Interrogating the RAS interactome for therapeutic vulnerabilities

项目总结和摘要 RAS基因KRAS、NRAS或HRAS通常在人类癌症中突变。临床上抑制RAS已被证明是具有挑战性的，RAS突变型癌症仍然是一些最难治的疾病，即使是免疫疗法。因此，阐明致癌RAS信号传导不仅对更好地理解肿瘤发生过程，而且对识别新的潜在治疗靶点至关重要。为此，我利用BirA介导的邻近标记的新技术，以确定每个RAS亚型的紧邻（相互作用组）内的蛋白质。然后，我筛选了一个sgRNA文库，该文库靶向相互作用组成分，以寻找促进RAS转化细胞生长的基因，鉴定出可药用的磷脂酰肌醇磷酸脂质激酶PIP5K1A特异性驱动KRAS肿瘤发生。PIP5K1A代表了KRAS突变型癌症的一个全新治疗靶点，并表明RAS相互作用组中的其他蛋白质可能类似地介导RAS肿瘤发生。我将在三个目标中利用这些发现。由于PIP5K1A是一种可药物化的激酶，它提供了一种特异性抑制KRAS肿瘤发生的方法，这可以用于增强靶向RAS效应子途径的药物的抗肿瘤活性。因此，在目标1中，我将阐明靶向PIP5K1A在KRAS突变型癌症中的作用和治疗潜力。PIP5K1A促进KRAS肿瘤发生的鉴定表明，其他相互作用组蛋白可能类似地介导RAS功能。因此，在目标2中，我将在RAS相互作用组中挖掘RAS肿瘤发生的新修饰剂，重点是相互作用组蛋白EFR 3A作为致癌RAS驱动的肿瘤发生的潜在一般介质。最后，RAS相互作用组肯定是动态的，在不同的条件下变化。因此，在不同的设置下确定RAS相互作用组的内容可以识别特定于不同细胞条件的新的脆弱性。因此，在目标3中，我将探测响应于细胞扰动的RAS相互作用组。总之，我将扩大我的发现，PIP5K1A促进KRAS肿瘤发生，探索这种激酶作为一个新的治疗靶点，并确定其他新的治疗漏洞，存在于RAS相互作用组。K99项目将完成我在RAS信号转导方面的培训，并将我的培训扩展到磷酸化蛋白质组学、异种移植和肿瘤发生的基因工程小鼠模型。R00部分将利用邻近标记来研究致癌RAS信号传导的动态性质。我的长期目标是转变为一名独立的研究者，并应用系统生物学方法来揭示癌基因驱动的信号通路，目的是确定RAS突变癌症的新治疗漏洞。

PROJECT SUMMARY AND ABSTRACT The RAS genes KRAS, NRAS, or HRAS, are commonly mutated in human cancers. Clinically inhibiting RAS has proven challenging and RAS-mutant cancers remain some of the most intractable diseases, even to immunotherapies. It is thus critical to elucidate oncogenic RAS signaling, not only to better understand the tumorigenic process, but also to identify new potential therapeutic targets. To this end, I exploited the novel technique of BirA-mediated proximity labeling to identify proteins within the immediate vicinity (interactome) of each RAS isoform. I then screened an sgRNA library targeting interactome components for genes promoting RAS transformed cell growth, identifying the druggable phosphatidylinositol phosphate lipid kinase PIP5K1A as specifically driving KRAS oncogenesis. PIP5K1A represents an entirely new therapeutic target in KRAS-mutant cancers, and suggests that other proteins in the RAS interactome may similarly mediate RAS oncogenesis. I will capitalized on these discoveries in three aims. As PIP5K1A is a druggable kinase it provides a way to specifically inhibit KRAS oncogenesis, which could be exploited to enhance the antineoplastic activity of drugs targeting RAS effector pathways. Thus, in aim 1 I will elucidate the role and therapeutic potential of targeting PIP5K1A in KRAS-mutant cancers. The identification of PIP5K1A promoting KRAS oncogenesis suggests that other interactome proteins may similarly mediate RAS function. Thus, in aim 2 I will mine the RAS interactome for novel modifiers of RAS oncogenesis, focusing on the interactome protein EFR3A as a potential general mediator of oncogenic RAS-driven tumorigenesis. Finally, the RAS interactome is most certainly dynamic, varying under different conditions. Determining the content of the RAS interactome under distinct settings may thus identify new vulnerabilities specific to diverse cellular conditions. Thus, in aim 3 I will probe the RAS interactome in response to cellular perturbations. In sum, I will expand upon my discovery that PIP5K1A promotes KRAS oncogenesis to explore this kinase as a new therapeutic target and identify other novel therapeutic vulnerabilities that exists within the RAS interactome. The K99 segment of this grant will complete my training in RAS signal transduction, extend my training into phosphoproteomics, xenograft and genetically engineered mouse models of tumorigenesis. The R00 segment will capitalize on the use of proximity labeling to study the dynamic nature of oncogenic RAS signaling. My long-term goal is to transition into an independent investigator and apply systems biology approaches to uncover the signaling circuitry of oncogene drivers with the objective of identifying novel therapeutic vulnerabilities in RAS-mutant cancers.