Role of TLR4 in Colitis Associated Neoplasia

TLR4 在结肠炎相关肿瘤中的作用

• 批准号: 9102094
• 负责人: Maria Teresa Abreu
• 金额: $ 33.39万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9102094
• 关键词: 1-Phosphatidylinositol 3-Kinase; Address; Animal Model; Animals; Automobile Driving; Bacteria; Biological Response Modifiers; Bone Marrow; Cells; Chimera organism; Chronic; Clinical; Colectomy; Colitis; Colon; Colon Carcinoma; Colonic Neoplasms; Colorectal Cancer; Data; Development; Dysplasia; Epithelial; Epithelial Cell Proliferation; Epithelial Cells; Epithelium; Gene Targeting; Grant; Growth; Health; Health Care Costs; Human; Immune; In Vitro; Inflammation; Inflammatory; Intestinal Cancer; Intestinal Neoplasms; Intestines; Knockout Mice; Laboratories; Lead; Leukocyte L1 Antigen Complex; Ligands; Maintenance; Malignant - descriptor; Malignant Neoplasms; Mediating; Molecular; Mucous Membrane; Mus; Mutate; Myelogenous; Neoplasms; Neoplastic Cell Transformation; Oncogenes; Pathway interactions; Patient Care; Patients; Phenotype; Play; Precancerous Conditions; Quality of life; Reporter; Role; S100A8 gene; S100A9 gene; Scientist; Signal Transduction; Stem cells; Suppressor-Effector T-Lymphocytes; TLR4 gene; Techniques; Testing; Tissue Banks; Transgenic Organisms; Ulcerative Colitis; Undifferentiated; Work; Xenograft procedure; autocrine; beta catenin; cancer stem cell; colitis associated cancer; colon cancer cell line; improved; in vivo; in vivo Model; microbiota; mouse model; mouse toll-like receptor 4; neoplastic cell; overexpression; paracrine; prevent; progenitor; programs; promoter; receptor; self-renewal; stemness; tumor; tumorigenesis; villin

DESCRIPTION (provided by applicant): The proposed project aims to understand the molecular underpinnings of inflammation-associated neoplasia. Patients with IBD continue to need colectomies for dysplasia largely because of our inability to halt IBD progression to cancer. Our previous work has demonstrated that innate immune signaling by toll-like receptor 4 (TLR4) contributes importantly to the development of colitis-associated cancer (CAC). We identified TLR4 as an oncogene which promotes colonic malignancy. We have shown that TLR4 is over-expressed in UC- associated dysplasia and in almost all CACs. We showed that animals deficient in TLR4 (TLR4-/- mice) are protected from colitis-associated neoplasia and have generated a mouse in which the villin promoter drives transgenic intestinal TLR4 overexpression (V-TLR4). These mice are highly prone to colitis-associated neoplasia. Mechanistically, we have shown that TLR4 promotes neoplasia by activating ß-catenin signaling through PI3 kinase in colonic epithelial cells. We present preliminary data that show that TLR4 drives expansion of Lgr5+ stem cells in both intestinal neoplasia and in normal mucosa suggesting that TLR4 signaling is driving stem cell self-renewal in this model in vivo. We also show that UC mucosa and TLR4- mediated inflammatory neoplasia in mouse models are characterized by an infiltrate of S100A8/A9 expressing myeloid-derived suppressor cells (MDSCs). In the current proposal we will test the hypothesis that TLR4 signaling plays both an autocrine role in malignant epithelial transformation and a paracrine role through activation of MDSCs to stimulate ß-catenin activation, epithelial cell proliferation and cancer stem cell expansion. This is pursued i the following specific aims: 1) Determine the role of TLR4 signaling in activation of intestinal stem cells in inflammatory neoplasia. Using our various TLR4 expressing animal models crossed to stem cell reporter Lgr5-EGFP mice we will investigate if TLR4 is required for expansion of lineage committed progenitors and of colon cancer stem cells during inflammation and neoplastic transformation in vivo. 2) Determine the role of TLR4 signaling in promoting stemness of colonic epithelial cells. We will use primary colonoid cultures to test if TLR4 signaling alters the phenotype (growth, budding) of primary colon stem cells in culture. We will use colon cancer cell lines to test whether TLR4 signaling promotes a cancer stem cell phenotype in vitro and increases tumorgenicity in vivo using xenografts. 3) Determine if S100A8/9+ MDSCs drive TLR4-dependent ß-catenin activation, stem cell activation, and tumorigenesis. We will determine whether S100A8/9 MDSCs are required for intestinal stem cell expansion and CAC. We will test if S100A8 or 9 activate ß-catenin in colonic epithelia in a TLR4-dependent manner. Human UC-associated MDSCs will be isolated and studied for their ability to stimulate ß-catenin signaling in colonic epithelia in vitro. The work proposed herein aims to provide the mechanistic justification for subsequent human studies to target innate immune signaling as a means to halt progression UC/inflammation to dysplasia.

