Hyperpolarized 13C probes for the one carbon metabolism

用于一碳代谢的超极化 13C 探针

• 批准号: 10647293
• 负责人: Zoltan Kovacs
• 金额: $ 45.1万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10647293
• 关键词: Adult; Anabolism; Attention; Back; Biochemical Pathway; Biological; Cancer Patient; Carbon; Cell Culture Techniques; Cell Proliferation; Cell physiology; Cells; Chemicals; Citric Acid Cycle; Communities; Cytoplasm; Cytosol; Development; Enzymes; Excretory function; Folic Acid; Formates; Funding; Generations; Glycine; Glycine Hydroxymethyltransferase; Glycolysis; Hematoma; Human; Image; In Vitro; Label; Magnetic Resonance Imaging; Malignant Neoplasms; Metabolic; Metabolism; Mitochondria; Monitor; Neoplasm Metastasis; Nuclear; Nucleotide Biosynthesis; Nucleotides; Organ; Oxidoreductase; Pathway interactions; Pattern; Phospholipids; Polyamines; Primary carcinoma of the liver cells; Process; Production; Prognosis; Proliferating; Rattus; Reaction; Relaxation; Role; Running; S-Adenosylhomocysteine; S-Adenosylmethionine; Serine; Signal Transduction; Source; Testing; Tetrahydrofolates; Time; Tissues; Tracer; Visualization; Warburg Effect; Xenograft procedure; cancer cell; cancer type; clinical translation; experience; hepatoma cell; imaging modality; in vivo; liver cancer model; magnetic resonance spectroscopic imaging; non-invasive imaging; nucleotide metabolism; overexpression; preservation; real time monitoring; tumor

Abstract One-carbon metabolism is a network of fundamental metabolic and biosynthetic pathways that occur in the cytoplasm and the mitochondria. Central to one-carbon metabolism is the folate cycle. This involves the activation and transfer of serine hydroxymethyl group to tetrahydrofolate intermediates and eventually formate, which is then converted back into serine to via the same intermediates. The folate cycle provides activated one carbon units for the biosynthesis of a variety of biomolecules necessary for normal cellular function and proliferation, most importantly, nucleotides. The activity of one-carbon metabolism is upregulated in cancer cells to support high rates of proliferation. The folate cycle is highly compartmentalized with separate sets of enzymes in the cytosol and in the mitochondria. When there is an increased need for one-carbon units for nucleotide biosynthesis, the cytosolic and mitochondrial folate cycles run in the opposite direction. The mitochondrial folate pathway produces formate, which is transported into the cytosol where it enters the folate cycle to produce activated one-carbon units for biosynthesis. In many types of cancer cells, the mitochondrial formate production exceeds the biosynthetic demand. Excess formate is excreted from these cells in a process known as formate overflow. Despite its great biological importance and central role in cancer, currently there is no clinically translatable, non–invasive imaging method for the real time monitoring of one carbon metabolism and formate overflow in vivo. In this R21 application we propose to use deuterated, 13C-labeled serines as hyperpolarized 13C-tracers to monitor one carbon metabolic activity and formate overflow in vivo by 13C magnetic resonance spectroscopic imaging. As serine is the main source of one carbon units, 13C-labeled serines are ideal probes for the mitochondrial folate cycle. Aim 1 will focus on the synthesis and in vitro characterization of deuterated, 13C-labeled serines as hyperpolarized 13C probes for the one carbon metabolism. In Aim 2, we will test the hyperpolarized probes in hepatoma cell cultures and in vivo in normal and orthotopic xenograft rat model for hepatocellular carcinoma. By the end of the two year funding period we expect to have demonstrated that upregulated mitochondrial folate pathway can be visualized in hepatoma bearing rats by 13C magnetic resonance spectroscopic imaging.

摘要 一碳代谢是一种基本的代谢和生物合成途径的网络，发生在 细胞质和线粒体。叶酸循环是一碳代谢的中心。这涉及到 丝氨酸羟甲基的活化和转移到四氢叶酸中间体并最终形成甲酸盐， 然后通过相同的中间体将其转化回丝氨酸。叶酸循环提供激活的叶酸循环 生物合成各种生物分子所需的碳单位，这些生物分子是正常细胞功能和 增殖，最重要的是，核苷酸。一碳代谢活性在癌症中上调 支持高增殖率的细胞。叶酸循环被高度分隔，由不同的 胞浆和线粒体中的酶。当对单碳单位的需求增加时 核苷酸生物合成时，胞质和线粒体的叶酸循环方向相反。这个 线粒体叶酸途径产生甲酸，甲酸被输送到细胞质，然后进入叶酸。 循环生产用于生物合成的活性单碳单元。在许多类型的癌细胞中，线粒体 甲酸盐产量超过生物合成需求。在一个过程中，过量的甲酸盐从这些细胞中排出。 称为甲酸盐溢出。尽管它具有巨大的生物学重要性和在癌症中的中心作用，但目前有 没有临床可翻译的、非侵入性的成像方法来实时监测一种碳代谢 甲酸盐在体内溢出。在这个R21应用中，我们建议使用氚，13C标记的丝氨酸作为 超极化~(13)C示踪剂监测~(13)C体内碳代谢活性和甲酸盐溢出 磁共振波谱成像。由于丝氨酸是一个碳单位的主要来源，13C标记 丝氨酸是线粒体叶酸循环的理想探针。目标1将重点放在合成和体外实验上 作为一碳超极化13C探针的~(13)H标记丝氨酸的表征 新陈代谢。在目标2中，我们将在肝癌细胞培养和正常体内测试超极化探针 和原位异种移植大鼠肝细胞癌模型。到两年资助期结束时，我们 除了已经证明，在肝癌中可以看到上调的线粒体叶酸途径 用~(13)C磁共振波谱成像方法测定大鼠的体重。