Colonic Cytokinetics and Cell Signaling: Dietary Effects

结肠细胞动力学和细胞信号传导：饮食影响

• 批准号: 8212304
• 负责人: Robert Stephen Chapkin
• 金额: $ 25.61万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-23 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8212304
• 关键词: Address; Adjuvant Therapy; Adopted; Adverse effects; Anti-Inflammatory Agents; Anti-inflammatory; Antioxidants; Apoptosis; Apoptotic; Arachidonic Acids; Attenuated; Azoxymethane; Binding; Butyrates; Cardiolipins; Caveolae; Cell Death Signaling Process; Cell Line; Chemoprotective Agent; Clinical; Cohort Studies; Colon; Colon Carcinoma; Colonic Neoplasms; Colorectal Adenoma; Colorectal Cancer; Consumption; Counseling; Coxibs; Data; Development; Diet; Dietary Fats; Dietary Fiber; Dinoprostone; Docosahexaenoic Acids; EP4 receptor; Eicosapentaenoic Acid; Epidemiologic Studies; Epidemiology; Epidermal Growth Factor Receptor; Experimental Models; Failure; Fatty Acids; Fatty acid glycerol esters; Fermentation; Fiber; Fish Oils; Funding; Future; Goals; Guanine Nucleotides; Human; Hydrogen Peroxide; In Vitro; Laboratories; Linoleic Acids; Lipids; Literature; Malignant - descriptor; Mediating; Membrane; Membrane Lipids; Membrane Microdomains; Mitochondria; Molecular; Molecular Mechanisms of Action; Molecular Target; Morphology; Mus; Nutrient; Nutritional; Observational Study; Oncogenic; Outcome; Oxygen; PTEN gene; Patients; Pectins; Permeability; Pharmaceutical Preparations; Phospholipids; Play; Polyunsaturated Fatty Acids; Property; Prostaglandin-Endoperoxide Synthase; Prostaglandins E; Proteins; Proto-Oncogene Proteins c-akt; Receptor Signaling; Role; SOD2 gene; Series; Signal Transduction; Signaling Protein; Stress; Structure; Superoxide Dismutase; Surface; Testing; Time; Transgenic Mice; Work; bioactive food component; cancer prevention; cancer risk; dosage; eicosanoid metabolism; extracellular; in vivo; mitochondrial membrane; mouse model; novel; oxidation; palmitoylation; prospective; prostaglandin E3; prostaglandin EP2 receptor; protective effect; protein transport; ras Proteins; receptor; segregation; systematic review; tumorigenesis

DESCRIPTION (provided by applicant): There are cogent data indicating a protective effect of n-3 polyunsaturated fatty acids (PUFA) e.g., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on colon cancer. In contrast, dietary lipids rich in n-6 PUFA, e.g., linoleic acid (LA) and arachidonic acid (AA), enhance the development of colon tumors. This is significant because the typical Western diet contains 10 to 20 times more n-6 than n-3 PUFA. Unfortunately, to date, a unifying mechanistic hypothesis addressing why n-3 PUFA selectively suppress colon cancer compared to n-6 PUFA (the major dietary form of PUFA in the U.S. diet) is lacking. In the current funding period, we demonstrated that (i) dietary n-3 PUFA induce perturbations in colonocyte membrane microdomain (caveolae) lipid composition, suppressing oncogenic signaling and Ras protein trafficking; (ii) n-3 PUFA supplant arachidonic acid (AA) in colonocyte membrane phospholipids, with EPA in particular being metabolized into a novel 3-series E-prostaglandin (PGE3), a putative antitumorigenic-cyclooxygenase (COX) metabolite; and (iii) the proapoptotic- chemoprotective effect of n-3 PUFA is enhanced when a highly fermentable fiber, pectin (or its fermentation product-butyrate) is added to the diet. We postulate that the failure to address an interaction between dietary fat and fiber may explain why the chemoprotective effects of fiber are obscured in prospective cohort studies. Therefore, the overall goal of this proposal is to further elucidate how dietary n-3 PUFA and fermentable fiber up-regulate apoptosis effector mechanisms in colonocytes, thereby reducing colon cancer risk. An array of experimental models will be used, including in vivo (azoxymethane-injected oxidatively stressed SOD2+/-, Gpx4+/- knock outs, Gpx4Tg and fat-1 transgenic mouse models) and in vitro (normal and malignant transformed mouse and human colonocyte cell lines) in order to test our primary hypothesis that n-3 PUFA and butyrate work in a coordinated manner to potentiate mitochondrial-mediated apoptosis. As a complementary hypothesis, we propose that DHA and possibly EPA alter colonocyte membrane lipid microdomain composition, thereby favorably modulating eicosanoid metabolism and the relay of extracellular signals from surface receptors to downstream signaling networks. The following specific aims are proposed: Aim #1 will determine the mechanisms by which n-3 PUFA and butyrate interaction modulate intrinsic (mitochondria-mediated) cell death signaling in the colon; Aim #2 will determine the mechanisms by which n-3 PUFA alter the spatio-temporal segregation of Ras-dependent signals; and Aim #3 will characterize the putative chemoprotective properties of a novel EPA-derived cyclooxygenase product, PGE3. The consumption of EPA and DHA may prove an effective adjuvant therapy in colon cancer. Therefore, it is both appropriate and timely to determine precisely how n-3 PUFA modulate cell signaling networks and reduce colon cancer risk.A growing body of literature supports the contention that bioactive food components containing n-3 polyunsaturated fatty acids (PUFA) are important in suppressing colon cancer. Consistent with the objectives and scope of PA-07-100, Prioritizing molecular targets for cancer prevention with nutritional combinations , the overall goal of this proposal is to elucidate how dietary n-3 PUFA and fermentable fiber up-regulate apoptosis effector mechanisms in colonocytes, thereby reducing colon cancer risk.

