Role of TLR4 in Colitis Associated Neoplasia

TLR4 在结肠炎相关肿瘤中的作用

• 批准号: 8761283
• 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/8761283
• 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; Commit; Data; Development; Dysplasia; Epithelial; Epithelial Cell Proliferation; Epithelial Cells; Epithelium; Gene Targeting; Grant; Growth; Health Care Costs; Human; Immune; In Vitro; Inflammation; Inflammatory; Intestinal Cancer; Intestinal Neoplasms; Intestines; 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; Techniques; Testing; Tissue Banks; Transgenic Organisms; Ulcerative Colitis; Undifferentiated; Work; Xenograft procedure; autocrine; cancer stem cell; colitis associated cancer; colon cancer cell line; improved; in vivo; in vivo Model; mouse model; mouse toll-like receptor 4; neoplastic cell; overexpression; paracrine; prevent; progenitor; programs; promoter; public health relevance; receptor; self-renewal; stemness; toll-like receptor 4; 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 ?-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 b-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 b-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 ?-catenin in colonic epithelia in a TLR4-dependent manner. Human UC-associated MDSCs will be isolated and studied for their ability to stimulate ?-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（由申请人提供）：拟议项目旨在了解炎症相关肿瘤的分子基础。 IBD 患者仍然需要进行结肠切除术来治疗发育不良，这主要是因为我们无法阻止 IBD 进展为癌症。我们之前的工作表明，Toll 样受体 4 (TLR4) 的先天免疫信号传导对结肠炎相关癌症 (CAC) 的发展发挥着重要作用。我们将 TLR4 确定为促进结肠恶性肿瘤的癌基因。我们已经证明 TLR4 在 UC 相关的发育不良和几乎所有 CAC 中过度表达。我们发现，TLR4 缺陷的动物（TLR4-/- 小鼠）可以免受结肠炎相关肿瘤的影响，并产生了绒毛启动子驱动转基因肠道 TLR4 过表达的小鼠（V-TLR4）。这些小鼠极易患结肠炎相关肿瘤。从机制上讲，我们已经证明 TLR4 通过结肠上皮细胞中的 PI3 激酶激活 β-catenin 信号传导来促进肿瘤形成。我们提供的初步数据表明，TLR4 驱动肠道肿瘤和正常粘膜中 Lgr5+ 干细胞的扩增，表明 TLR4 信号传导正在该体内模型中驱动干细胞自我更新。我们还表明，小鼠模型中的 UC 粘膜和 TLR4 介导的炎性肿瘤的特征是表达 S100A8/A9 的骨髓源性抑制细胞 (MDSC) 的浸润。在当前的提案中，我们将测试以下假设：TLR4 信号传导在恶性上皮转化中发挥自分泌作用，并通过激活 MDSC 刺激 β-连环蛋白激活、上皮细胞增殖和癌症干细胞扩增发挥旁分泌作用。这是为了实现以下具体目标：1)确定TLR4信号传导在炎症性肿瘤中肠干细胞激活中的作用。使用我们的各种表达 TLR4 的动物模型与干细胞报告基因 Lgr5-EGFP 小鼠杂交，我们将研究在体内炎症和肿瘤转化过程中谱系定型祖细胞和结肠癌干细胞的扩增是否需要 TLR4。 2)确定TLR4信号在促进结肠上皮细胞干性中的作用。我们将使用原代结肠培养物来测试 TLR4 信号传导是否会改变培养物中原代结肠干细胞的表型（生长、出芽）。我们将使用结肠癌细胞系来测试 TLR4 信号传导是否在体外促进癌症干细胞表型，并使用异种移植物在体内增加致瘤性。 3) 确定S100A8/9+ MDSC是否驱动TLR4依赖性b-连环蛋白激活、干细胞激活和肿瘤发生。我们将确定肠道干细胞扩增和 CAC 是否需要 S100A8/9 MDSC。我们将测试S100A8或9是否以TLR4依赖性方式激活结肠上皮细胞中的β-连环蛋白。将分离人类 UC 相关 MDSC，并研究其在体外刺激结肠上皮细胞中β-连环蛋白信号传导的能力。本文提出的工作旨在为后续人类研究提供机制依据，以先天免疫信号为目标，作为阻止 UC/炎症进展为不典型增生的手段。