Investigating metabolic adaptations of Myc-dependent cancers

项目摘要 癌细胞已经进化出特定的代谢程序来支持它们的生长和能量需求。 几十年前，奥托瓦尔堡描述了一种机制，癌细胞通过这种机制获得中间代谢物， 生物质在称为有氧糖酵解的过程中从葡萄糖转化。这种“瓦尔堡效应”表明癌细胞 即使在氧气存在下，也优先将葡萄糖转化为乳酸。虽然能源生产效率低下， 这一过程允许脂质、蛋白质和核苷酸中使用的代谢中间体的积累 合成.最近的发展表明，一种用于维持ATP生产的细胞机制， 活跃的增殖增加了谷氨酰胺进入TCA循环的流量（回补），这是一种现象， 在由癌基因Myc的扩增驱动的癌症中尤其占优势。这些肿瘤是如何在 限制谷氨酰胺的条件仍然未知。 该提案描述了一种无偏见的方法，旨在发现新的分子途径， 在谷氨酰胺耗尽的情况下，Myc驱动的癌细胞具有生长优势。Myc扩增的 细胞高度依赖谷氨酰胺以支持其生长的大量代谢需求， 增殖，以及减少氧化应激。谷氨酰胺耗竭对这些细胞具有高度毒性，这表明 为了生存，特定的种群必须发展独特的代谢适应。此外，毒品 目前正在进行临床试验。 预期这种靶向策略被证明是成功的，重要的是预测什么新的代谢 这些细胞可以响应于谷氨酰胺代谢抑制剂的长期处理而获得适应。 该提案旨在：首先，分析来自谷氨酰胺耗尽筛选策略的测序数据， 确认热门歌曲引人注目的是，在初步工作中，我们发现克隆不仅在谷氨酰胺中存活， 撤回，但也积极增殖，这表明这些细胞能够利用替代代谢 保持增长的途径。第二，将使用代谢方法对经验证的命中进行代谢表征， 通量分析和营养挑战，以确定已重新编程的关键代谢途径， 支持积极扩散。第三，这些途径将在离体和体内模型中进行研究 Myc驱动的癌症，以确定治疗开发的生理相关性和可行性。 这项提案的发现将增强对细胞代谢重编程的理解，以及它是如何影响细胞代谢的。 有助于肿瘤发生。这些适应性的识别不仅可以提供对以下问题的机械见解： 新的代谢途径尚未被确定为癌细胞中的关键适应性途径，但也可能导致 为Myc驱动的恶性肿瘤开发下一代代谢靶向疗法。

PROJECT SUMMARY Cancer cells have evolved specific metabolic programs to support their growth and energetic demands. Decades ago, Otto Warburg described a mechanism by which cancer cells obtain intermediate metabolites for biomass from glucose in a process termed aerobic glycolysis. This “Warburg effect” indicated that cancer cells preferentially convert glucose to lactate, even in the presence of oxygen. While inefficient in energy production, this process allows for the accumulation of metabolic intermediates used in lipid, protein, and nucleotide synthesis. Recent developments show that one cellular mechanism used to maintain ATP production during active proliferation is increasing the flux of glutamine into the TCA cycle (anaplerosis), a phenomenon particularly dominant in cancers driven by amplification of the oncogene Myc. How these tumors survive under conditions of limited glutamine remains unknown. This proposal describes an unbiased approach designed to discover novel molecular pathways that offer Myc-driven cancer cells a growth advantage, when challenged with glutamine depletion. Myc-amplified cells are highly dependent on glutamine in order to support their massive metabolic needs for growth and proliferation, as well as decrease oxidative stress. Glutamine depletion is highly toxic to these cells, suggesting that in order to survive, specific populations must develop unique metabolic adaptations. Furthermore, drugs intended to target glutamine metabolism for Myc-driven cancers are currently undergoing clinical trials. Anticipating that this targeting strategy proves successful, it is important to predict what novel metabolic adaptations these cells may acquire in response to prolonged treatment with glutamine metabolism inhibitors. This proposal aims to: First, analyze sequencing data from a glutamine-depleted screening strategy, and validate the top hits. Strikingly, in preliminary work we identified clones that not only survive glutamine withdrawal but also actively proliferate, suggesting that these cells are able to utilize alternative metabolic pathways to sustain growth. Second, validated hits will be metabolically characterized, using metabolic flux analyses and nutrient challenges to determine key metabolic pathways that have been reprogrammed to support active proliferation. Third, these pathways will be investigated in both ex vivo and in vivo models of Myc-driven cancer, to determine physiological relevance and feasibility of treatment development. This proposal's findings will enhance understanding of cellular metabolic reprogramming, and how it contributes to oncogenesis. Identification of these adaptations will not only provide mechanistic insights into novel metabolic pathways yet to be identified as key adaptive pathways in cancer cells, but could also lead to the development of the next generation of metabolism-targeted therapies for Myc-driven malignancies.