Inducible colon-specific transgenic mouse for cancer research

用于癌症研究的诱导性结肠特异性转基因小鼠

• 批准号: 8246227
• 负责人: James C. Fleet
• 金额: $ 16.27万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-16 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8246227
• 关键词: APC gene; Aberrant crypt foci; Address; Adult; Affect; Affinity; Alleles; Animal Model; Automobile Driving; Biology; Birth; Cancer Etiology; Cancer Model; Carcinogenesis Mechanism; Cecum; Colon; Colon Carcinoma; Core Facility; Crohn' s disease; Development; Diagnosis; Dietary Factors; Disease; Distal; Drug or chemical Tissue Distribution; Embryo; Environmental Risk Factor; Epithelial Cells; Epithelium; Estrogen Analogues; Estrogen Receptors; Etiology; Gene Mutation; Genes; Goals; Health; Hereditary Malignant Neoplasm; Human; Hyperplasia; Incidence; Induced Mutation; Inflammation; Inflammatory; Intestines; Knockout Mice; Knowledge; Large Intestine; Learning; Life; Ligand Binding Domain; Location; Malignant Neoplasms; Modeling; Modification; Molecular; Molecular Profiling; Mus; Mutation; Normal tissue morphology; Nuclear; Prevention; Prevention strategy; Research; Research Personnel; Rodent Model; Scientist; Sodium Dextran Sulfate; Staging; Surface; Syndrome; Tamoxifen; Testing; Therapeutic Agents; Time; Tissues; Transgenes; Transgenic Animals; Transgenic Mice; Transgenic Model; Work; animal model development; anticancer research; base; cancer prevention; cancer therapy; carbonate dehydratase; disorder risk; effective therapy; flexibility; fusion gene; improved; interest; mouse genome; mouse model; programs; promoter; recombinase; transgene expression; treatment strategy; tumor; vector

DESCRIPTION (provided by applicant): Over the past 20 years our understanding of the molecular etiology of colon cancer has expanded dramatically. Despite this, colon cancer remains a significant health problem in the US. One of the barriers to progress in the field is the lack of well-characterized animal models that recapitulate the etiology of human colon cancer. While we have learned a great deal from cancers resulting from various chemically induced- or genetically programmed-rodent models, the cancer that develops in these models is often significantly different from human colon cancer in terms of latency, intestinal location, or molecular signature. Mechanistic and prevention focused colon cancer research requires the development of animal models that permit precisely timed, colon-specific modification of intestinal biology. Our goal for the proposed research is to use the promoter that drives large intestine-specific expression of the carbonic anhydrase 1 (CA1) gene to create a transgenic mouse with colon-epithelial cell-specific expression of Cre recombinase (Cre)-fused to a modified estrogen receptor (ER) ligand binding domain with high affinity only for the estrogen analog tamoxifen (CAC- ERT2). The ERT2 portion of the fusion gene confers taxomifen-inducibility to the transgene and permits temporally controlled deletion of floxed alleles in the mouse genome. A transgene vector has been produced and it will be used to produce mice at the Purdue Transgenic Mouse Core Facility. Transgene expression level and tissue distribution will be assessed by PCR. Inducibility of transgene function by tamoxifen will be assessed after crossing the CAC-ERT2 mouse to the ROSA26R indicator mouse. The ability of tamoxifen to induce tumor formation will be assessed in CAC-ERT2 mice crossed to mice with one or two floxed APC alleles. Additional studies will be done in the presence of colonic inflammation induced by dextran sulfate sodium (DSS). Upon completion of the project, the CAC-ERT2 mouse will be the only transgenic model that both limits Cre expression to the epithelial cells of the large intestine and permits control over when Cre functions to delete floxed alleles. This will permit colon cancer researchers to easily combine genetic mutations (i.e. with multiple floxed alleles relevant to colon cancer etiology) and initiate colon cancer at any stage of life. This will permit more careful assessment of mechanisms of carcinogenesis and improved testing of chemopreventative or therapeutic agents in adult mice. While our interests are in using this model for colon cancer, this model will also be useful for researchers interested in inflammatory conditions of the lower bowel (i.e. IBD, Crohn's disease). 1 PUBLIC HEALTH RELEVANCE: Colon cancer is a common form of cancer in the US and scientists. Research to develop effective treatment and prevention strategies is hampered by the lack of animal models that reproduce the features of human sporadic colon cancer. Our proposed research will create a new genetically modified mouse model that overcomes the limitations of existing animal models for colon cancer research.

描述（由申请人提供）：在过去的 20 年里，我们对结肠癌分子病因学的了解急剧扩大。尽管如此，结肠癌仍然是美国的一个重大健康问题。该领域取得进展的障碍之一是缺乏能够概括人类结肠癌病因的良好表征的动物模型。虽然我们从各种化学诱导或基因编程的啮齿动物模型产生的癌症中学到了很多东西，但在这些模型中形成的癌症在潜伏期、肠道位置或分子特征方面通常与人类结肠癌显着不同。以机制和预防为重点的结肠癌研究需要开发动物模型，以允许对肠道生物学进行精确定时、结肠特异性的修改。我们的研究目标是利用驱动碳酸酐酶 1 (CA1) 基因大肠特异性表达的启动子来创建具有结肠上皮细胞特异性表达 Cre 重组酶 (Cre) 的转基因小鼠，该小鼠与修饰的雌激素受体（ER）配体结合域仅对雌激素类似物他莫昔芬（CAC-ERT2）具有高亲和力。融合基因的 ERT2 部分赋予转基因紫杉米芬诱导性，并允许暂时控制小鼠基因组中 floxed 等位基因的删除。转基因载体已经生产出来，并将用于在普渡大学转基因小鼠核心设施中生产小鼠。将通过PCR评估转基因表达水平和组织分布。将 CAC-ERT2 小鼠与 ROSA26R 指示小鼠杂交后，将评估他莫昔芬对转基因功能的诱导能力。他莫昔芬诱导肿瘤形成的能力将在与具有一两个 floxed APC 等位基因的小鼠杂交的 CAC-ERT2 小鼠中进行评估。将在葡聚糖硫酸钠（DSS）诱导的结肠炎症存在的情况下进行额外的研究。该项目完成后，CAC-ERT2 小鼠将成为唯一的转基因模型，它既限制大肠上皮细胞的 Cre 表达，又允许控制 Cre 何时发挥作用以删除 floxed 等位基因。这将使结肠癌研究人员能够轻松地结合基因突变（即与结肠癌病因学相关的多个 floxed 等位基因）并在生命的任何阶段引发结肠癌。这将允许更仔细地评估成年小鼠的致癌机制并改进化学预防或治疗药物的测试。虽然我们的兴趣在于将该模型用于结肠癌，但该模型对于对下肠炎症（即 IBD、克罗恩病）感兴趣的研究人员也很有用。 1 公共卫生相关性：结肠癌是美国和科学家的一种常见癌症形式。由于缺乏再现人类散发性结肠癌特征的动物模型，开发有效治疗和预防策略的研究受到阻碍。我们提出的研究将创建一种新的转基因小鼠模型，克服现有结肠癌研究动物模型的局限性。