Identification of Metabolic Vulnerabilities of Ras-Driven Cancer Cells

描述(由申请人提供)：鉴定RAS驱动的癌细胞的代谢脆弱性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。与新陈代谢在癌症生长中的中心作用一致，新陈代谢改变是癌症的标志。最著名的例子是即使在氧气存在的情况下也能进行贪婪的葡萄糖发酵，即“沃堡效应”。最近，癌基因的一个主要功能是诱导代谢变化，包括Warburg效应，为生物合成提供底物和能量，从而使肿瘤生长。因此，癌细胞很容易受到代谢途径的干扰，因此有必要针对新陈代谢进行癌症治疗。RAS基因是癌症中最常见的突变癌基因之一，它们的突变激活导致了Warburg效应。与许多致癌信号蛋白不同的是，没有安全有效的RAS激活的药理抑制剂，这增加了了解RAS驱动的肿瘤代谢易感性的重要性。我们最近通过代谢组学和同位素示踪剂研究，研究了RAS激活对肿瘤细胞代谢的影响。这表明，RAS不仅诱导有氧糖酵解，而且减少葡萄糖和脂肪酸产生乙酰辅酶A，并增强TCA循环对谷氨酰胺的依赖，揭示了代谢的脆弱性。此外，我们发现RAS激活了自噬的分解代谢细胞的自我消化过程，自噬支持TCA循环代谢，激活了RAS的肿瘤细胞依赖自噬生存和肿瘤发生。因此，激活的RAS导致自噬成瘾，揭示了另一个代谢脆弱性。我们的统一假设是RAS减少了葡萄糖和脂肪酸对TCA循环的输入，创造了维持肿瘤细胞新陈代谢所需的谷氨酰胺和其他自噬提供的TCA循环底物。在这里，我们的目标是检验这一假说，并更全面地了解RAS诱导的代谢变化的潜在机制、共性以及开发它们的最佳方式。为此，我们将把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结合起来。这项研究的最终效果将是显著增加对癌基因信号和新陈代谢相互作用的理解，并通过这样做来确定RAS驱动的癌症的新治疗靶点。该项目是罗格斯大学的艾琳·怀特博士和普林斯顿大学的乔什·拉比诺维茨博士的实验室之间卓有成效的合作的直接延伸，此前由美国国立卫生研究院癌症新陈代谢挑战基金资助。 公共卫生相关性：50多年来，我们已经知道，正常细胞与癌细胞的一个主要区别特征是新陈代谢改变。直到最近才发现，癌基因的激活和抑癌基因的丢失重新编程新陈代谢，以产生新的肿瘤细胞和满足癌细胞生长所需的能量。致癌形式的RAS显著改变细胞代谢，促进肿瘤发生，并与不良预后相关。靶向RAS的治疗一直是困难的，需要采取方法来阻断RAS下游的途径，如代谢途径。我们建议使用最先进的质谱学和癌症模型来确定RAS如何改变新陈代谢。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.