Crosstalk between Desmogleins and Canonical Hedgehog Signaling

桥粒糖蛋白和典型 Hedgehog 信号之间的串扰

• 批准号: 8526204
• 负责人: Donna Brennan-Crispi
• 金额: $ 4.22万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8526204
• 关键词: 1-Phosphatidylinositol 3-Kinase; Accounting; Agonist; Alleles; Asses; Basal Cell; Basal cell carcinoma; Biological Assay; Bromodeoxyuridine; Cadherins; Carcinoma; Caspase; Cell Adhesion; Cell Adhesion Molecules; Cell Line; Cell Proliferation; Cell Survival; Cell physiology; Cell-Cell Adhesion; Chemicals; Classification; Congenital Abnormality; Cyclic AMP-Dependent Protein Kinases; Data; Development; Diagnosis; Disease; Disease Progression; Epidermal Growth Factor Receptor; Epidermis; Epithelial; Erinaceidae; Genetic Transcription; Goals; Growth; Human; Immigration; Incidence; LacZ Genes; Luciferases; Malignant Epithelial Cell; Malignant Neoplasms; Mediating; Metalloproteases; Molecular Target; Monitor; Mus; Mutation; Oncogenic; Pathway interactions; Predisposition; Process; Proteins; Proteolytic Processing; Proto-Oncogene Proteins c-akt; RNA Interference; Regulation; Relative (related person); Reporter; Research; Role; Sampling; Signal Pathway; Signal Transduction; Signaling Molecule; Skin; Skin Cancer; Skin Neoplasms; Squamous cell carcinoma; Testing; Tissue Microarray; Transcriptional Activation; Transgenic Mice; Tumor Tissue; United States; Work; cancer therapy; cancer type; carcinogenesis; cell growth; design; desmoglein; desmoglein 2; in vitro activity; in vivo; inhibitor/antagonist; insight; keratinocyte; mouse model; novel; overexpression; programs; receptor; smoothened signaling pathway; therapeutic target; transcription factor; translational approach; translational study; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Skin cancer is the most common human cancer and BCCs and SCCs make up a vast majority of these malignancies. In the case of BCCs a causal role of canonical Hedgehog (Hh) pathway activation has been well-established, and recent evidence further supports a role for canonical Hedgehog signaling in SCCs as well. Hh signaling is a key developmental pathway involved in cells proliferation and survival through downstream activation of Gli transcription factors. The Hh pathway can be regulated by other signaling cascades; including EGFR, Wnt/-catenin, IGFR and TGF. Key signaling molecules have been shown to be required for Gli activation including Gi proteins, PI3K and AKT; while PKA and GSK3¿ promote partial Gli degradation. Interestingly, BCCs and SCCs, among other cancer types, are also characterized by increased expression of the desmosomal cadherin Desmoglein 2 (Dsg2). Furthermore, overexpression of DSg2 in transgenic mice results in epidermal hyperproliferation, enhanced cell survival, and renders keratinocytes more susceptible to chemically induced carcinogenesis. Thus the goal of this project is to elucidate a potential crosstalk between Dsg2 and canonical Hh signaling. Using a transgenic mouse model overexpressing Dsg2, our preliminary results indicate a significant correlation between Dsg2 expression and Hh target gene transcription. Since these mice are more susceptible to chemically induced carcinogenesis, the potential for Dsg2 to mediate changes in cell growth and survival could be in part mediated by enhanced Gli activity. Gli-luciferase assays demonstrate that the expression of Dsg2 can enhance Gli activity in vitro. Finally, knockdown of Dsg2 in an SCC cell line results in decreased Gli expression. Taken together, these results suggest a role for Dsg2 as a positive regulator of canonical Hh signaling. The studies proposed here are designed to elucidate the mechanism by which Dsg2 enhances Gli activity, by both determining at what level of Hh signaling Dsg2 is acting and if Dsg2 processing by metalloproteases and/or caspases is necessary for this regulation. In vivo work using mice that overexpress Dsg2 and which are prone to Hh signaling activation (Ptc1+/lacZ) will provide insights into the consequences of simultaneous deregulation of both pathways in the skin. Finally, a translational study looking at the expression of Dsg2 and Hh proteins in human BCC and SCC samples will allow for the correlation of the deregulation of both pathways with tumor type and classification. Together these mechanistic studies will offer a clearer understanding of how canonical Hh signaling can be regulated by cell adhesion proteins; the ramifications of said deregulation with regards to cell proliferation, survival and oncogenic potential; and provide potential targets for novel cancer therapies.

描述（由申请人提供）：皮肤癌是最常见的人类癌症，BCC 和 SCC 构成了这些恶性肿瘤的绝大多数。就 BCC 而言，典型的 Hedgehog (Hh) 通路激活的因果作用已得到充分证实。最近的进一步证据支持经典 Hedgehog 信号在 SCC 中的作用，Hh 信号是通过下游 Gli 转录因子激活参与细胞增殖和存活的关键发育途径。 Hh 通路可以通过其他信号级联进行调节；包括 EGFR、Wnt/-连环蛋白、IGFR 和 TGF，已被证明是 Gli 蛋白、PI3K 和 AKT 等关键信号分子，而 PKA 和 GSK3¿提示，除其他癌症类型外，BCC 和 SCC 的特征还在于桥粒钙粘蛋白 Desmoglein 2 (Dsg2) 的表达增加。此外，转基因小鼠中 DSg2 的过度表达会导致表皮过度增殖、细胞存活率提高。使角质形成细胞更容易受到化学诱导的致癌作用，因此该项目的目标是阐明 Dsg2 和 Dsg2 之间潜在的串扰。使用过度表达 Dsg2 的转基因小鼠模型，我们的初步结果表明 Dsg2 表达与 Hh 靶基因转录之间存在显着相关性，因为这些小鼠更容易受到化学诱导的致癌作用，因此 Dsg2 介导细胞生长和变化的潜力。存活可能部分由 Gli 活性增强介导，Dsg2 的表达可以增强体外的 Gli 活性。综上所述，这些结果表明 Dsg2 作为经典 Hh 信号传导的正调节剂，旨在通过确定 Dsg2 增强 Gli 活性的机制来阐明 Dsg2 增强 Gli 活性的机制。 Hh 信号传导 Dsg2 在什么水平上发挥作用，以及金属蛋白酶和/或半胱天冬酶对 Dsg2 的处理是否是这种调节所必需的，使用过度表达的小鼠进行体内工作。 Dsg2 和 Hh 信号通路易于激活 (Ptc1+/lacZ) 将深入了解皮肤中两条通路同时失调的后果。最后，一项针对人类 BCC 和 SCC 样本中 Dsg2 和 Hh 蛋白表达的转化研究。这些机制研究将允许将两条通路的失调与肿瘤类型和分类相关联，从而更清楚地了解细胞粘附蛋白如何调节典型的 Hh 信号传导；所述放松管制对细胞增殖、存活和致癌潜力的影响；并为新型癌症疗法提供潜在靶标。