Prevention of COX-2 Derived DNA and Histone Modifications in Cancer

预防癌症中 COX-2 衍生的 DNA 和组蛋白修饰

基本信息

批准号：
9248194
负责人：
JOHN Alexander OATES
金额：
$ 15.85万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-04-01 至 2018-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9248194
关键词：
Accounting Address Amines Animal Model Biology Breast Cancer cell line Carcinogens Cell Nucleus Cells Cessation of life Chromosomal Instability Colon Colon Carcinoma Controlled Clinical Trials Cytidine DNA DNA Adducts DNA Methylation DNA Modification Process Deoxycytidine Development Dinoprostone Effectiveness Enzymes Epidemiologic Studies Epigenetic Process Epithelial Cells Event Evolution Genes Genomics Growth HMGA1 gene Health High Pressure Liquid Chromatography Histones Histopathology Human Intervention Investigation Lactams Lipid Peroxidation Lung Lysine Malignant - descriptor Malignant Neoplasms Malignant neoplasm of lung Malondialdehyde Metabolic Biotransformation Methods Modification Mus Mutagenesis Neoplasms Pancreas Prevention Prostaglandin D2 Prostaglandin-Endoperoxide Synthase Prostaglandins Protein Isoforms Proteins Pyrroles Research Sampling Series Structure Testing Thromboxane A2 Time Transcription Alteration Transgenic Mice Tumor Suppressor Genes Uterine Corpus Sarcoma Xenograft procedure adduct base cancer prevention carcinogenesis cyclooxygenase 2 histone modification in vivo inhibitor/antagonist insight ketoaldehyde malignant phenotype new technology novel novel strategies prevent stable isotope tool tumor tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): The hypothesis that highly reactive metabolites of the cyclooxygenase (COX) enzymes contribute to the COX-dependent growth of cancers will be examined in the proposed research. A concerted body of evidence indicates that the COXs contribute to the evolution of malignant neoplasms, and it includes findings from epidemiological studies and controlled clinical trials as well as investigations in animal models and cells. The inducible COX-2 isoform is expressed in many epithelial cell tumors, including those of the colon, lung, breast, and pancreas. The product of the COXs is prostaglandin H2 (PGH2) which undergoes cell specific enzymatic biotransformation to the prostaglandins D2, E2, F2a, I2, and thromboxane A2. All current research on the mechanism by which the COXs contribute to cancer addresses the actions of these enzymatically derived prostanoids. However, PGH2 also undergoes non-enzymatic rearrangement yielding the highly reactive -ketoaldehydes, levuglandins (LG) E2 and D2 as 20% of the total products. The LGs react almost instantaneously to form covalent adducts of primary amines. We have demonstrated that LGE2 forms a covalent adduct with deoxycytidine bases in DNA. The stable form of the adduct has been characterized as a pyrrole, and we have developed an HPLC/tandem mass spectrometric analysis for it, employing stable isotope dilution. This has permitted identification of COX-2 dependent formation of the LG-DNA adduct in two cancer cell lines. The formation of this bulky COX-derived covalent adduct suggests that it could engender mutagenesis and/or chromosomal instability. In addition to this modification of DNA, LG reacts with the epsilon-amine of lysine to form stable adducts with a lactam structure. COX-2 derived LG-histone adducts also have been identified in a human lung cancer cell line, raising the possibility of epigenetic alteration of the transcription of driver genes or tumor suppressor genes. We have developed a potent scavenger of LGs, ethyl-salicylamine, that prevents formation of LG adducts of DNA and histones but does not inhibit the COXs. It also scavenges other reactive carbonyls such as malondialdehyde which is a product of the cyclooxygenases and of lipid peroxidation. The proposed research will employ ethyl-salicylamine as a tool with which to address the hypothesis that modification of DNA and histone by reactive carbonyls such as LG and malondialdehyde contribute to the growth of COX-2 dependent cancers. The presence of these DNA and histone modifications in in vivo cancers as well as reduction of these modifications by ethyl-salicylamine will be determined to verify the efficacy of the pharmacologic intervention. COX-2 is associated with highly malignant cancers that result in >200,000 deaths annually in the US alone. Accordingly, understanding how it contributes to the evolution of malignancy is important.

描述（由申请人提供）：在拟议的研究中将检验环氧合酶（COX）的高反应性代谢物有助于 COX 依赖性癌症生长的假设。一致的证据表明 COX 有助于进化。它包括流行病学研究和对照临床试验以及动物模型和细胞研究的结果，诱导型 COX-2 亚型在许多细胞中表达。上皮细胞肿瘤，包括结肠、肺、乳腺和胰腺的肿瘤，COX 的产物是前列腺素 H2 (PGH2)，它经过细胞特异性酶促生物转化为前列腺素 D2、E2、F2a、I2 和血栓素 A2。目前关于 COX 导致癌症的机制的研究解决了这些酶促衍生的前列腺素的作用。然而，PGH2 也发生了变化。非酶重排产生高反应性的 β-酮醛、左旋糖醛素 (LG) E2 和 D2，占总产物的 20%。 LG 几乎立即反应形成伯胺的共价加合物。 DNA 中的脱氧胞苷碱基的加合物的稳定形式已被表征为吡咯，并且我们开发了一种采用稳定同位素稀释对其进行 HPLC/串联质谱分析，这使得可以在两种癌细胞系中鉴定出 COX-2 依赖性的 LG-DNA 加合物的形成。这种大的 COX 衍生的共价加合物的形成表明它可以。除了这种 DNA 修饰之外，LG 还与赖氨酸的ε-胺反应，形成具有内酰胺结构的稳定加合物。 COX-2 衍生的 LG-组蛋白加合物也在人肺癌细胞系中被发现，这提高了驱动基因或肿瘤抑制基因转录的表观遗传改变的可能性。我们开发了一种有效的 LG 清除剂，乙基水杨胺，它可以防止 DNA 和组蛋白形成 LG 加合物，但不会抑制 COX。它还能清除其他反应性羰基化合物，例如丙二醛的产物。拟议的研究将采用乙基水杨胺作为工具来解决 DNA 和组蛋白被 LG 和丙二醛等反应性羰基修饰导致 COX-2 依赖性癌症生长的假设。将测定体内癌症中这些 DNA 和组蛋白修饰的变化以及乙基水杨胺对这些修饰的减少，以验证药物干预的功效。 COX-2 与高度恶性的癌症相关，仅在美国每年就会导致超过 200,000 人死亡。因此，了解它如何促进恶性肿瘤的演变非常重要。