Roles of EGFR and miR-143/miR-145 in Western diet-promoted colonic tumorigenesis

EGFR 和 miR-143/miR-145 在西方饮食促进的结肠肿瘤发生中的作用

• 批准号: 8372732
• 负责人: Bruce Marc Bissonnette
• 金额: $ 32.79万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-08 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8372732
• 关键词: Address; Azoxymethane; Binding; Calcium; Cancer Etiology; Cells; Cessation of life; Cleaved cell; Colon Carcinoma; Colorectal; Data; Diet; Down-Regulation; Elements; Epidermal Growth Factor Receptor; Event; Fatty Acids; Feedback; Figs - dietary; Genetic; Genetic Transcription; Growth; Growth Factor; Human; In Vitro; Knockout Mice; Laboratories; Ligands; Malignant - descriptor; Marimastat; Mediating; Membrane; Membrane Microdomains; Metalloproteases; MicroRNAs; Modeling; Molecular; Mucous Membrane; Mus; Neoplasms; Neoplastic Cell Transformation; Pathway interactions; Play; Process; Proteins; Publishing; Receptor Signaling; Regulation; Regulatory Element; Risk; Role; Signal Transduction; Staging; Stimulation of Cell Proliferation; Stream; Sum; Testing; Transcription Process; Transgenic Mice; Tumor Promotion; Up-Regulation; Vitamin D; Work; base; cancer cell; cancer risk; carcinogenesis; in vivo; in vivo Model; inhibitor/antagonist; mouse model; mutant; neoplastic; novel; novel strategies; prevent; promoter; saturated fat; tumor; tumorigenesis; villin

DESCRIPTION (provided by applicant): While Western diets are implicated in increased colon cancer risk, molecular underpinnings of these dietary effects remain largely unknown. The azoxymethane (AOM) and Apc+/min mouse models mimic many features of human colon cancer, including tumor promotion by Western diet. We showed that Western diet up-regulated ligands for epidermal growth factor receptors (EGFR). Furthermore, EGFR was required for tumor promotion. Several EGFR ligands are released from membrane-bound pro-ligands by the lipid-raft-associated metalloproteinase ADAM17. Our recent studies indicate that ADAM17 is down-regulated by microRNA-145 (miR-145), whereas K-ras, an EGFR effector is suppressed by miR-143. These co-transcribed miRNAs are down-regulated in human colon cancer. We recently showed that EGFR signals downregulate miR-143 and miR-145 in AOM and Apc+/min tumors. Furthermore, these miRNA reductions are necessary for EGFR mitogenic effects. Based on our data we hypothesize that ADAM17 up-regulation and miR-143 and miR-145 down-regulation play essential roles in Western diet-induced tumor promotion. We propose several aims to address this hypothesis: Aim 1: Elucidate the requirement for ADAM17 in diet-promoted colonic tumorigenesis. We hypothesize that ADAM17 inhibition or deletion will suppress diet-related tumor promotion. We will use 1a) the AOM model in conditional ADAM17-deleted mice; 1b) the Apc+/min model with a novel ADAM17 pharmacological inhibitor INCB3619 to dissect the role of ADAM17 in diet-promoted tumorigenesis; 1c) in vitro studies of lipid rafts to dissect fatty acid effects on ADAM17 in colon cancer cells. Aim 2: To determine contributions of miR-143 and miR-145 in diet-promoted colonic tumorigenesis. We hypothesize that loss of these miRNAs is necessary for diet-induced tumor promotion. We will employ Apc+/min mouse interbred with 2a) transgenic mice expressing villin-promoter regulated pre-miR-143 and pre-miR-145; or with 2b) miR-143 null mice or with 2c) miR-145 null mice to uncover the role of these miRNAs in diet- promoted tumorigenesis. In aim 2d), we will examine other miRNAs implicated in ADAM17 regulation and/or diet-related tumorigenesis, including miR-1, -31, -148, and -152. Aim 3: Determine the regulation of miR-143 and miR-145 by Western diet and tumorigenesis. We hypothesize that Western diet and malignant transformation suppress transcription, while neoplastic transformation also deranges processing. We will 3a) assess effects of ADAM17, diet and neoplastic stage on pri-, pre- and mature levels of miR-143, -145 in in vivo models; 3b) dissect EGFR and fatty acid effects on miR-143/-145 promoter activity using mutant deletions to identify cis regulatory elements; 3c) Determine proteins differentially co-associating with biotinylated miR-143 or miR-145 in murine processing-competent YAMC and processing-incompetent CT26 colon cancer cells to discover deregulated processing factors. Our proposal will clarify the role of ADAM17 and test a novel hypothesis that EGFR and these miRNAs form a self-amplifying loop that drives diet-promoted tumorigenesis. PUBLIC HEALTH RELEVANCE: Colon cancer is a leading cause of cancer-related deaths in the US. Western diets increase the risk of colon cancer in part by increasing growth factor signals. Elucidating how diet controls growth factors will help us understand how tumors develop and suggest new approaches to block their growth.