描述（由申请人提供）： 有确凿的数据表明 n-3 多不饱和脂肪酸 (PUFA) 例如二十碳五烯酸 (EPA) 和二十二碳六烯酸 (DHA) 对结肠癌具有保护作用。相比之下，富含n-6 PUFA（例如亚油酸（LA）和花生四烯酸（AA））的饮食脂质会促进结肠肿瘤的发展。这一点很重要，因为典型的西方饮食中 n-6 多不饱和脂肪酸含量是 n-3 多不饱和脂肪酸的 10 到 20 倍。不幸的是，迄今为止，还缺乏一个统一的机制假说来解释为什么与 n-6 PUFA（美国饮食中 PUFA 的主要膳食形式）相比，n-3 PUFA 选择性抑制结肠癌。在当前资助期间，我们证明了（i）膳食 n-3 PUFA 会引起结肠细胞膜微区（小凹）脂质成分的扰动，抑制致癌信号传导和 Ras 蛋白运输； (ii) n-3 PUFA 取代结肠细胞膜磷脂中的花生四烯酸 (AA)，特别是 EPA 被代谢为新型 3 系列 E-前列腺素 (PGE3)，一种推定的抗肿瘤环加氧酶 (COX) 代谢物； (iii) 当在饮食中添加高度可发酵纤维果胶（或其发酵产物丁酸盐）时，n-3 PUFA 的促细胞凋亡化学保护作用会增强。我们假设，未能解决膳食脂肪和纤维之间的相互作用可能可以解释为什么纤维的化学保护作用在前瞻性队列研究中被掩盖。因此，该提案的总体目标是进一步阐明膳食n-3 PUFA和可发酵纤维如何上调结肠细胞凋亡效应机制，从而降低结肠癌风险。将使用一系列实验模型，包括体内（注射偶氮甲烷的氧化应激 SOD2+/-、Gpx4+/- 敲除、Gpx4Tg 和 fat-1 转基因小鼠模型）和体外（正常和恶性转化小鼠和人类结肠细胞系），以测试我们的主要假设，即 n-3 PUFA 和丁酸盐以协调方式发挥作用，以增强 线粒体介导的细胞凋亡。作为补充假设，我们提出 DHA 和可能的 EPA 改变结肠细胞膜脂质微区组成，从而有利地调节类二十烷酸代谢和细胞外信号从表面受体到下游信号网络的传递。提出了以下具体目标： 目标#1 将确定 n-3 PUFA 和丁酸盐相互作用调节结肠中内在（线粒体介导）细胞死亡信号传导的机制；目标 #2 将确定 n-3 PUFA 改变 Ras 依赖性信号时空分离的机制；目标#3 将表征新型 EPA 衍生的环氧合酶产品 PGE3 的假定化学保护特性。摄入 EPA 和 DHA 可能被证明是结肠癌的有效辅助疗法。因此，准确确定 n-3 PUFA 如何调节细胞信号网络并降低结肠癌风险是适当且及时的。越来越多的文献支持这样的论点：含有 n-3 多不饱和脂肪酸 (PUFA) 的生物活性食品成分对于抑制结肠癌非常重要。与 PA-07-100“优先考虑营养组合预防癌症的分子靶标”的目标和范围一致，该提案的总体目标是阐明膳食 n-3 PUFA 和可发酵纤维如何上调结肠细胞中的细胞凋亡效应机制，从而降低结肠癌风险。