Interrogating the RAS interactome for therapeutic vulnerabilities

项目摘要和摘要 RAS基因KRAS、NRAS或HRAS在人类癌症中通常发生突变。临床上抑制RAS已被证明具有挑战性，RAS突变的癌症仍然是一些最难治疗的疾病，甚至对免疫疗法也是如此。因此，阐明致癌的RAS信号，不仅对于更好地理解肿瘤的发生过程，而且对于识别新的潜在的治疗靶点是至关重要的。为此，我利用BIRA介导的邻近标记的新技术来识别每个RAS亚型的直接邻近(相互作用体)内的蛋白质。然后，我筛选了一个针对促进RAS转化细胞生长的基因的相互作用组成分的sgRNA文库，确定了可药物磷脂酰肌醇磷脂激酶PIP5K1A特异性地驱动KRAS肿瘤的发生。PIP5K1A代表了KRAS突变癌症的一个全新的治疗靶点，并表明RAS相互作用体中的其他蛋白可能类似地介导RAS肿瘤的发生。我将在三个目标中利用这些发现。由于PIP5K1A是一种可药物作用的激酶，它提供了一种特异性抑制KRAS肿瘤发生的方法，这可以被用来增强靶向RAS效应通路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也可能类似地介导RAS的功能。因此，在目标2中，我将挖掘RAS相互作用组以寻找RAS致癌的新修饰物，重点关注相互作用组蛋白EFR3A作为致癌RAS驱动的肿瘤发生的潜在一般介导物。最后，RAS互动组肯定是动态的，在不同的条件下是不同的。因此，在不同的环境下确定RAS互动组的内容可能会识别出针对不同细胞条件的新的脆弱性。因此，在目标3中，我将探索RAS互动组对细胞扰动的反应。总之，我将扩展我的发现，即PIP5K1A促进KRAS肿瘤发生，以探索该激酶作为新的治疗靶点，并确定存在于RAS相互作用体中的其他新的治疗脆弱性。这笔赠款的K99部分将完成我在RAS信号转导方面的培训，将我的培训扩展到磷酸蛋白质组学、异种移植和肿瘤发生的基因工程小鼠模型。R00片段将利用邻近标记来研究致癌RAS信号的动态性质。我的长期目标是过渡到一名独立的研究人员，并应用系统生物学方法来揭示癌基因驱动因素的信号电路，目的是识别RAS突变癌症的新的治疗脆弱性。

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.