Colon-specific Transgenic Mouse for Cancer Research

描述（由申请人提供）：理解结肠癌分子病因学的一个障碍是缺乏能够概括人类散发性结肠癌病因学的具有良好特征的动物模型。虽然我们已经从各种化学诱导或基因编程的啮齿动物模型中了解到很多癌症，但在这些模型中发生的癌症在潜伏期、肠道位置或分子特征方面通常与人类结肠癌有很大不同。以结肠癌的机制和预防为重点的研究需要开发动物模型，以允许精确定时、结肠特异性的肠道生物学修饰。我们提案的目标是解决PA-06-149中列出的一个特别感兴趣的领域：“胃肠道疾病（包括相关癌症）的新型细胞和动物模型的开发、表征和利用。”为了应对这一挑战，我们为拟议的研究制定了两个具体目标。首先，我们将使用驱动结肠特异性表达碳酸酐酶1 （CA1）基因的启动子来创建具有结肠上皮细胞特异性表达Cre重组酶的转基因小鼠。该模型为构建结肠特异性基因敲除小鼠奠定了基础。通过PCR分析、免疫组织化学以及将我们的转基因小鼠与ROSA26R指标小鼠杂交来评估Cre转基因表达的特性。其次，我们将把我们的CA1-Cre转基因小鼠与带有固定APC等位基因的小鼠杂交，以创建具有结肠特异性缺失这一关键癌基因的小鼠；APC失活突变是散发性远端结肠癌发生的早期分子事件。双转基因小鼠结肠癌的发展将在基础条件下和炎症剂促进后进行评估。结肠特异性APC缺失小鼠可作为散发性结肠癌的改良模型。更重要的是，这将证实我们的新CA1-Cre模型在未来制造结肠特异性敲除和转基因小鼠方面的实用性和灵活性。这项工作对公共卫生至关重要，因为它将为更好地研究结肠癌机制的动物模型奠定基础。此外，用新的转基因小鼠制作的结肠癌模型将有助于测试药物治疗和预防癌症的能力。

DESCRIPTION (provided by applicant): A barrier to understanding the molecular etiology of colon cancer is the lack of well-characterized animal models that recapitulate the etiology of human sporadic colon cancer. While we have learned a great deal from cancers resulting from various chemically induced- or genetically programmed-rodent models, the cancers that develop in these models are 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. The goal of our proposal is to address an area of special interest listed in PA-06-149: "Development, characterization and utilization of novel cellular and animal models of gastrointestinal diseases, including associated cancers." To meet this challenge we have developed two specific aims for the proposed research. First, we will use the promoter that drives colon-specific expression of the carbonic anhydrase 1 (CA1) gene to create a transgenic mouse with colon-epithelial cell-specific expression of Cre recombinase. This model will be useful for making colon specific gene knockout mice. Characterization of Cre transgene expression will be assessed by PCR analysis, immunohistochemistry, and by crossing our transgenic mice to the ROSA26R indicator mouse. Second, we will cross our CA1-Cre transgenic mice to mice with a floxed APC allele to create mice with colon-specific deletion of this critical oncogene; APC inactivating mutations are an early molecular event in the development of sporadic cancer of the distal colon. The development of colon cancer in the double transgenic mice will be assessed under basal conditions and after promotion with an inflammatory agent. The colon-specific APC null mouse will be an improved model of sporadic colon cancer. More importantly, it will confirm the utility and flexibility of our new CA1-Cre model for making future colon-specific knockout and transgenic mice. This work is critical to public health because it will serve as a foundation for making better animal models to study the mechanism of colon cancer. In addition, colon cancer models made with the new transgenic mouse will be useful for testing agents for their ability to treat and prevent cancer.