Characterization of RAS-Driven Human Epidermal Neoplasia

描述(由申请人提供)：RAS驱动的人类表皮肿瘤的特征。在美国，包括皮肤鳞状细胞癌(SCC)在内的两种最常见的癌症发生在表皮。RAS是人类癌症中最常见的突变基因之一，已被认为与小鼠鳞状细胞癌的发生有关。然而，小鼠对鳞状细胞癌和其他癌症的研究的医学相关性受到小鼠和人类皮肤之间的主要差异以及小鼠组织更容易转化的限制。最近，我们已经证明RAS和CDK4在人鳞状细胞癌的一个亚群中被诱导，并且共表达RAS和CDK4诱导了侵袭性的人表皮肿瘤，在所有研究水平上都与鳞癌无法区分。这项建议的总体目标是表征RAS驱动的人类表皮肿瘤的机制基础，作为一种增强我们对人类组织肿瘤发生的理解的手段。首先，我们计划表征三个主要的近端RAS效应通路，Raf，PI3K和Ralgef，在CDK4的肿瘤发生中的作用。这些效应物可以触发在许多癌症中发现的变化，如增殖、分化抑制、血管生成和侵袭。对于这些途径的选择性RAS突变体以及效应器本身将被用来确定它们在RAS驱动的人类肿瘤中的相对贡献。这些研究旨在确定单个RAS效应通路的影响，以及它们在多大程度上是启动表皮肿瘤发生的必要条件和充分条件。第二，我们计划确定特定的表皮黏附蛋白在RAS驱动的人类表皮肿瘤中的必要性。在这些黏附蛋白中，BP180和VI型胶原是人类表皮-真皮凝聚力所必需的，并且在鳞状细胞癌中过表达，然而，它们在表皮癌中的潜在作用尚不清楚。为了解决这一问题，将在我们的RAS驱动的表皮癌模型中使用来自大疱性表皮松解症患者的BP180和II型胶原缺乏的原代人类角质形成细胞。确定在缺乏BP180和VII型胶原的情况下，表皮肿瘤的发生是否可以进行，以及确定这些蛋白质的特定结构域对这一过程的影响程度，将有助于确定它们在人类表皮肿瘤中的作用。在拟议的资助期结束时，我们希望将RAS驱动的人类表皮肿瘤的特征描述为洞察人类组织肿瘤发生的基础，并为未来针对皮肤癌和其他器官癌症的靶向分子疗法的开发奠定基础。

DESCRIPTION (provided by applicant): CHARACTERIZATION OF RAS-DRIVEN HUMAN EPIDERMAL NEOPLASIA. The 2 most common cancers in the U.S., including cutaneous squamous cell carcinoma (SCC), arise from the epidermis. RAS, among the most commonly mutated genes in human cancer, has been implicated in SCC development in mice. The medical relevance of murine studies of SCC and other cancers, however, is limited by major differences between mouse and human skin and by the greater ease of transformation of murine tissues. Recently, we have demonstrated that Ras and CDK4 are induced in a subset of human SCC and that coexpressing Ras with CDK4 induces invasive human epidermal neoplasia indistinguishable from SCC at all levels studied. The overall goal of this proposal is to characterize the mechanistic basis for Ras-driven human epidermal neoplasia as a means of enhancing our understanding of human tissue tumorigenesis. First, we plan to characterize the function of the 3 major proximal Ras effector pathways, Raf, PI3K and RalGEF, in tumorigenesis with CDK4. These effectors can trigger changes found in many cancers, such as proliferation, inhibition of differentiation, angiogenesis and invasion. Ras mutants selective for these pathways as well as the effectors themselves will be used to define their relative contributions to Ras-driven human neoplasia. These studies are designed to define the impacts of individual Ras effector pathways and the degree to which they are necessary and sufficient for initiation of epidermal tumorigenesis. Second, we plan to define the necessity of specific epidermal adhesion proteins in Ras-driven human epidermal neoplasia. Among such adhesion proteins, BP180 and type VI/ collagen are required for epidermal-dermal cohesion in humans and are overexpressed in SCC, however, their potential roles in epidermal cancer are unknown. To address this, will use BP180 and collagen VII-deficient primary human keratinocytes from patients with epidermolysis bullosa _B) in our Ras-driven epidermal cancer model. Determining whether epidermal tumorigenesis can proceed in the absence of BP180 and collagen VII as well as defining the degree to which specific domains of these proteins influence this process will help define their role in human epidermal neoplasia. At the end of the proposed funding period, we hope to have characterized Ras-driven human epidermal neoplasia as a basis for insight into human tissue tumorigenesis and for development of future targeted molecular therapies for cancers of the skin and other organs.