15-LOX-1 Modulation of Colon Cancer Promotion by Linoleic Acid

亚油酸对 15-LOX-1 促进结肠癌的调节

• 批准号: 9886073
• 负责人: Imad Shureiqi
• 金额: $ 35.29万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9886073
• 关键词: Acids; Advocate; Affect; Alkaline Phosphatase; American diet; Animals; Arachidonate 15-Lipoxygenase; Attention; Automobile Driving; Azoxymethane; Biological Markers; CDX2 gene; Cancerous; Cell Differentiation process; Cell Proliferation; Cell Respiration; Chemopreventive Agent; Colon Carcinoma; Colorectal Cancer; Colorectal Polyp; Consumption; Coronary Arteriosclerosis; Cyclin D1; Data; Development; Diet; Dietary intake; Disease; Down-Regulation; Enzymes; Epithelial Cells; Event; Exposure to; Gene Expression; Generations; Genes; Homologous Gene; Human; Incidence; Intake; Integration Host Factors; Intervention; Intestines; Knock-out; Knockout Mice; Knowledge; LOX gene; Lead; Length; Lentivirus Vector; Ligands; Linoleic Acids; Lipoxygenase 1; Messenger RNA; Metabolism; Molecular; Mus; Mutation; Nuclear; Omega-6 Fatty Acids; Organoids; Outcome Measure; PPAR gamma; Patients; Phase; Polyunsaturated Fatty Acids; Proteins; Regulation; Risk; Rodent; Role; Signal Transduction; Subfamily lentivirinae; System; Tamoxifen; Testing; Tissues; Transgenic Mice; Transgenic Organisms; beta catenin; c-myc Genes; colon cancer risk; colon tumorigenesis; colonic crypt; colorectal cancer prevention; colorectal cancer progression; colorectal cancer risk; dietary excess; functional loss; gain of function; insight; intestinal epithelium; liquid chromatography mass spectrometry; mouse model; novel; preclinical study; promoter; public health relevance; small hairpin RNA; tumor; tumorigenesis; villin

 DESCRIPTION (provided by applicant): Linoleic acid (LA) consumption is high in humans. LA increases azoxymethane (AOM)-induced colorectal tumorigenesis in rodents, but the impact of LA on colorectal cancer (CRC) in humans is unknown. 15- Lipoxygenase-1 (15-LOX-1) is the rate-limiting enzyme for the oxidative metabolism of LA to generate 13-S- HODE, a natural activating ligand of PPAR-gamma. PPAR-gamma suppresses aberrant Wnt/B-catenin signaling, a critical event initiating and driving CRC tumorigenesis. 15-LOX-1 is downregulated in human colorectal polyps and CRCs, but the influence of 15-LOX-1 on dietary LA modulation of CRC risk is unknown. In mice with intestinally targeted human 15-LOX-1 (15-LOX-1-Gut), we found that transgenic 15-LOX-1 expression suppressed CRC tumorigenesis, and 15-LOX-1 expression was downregulated in all experimentally-induced tumors. Furthermore, the increase in AOM-induced CRC with high LA dietary concentrations was repressed in 15-LOX-1-Gut mice; and 15-LOX-1 inhibited B-catenin activation. We therefore hypothesize that 15-LOX-1 loss in colonic epithelial cells is critical for excess LA to promote CRC tumorigenesis via augmenting Wnt/B-catenin signaling. We will test this hypothesis via 3 specific aims: Aims 1 and 2: Determine the effects of 15-LOX-1 expression (aim 1) and loss of expression (aim 2) in colonic epithelial cells on dietary LA promotion of CRC tumorigenesis and aberrant Wnt/B-catenin signaling. For aim 1, we will breed 15-LOX-1-Gut and Apc580mu mice to generate Apc580mu-15-LOX-1-Gut mice and examine the effects of 15-LOX-1 expression in mice fed high- or low-LA-content diets on CRC (tumor incidence and multiplicity), crypt proliferative zone length (Ki-67 IHC), activated B-catenin protein levels, and Wnt/B-catenin target gene (c-Myc, Cyclin D1, and Axin2) mRNA levels. For aim 2, we will replace 12-S-LOX in intestinal epithelial cells of 12/15-LOX knockout mice to generate mice with functional 15-LOX-1 loss and examine the effects in mice fed high- or low-LA-content diets on AOM-induced CRC, crypt proliferative zone length, and 13- HODE levels. We will also evaluate the effect of 15-LOX-1 gain of function (aim 1) and downregulation (aim 2) in human colonic cancerous and normal organoids (isolated from patients' colonic crypts) and cultured with various concentrations of LA on 13-HODE generation, cell proliferation, cell differentiation, and Wnt/B-catenin signaling. Aim 3: Determine the tempora and spatial effects of 15-LOX-1 expression in colonic epithelial cells on CRC tumorigenesis in relation to dietary LA intake. We will generate mice with conditional 15-LOX-1 expression, treat them with AOM, and feed them high- or low-LA-content diets. 15-LOX-1 expression will be induced during initiation or progression of CRC tumorigenesis, and we will examine the effects on the outcomes measured in aim 1. We expect these studies to provide important new information to direct development of novel interventions for CRC prevention and to identify subjects with low 15-LOX-1 expression as having increased risk of CRC tumorigenesis with high LA intake.

