FDH: A Novel Determinant of Tumor Suppression

FDH：肿瘤抑制的新决定因素

基本信息

批准号：
8895055
负责人：
SERGEY A KRUPENKO
金额：
$ 24.09万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-12 至 2016-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8895055
关键词：
Actins Address Anabolism Apoptosis Apoptotic Binding Biochemical Reaction Cancer Biology Cancer cell line Carbon Cell Death Cell Survival Cell physiology Cells Complex Cytoplasm DHFR gene DNA DNA Repair Diagnostic Diet Disease Down-Regulation Enzyme Inhibitor Drugs Enzyme Inhibitors Enzymes Epidemiologic Studies Equilibrium Evaluation Folate Folic Acid Deficiency Formyltetrahydrofolates Genes Goals Growth Human Hypermethylation Impairment Investigation Kidney Knock-out Link Liver MAPK8 gene MAPK9 gene Malignant - descriptor Malignant Neoplasms Metabolic Metabolic Pathway Metabolism Methylation Molecular NADP Names Normal Cell Nucleotide Biosynthesis Onset of illness Oxidoreductase Pathway interactions Phosphorylation Physiological Preventive Process Protein p53 Proteins Publishing Purines RNA biosynthesis Reaction Regulation Resistance Role Signal Transduction Stream Stress Supplementation Susceptibility Gene Targeted Research Testing Tetrahydrofolates Transcriptional Activation Tumor Suppression Tumor Suppressor Proteins Tumor Tissue base cancer cell carcinogenesis cell motility cytotoxicity design folic acid metabolism in vivo insight mouse model mutant neoplastic cell novel promoter purine research study tumor tumor initiation tumorigenesis tumorigenic

项目摘要

ABSTRACT The overall goal of this proposal is to characterize the novel tumor suppressor activity of a key metabolic enzyme and determine the mechanisms transforming metabolic effects into regulation of proliferation. FDH (10-formyltetrahydrofolate dehydrogenase) irreversibly converts 10-formyltetrahydrofolate, an essential substrate for de novo purine biosynthesis, to tetrahydrofolate. Through depletion of this substrate, FDH can restrict purine biosynthesis. In turn, this interferes with important downstream cellular processes, including DNA/RNA biosynthesis and DNA repair. Because of this critical metabolic function, down-regulation of FDH in cancer cells was predicted to be pro-survival. Indeed, we have initially made the important observation that FDH is strongly and ubiquitously down-regulated in tumors through the promoter hypermethylation. We have further demonstrated that moderate FDH expression in FDH-deficient cancer cells induces apoptotic cell death. In contrast, non-cancer cells are insensitive to high levels of the enzyme. Therefore, it is proposed that cancer cells silence the FDH gene in order to escape cytotoxicity. Studies of phenotypic effects upon reactivation of normal FDH expression in FDH-deficient tumor cells have further explored JNK1/2 and p53 as key components of FDH-induced apoptotic signaling, and determined DHFR and folate supplementation as proliferation rescue factors. Importantly, a novel pathway linking FDH, through intracellular folate regulation, to control of cell motility, was discovered. The current proposal extends previous studies of antiproliferative mechanisms of FDH, and related folates, to direct interaction with p53 and evaluation of its role in vivo in mouse model. Our central hypothesis is that FDH down-regulation through promoter hypermethylation is one of the important means by which malignancies gain pro-survival advantage over normal cells. We further suggest that FDH exerts its regulatory effects through multiple mechanisms. The Specific Aims to probe these mechanisms and test our hypothesis are: (1) Investigate the functional interaction of FDH with p53 tumor suppressor protein in cytoplasm. (2) Determine the impact of FDH silencing on tumor initiation/progression using FDH deficient mouse model. Investigation of the critical role of FDH, in cancer cell survival/induction of folate stress at the onset of the disease, will provide important insight into the malignant process itself and link deregulation of key metabolic pathways to cancer disease, as well as establish new targets for diagnostics of the malignant transformation.

抽象的该提案的总体目标是表征关键代谢的新型肿瘤抑制活性酶并确定将代谢作用转化为增殖调节的机制。 FDH （10甲基四氢叶酸脱氢酶）不可逆转地转换10种基甲基四氢叶酸，这是必不可少的从头嘌呤生物合成的底物，至四氢叶酸。通过耗尽该基材，FDH可以限制嘌呤生物合成。反过来，这会干扰重要的下游蜂窝过程，包括 DNA/RNA生物合成和DNA修复。由于这种关键的代谢功能，FDH的下调预计癌细胞是促生存的。确实，我们最初已经做出了一个重要的观察结果 FDH通过启动子高甲基化在肿瘤中强烈而普遍下调。我们有进一步证明，FDH缺陷癌细胞中的中等FDH表达会诱导凋亡细胞死亡。相反，非癌细胞对高水平的酶不敏感。因此，有人提出癌细胞使FDH基因保持沉默，以避免细胞毒性。对表型影响的研究 FDH缺陷型肿瘤细胞中正常FDH表达的重新激活进一步探索了JNK1/2和p53 FDH诱导的凋亡信号的关键组成部分，并确定DHFR和叶酸补充为扩散救援因素。重要的是，通过细胞内叶酸调节将FDH连接起来的新型途径与发现了细胞运动的控制。当前的建议扩展了先前的抗增生性研究 FDH及相关叶酸的机制直接与p53的相互作用及其在体内的作用评估鼠标模型。我们的中心假设是，FDH通过启动子高甲基化的下调是恶性肿瘤优于正常细胞的重要手段。我们进一步建议 FDH通过多种机制发挥其调节作用。具体目的是探究这些机制和测试我们的假设是：（1）研究FDH与p53肿瘤的功能相互作用细胞质中抑制蛋白。（2）确定使用FDH沉默对使用肿瘤起始/进展的影响 FDH缺陷鼠标模型。研究FDH的关键作用，在叶酸的癌细胞存活/诱导中疾病开始时的压力将为恶性过程本身提供重要的见解并联系放松对癌症疾病的主要代谢途径的管制，以及为诊断的新目标建立恶性转化。