描述（由适用提供）：拟议的项目旨在了解与炎症相关的肿瘤的分子基础。 IBD患者继续需要结肠症患者，这很大程度上是因为我们无法阻止IBD进展为癌症。我们以前的工作表明，Toll样受体4（TLR4）的先天免疫信号传导对与结肠炎相关癌症（CAC）的发展重要贡献。我们将TLR4确定为促进结肠恶性肿瘤的癌基因。我们已经表明，TLR4在UC-相关的发育不良和几乎所有CAC中都过表达。我们表明，缺乏TLR4（TLR4 - / - 小鼠）的动物受到了与结肠炎相关的肿瘤的保护，并产生了一只小鼠，其中villin启动子驱动转基因肠TLR4过表达（V-TLR4）。这些小鼠易于结肠炎相关的肿瘤。从机械上讲，我们已经表明，TLR4通过在结肠上皮细胞中通过PI3激酶激活ß-catenin信号传导来促进肿瘤。我们提供了初步数据，这些数据表明TLR4驱动肠道肿瘤和正常粘膜中LGR5+干细胞的扩展，这表明TLR4信号在体内驱动干细胞自我更新。我们还表明，在小鼠模型中，UC粘膜和TLR4-介导的炎症性肿瘤的特征在于表达髓样衍生的抑制细胞（MDSC）的S100A8/A9的浸润。在当前的建议中，我们将检验以下假设：TLR4信号传导既在恶性上皮转化中起着自分泌作用，又通过激活MDSC来刺激ß-catenin激活，上皮细胞增殖和癌症干细胞的扩张来发挥自分泌作用。这是以下具体目的：1）确定TLR4信号在炎症性肿瘤中激活肠道干细胞中的作用。使用我们的各种TLR4表达的动物模型越过干细胞报告基因LGR5-EGFP小鼠，我们将研究是否需要TLR4在体内炎症和肿瘤转化期间谱系延伸的谱系承诺的祖细胞和结肠癌干细胞的扩展是否需要。 2）确定TLR4信号传导在促进结肠上皮细胞的干性中的作用。我们将使用原发性结肠培养物来测试TLR4信号是否改变了培养中原代结肠细胞的表型（生长，发芽）。我们将使用结肠癌细胞系测试TLR4信号是否在体外促进癌细胞表型，并使用异种移植物在体内增加肿瘤性。 3）确定S100A8/9+ MDSC是否驱动TLR4依赖性ß-catenin激活，干细胞激活和肿瘤发生。我们将确定S100A8/9 MDSC是否需要肠道干细胞膨胀和CAC。我们将测试S100A8或9是否以TLR4依赖性方式激活结肠上皮中的ß-catenin。将分离与人UC相关的MDSC，并研究其在体外刺激结肠上皮中β-catenin信号传导的能力。本文提出的工作旨在为随后的人类研究提供机械依据，以靶向先天免疫信号传导，以阻止进展UC/炎症到发育不良。