(PQ1) Progression of the airway field of injury to Kras mutant lung cancer

项目摘要 美国有超过9000万吸烟者，他们患肺腺癌的风险较高 （LUAD），最常见的肺癌亚型。吸烟者的LUAD经常（超过25%）表现出 Kras癌基因突变。相对于吸烟者中发现的其他LUAD，Kras突变LUAD显示 预后不佳在大多数情况下，试图重新瞄准克拉斯的努力都失败了， 需要新的战略来预防和早期治疗这一致命疾病。尽管情况紧急， 对促使吸烟者发生Kras突变LUAD的事件了解不多， 成为早期治疗的目标。以前的研究表明，视觉正常的吸烟暴露气道， 携带具有邻近LUAD特征的改变，这种效应被称为“气道损伤区”。而 这个领域是丰富的恶性属性，我们不知道哪些领域的变化是诱导或进展， 正常或癌前细胞产生Kras突变LUAD，如果是这样，我们如何阻止这一过程。我们 我们的目标是解决这一知识差距，首先确定分子 在进展的变化， Kras突变LUAD表型损伤的表现正常的气道野，和第二鉴定剂， 靶向这些场改变并防止恶性肿瘤的发展。在我们的初步数据中，我们发现， 敲除G蛋白偶联受体5A（Gprc 5a-/-）的小鼠，Gprc 5a-/-是一种类维生素A调节基因， 与正常肺相比，人LUAD中的抑制，不仅与野生型同窝出生仔相反， 癌前病变（PMLs）和LUAD后，烟草致癌物暴露，而且这些病变 携带体细胞Kras突变，相同的变体被认为是吸烟者中人类LUAD的驱动因素。我们 然后研究烟草致癌物对Gprc 5a-/-小鼠正常气道基因表达的影响， 了解Kras突变LUAD发病机制的早期事件。使用RNA测序，我们发现 与未暴露的细胞相比，暴露于烟草致癌物的正常气道中的致癌途径 基线，提示Kras突变LUAD发作前诱导的气道损伤。我们将使用 烟草致癌物暴露的Gprc 5a-/-小鼠作为模型，以研究和靶向进展的气道领域， Kras突变LUAD损伤。在目标1中，我们将通过外显子组测序来调查表征基因突变的突变。 吸烟暴露气道细胞的Kras突变PMLs和LUAD的演变。在目标2中，我们将确定 进化保守的气道表达谱在开始吸烟后随着时间的推移而发展， 表明Kras突变PML和LUAD的发展。在目标3中，我们将利用现场签名， 使用计算药物发现方法来识别 防止Kras突变体发展的药物 PML并抑制PML向LUAD的进展。 在我们的研究结束时，我们将开始 了解Kras突变LUAD的演变，指出这种致命疾病的化学预防方法 为研究LUAD的发病机制和促肿瘤场效应提供了新的模型。

PROJECT SUMMARY There are more than 90 million smokers in the United States who are at elevated risk for lung adenocarcinoma (LUAD), the most common lung cancer subtype. LUADs in smokers frequently (more than 25%) exhibit mutations in the Kras oncogene. Relative to other LUADs found in smokers, Kras mutant LUAD displays dismal prognosis. Attempts to pharmacologically target Kras have, for the most part, failed, warranting the need for new strategies for prevention and early treatment of this fatal disease. Despite this urgency, we have a poor understanding of events that drive development of Kras mutant LUAD in smokers and that would constitute targets for early treatment. Previous work revealed that visually normal smoking exposed airways carry alterations that are characteristic of adjacent LUADs, an effect referred to as “airway field of injury”. While this field is enriched with malignant properties, we do not know which field changes are induced or progress in normal or premalignant cells to give rise to Kras mutant LUAD and, if so, how we can impede this process. Our goal is to address this gap in knowledge, first determining molecular alterations in the progression of the normal-appearing airway field of injury to a Kras mutant LUAD phenotype, and second identifying agents that target these field alterations and prevent development of the malignancy. In our preliminary data, we found that mice with knockout of G-protein coupled receptor 5A (Gprc5a-/-), a retinoid-regulated gene that is prominently suppressed in human LUADs compared to normal lung, not only developed, in contrast to wild type littermates, premalignant lesions (PMLs) and LUADs after tobacco carcinogen exposure but also that these lesions harbored somatic Kras mutations, the same variants thought to act as drivers of human LUAD in smokers. We then studied the effects of tobacco carcinogen on gene expression in normal airways of Gprc5a-/- mice in order to understand early events in Kras mutant LUAD pathogenesis. Using RNA-sequencing, we found activation of oncogenic pathways in tobacco carcinogen exposed normal airways when compared to non-exposed cells at baseline, suggestive of an airway field of injury induced prior to onset of Kras mutant LUAD. We will use the tobacco carcinogen exposed Gprc5a-/- mouse as a model to study and target progression of the airway field of injury to Kras mutant LUAD. In Aim 1, we will survey, by exome sequencing, mutations that characterize the evolution of smoking exposed airway cells to Kras mutant PMLs and LUADs. In Aim 2, we will determine evolutionarily conserved airway expression profiles that progress with time following onset of smoking and signify the development of Kras mutant PMLs and LUADs. In Aim 3, we will harness the field signatures and use computational drug discovery approaches to identify agents that prevent the development of Kras mutant PMLs and inhibit progression of PMLs to LUADs. At the conclusion of our studies, we will have started to understand the evolution of Kras mutant LUAD, pointed to chemoprevention approaches for this fatal disease and contributed novel models for studying LUAD pathogenesis and tumor promoting field effects.