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

项目总结 美国有9000多万吸烟者患肺腺癌的风险增加 (LUAD)，最常见的肺癌亚型。吸烟者经常(超过25%)表现出LUAD Kras癌基因的突变。相对于在吸烟者中发现的其他LUAD，Kras突变体LUAD显示 预后很差。在大多数情况下，以Kras为药物靶点的尝试都失败了，这证明了 需要制定预防和早期治疗这一致命疾病的新战略。尽管迫在眉睫，但我们有 对导致吸烟者发生Kras突变LUAD的事件缺乏了解，这将 制定早期治疗的目标。先前的研究表明，视觉上正常的吸烟暴露在呼吸道中 这种改变是邻近LUAD的特征，这种影响被称为“呼吸道损伤场”。而当 这一领域是丰富的恶性性质，我们不知道哪些领域的变化是诱发或进展 正常或癌前细胞产生Kras突变体LUAD，如果是这样，我们如何阻止这一过程。我们的 目标是解决这一知识差距，首先确定分子 改革进程中的变化 Kras突变LUAD表型的正常外观气道场损伤，以及第二种识别药物 针对这些领域的改变，防止恶性肿瘤的发展。在我们的初步数据中，我们发现 G蛋白偶联受体5A(Gprc5a-/-)基因敲除的小鼠，这是一个由维甲酸调节的基因，显著 与正常肺相比，人类LUADs中的抑制不仅发育，与野生型相比， 烟草致癌物暴露后的癌前病变(PML)和LUADs，以及这些病变 隐藏着体细胞Kras突变，这些突变被认为是吸烟者体内人类LUAD的驱动因素。我们 然后依次研究了烟草致癌物对Gprc5a-/-小鼠正常呼吸道基因表达的影响。 了解Kras突变型LUAD发病机制的早期事件。使用RNA测序，我们发现了激活的 烟草致癌物暴露于正常呼吸道的致癌途径与未暴露的细胞相比 基线，提示在Kras突变型LUAD发病前引起的呼吸道损伤。我们将使用 烟草致癌物暴露Gprc5a-/-小鼠作为模型研究和靶向进展的气道场 对克拉斯突变体卢阿德的伤害。在目标1中，我们将通过外显子组测序来调查表征 吸烟暴露的呼吸道细胞对Kras突变PML和LUAD的进化。在目标2中，我们将确定 随着吸烟的开始和时间的延长，进化上保守的气道表达谱 标志着Kras突变体PML和LUAD的发展。在目标3中，我们将利用现场签名和 使用计算药物发现方法来识别 阻止Kras突变型发展的药物 PMLS和抑制PMLS向LUAD的进展。 在我们的研究结束时，我们将开始 了解Kras突变体LUAD的进化，指出了这种致命疾病的化学预防方法 为研究LUAD的发病机制和促癌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.