 描述（由适用提供）：人类的亚油酸（LA）消耗量很高。 LA会增加啮齿动物中甲氧烷甲烷（AOM）诱导的结直肠肿瘤发生，但是LA对大型直肠癌（CRC）在人类中的影响尚不清楚。 15-脂蛋白酶-1（15-LOX-1）是LA氧化代谢的速率限制酶，生成13-S-Hode，这是PPAR-GAMMA的自然激活配体。 PPAR-GAMMA抑制异常的Wnt/B-catenin信号传导，这是一个启动和驱动CRC肿瘤发生的关键事件。 15-LOX-1在人类结肠息肉和CRC中被下调，但是15-LOX-1对CRC饮食LA调节的影响尚不清楚。在靶向人15-LOX-1（15-LOX-1-GUT）的小鼠中，我们发现转基因15-LOX-1表达抑制了CRC肿瘤发生，并且在所有实验诱导的肿瘤中都下调了15-LOX-1表达。此外，在15-lox-1甲状腺凝结小鼠中抑制了AOM诱导的CRC的增加。 15-LOX-1抑制B-catenin的激活。因此，我们假设结肠上皮细胞中的15-LOX-1损失对于通过增强Wnt/B-catenin信号传导促进CRC肿瘤发生的超过LA至关重要。我们将通过3个特定目的来检验这一假设：目标1和2：确定15-LOX-1表达（目标1）和结肠上皮细胞中表达丧失（AIM 2）对CRC肿瘤发生和异常WNT/B-catenin信号的饮食中促进饮食中的影响。 For aim 1, we will breed 15-LOX-1-Gut and Apc580mu mice to generate Apc580mu-15-LOX-1-Gut mice and examining the effects of 15-LOX-1 expression in mice fed high- or low-LA-content diets on CRC (tumor incidence and multiplicity), crypto proliferating zone length (Ki-67 IHC), activated B-catenin protein levels, and Wnt/B-catenin靶基因（C-Myc，Cyclin D1和Axin2）mRNA水平。对于AIM 2，我们将替换12/15-LOX敲除小鼠的肠上皮细胞中的12-S-LOX，以产生具有功能性15-LOX-1损失的小鼠，并检查喂养高或低LA-LA饮食对AOM诱导的CRC的小鼠的作用，对AOM诱导的CRC，加密蛋白的增殖区长度长度和13-螺旋水平。我们还将评估15-LOX-1功能增益（AIM 1）和下调（AIM 2）对人类结肠取消和正常类器官（与患者的结肠隐窝分离）的影响，并用不同浓度的LA对13-牛群产生，细胞增殖，细胞分化和Wnt/B-catenin信号进行培养。 AIM 3：确定15-LOX-1表达在结肠上皮细胞中与饮食LA摄入有关的CRC肿瘤发生的颞和空间效应。我们将产生有条件的15-LOX-1表达的小鼠，用AOM对其进行处理，并将其喂养高或低含量的饮食。在CRC肿瘤发生的开始或进展过程中，将诱导15-LOX-1表达，我们将研究对AIM 1中测得的结果的影响。我们希望这些研究能够为预防CRC预防的新型干预措施提供重要的新信息，并以低15-lox-1表达的受试者确定具有高LA摄入CRC肿瘤的风险增加了CRC肿瘤的风险。