Laminin-332 and its Receptors in Carcinoma Progression

描述（由申请人提供）：皮肤浸润性鳞状细胞癌是美国的一个重大问题，每年有超过100万例。随着发病率的上升，手术和放射治疗是唯一可行的治疗选择，需要开发更具体的分子药物来对抗这种疾病。为此，本研究试图对真皮-表皮交界处的重要组成部分进行功能表征，以确定基底膜蛋白如何在皮肤鳞状细胞癌的侵袭和进展中发挥重要的驱动作用。层粘连蛋白332是表皮基底膜的重要组成部分，是表皮肿瘤发生所必需的，正如我们通过使用人皮肤鳞状细胞癌的体内模型所显示的那样。最近的数据表明，层粘连蛋白332的蛋白水解修饰、与胶原VII的结合以及与a6¿4整合素的相互作用在SCC的肿瘤发生中都起着重要作用，然而，缺乏一个统一的模型来描述层粘连蛋白332在SCC中的功能，该模型包含了所有这些特征。除了a6¿4整合素外，还有其他几种细胞表面受体与层粘连蛋白332相互作用，包括syndecan-1、c-Met和EGFR，这些受体也可能参与SCC肿瘤发生过程中层粘连蛋白332衍生的信号传导。这些分子如何协同激活SCC中致瘤前信号通路仍有待充分阐明，这也是本研究的重点。首先，我们计划通过基因缺失和抗体抑制来研究层粘连蛋白332的各个结构域对这一过程的贡献。我们还将阐明整合素中含有的特定残基所贡献的促肿瘤信号。其次，我们将研究¿4整合素相关分子的作用，以了解它们如何与层粘连蛋白332和¿4整合素一起协调增殖、细胞侵袭、层粘连蛋白332沉积、金属蛋白酶活性和其他对癌症进展至关重要的功能。最后，基于初步数据显示特异性抑制SCC肿瘤发生而不破坏正常皮肤内聚，使用针对lamin332的G45结构域的抗体，我们计划开发和测试一组针对其他lamin332结构域的抗体以及胶原VII NC1抗体。在这些研究中，我们将功能表征这些抗体如何作用于SCC肿瘤发生，以及正常皮肤。我们还将确定联合抗体治疗是否能产生协同抑癌作用。在计划的资助期结束时，我们希望能够回答关于细胞外基质在鳞状细胞癌发生中的作用的基本问题，并学习新的信息，这些信息有可能开发出新的和特异性的皮肤鳞状细胞癌治疗方法。公共卫生相关性：皮肤鳞状细胞癌（SCC）是第二常见的人类癌症，但缺乏有效和特异性的分子治疗方法。本研究的重点是了解真皮-表皮基底膜蛋白laminin-332和a6¿4整合素在促进SCC进展和侵袭中的关键作用。该建议还寻求开发新的特异性分子疗法，在不破坏正常皮肤组织的情况下抑制层粘连蛋白332和相关分子在SCC中的功能。

DESCRIPTION (provided by applicant): Invasive squamous cell carcinoma of the skin is a significant problem in the U.S. with over one million cases annually. With a rising incidence and with surgery and radiation therapy as the only feasible treatment options, the need for development of more specific molecular agents to combat this disease is great. Towards this end, this proposal seeks to functionally characterize important components of the dermal-epidermal junction to determine how basement membrane proteins act as a significant driving force for invasion and progression of cutaneous squamous cell carcinoma. Laminin-332 is an essential component of the epidermal basement membrane, and is required for epidermal tumorigenesis as we have shown through use of an in vivo model of human cutaneous SCC. Recent data suggest that laminin-332's proteolytic modifications, its binding to collagen VII and its interaction with a6¿4 integrin each play important roles in SCC tumorigenesis, however a unified model of laminin-332 function in SCC which incorporates all of these features is lacking. In addition to a6¿4 integrin, several other cell surface receptors interact with laminin-332, including syndecan-1, c-Met and EGFR, and these receptors may also participate in laminin-332 derived signaling during SCC tumorigenesis. How these molecules coordinate together to activate pro-tumorigenic signaling pathways in SCC remains to be fully elucidated and is the focus of this proposal. First we plan to study the contributions of individual domains of laminin-332 to this process by both genetic deletion and antibody inhibition. We will also elucidate the pro-tumorigenic signaling contributed by specific residues contained in ¿4 integrin. Second, we will examine the role of ¿4 integrin associated molecules to understand how they, with laminin-332 and ¿4 integrin, coordinate proliferation, cellular invasion, laminin-332 deposition, metalloproteinase activity and other functions essential for carcinoma progression. Finally, based on preliminary data showing specific inhibition of SCC tumorigenesis without disruption of normal skin cohesion, using an antibody against the G45 domain of laminin-332, we plan to develop and test a panel of antibodies against other laminin-332 domains as well as a collagen VII NC1 antibody. In these studies, we will functionally characterize how these antibodies act on SCC tumorigenesis, as well as normal skin. We will also determine whether combination antibody therapy can produce synergistic carcinoma inhibition. At the end of the proposed funding period, we hope to have answered fundamental questions about the role of the extracellular matrix in SCC tumorigenesis and to learn new information which has the potential for the development of novel and specific therapies for cutaneous SCC. PUBLIC HEALTH RELEVANCE: Squamous cell carcinoma (SCC) of the skin is the second most common human cancer, but effective and specific molecular therapies for this disease are lacking. This proposal focuses on understanding the critical role that the dermal-epidermal basement membrane proteins laminin-332 and a6¿4 integrin play in facilitating SCC progression and invasion. This proposal also seeks to develop novel and specific molecular therapies to inhibit the function of laminin-332 and associated molecules in SCC without disrupting normal skin tissue.