描述（由申请人提供）：虽然西方饮食与结肠癌的风险增加有关，但这些饮食效应的分子基础在很大程度上尚不清楚。甲氧基甲烷（AOM）和APC+/min小鼠模型模仿了人类结肠癌的许多特征，包括西方饮食促进肿瘤。我们表明西方饮食上调表皮生长因子受体（EGFR）的配体。此外，肿瘤促进需要EGFR。通过脂质与脂质相关的金属蛋白酶ADAM17，从膜结合的培养基中释放了几种EGFR配体。我们最近的研究表明，ADAM17被MicroRNA-145（miR-145）下调，而K-Ras，EGFR效应子被miR-143抑制。这些共转录的miRNA在人类结肠癌中被下调。我们最近表明，EGFR信号在AOM和APC+/min肿瘤中下调miR-143和miR-145。此外，这些miRNA减少是EGFR有丝分裂作用所必需的。根据我们的数据，我们假设ADAM17上调，miR-143和miR-145下调在西方饮食诱导的肿瘤促进中起着重要作用。我们提出了几个目的来解决这一假设：目标1：阐明饮食促进结肠肿瘤发生中ADAM17的需求。我们假设ADAM17抑制或缺失将抑制与饮食相关的肿瘤促进。我们将在条件ADAM17删除的小鼠中使用1A）模型； 1B）具有新型ADAM17药理学抑制剂INCB3619的APC+/min模型，以剖析ADAM17在饮食促进的肿瘤发生中的作用； 1C）在体外研究脂质筏，以剖析脂肪酸对结肠癌细胞中ADAM17的影响。目标2：确定miR-143和miR-145在饮食促进的结肠肿瘤发生中的贡献。我们假设这些miRNA的损失对于饮食诱导的肿瘤促进是必要的。我们将采用APC+/min小鼠与2A）的转基因小鼠交织，表达villin促销的前MIR-143和MIR-145前。或与2B）miR-143无效小鼠或2C）miR-145无效小鼠，以发现这些miRNA在饮食促进的肿瘤发生中的作用。在AIM 2D中，我们将检查与ADAM17调节和/或与饮食相关的肿瘤发生有关的其他miRNA，包括miR -1，-31，-148和-152。目标3：通过西方饮食和肿瘤发生来确定miR-143和miR-145的调节。我们假设西方饮食和恶性转化抑制了转录，而肿瘤转化也造成了处理。我们将3A）评估ADAM17，饮食和肿瘤阶段对体内模型中miR-143，-145的Pri-，前和成熟水平的影响； 3b）使用突变体缺失来鉴定CIS调节元件，解剖EGFR和脂肪酸对miR-143/-145启动子活性的影响； 3C）确定蛋白质与鼠加工能力的YAMC和无效的CT26结肠癌细胞中的生物素化的miR-143或miR-145差异化，以发现失控的加工因子。我们的建议将阐明ADAM17的作用，并检验一个新的假设，即EGFR和这些miRNA形成了一种自我放大环路，可驱动饮食促进的肿瘤发生。 公共卫生相关性：结肠癌是美国与癌症有关的主要原因。西方饮食会通过增加生长因子信号来部分增加结肠癌的风险。阐明饮食如何控制生长因素将有助于我们了解肿瘤如何发展并建议阻止其生长的新方法。