GENISTEIN AS MODULATOR OF ANTIOXIDANT PROTEIN EXPRESSION

染料木黄酮作为抗氧化蛋白表达的调节剂

• 批准号: 6177791
• 负责人: SHIU-MING KUO
• 金额: $ 16.24万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6177791
• 关键词: antioxidants; cadmium; cancer prevention; copper; dietary constituent; dietary supplements; gene expression; gene interaction; genetic transcription; genetically modified animals; genistein; interleukin 6; intestines; laboratory mouse; messenger RNA; metallothionein; nutrient interaction; nutrition aspect of cancer; nutrition related tag; phorbols; protein kinase C; soybeans; tissue /cell culture; western blottings; zinc

Flavonoids represent a family of phytochemicals found in many human food items. Among them, genistein (Gn) is found especially at high concentration in soybeans, an important element of Oriental diet. Epidemiological studies, in vivo animal studies and in vitro cell studies all suggested that Gn could play a role in the prevention of cancer. More work at the molecular level is needed to define the mechanism. This proposal addresses one potential mechanism: the ability of Gn to increase the expression of an antioxidant protein, metallothionein (MT). We have found that Gn increased the levels of MT protein and mRNA in human intestinal cells, Caco-2. The induction was synergistic with the stimulatory effect of zinc. Based on these observations, the proposal is designed to determine the physiological significance of MT induction; and the mode of Gn-MT gene interaction. We will compare the level of oxidative byproduct after tert- butylhydroperoxide challenge in cells with and without Gn treatment. In addition, animal study will be conducted to show that Gn feeding leads to an increase in the organ MT level and a decrease in the organ oxidative byproduct level. The mode of Gn-MT gene interaction will be investigated indirectly through the combination treatment of cells with Gn and other inducers of MT expression like copper, cadmium or cytokines. We will also perform nuclear run-on experiment and mRNA stability analysis in cells to directly confirm the effect of Gn at the transcriptional level. Reporter gene assays will then be conducted to determine the site of Gn-MT gene interaction on the cloned sequence of human MTIIA promoter. The results from the proposed studies will help to assess the essentiality of Gn in the human diet for reduction of cancer risk. These studies may also lead to the identification of a previous unknown pathway for Gn to regulate mammalian genes.

类黄酮类代表了在许多人类食物中发现的一类植物化学物质。其中，染料木素(Gn)在大豆中的含量特别高，是东方饮食中的重要元素。流行病学研究、体内动物研究和体外细胞研究都表明，Gn可能在预防癌症中发挥作用。需要在分子水平上进行更多的工作来确定这一机制。这项建议解决了一个潜在的机制：Gn增加抗氧化蛋白金属硫蛋白(MT)的表达的能力。我们发现Gn增加了人肠道细胞Caco-2中MT蛋白和mRNA的水平。锌的诱导作用与锌的刺激作用具有协同作用。基于这些观察结果，本研究旨在确定MT诱导的生理意义以及Gn-MT基因相互作用的方式。我们将比较有和没有Gn处理的细胞在叔丁基氢过氧化氢挑战后的氧化副产物水平。此外，还将进行动物研究，以表明Gn喂养会导致器官MT水平增加，器官氧化副产物水平降低。通过Gn和铜、镉或细胞因子等其他MT表达诱导剂联合处理细胞，间接研究Gn-MT基因相互作用的方式。我们还将在细胞内进行核跑动实验和mRNA稳定性分析，以直接在转录水平上证实Gn的作用。然后进行报告基因分析，以确定Gn-MT基因在克隆的人MTIIA启动子序列上的相互作用位置。拟议研究的结果将有助于评估人类饮食中Gn对降低癌症风险的重要性。这些研究也可能导致以前未知的Gn调节哺乳动物基因的途径的确定。