EGFR-VDR signals in diet-promoted inflammation and cancer

饮食促进的炎症和癌症中的 EGFR-VDR 信号

• 批准号: 7896371
• 负责人: Bruce Marc Bissonnette
• 金额: $ 16.97万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7896371
• 关键词: Animal Model; Anti-Inflammatory Agents; Anti-inflammatory; Azoxymethane; Bile Acids; Binding; Biological; Biological Assay; Caco-2 Cells; Cancer Etiology; Cell Culture Techniques; Cells; Cessation of life; Chemopreventive Agent; Co-Immunoprecipitations; Colon; Colon Carcinoma; Colonic Neoplasms; Complementary DNA; Cytokine Signaling; Development; Diet; Diet Modification; Dietary Fats; Dietary Supplementation; Dominant-Negative Mutation; EGF gene; Epidermal Growth Factor Receptor; Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor; Experimental Models; Fatty acid glycerol esters; Fibroblasts; Figs - dietary; Foundations; Funding; Gefitinib; Genomics; Goals; Grant; Growth; Growth Factor; Half-Life; Human; In Vitro; Inflammation; Inflammation Mediators; Inflammatory; Knockout Mice; Label; Lesion; Ligands; Link; Lithocholic Acid; Malignant - descriptor; Malignant Neoplasms; Measures; Mediating; Messenger RNA; Metabolic; Modeling; Mutant Strains Mice; Oncogenic; Pathway interactions; Physiological; Play; Premalignant; Proteins; Proteomics; Receptor Activation; Receptor Down-Regulation; Receptor Inhibition; Receptor Signaling; Regulation; Reporter; Risk; Role; Signal Transduction; Small Interfering RNA; Solid; Time; Transcript; Transcription Factor AP-1; Tumor Promotion; Vitamin D; Vitamin D Analog; Vitamin D3 Receptor; Wild Type Mouse; cancer cell; carcinogenesis; cyclooxygenase 2; cytokine; dietary constituent; dietary supplements; in vitro testing; in vivo; in vivo Model; knock-down; promoter; public health relevance; receptor expression; response; transcription factor; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Diet is believed to play a major role in the development of sporadic colon cancer. The azoxymethane (AOM) model of experimental colon cancer mimics many features of human colon cancer, including tumor promotion by Western style high fat diets. Inflammation is thought to contribute to diet-enhanced tumorigenesis. We recently showed that tumor promotion induced by dietary fat required epidermal growth factor receptor (EGFR) signals and involved increased pro-inflammatory cyclooxygenase-2 (Cox-2). In contrast, we demonstrated that dietary supplementation with a vitamin D analogue F6-D3 inhibited inflammation and tumorigenesis. Vitamin D effects are mediated by the vitamin D receptor (VDR). We showed that the VDR could antagonize signals from key inflammatory and oncogenic transcription factors, including NFkB and b-catenin. In recent preliminary studies, we demonstrated that EGFR signals, which are up-regulated in tumorigenesis, suppressed VDR expression. Furthermore, VDR null mice appear to be more susceptible to tumorigenesis. In Aim 1 using the AOM model we will characterize the relationships between diet and EGFR signals and VDR down- regulation and identify VDR pathways that inhibit diet-promoted inflammation and tumorigenesis. We will utilize AOM-treated VDR wild type and VDR null mutant mice to dissect VDR pathways. We will modulate dietary fat to assess the effects of diet on inflammation and tumorigenesis. We will also include a diet supplemented with F6-D3 alone, or F6-D3 plus EGFR inhibitor Gefitinib to dissect VDR and EGFR signals in diet-promoted inflammation and tumorigenesis. We postulate that dietary fat will increase EGFR signals and decrease VDR expression, whereas F6-D3 will increase VDR levels and reduce inflammatory and oncogenic signals and inhibit tumorigenesis. In Aim 2 we will dissect EGFR pathways in colon cancer cells and colonic fibroblasts that down-regulate VDR and uncover VDR mechanisms that oppose EGFR and pro- inflammatory cytokine signals. Caco-2 colon cancer cells and colonic fibroblasts express functional EGFR and VDR. In preliminary studies, EGF down-regulated the VDR in these cells, whereas EGFR inhibition or active vitamin D up-regulated VDR. Thus, EGFR activation in these transformed and non-transformed colonic cells mimics in vitro the effects of EGFR signals on VDR expression in colonic tumorigenesis in vivo. We will uncover the transcriptional and post-transcriptional mechanisms that mediate this VDR down-regulation by EGFR. Potential mechanisms include inhibited promoter activation, and reduced transcript or protein half-life. Using inducible dominant negative EGFR expressing transfectants to control EGFR, and siRNA and cDNA strategies to modulate VDR levels, we will also dissect EGFR and VDR pathways that control inflammation and oncogenesis. Using pathway-specific proteomic and genomic approaches, we will also search for new EGFR and VDR-regulated cytokine and growth factor signals that control inflammation in vitro and test their relevance in our in vivo models. These studies will identify potential new targets to exploit for chemopreventive strategies. PUBLIC HEALTH RELEVANCE: Colon cancer is the 3rd leading cause of cancer-related deaths in the US. More than half of these malignancies are believed to be preventable by dietary modifications. We have shown that tumor promotion by Western style high fat diets requires epidermal growth factor receptor (EGFR) signals that inhibit anti-inflammatory vitamin D signals. We will uncover EGFR and vitamin D cellular pathways that interact to modulate dietary inflammation and colonic tumor risk.

