Stem Cell Selection & Expansion Via HOX Gene Activation

干细胞选择

• 批准号: 6321190
• 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/6321190
• 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：（申请人摘要）干细胞疗法发挥着重要作用 在癌症治疗中的作用日益增强。如果我们能够隔离重新繁殖 干细胞，在体外扩增它们并在使用之前对它们进行基因操作 回输，我们将能够探索许多保护性疗法的途径， 包括用于多周期化疗的干细胞扩增、保护 具有化疗抗性基因的干细胞，以及干细胞的改善 具有DNA修复基因的品质。已发表的研究表明同源盒 HOXB4 基因在原始造血细胞中表达，其强制执行 表达诱导干细胞对称循环。我们的初步数据表明 我们已经分离出人类 HOXB4 基因及其启动子，并且我们有 分离出至少两个转录因子，在两者中激活该启动子 白血病细胞和正常CD34+细胞。另外，我们发现CD34+ 激活 HOXB4 表达构建体的细胞显着富集于 长期培养起始细胞（LTCIC）。该提案旨在确定并 刺激能够自我更新的干细胞部分，如 他们转录同源框基因 HOXB4 的能力就说明了这一点。在 特别是，我们建议： 1) 测试激活的 HOXB4 启动子的能力 异种移植后 NOD/SCID 再生细胞； 2) 识别 转录因子激活 HxRE-1 (NF-1) 位点的 HOXB4 启动子； 3) 识别其他更遥远的遗传元件，以增强 HOXB4 启动子的体内活性。这些目标结合在一起，将 为干细胞的分子识别和操作定义了一个新的范式 用于造血支持和基因改造的细胞。如果成功的话，这 未来模型应该可以直接转化为临床实践。