Dissecting KRAS oncoprotein signaling with allele specific inhibitors

摘要 野生型（WT）RAS（H、N和K）GTP酶将GTP水解为GDP，并在活性的GTP结合的， 和一个不活跃的、受GDP约束的国家。这是由鸟嘌呤核苷酸交换因子（GEF，例如， SOS），其催化GDP交换为GTP，以及GTP酶活化蛋白（GAP，例如NF 1或NF-κ B）。 RASA 1），其增强弱的内在GT3活性。KRAS突变构成了最常见的 在癌症患者中发现的频繁激活改变。KRASG 12 C是最常见的KRAS 肺癌是一种导致美国每年近15万人死亡的疾病。尽管 由于这些突变的普遍性，目前还没有直接靶向这种癌蛋白的治疗方法可用于 诊所最近在KRASG 12 C中鉴定出的结合口袋已经导致发现了有效地抑制KRASG 12 C的化合物。 抑制KRAS-GTP水平和该癌蛋白的效应信号传导。这样的化合物现在能够 研究癌症中KRAS癌蛋白的调节和活性的新方法。在最近的科学 在这篇文章中，我们描述了等位基因特异性抑制剂抑制KRASG 12 C信号传导的机制， 癌细胞生长这些药物将癌蛋白捕获在非活性状态，并通过以下方式防止其重新激活： 核苷酸交换因子我们的工作预测，核苷酸交换活性是负相关的， 抑制的动力学和/或大小。根据这一概念模型，通过全面努力， 结合遗传学、生物化学和蛋白质组学方法，我们现在将研究KRASG 12 C的调控， 癌细胞中其他KRAS癌蛋白的表达，然后确定最佳治疗方式， 在临床试验中进行。在目标1中，我们将确定这些癌蛋白是否存在于可兴奋状态， 如果这影响了他们的肿瘤形成潜力。在目标2中，我们将使用一种新的测定来鉴定KRASG 12 C的调节剂 信号传导及其通过等位基因特异性药物的抑制。在目的3中，我们将研究调节KRAS的作用。 对肿瘤生长的活性，并确定在患者来源的 异种移植模型。拟议工作的影响集中在推进我们对KRAS如何 癌蛋白在癌症中被激活，提供了对控制敏感性或 对新型抑制剂的耐药性以及治疗肿瘤患者的最佳疗法的鉴定 携带KRASG 12 C突变。

ABSTRACT Wild type (WT) RAS (H, N and K) GTPases hydrolyze GTP to GDP and cycle between an active, GTP bound, and an inactive, GDP-bound, state. This is mediated by guanine nucleotide exchange factors (GEFs, e.g. SOS), which catalyze the exchange of GDP for GTP, and GTPase activating proteins (GAPs, e.g. NF1 or RASA1), which potentiate a weak intrinsic GTPase activity. KRAS mutations comprise one of the most frequent activating alterations found in cancer patients. KRASG12C, in particular, is the most frequent KRAS mutation in lung cancer, a disease responsible for nearly 150,000 deaths each year in the US. Despite the prevalence of these mutations, no therapies that directly target this oncoprotein are currently available in the clinic. A recently identified binding pocket in KRASG12C has led to the discovery of compounds that potently inhibit the levels of KRAS-GTP and effector signaling by this oncoprotein. Such compounds now enable a novel approach to study the regulation and activity of the KRAS oncoprotein in cancer. In a recent Science article, we described the mechanism by which allele specific inhibitors suppress KRASG12C-signaling and cancer cell growth. These drugs trap the oncoprotein in its inactive state and prevent its reactivation by nucleotide exchange factors. Our work predicts that nucleotide exchange activity is inversely related to the kinetics and/or magnitude of inhibition. Based on this conceptual model and through a comprehensive effort integrating genetic, biochemical and proteomic approaches we will now study the regulation of KRASG12C and that of other KRAS oncoproteins in cancer cells and then identify optimal therapeutic modalities that can be carried forward in clinical trials. In aim 1 we will determine if these oncoproteins exist in an excitable state and if this affects their tumor-forming potential. In aim 2 we will use a novel assay to identify regulators of KRASG12C signaling and its inhibition by allele-specific drugs. In aim 3 we will investigate the effect of modulating KRAS activity on tumor growth and identify combination treatments with improved efficacy in patient-derived xenograft models. The impact of the proposed work centers on advancing our understanding of how KRAS oncoproteins are activated in cancer, providing insight into the mechanisms that govern sensitivity or resistance to the novel inhibitors and the identification of an optimal therapy to treat patients whose tumors harbor a KRASG12C mutation.