + 激活HOXB 4表达构建体的细胞基本上富集 长期培养起始细胞（LTCIC）。这项建议旨在确定和 刺激能够自我更新的干细胞部分， 通过它们转录同源框基因HOXB 4的能力来说明。在 具体而言，我们提出：1）测试活化的HOXB 4启动子的能力 NOD/SCID细胞在异种移植后的再增殖; 2）鉴定 转录因子在HxRE-1（NF-1）位点激活HOXB 4启动子的研究 和3）确定额外的更远的遗传因素，提高 HOXB 4启动子的体内活性。综合起来，这些目标将 为茎的分子鉴定和操作定义了一个新的范例 用于造血支持和遗传修饰的细胞。如果成功，这 该模型在未来应可直接转化为临床实践。