描述（由申请人提供）：饮食被认为在散发性结肠癌的发展中发挥着重要作用。实验性结肠癌的氧化偶氮甲烷（AOM）模型模仿了人类结肠癌的许多特征，包括西式高脂肪饮食对肿瘤的促进作用。炎症被认为有助于饮食增强的肿瘤发生。我们最近表明，饮食脂肪诱导的肿瘤促进需要表皮生长因子受体（EGFR）信号，并涉及促炎环加氧酶-2（Cox-2）的增加。相比之下，我们证明膳食补充维生素 D 类似物 F6-D3 可以抑制炎症和肿瘤发生。维生素 D 的作用是由维生素 D 受体 (VDR) 介导的。我们发现 VDR 可以拮抗来自关键炎症和致癌转录因子（包括 NFkB 和 b-catenin）的信号。在最近的初步研究中，我们证明在肿瘤发生过程中上调的 EGFR 信号可抑制 VDR 表达。此外，VDR 缺失小鼠似乎更容易发生肿瘤。在目标 1 中，我们将使用 AOM 模型来表征饮食与 EGFR 信号和 VDR 下调之间的关系，并确定抑制饮食促进的炎症和肿瘤发生的 VDR 途径。我们将利用 AOM 处理的 VDR 野生型和 VDR 无效突变小鼠来剖析 VDR 通路。我们将调节膳食脂肪以评估饮食对炎症和肿瘤发生的影响。我们还将包括单独补充 F6-D3 或 F6-D3 加 EGFR 抑制剂吉非替尼的饮食，以剖析饮食促进的炎症和肿瘤发生中的 VDR 和 EGFR 信号。我们假设膳食脂肪会增加 EGFR 信号并减少 VDR 表达，而 F6-D3 将增加 VDR 水平并减少炎症和致癌信号并抑制肿瘤发生。在目标 2 中，我们将剖析结肠癌细胞和结肠成纤维细胞中下调 VDR 的 EGFR 通路，并揭示对抗 EGFR 和促炎细胞因子信号的 VDR 机制。 Caco-2 结肠癌细胞和结肠成纤维细胞表达功能性 EGFR 和 VDR。在初步研究中，EGF 下调了这些细胞中的 VDR，而 EGFR 抑制或活性维生素 D 则上调了 VDR。因此，这些转化和非转化结肠细胞中的EGFR激活在体外模拟了体内结肠肿瘤发生中EGFR信号对VDR表达的影响。我们将揭示 EGFR 介导 VDR 下调的转录和转录后机制。潜在的机制包括抑制启动子激活以及缩短转录物或蛋白质半衰期。使用诱导型显性失活 EGFR 表达转染子来控制 EGFR，并使用 siRNA 和 cDNA 策略来调节 VDR 水平，我们还将剖析控制炎症和肿瘤发生的 EGFR 和 VDR 途径。使用途径特异性蛋白质组学和基因组学方法，我们还将寻找新的 EGFR 和 VDR 调节的细胞因子和生长因子信号，以在体外控制炎症，并测试它们在我们的体内模型中的相关性。这些研究将确定化学预防策略的潜在新目标。 公共卫生相关性：结肠癌是美国癌症相关死亡的第三大原因。据信，超过一半的恶性肿瘤可以通过饮食调整来预防。我们已经证明，西式高脂肪饮食促进肿瘤生长需要表皮生长因子受体 (EGFR) 信号抑制抗炎维生素 D 信号。我们将揭示 EGFR 和维生素 D 细胞通路相互作用，调节饮食炎症和结肠肿瘤风险。