Biology of Single Activity PGH Synthases

单活性 PGH 合成酶的生物学

• 批准号: 6636654
• 负责人: COLIN D. FUNK
• 金额: $ 27.69万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6636654
• 关键词: binding sites; chemical carcinogen; chemical carcinogenesis; drug metabolism; embryonic stem cell; enzyme activity; enzyme mechanism; gene targeting; genetic strain; isozymes; laboratory mouse; nonsteroidal antiinflammatory agent; prostaglandin endoperoxide synthase; binding sites; chemical carcinogen; chemical carcinogenesis; drug metabolism; embryonic stem cell; enzyme activity; enzyme mechanism; gene targeting; genetic strain; isozymes; laboratory mouse; nonsteroidal antiinflammatory agent; prostaglandin endoperoxide synthase

DESCRIPTION(adapted from applicant's abstract): Prostaglandin H synthase-1 (PGHS-1) is the key enzyme in the biosynthesis of prostaglandins, homeostatic lipid mediators in the cardiovascular, gastrointestinal, renal and other organ systems. PGHS-2, on the other hand, is a separate gene product, is highly regulated, inducible and is regarded as the form involved in cancer and inflammation. While the simplistic viewpoint of "housekeeping" PGHS-l vs "inducible, pro-inflammatory" PGHS-2 is practical, data is emerging that is not entirely consistent with this hypothesis. PGHS isozymes are bifunctional, with a cyclooxygenase (COX) activity and a functionally linked peroxidase (POX) activity. Non-steroidal antiinflammatory drugs (NSAIDs) act by inhibition of the COX activity, leaving POX activity intact. Substantial data, primarily from in vitro model systems, has implicated the POX component of PGHS in the metabolic activation of xenobiotics and other non-prostaglandin related activities. The main objective of this proposal is to delineate the distinct functions of the COX and POX activities of the PGHS isozymes in carcinogenesis and inflammation using mice with induced mutations created by gene targeting in embryonic stem cells. In Aim 1, COX gene-disrupted mice will be generated by mutation of the aspirin-binding site (serine 530 to asparagine or glutamine), while POX gene-disrupted mice will be created via mutation of the proximal heme ligand (histidine 388 to tyrosine) in Aim 3. The involvement of PGHS POX in the metabolic activation of the nitrofuran compound FANFT, a potent urinary bladder carcinogen, will be analyzed by examination of tumor formation in the mutant mice. Also, the effects of separate COX and POX ablation on skin carcinogenesis using the two-stage DMBA/phorbol ester initiation/promotion protocol and models of inflammation will be assessed in Aims 2 and 4. The COX-disrupted mice, in essence, are perfect in vivo models for complete and selective PGHS-1 arid PGHS-2 inhibition and will be invaluable for studying non-PGHS dependent actions of NSAIDs. Results obtained from this proposal should have broad implications for understanding mechanisms of human cancer and inflammatory disease.

描述（改编自申请人的摘要）：前列腺素H Synthase-1 （PGHS-1）是前列腺素生物合成的关键酶，稳态 心血管，胃肠道，肾脏和其他器官中的脂质介质 系统。另一方面，PGHS-2是一个单独的基因产品，是高度的 受监管，可诱导，被认为是参与癌症的形式， 炎。虽然“家政” PGHS-L与 “诱导，促炎” PGHS-2是实用的，数据正在出现不是 完全与这一假设一致。 PGHS同工酶是双功能，有 环氧酶（COX）活性和功能连接的过氧化物酶（POX） 活动。非甾体类抗炎药（NSAIDS）通过抑制 Cox活性，使POX活性完好无损。实质数据，主要来自 体外模型系统已将PGH的POX成分牵涉到 异种生物的代谢激活和其他与非局素蛋白有关 活动。该提议的主要目的是描述独特的 PGHS同工酶在致癌作用中的COX和POX活性的功能 和使用小鼠具有基因靶向产生的诱导突变的炎症 胚胎干细胞。在AIM 1中，Cox基因干扰小鼠将由 阿司匹林结合位点的突变（丝氨酸530至天冬酰胺或谷氨酰胺）， 虽然将通过近端血红素的突变创建痘痘基因中断的小鼠 AIM 3中的配体（组氨酸388对酪氨酸）。 硝基呋喃复合扇形的代谢激活，这是一种有效的膀胱 致癌物将通过检查突变体中的肿瘤形成来分析 老鼠。另外，单独的Cox和Pox消融对皮肤致癌的影响 使用两阶段DMBA/Phorbol酯的启动/促销协议和模型 炎症将在目标2和4中评估。 本质是完整和选择性PGHS-1干旱的体内模型的完美模型 PGHS-2抑制作用，对于研究非PGH的抑制作用是无价的 NSAID的行动。从该提案中获得的结果应具有广泛的 对理解人类癌症和炎症机制的影响 疾病。