Regulation of esophageal gene expression and function by KLF5 and p53

描述(申请人提供)：食道衬里经常暴露在刺激性物质中，如酒精、香烟烟雾、热饮料、饮食中的亚硝基化合物和胃-十二指肠内容物的反流，在美国和世界各地，食道疾病是严重的健康问题。例如，胃食道反流病(GERD)每年导致美国890万人次就诊，食道癌是全球第六大常见癌症死亡原因。在食道上皮细胞中，关键的转录调节因子Kr�pPEL样因子5(KLF5)促进正常的增殖和迁移，我们最近在食道上皮细胞中发现了KLF5与P53之间的一种新的关系，P53充当KLF5的分子开关。原代人食道角质形成细胞中的P53突变将KLF5从促增殖转化为抗增殖，这一作用主要由p21Waf1/Cip1介导，当P53突变而不是野生型P53时，KLF5转录激活角质形成细胞肿瘤抑制因子NOTCH1。在更多的初步数据中，我们证明了KLF5抑制了食道角质形成细胞中的P53，并为KLF5和P53在全基因组范围内的协同调控提供了证据。我们的主要假设是KLF5和P53在食道角质形成细胞中编排了一个广泛的转录程序，控制着增殖、生长停滞、凋亡和转化。为了验证这一假设，我们将追求以下相互关联的具体目标：1.我们将划定 我们将确定KLF5在p21Waf1/Cip1~3上的功能转换机制。我们将在野生型和突变型P53~和4的背景下确定KLF5的共同和独占靶点。我们将在体内确定KLF5缺失和P53突变的功能后果。这些互补的方法得到了我们稳健的初步数据的支持，无论是已公布的还是未公布的。此外，PI是一位经验丰富的研究人员，他是Kr�蛋白样因子(KLF)、转录调控、胃肠道疾病动物模型和食道鳞状细胞生物学方面的专家，最近发表在癌症研究、公共科学图书馆·综合、细胞周期和肿瘤方面的相关通讯作者出版物证明了这一点。此外，PI得到了一支精湛的研究团队的支持，并得到了专家合作者的补充，以及宾夕法尼亚大学和NIH资助的消化和肝病分子研究中心的特殊资源、设施和智力环境。总体而言，拟议的研究将为食道上皮内稳态的转录调控以及食道疾病的分子途径提供关键的见解，无论是良性还是恶性疾病。

DESCRIPTION (provided by applicant): The esophageal lining is regularly exposed to irritants such as alcohol, cigarette smoke, hot beverages, dietary nitroso-compounds, and refluxate of gastro-duodenal contents, and disorders of the esophagus are significant health problems in the U.S. and throughout the world. For example, gastroesophageal reflux disease (GERD) leads to 8.9 million U.S. clinic visits annually, and esophageal cancer is the 6th most common cause of cancer death worldwide. In esophageal epithelia, the key transcriptional regulator Kr�ppel-like factor 5 (KLF5) promotes normal proliferation and migration, as we have shown, and we recently identified a novel relationship between KLF5 and p53 in esophageal epithelial cells, whereby p53 acts as a "molecular switch" for KLF5. p53 mutation in primary human esophageal keratinocytes converts KLF5 from pro-proliferative to anti-proliferative, an effect mediated predominantly by p21Waf1/Cip1, and KLF5 transcriptionally activates the keratinocyte tumor suppressor NOTCH1 when p53 is mutant but not with wild-type p53. In additional Preliminary Data, we demonstrate that KLF5 suppresses p53 in esophageal keratinocytes and provide evidence for genome-wide coordinate regulation by KLF5 and p53. Our overarching hypothesis is that KLF5 and p53 orchestrate a broad transcriptional program in esophageal keratinocytes that controls proliferation, growth arrest, apoptosis, and transformation. To test this hypothesis, we will pursue the following interrelated Specific Aims: 1. We will delineate the mechanisms through which KLF5 regulates p53 levels and function~ 2. We will define the mechanism for KLF5 functional switching on p21Waf1/Cip1~ 3. We will identify common and exclusive targets of KLF5 in the context of wild-type and mutant p53~ and 4. We will determine the functional consequences of KLF5 loss and p53 mutation in vivo. These complementary approaches are supported by our robust Preliminary Data, both published and unpublished. Moreover, the PI is an experienced investigator who is an expert in the Kr�ppel-like factors (KLFs), transcriptional regulation, animal models of gastrointestinal diseases, and esophageal squamous cell biology, as demonstrated by recent, relevant corresponding-author publications in Cancer Research, PLoS One, Cell Cycle, and Neoplasia. In addition, the PI is supported by a superb research team, complemented by expert collaborators, and by the exceptional resources, facilities, and intellectual environment of the University of Pennsylvania and the NIH-funded Center for Molecular Studies in Digestive and Liver Diseases. Overall, the proposed studies will provide key insights into the transcriptional regulation of esophageal epithelial homeostasis and the molecular pathways that underlie esophageal diseases, both benign and malignant.