Dissecting KRAS oncoprotein signaling with allele specific inhibitors

摘要 野生型(WT)RAS(H，N和K)GTP酶将GTP水解成GDP，并在活性、GTP结合、 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)介导的。 SOS)，它催化GDP交换为GTP，以及GTP酶激活蛋白(GAP，例如NF1或 RASA1)，它增强了弱的固有GTP酶活性。KRAS突变构成了最重要的 癌症患者中发现的频繁的激活改变。尤其是KRASG12C是最常见的KRAS 肺癌的突变每年在美国造成近15万人死亡。尽管 这些突变的流行率，目前还没有直接针对这种癌蛋白的治疗方法 诊所。最近在KRASG12C中发现的一个结合口袋导致了一种有效的化合物的发现 通过该癌蛋白抑制KRAS-GTP和效应信号的水平。这样的化合物现在能够 研究KRAS癌蛋白在癌症中的调节和活性的新方法。在最新的《科学》杂志上 文章描述了等位基因特异性抑制物抑制KRASG12C信号转导的机制。 癌细胞生长。这些药物捕获处于非活性状态的癌蛋白，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动与 动力学和/或抑制程度。在此概念模型的基础上，通过综合努力 结合遗传学、生化和蛋白质组学方法，我们现在将研究KRASG12C和KRASG12C的调控。 其他KRAS癌蛋白在癌细胞中的表达，然后确定可以 在临床试验中得到推广。在目标1中，我们将确定这些癌蛋白是否以可兴奋状态存在 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方法来鉴定KRASG12C的调控因子 信号转导及其等位基因特异性药物的抑制。在目标3中，我们将研究调节KRAS的效果 对肿瘤生长的活性，并确定联合治疗可提高患者来源的疗效 异种移植模型。拟议工作的影响集中在促进我们对KRAS如何 癌蛋白在癌症中被激活，提供了对控制敏感性或 肿瘤患者对新型抑制剂的耐药性及最佳治疗方法的确定 港湾KRASG12C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.