METABOLIC REGULATORS OF TUMOR CELL GROWTH

 描述(由申请人提供)：代谢重新编程被认为是恶性肿瘤的标志和新的治疗靶点的来源。然而，到目前为止，绝大多数关于肿瘤细胞代谢的知识都来自于对培养细胞系的研究，而不是完整的肿瘤。我们在该奖项前五年的工作表明，a)肿瘤细胞含有支持生存和增殖的多种代谢程序，有许多不同的三羧酸(TCA)循环的配置，受细胞内在和外在因素的组合调节；b)术中输注13C-葡萄糖和其他同位素标记的燃料可用于探测小鼠和人类完整肿瘤的新陈代谢；c)肿瘤细胞在培养和体内之间存在重要的代谢差异，表明需要改进体内分析技术；d)人类肺癌通过在体内氧化葡萄糖和各种其他底物来支持其生物能量；和e)术前MRI、FDG-PET和其他成像技术可用于预测肿瘤代谢的信息方面，并识别单个人类肺肿瘤内的代谢异质性区域。我们现在准备使用一种独特的和高度创新的方法组合来测试关于完整肿瘤在人类和小鼠体内代谢的假说，重点是体内代谢异质性的驱动因素。我们提出了三个具体目标来解决非小细胞肺癌(NSCLC)的这些问题，非小细胞肺癌是全球最常见的癌症相关死亡原因。在目标1中，我们将实施一种新的技术来获得13C的质谱学位置归属。这将使我们能够最大限度地增加从非常小的样本中获得的信息量，可能只有标准方法目前所需碎片大小的1%。这将极大地增强我们在体内绘制单个肿瘤内区域代谢异质性的能力。在目标2中，我们将使用术前成像、13C注射和代谢组学来检查完整肿瘤中葡萄糖和其他燃料的代谢。我们将确定组织灌注如何改变患者的营养偏好 活体实验，并验证TCA循环中葡萄糖氧化增强是肿瘤细胞增殖的特殊标志这一假说。这一目标将使用来自NSCLC细胞系的异种移植，来自患者的NSCLC异种移植，以及一项以在人类NSCLC患者中术中输注13C为特色的临床研究。在目标3中，我们将测试一种假设，即乳酸是一种丰富的循环燃料，长期以来被认为是肿瘤新陈代谢的废物，在灌注度较高的NSCLC肿瘤中也被用作TCA循环的燃料来源。我们将使用13C标记的乳酸输注来识别和定位完整的人类和小鼠肿瘤中乳酸的利用途径。总之，这些目标将产生对非小细胞肺癌新陈代谢的独特看法，具有前所未有的详细程度、生物学准确性和与人类疾病的相关性。他们有可能在癌症的代谢调节和异质性方面建立新的范例，并预测哪些肿瘤对代谢治疗有反应。

 DESCRIPTION (provided by applicant): Metabolic reprogramming is considered to be a hallmark of malignancy and source of novel therapeutic targets. However, the vast majority of knowledge so far established for tumor cell metabolism is derived from studies in cultured cell lines rather than intact tumors. Our work over the previous five years of this Award demonstrated that a) tumor cells contain a diversity of metabolic programs to support survival and proliferation, with many distinct configurations of the tricarboxylic acid (TCA) cycle regulate by combinations of cell-intrinsic and extrinsic factors; b) intra-operative infusions of 13C-glucos and other isotope-labeled fuels can be used to probe the metabolism of intact tumors in mice and humans; c) important metabolic differences exist between tumor cells in culture and in vivo, indicating a need to improve techniques for in vivo analysis, particularly in humans; d) human lung tumors support their bioenergetics by oxidizing glucose and a variety of other substrates in vivo; and e) pre-operative MRI, FDG-PET and other imaging techniques can be used to predict informative aspects of tumor metabolism and identify areas of metabolic heterogeneity within individual human lung tumors. We are now poised to use a unique and highly innovative combination of approaches to test hypotheses about the metabolism of intact tumors in humans and mice, focusing on the drivers of metabolic heterogeneity in vivo. We propose three Specific Aims to address these issues in non-small cell lung cancer (NSCLC), the most common cause of cancer-related deaths worldwide. In Aim 1, we will implement a novel technique to derive positional assignment of 13C by mass spectrometry. This will enable us to maximize the information content derived from very small samples, potentially as little as 1% the size of fragments currently required by standard approaches. This will greatly enhance our ability to map regional metabolic heterogeneity within individual tumors in vivo. In Aim 2, we will use pre-surgical imaging, 13C infusions and metabolomics to examine the metabolism of glucose and other fuels in intact tumors. We will determine how tissue perfusion alters nutrient preferences in vivo and test the hypothesis that enhanced glucose oxidation in the TCA cycle is a specific hallmark of proliferating tumor cells. This aim will use xenografts derived from NSCLC cell lines, patient-derived NSCLC xenografts, and a clinical study featuring intra-operative 13C infusions in human NSCLC patients. In Aim 3, we will test the hypothesis that lactate, an abundant circulating fuel long considered a waste product of tumor metabolism, is also used as a fuel source for the TCA cycle in a subset of well-perfused NSCLC tumors. We will use infusions of 13C-labeled lactate to identify and localize pathways of lactate utilization within intact tumors i humans and mice. Altogether, these Aims will generate a unique view of NSCLC metabolism with an unprecedented level of detail, biological accuracy and relevance to human disease. They have the potential to establish new paradigms in metabolic regulation and heterogeneity in cancer and in predicting which tumors will respond to metabolic therapies.