Inhibition of UVB-induced COX-2 expression by apigenin

芹菜素抑制 UVB 诱导的 COX-2 表达

• 批准号: 7119019
• 负责人: JILL C. PELLING
• 金额: $ 28.17万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7119019
• 关键词: DNA binding protein; antineoplastics; carcinogenesis inhibitor; cell growth regulation; cell proliferation; chemoprevention; enzyme mechanism; flavonoids; gel mobility shift assay; genetically modified animals; hairless mouse; interleukin 6; keratinocyte; laboratory mouse; prostaglandin endoperoxide synthase; protein protein interaction; radiation carcinogenesis; radiation related neoplasm /cancer; receptor expression; skin neoplasms; tissue /cell culture; transcription factor; ultraviolet radiation; western blottings

DESCRIPTION (provided by applicant): Apigenin is a nonmutagenic bioflavonoid that inhibits UV-induced skin cancer when topically applied to mouse skin and we are currently investigating its molecular mechanism(s) of action. Recent results from our laboratory indicate that inhibition of the cyclooxygenase-2 (COX-2) pathway is one of the ways that apigenin exerts its chemopreventive effect. We have demonstrated that apigenin is a specific inhibitor of UV-induced cyclooxygenase-2 (COX-2) transcription in UV-induced keratinocytes. We have also obtained new evidence since the previous submission that UV-induction of COX-2 expression in keratinocytes requires the E-box and ATF/CRE transcription factor binding sites in the first 200 bases of the COX-2 promoter region, as well as demonstrating a role for the NF-IL6 site. These results suggest that one mechanism by which apigenin inhibits UV-induced skin carcinogenesis is by modulating the function of DNA binding proteins specific for these sites. Recent reports from other laboratories including our collaborator Dr. Aubrey Morrison indicate that COX-2 expression is regulated post-transcriptionally as well, by trans-acting factors which affect COX-2 mRNA stability and modulate translational efficiency. Therefore the hypothesis to be tested in this revised application is that one of the mechanisms by which the bioflavonoid apigenin inhibits UV-induced skin carcinogenesis is through modulation of transcriptional and post-transcriptional control of COX-2 expression. The following aims will test this hypothesis: In Aim #1we will continue our efforts to identify the DNA binding proteins in the COX-2 promoter required for UVB-induced COX-2 transcription and for inhibition by apigenin in keratinocytes and mouse epidermis in vivo. In Aim #2 we will investigate the mechanism by which apigenin treatment of keratinocytes modulates the function of the DNA binding proteins identified in Aim #1. In Aim #3 we will characterize the post-transcriptional control mechanisms which affect UVB-induced COX-2 expression in keratinocytes treated with apigenin, using regions of the COX-2 3'-UTR to investigate apigenin's ability to interfere with UV-induced mRNA stabilization and/or translational efficiency. In Aim #4 we will use SKH-1 mice and SKH-1 COX-2 null mice to confirm the ability of apigenin to block UVB-induced COX-2 expression and tumorigenesis in vivo.

描述（由申请方提供）：芹菜素是一种非致突变生物活性物质，局部应用于小鼠皮肤时可抑制UV诱导的皮肤癌，我们目前正在研究其分子作用机制。本实验室最近的研究结果表明，抑制环氧化酶-2（考克斯-2）途径是芹菜素发挥其化学预防作用的途径之一。我们已经证明，芹菜素是一个特定的抑制剂，紫外线诱导的环氧合酶-2（考克斯-2）在紫外线诱导的角质形成细胞的转录。我们还获得了新的证据，因为以前的提交，紫外线诱导的考克斯-2在角质形成细胞的表达需要在前200个碱基的考克斯-2启动子区域的E-box和ATF/CRE转录因子结合位点，以及证明了一个作用的NF-IL 6的网站。这些结果表明，芹菜素抑制紫外线诱导的皮肤癌发生的机制之一是通过调节这些网站的DNA结合蛋白的功能。包括我们的合作者奥布里莫里森博士在内的其他实验室最近的报告表明，考克斯-2的表达也是通过影响考克斯-2 mRNA稳定性和调节翻译效率的反式作用因子进行转录后调节的。因此，在该修改的申请中要检验的假设是，双甘草芹菜素抑制UV诱导的皮肤癌发生的机制之一是通过调节考克斯-2表达的转录和转录后控制。下面的目标将测试这一假设：在目标#1中，我们将继续我们的努力，以确定DNA结合蛋白的考克斯-2启动子所需的UVB诱导的考克斯-2转录和抑制芹菜素在角质形成细胞和小鼠表皮在体内。在目标#2中，我们将研究芹菜素处理角质形成细胞调节目标#1中鉴定的DNA结合蛋白的功能的机制。在目标#3中，我们将表征在用芹菜素处理的角质形成细胞中影响UVB诱导的考克斯-2表达的转录后控制机制，使用考克斯-2 3 '-UTR的区域来研究芹菜素干扰UV诱导的mRNA稳定化和/或翻译效率的能力。在目标#4中，我们将使用SKH-1小鼠和SKH-1考克斯-2缺失小鼠来证实芹菜素在体内阻断UVB诱导的考克斯-2表达和肿瘤发生的能力。