PHOSPHOMONOESTER METABOLISM IN TUMOR CELLS

肿瘤细胞中的磷酸单酯代谢

• 批准号: 2099510
• 负责人: Robert J. Gillies
• 金额: $ 23.65万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-03-01 至 1998-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2099510
• 关键词: amines; animal tissue; breast neoplasms; cell growth regulation; cell type; chemical kinetics; glioma; high performance liquid chromatography; human tissue; nuclear magnetic resonance spectroscopy; phosphatidylethanolamines; phosphoric ester; phosphorus metabolism; phosphorylcholine; protein isoforms; radiotracer; tissue /cell culture

31P Magnetic Resonance Spectroscopy (MRS) of tissues in vivo has revealed that phospho-monoesters (PMEs), in particular phosphorylcholine (PCho) and phosphorylethanolamine (PEth), are usually higher in proliferating tissues (e.g. tumors) than in non-proliferating normal tissues. There is considerable excitement about the use of these resonances as markers for tumor staging and therapeutic efficacy. Radiodiagnostic use of these resonances requires a more solid understanding of the factors and mechanisms regulating their metabolism. Most work to date has investigated these compounds vis-a-vis their roles in phospholipid synthesis. Consequently, phosphomonoesters themselves have not been greatly studied. In vitro, we and others have observed that the levels of PCho and PEth vary with culture density, perfusion and proliferation, suggesting that PME levels are influenced by both the extrinsic availability of substrates and by intrinsic differences between cell type and proliferative status. We hypothesize that the rate-limiting step(s) in PCho and PEth metabolism will vary between cell type and with proliferative status and that, in some cases more than one step may be involved (e.g. synthesis, diffusion, transport and phosphorylation of precursor amines, as well as the utilization of the PMEs in phospholipid synthesis). Defining the regulation of PME metabolism in a predictive model will allow PCho and PEth levels to be useful in determining the physiology and the environment of tumor cells in vivo. We propose to characterize the behavior and biochemistry of PCho and PEth in rat gliomas and human breast cancer cells grown in vitro and in vivo. These cell types were chosen because of their clinical importance and because previous work using these cell lines in our laboratory has indicated that they regulate their PME levels differently. Understanding the mechanism(s) behind these different phenotypes will help us understand the regulation of PME levels in vivo. The regulation of PME levels will be characterized using a combination of 31P MRS, 13C MRS and radiolabel techniques. 31P MRS will be used to assess the effects of exogenous amines and proliferation on steady-state PME levels, 13C MRS will identify the pathways of PME metabolism, and radiolabels will be used to quantify the kinetics of the PME-metabolizing pathways. These data will be used to identify the factors regulating PME metabolism and to develop a general model for PME metabolism in vivo. This project will test these models by comparing the behavior of PMEs in vitro to the same cells grown in vivo.

体内组织的31P磁共振波谱（MRS）揭示了 磷酸单酯（PME），特别是磷酸胆碱（PCo）和 磷酸乙醇胺（PEth）通常在增殖组织中较高 (e.g.肿瘤）比非增殖的正常组织中的多。 有 相当兴奋的使用这些共振作为标记， 肿瘤分期和治疗效果。 放射诊断使用这些 共振需要对因素有更扎实的理解， 调节其新陈代谢的机制。 迄今为止，大多数工作 研究了这些化合物在磷脂中的作用 合成. 因此，磷酸单酯本身还没有被 研究得很深。 在体外，我们和其他人已经观察到， PCo和PEth随培养密度、灌注和增殖而变化， 这表明PME水平受到两种外在因素的影响 底物的可用性和细胞类型之间的内在差异 和增殖状态。 我们假设限速步骤 在PCho和PEth代谢中，细胞类型之间会有变化， 增殖状态，并且在某些情况下，可以是多于一个步骤， 参与（例如合成，扩散，运输和磷酸化） 前体胺，以及利用的PMEs在磷脂 合成）。 在一个预测性模型中定义PME代谢的调节 模型将允许PCho和PEth水平在确定 生理学和体内肿瘤细胞的环境。 我们建议表征PCho和PEth的行为和生物化学 在体外和体内生长的大鼠胶质瘤和人类乳腺癌细胞中。 选择这些细胞类型是因为它们的临床重要性， 因为之前在我们实验室使用这些细胞系的工作 表明它们调节PME水平的方式不同。 理解 这些不同表型背后的机制将帮助我们理解 体内PME水平的调节。 PME水平的监管将 使用31 P MRS、13 C MRS和放射性标记的组合进行表征 技术. 31P MRS将用于评估外源性 胺和增殖的稳态PME水平，13 C MRS将确定 PME代谢途径和放射性标记将用于定量 PME代谢途径的动力学。 这些数据将用于 确定调节PME代谢的因素，并制定一个通用的 体内PME代谢模型。 本项目将通过以下方式测试这些模型： 将体外PME的行为与体内生长的相同细胞进行比较。