Integrative mouse pathobiology: GI epithelial biology and genetics

描述（由申请人提供）：Notch信号在食管鳞状上皮生物学和疾病中的作用知之甚少。特别是，在了解Notch信号如何促进正常食管上皮鳞状分化，癌变和瘤内细胞异质性方面存在根本差距，其特征是共存的高分化细胞巢（即角蛋白珍珠）和弥散性，侵袭性低分化细胞具有间质特征，在食管鳞状细胞癌（ESCC）中发现，这是最致命的癌症之一。这一缺口的持续存在代表了一个重要的问题，因为直到它被填补，缺口介导的食管上皮细胞命运调节的机制将在很大程度上仍然是不可理解的。长期目标是更好地了解组织微环境影响食管鳞状上皮细胞恶性转化的分子机制。本提案的目的是利用创新的基因工程小鼠模型来定义Notch信号在食管正常生物学和肿瘤生物学中的作用。中心假设是Notch诱导鳞状分化和衰老以csl依赖的方式。在肿瘤进展过程中，微环境信号激活了一个不依赖于csc的途径来丰富迁移性癌症干细胞（CSCs）。这一假设是根据申请人实验室产生的初步数据制定的。这项研究的基本原理是，一旦知道Notch如何控制细胞命运，就可以从药理学上操纵它们，从而在ESCC的预防和治疗中产生新颖和创新的方法。在强有力的初步数据的指导下，这一假设将通过追求三个相互关联的特定目标来验证：(1)阐明Notch活性如何在新小鼠模型中促进食管癌的早期发生；(2)在条件p120-catenin敲除小鼠模型中确定Notch在肿瘤进展中的作用；(3)在一种新的原位移植模型中描述Notch在小鼠CSCs中的作用，该模型再现了肿瘤微环境。基因功能获得和功能丧失实验将在新的小鼠模型中以可诱导的方式进行。将在体内进行实时成像以评估notch调节的CSC在体内的活性。该研究具有重要意义，因为它有望垂直推进和扩展对食管上皮稳态调节机制的理解，进而在食管疾病（包括良性和恶性）以及其他组织类型的潜在鳞状疾病中解除调节，所有这些都是通过对小鼠病理生物学的欣赏。这些知识将导致创新药理学策略的发展，这些策略将操纵Notch信号来改变食管细胞命运，并有可能推进ESCC的治疗和疾病进展的预防。

DESCRIPTION (provided by applicant): Little is known about the role of Notch signaling in esophageal squamous epithelial biology and diseases. In particular, there is a fundamental gap in understanding how Notch signaling contribute to normal esophageal epithelial squamous differentiation, carcinogenesis, and intratumoral cell heterogeneity, characterized by co- existing well-differentiated cell nests (i.e. keratin pearl) and disseminated, invasive poorly differentiated cells with mesenchymal traits found in esophageal squamous cell carcinoma (ESCC), one of the most deadly cancers. Continued existence of this gap represents an important problem because, until it is filled, mechanisms for Notch-mediated esophageal epithelial cell fate regulation will remain largely incomprehensible. The long-term goal is to better understand the molecular mechanisms by which tissue microenvironment influences malignant transformation of esophageal squamous epithelial cells. The objective in this proposal is to define the roles of Notch signaling in normal biology and tumor biology of the esophagus using innovative genetically engineered mouse models. The central hypothesis is that Notch induces squamous differentiation and senescence in a CSL-dependent manner. During tumor progression, microenvironmental cues activate a CSL-independent pathway to enrich migratory cancer stem cells (CSCs). This hypothesis has been formulated on the basis of preliminary data produced in the applicants' laboratories. The rationale for the proposed research is that, once it is known how Notch control cell fates, they can be manipulated pharmacologically, resulting in novel and innovative approaches in the prevention and treatment of ESCC. Guided by strong preliminary data, this hypothesis will be tested by pursuing three interrelated Specific Aims: (1) To elucidate how Notch activities contribute to the early stages of esophageal carcinogenesis in new mouse models; (2) To determine the roles of Notch for tumor progression in a conditional p120-catenin knockout mouse model; and (3) To delineate the roles of Notch in mouse CSCs in a novel orthotopic transplantation model where the tumor microenvironment is recapitulated. Genetic gain-of-function and loss-of-function experiments will be done in an inducible fashion in new mouse models. In vivo live imaging will be performed to assess the Notch-regulated CSC activities in vivo. The proposed research is significant, because it is expected to vertically advance and expand understanding of mechanisms by which esophageal epithelial homeostasis is regulated and in turn, deregulated in esophageal diseases, both benign and malignant, and potentially other squamous diseases in other tissue types, all through an appreciation of mouse pathobiology. Such knowledge will lead to development of innovative pharmacological strategies that will manipulate Notch signaling to alter esophageal cell fates and have the potential to advance in the therapy of ESCC and prevention of disease progression. PUBLIC HEALTH RELEVANCE (provided by applicant): The proposed research is relevant to public health because detailed understanding of the regulatory mechanisms of esophageal squamous differentiation and esophageal cancer stem cells by Notch will fundamentally advance the fields of Notch signaling and esophageal epithelial biology and tumor biology, and provide a platform for new avenues of translational biologically based applications for therapy of esophageal squamous cell carcinoma. Thus, proposed research is relevant to the part of NIH's mission that pertains to developing fundamental knowledge that will help to reduce the burdens of human diseases through the power of mouse pathobiology.