Regulation of Human Epidermal Tumorigenesis by the mRNA Degradation Pathway

项目摘要/摘要 背景：调节表皮动态平衡的转录机制和 肿瘤已经确立，但最近我们发现，后- 转录机制在维持表皮自我更新方面起着重要作用。 我们已经证明了外切体介导的3‘-5’mRNA降解途径。 复合体是维持表皮自我更新所必需的。具体地说，外显体 EXOSC7、EXOSC9和EXSCO10亚基是预防早产所必需的 靶向和降解编码转录本诱导表皮干细胞分化 寻找强有力的促分化转录因子。 目标/假设：这个提议试图理解分子机制。 使用RAS驱动的人控制从正常皮肤到肿瘤皮肤的进展 表皮肿瘤模型。我们的初步数据显示，一个5亚基的外切体 亚复合体在肿瘤起始和靶向/降解转录本中上调 编码抑制肿瘤生长和存活的因素。我们的目标是 描述每个肿瘤诱导的外切体亚单位在肿瘤进展中的作用 正常到肿瘤性皮肤。此外，我们试图确定特定的成绩单 每个外切体亚单位在肿瘤发生过程中结合，促进肿瘤的发生。 具体目标：(1)确定外切体亚单位在慢性前列腺癌进展中的作用。 正常皮肤到肿瘤皮肤以及(2)鉴定和表征相关转录本 带有外切体亚单位。 研究设计：为了在更具临床相关性的环境中研究表皮动态平衡，我们 生成三维完整的人类皮肤，包含人类表皮细胞(即 已经被永久地拆除为外切体亚基)在人类的上下文中 真皮基质和基底膜，在免疫受损的小鼠身上再生。 利用该模型，我们可以对外切体亚单位进行功能丧失实验 以确定它们在表皮生长、分化、 并进展为肿瘤。我们将使用Clip-Seq来确定关联的RNA 在从正常表皮到肿瘤表皮的过程中与外切体亚单位结合。

Project Summary/Abstract Background: Transcriptional mechanisms that regulate epidermal homeostasis and neoplasia have been well established but recently we have discovered that post- transcriptional mechanisms play prominent roles in maintaining epidermal self-renewal. We have shown that the 3'-5' mRNA degradation pathway mediated by the exosome complex is necessary to maintain epidermal self-renewal. Specifically, the exosome subunits, EXOSC7, EXOSC9, and EXSCO10 are necessary to prevent premature differentiation of epidermal stem cells by targeting and degrading transcripts that code for potent pro-differentiation transcription factors. Objective/hypothesis: This proposal seeks to understand the molecular mechanisms governing the progression from normal to neoplastic skin using a RAS driven human epidermal tumor model. Our preliminary data suggests that a 5 subunit exosome subcomplex is upregulated during tumor initiation and targets/degrades transcripts coding for factors that would inhibit tumor growth and survival. Our objective is to characterize the role of each tumor induced exosome subunit in the progression of normal to neoplastic skin. Furthermore we seek to determine the specific transcripts that each exosome subunit binds during tumor initiation to promote tumorigenesis. Specific Aims: (1) To determine the role of exosome subunits on the progression from normal to neoplastic skin and (2) to identify and characterize the transcripts associated with exosome subunits. Study Design: To study epidermal homeostasis in a more clinically relevant setting, we generate 3-dimensionally intact human skin, containing human epidermal cells (that have been permanently knocked down for exosome subunits) in the context of human dermal stroma and basement membrane, regenerated on immune compromised mice. By using this model, we can perform loss of function experiments on exosome subunits in regenerated human skin to characterize their role in epidermal growth, differentiation, and progression to neoplasia. We will use CLIP-Seq to determine the RNAs associated with the exosome subunits during the progression from normal to neoplastic epidermis.