Identification of Metabolic Vulnerabilities of Ras-Driven Cancer Cells

描述（由申请人提供）：Ras驱动的癌细胞的代谢脆弱性的鉴定肿瘤生长需要蛋白质、DNA、RNA和膜的生物合成。细胞代谢为这种生物合成提供底物和能量。与代谢在癌症生长中的中心作用一致，代谢改变是癌症的标志。最著名的例子是即使在氧气存在下也能进行强烈的葡萄糖发酵，即，“瓦尔堡效应”。最近，已经清楚的是，癌基因的主要功能是诱导代谢变化，包括瓦尔堡效应，以提供生物合成的底物和能量，使肿瘤生长。因此，癌细胞易受代谢途径的干扰，因此需要靶向代谢用于癌症治疗。Ras基因是癌症中最常突变的癌基因之一，其突变激活诱导瓦尔堡效应。与许多致癌信号蛋白不同，没有安全有效的激活Ras的药理学抑制剂，这增加了了解Ras驱动肿瘤的代谢脆弱性的重要性。我们最近通过代谢组学和同位素示踪研究研究了肿瘤细胞中Ras激活的代谢后果。这表明Ras不仅诱导有氧糖酵解，而且减少葡萄糖和脂肪酸的乙酰辅酶A产生，并增强TCA循环对谷氨酰胺的依赖性，揭示了代谢脆弱性。此外，我们发现Ras激活自噬的分解代谢细胞自我消化过程，自噬维持TCA循环代谢，并且具有激活Ras的肿瘤细胞依赖于自噬来存活和肿瘤发生。因此，激活的Ras导致自噬成瘾，揭示了另一种代谢脆弱性。我们的统一假设是Ras减少了从葡萄糖和脂肪酸进入TCA循环的输入，产生了对谷氨酰胺和其他自噬提供的TCA循环底物的需求，以维持肿瘤细胞的代谢。在这里，我们的目标是测试这一假设，并更全面地了解潜在的机制，Ras诱导的代谢改变的一般性以及利用它们的最佳方法。为此，我们将联合收割机最先进的代谢组学与Ras或下游激酶Akt和Raf驱动的体外和体内癌症模型相结合。这项研究的净效应将是极大地增加对癌基因信号传导和代谢相互作用的理解，并在此过程中为Ras驱动的癌症确定新的治疗靶点。该项目是Eileen白色博士（罗格斯大学）和Josh Rabinowitz博士（普林斯顿大学）实验室之间非常富有成效的合作的直接延伸，此前由NIH癌症代谢挑战基金资助。 公共卫生相关性：50多年来，我们已经知道区分正常细胞和癌细胞的一个主要特征是新陈代谢的改变。直到最近才变得清楚，癌基因的激活和肿瘤抑制基因的丢失重新编程代谢，以产生用于产生新肿瘤细胞的构建模块，并满足癌细胞生长的能量需求。Ras的致癌形式显著改变细胞代谢，促进肿瘤发生并与不良预后相关。在治疗上靶向Ras一直很困难，需要采取方法来阻断Ras下游的途径，例如代谢途径。我们建议使用最先进的质谱和癌症模型来确定Ras如何改变代谢。这将暴露出在开发新的癌症疗法时可以利用的漏洞。

DESCRIPTION (provided by applicant): Identification of Metabolic Vulnerabilities of Ras-Driven Cancer Cells Tumor growth requires biosynthesis of protein, DNA, RNA, and membrane. Cellular metabolism provides the substrates and energy for this biosynthesis. Consistent with the central role of metabolism in cancer growth, altered metabolism is a hallmark of cancer. The best-known example is avid glucose fermentation even in the presence of oxygen, i.e., the "Warburg effect". Recently, it has become clear that a major function of oncogenes is to induce metabolic changes, including the Warburg effect, to provide substrates and energy for biosynthesis that enables tumor growth. Thus cancer cells are vulnerable to interference in metabolic pathways, hence the need to target metabolism for cancer therapy. Ras genes are among the most frequently mutated oncogenes in cancer, and their mutational activation induces the Warburg effect. Unlike for many oncogenic signaling proteins, there are no safe and effective pharmacological inhibitors of activated Ras, increasing the importance of understanding metabolic vulnerabilities of Ras-driven tumors. We have recently examined the metabolic consequences of Ras activation in tumor cells via metabolomics and isotope-tracer studies. This revealed that Ras not only induces aerobic glycolysis, but also decreases acetyl-CoA production from glucose and fatty acids, and enhances dependence of the TCA cycle on glutamine, revealing a metabolic vulnerability. Moreover, we found that Ras activates the catabolic cellular self-digestion process of autophagy, that autophagy sustains TCA cycle metabolism, and that tumor cells with activated Ras are dependent on autophagy for survival and tumorigenesis. Thus, activated Ras leads to autophagy addiction, revealing another metabolic vulnerability. Our unifying hypothesis is that Ras decreases input into the TCA cycle from glucose and fatty acids, creating the requirement for glutamine and other autophagy-supplied TCA cycle substrates to sustain tumor cell metabolism. Here we aim to test this hypothesis and understand more comprehensively the underlying mechanisms, generality of the metabolic alterations induced by Ras and the best ways to exploit them. To this end we will combine state-of-the-art metabolomics with in vitro and in vivo cancer models driven by Ras or the downstream kinases Akt and Raf. The net effect of this research will be to dramatically increase understanding of the interplay of oncogene signaling and metabolism, and in so doing to identify new therapeutic targets for Ras-driven cancers. This project is a direct extension of the very productive collaboration between the laboratories of Dr. Eileen White (Rutgers University) and Dr. Josh Rabinowitz (Princeton University) previously funded by a NIH Challenge Grant on cancer metabolism. PUBLIC HEALTH RELEVANCE: We have known for over 50 years that a major feature that distinguishes normal cells from cancer cells is altered metabolism. Only recently has it become clear that activation of oncogenes and loss of tumor suppressor genes reprograms metabolism to generate the building blocks for production of new tumor cells and to meet the energy requirements for cancer cell growth. Oncogenic forms of Ras dramatically alter cellular metabolism, promote tumorigenesis and are associated with poor prognosis. Targeting Ras therapeutically has been difficult, necessitating approaches to block pathways, such as metabolic pathways, downstream of Ras. We propose to use state-of-the-art mass spectrometry and cancer models to determine how Ras alters metabolism. This will expose vulnerabilities that can be exploited in the development of new cancer therapies.