Epigenetic Regulation of Cutaneous Tumorigenesis

项目概要/摘要： 该提案描述了一个为期五年的职业发展计划，旨在支持学术，医生- 科学家生涯拟议的研究项目将利用现有的专业知识和资源， 华盛顿大学医学院，拥有培养医生科学家的悠久传统。博士 Timothy Ley，癌症基因组学和表观遗传学专家，多个导师奖获得者 在全国和华盛顿大学，将担任主要的研究导师。的最终目标 候选人是一个独立的研究人员在学术医学中心，研究表观遗传控制 皮肤癌的发生和皮肤恶性肿瘤患者的护理。 这项研究的长期目标是确定表皮细胞表观遗传“状态”的改变， 角质形成细胞在正常衰老过程中产生的作用，以及它们在产生与年龄相关的 皮肤癌年龄增长和紫外线照射是两个最突出的流行病学危险因素， 皮肤白皙人群中皮肤癌的发展。最近的研究发现， 来自临床正常皮肤的携带致癌突变的细胞，表明额外的遗传或表观遗传 是转化为皮肤癌所必需的。老化和紫外线照射不仅会导致DNA 损伤和突变，但也已被证明会导致皮肤中的DNA甲基化变化， 人类患者;这些改变是否与皮肤癌发病机制有关目前尚不清楚。我们 初步数据表明，表皮细胞的DNA甲基化状态经历了程序性变化， 在小鼠的特定位点，随着年龄的增长，基因表达的刻板变化也会导致 我们将其命名为“基底老化特征角质形成细胞”（BASKs）。我们 将探讨与年龄相关的表观遗传变化，包括DNA甲基化，可能会增加的假设， 皮肤癌发展的易感性，具体目标如下：目标1：我们将定义表观遗传 小鼠表皮中由正常衰老引起的事件，将其与功能变化联系起来，并评估其 在皮肤癌发展中的作用。我们将定义BASK细胞中的表观遗传变化， 允许纯化该群体的生物标志物，并测试老化皮肤对KRASG 12 D的易感性。 介导的皮肤肿瘤发生和UVB诱导的皮肤中突变的Trp 53克隆岛的发展。 目的2：我们将确定个体DNA甲基转移酶在年龄依赖性肿瘤发生中的作用。 甲基化状态和皮肤的肿瘤转化。使用Dnmt 1有条件缺陷的小鼠， Dnmt 3a和/或Dnmt 3b，我们将确定这些酶是否有助于与年龄相关的 BASK表型的发展，以及它们的缺陷是否与KRASG 12 D介导的皮肤 肿瘤发生如果成功的话，从这项工作中获得的见解可能会允许创造新的治疗或治疗方法。 角化细胞癌、基底细胞癌和鳞状细胞癌的预防方法。

Project Summary/Abstract: This proposal describes a five-year career development program designed to support an academic, physician- scientist career. The proposed research project will capitalize on the expertise and resources available at Washington University School of Medicine, which has a strong tradition of developing physician-scientists. Dr. Timothy Ley, an expert in cancer genomics and epigenetics, and a recipient of multiple mentorship awards nationally and at Washington University, will serve as the primary research mentor. The ultimate goal of the candidate is to be an independent investigator in an academic medical center, studying epigenetic control of cutaneous carcinogenesis, and caring for patients with cutaneous malignancies. The long-term goal of this study is to define alterations in the epigenetic “state” of epidermal keratinocytes that arise during normal aging and their roles in creating age-related susceptibilities for skin cancer. Increasing age and UV light exposure are the two most prominent epidemiologic risk factors for the development of skin cancer in fair skinned populations. Recent studies have identified clonal expansions of cells harboring oncogenic mutations from clinically normal skin, suggesting that additional genetic or epigenetic events are required for transformation to skin cancer. Aging and UV light exposure not only cause DNA damage and mutations, but also have been demonstrated to cause DNA methylation changes in the skin of human patients; whether these alterations are relevant for skin cancer pathogenesis is currently unknown. Our preliminary data suggests that the DNA methylation state of epidermal cells undergoes a programmed change at specific loci in mice as they age, as do stereotypical changes in gene expression resulting in the development of a population of cells that we have named “basal aging-signature keratinocytes” (BASKs). We will explore the hypothesis that age-related epigenetic changes, including DNA methylation, may increase susceptibility to skin cancer development with the following specific aims: Aim 1: We will define the epigenetic events in murine epidermis that result from normal aging, relate them to functional changes, and assess their roles in the development of skin cancers. We will define the epigenetic changes in BASK cells, define biomarkers that allow for the purification of this population, and test the susceptibility of aged skin to KRASG12D- mediated skin tumorigenesis and the development of UVB-induced, mutated Trp53 clonal islands in the skin. Aim 2: We will define the roles of individual DNA methyltransferases for the development of age-dependent methylation states and for the neoplastic transformation of skin. Using mice conditionally deficient in Dnmt1, Dnmt3a, and/or Dnmt3b in epidermal cells, we will determine whether these enzymes contribute to age-related development of the BASK phenotype, and whether their deficiencies are relevant for KRASG12D-mediated skin tumorigenesis. If successful, insights gained from this work may allow for the creation of novel therapeutic or preventative approaches for the keratinocyte cancers, basal cell and squamous cell carcinoma.