Natural EGFR Antagonists and Cancer

天然 EGFR 拮抗剂与癌症

基本信息

批准号：
7472307
负责人：
RENATO V. IOZZO
金额：
$ 23.56万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2011-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7472307
关键词：
Address Affect Affinity Applications Grants Attention Basic Cancer Research Binding Binding Sites Biochemical Genetics Biological Biology Breast Carcinoma Carcinoma Cell surface Cells Depth Development Dimerization Dose EGF gene Engineering Environment Epidermal Growth Factor Receptor Event Evolution Future Genetic Glycosaminoglycans Growth Growth Factor Hela Cells In Vitro Integral Membrane Protein Invaded Knowledge Lead Learning Leucine Leucine-Rich Repeat Ligands Light Malignant Epithelial Cell Malignant Neoplasms Mediating Modeling Molecular Molecular Conformation Mutation N-terminal Neoplasm Metastasis Numbers Oncogenic Proteins Proteoglycan Receptor Activation Receptor Protein-Tyrosine Kinases Receptor Signaling Regulation Research Research Personnel Role Signal Pathway Signal Transduction Site Therapeutic Intervention Time Tissues Tumor Cell Invasion Tumorigenicity attenuation base cancer therapy cell growth decorin dosage extracellular in vivo inhibitor/antagonist multidisciplinary mutant neoplastic cell novel prevent programs receptor receptor expression research study response tumor tumor progression tumor xenograft

项目摘要

DESCRIPTION (provided by applicant): To prevent the dire consequences of uncontrolled activation of tyrosine kinase receptors, such as the epidermal growth factor receptor (EGFR), both extracellular and intracellular controlling mechanisms have been devised during evolution. One such extracellular mechanism of EGFR regulation is provided by decorin, a leucine-rich proteoglycan that binds to and downregulates EGFR activity both in vitro and in vivo. We hypothesized that other soluble forms of proteins harboring leucine-rich repeats could similarly affect the EGFR signaling pathway. Thus, we focused our attention on LRIG1, a transmembrane protein containing fifteen leucine-rich repeats and three Ig-like repeats in its ectodomain. We generated a soluble ectodomain of LRIG1 containing only the leucine-rich repeats and flanking Cys-rich caps. We discovered that nanomolar concentrations of LRIG1 ectodomain inhibit both basal and ligand-dependent EGFR activation and Erk1/2 signaling in a dose-dependent fashion. This, in turn, causes growth inhibition of EGFR-expressing carcinoma cells but not of cells lacking expression of the receptor. Furthermore, we provide genetic evidence for EGFR requirement in the LRIG1-mediated function, and demonstrate the existence of high-affinity (Kd=10 nM) binding sites on the A431 cells, the vast majority (up to 75%) of which can be competitively displaced by EGF. These novel results suggest that the soluble ectodomain of LRIG1, which could conceivably be released at sites of tissue remodeling and tumor invasion, might act as negative regulator of EGFR activity. The central hypothesis of this new grant application is that release of soluble LRIG1 ectodomain from the cell surface around or within carcinomas could represent a biological mechanism to counteract the invading tumor cells, thereby functioning as a natural EGFR antagonist. Specifically, we plan to: [1] Decipher the mechanism of action of LRIG1 ectodomain in suppressing EGFR activity, [2] Determine the mechanism of LRIG1-evoked signaling via the EGFR and its ability to inhibit cell growth , and [3] Investigate the in vivo function of LRIG1 ectodomain as an anti-oncogenic factor. These concerted research lines should firmly establish the functional roles of LRIG1 in tumorigenicity and shed light on its mechanism of action. The expected results could open novel perspectives for basic cancer research, and could lead to future approaches of cancer treatment by using a natural inhibitor of tumor cell growth.

描述（由申请人提供）：为防止酪氨酸激酶受体不受控制激活的可怕后果，例如表皮生长因子受体（EGFR），在进化过程中已经设计了细胞外和细胞内控制机制。 EGFR调控的一种细胞外机理是由Decorin提供的，Decorin是一种富含亮氨酸的蛋白聚糖，它在体外和体内结合并下调EGFR活性。我们假设携带含亮氨酸富集的蛋白质的其他可溶性形式可能会影响EGFR信号通路。因此，我们将注意力集中在LRIG1上，LRIG1是一种含有15个亮氨酸重复序列的跨膜蛋白，其外生域中的三个Ig样重复序列。我们仅产生了仅包含富含亮氨酸的重复序列和富含Cys的帽的LRIG1的可溶性外生域。我们发现，LRIG1胞外域的纳摩尔浓度抑制了基础和配体依赖性EGFR激活，而ERK1/2信号以剂量依赖性方式抑制。反过来，这会导致表达EGFR表达癌细胞的生长抑制，而不是缺乏受体表达的细胞。此外，我们为LRIG1介导的功能提供了EGFR要求的遗传证据，并证明了A431细胞上的高亲和力（KD = 10 nm）结合位点的存在，其中绝大多数（最多75％）可以由EGF取代。这些新的结果表明，LRIG1的可溶性外生域可以在组织重塑和肿瘤侵袭的部位释放，可能是EGFR活性的负调节剂。这种新的赠款应用的中心假设是，可溶性LRIG1外生域从细胞表面或癌中释放可以代表一种生物学机制来抵消入侵的肿瘤细胞，从而充当天然EGFR拮抗剂。具体来说，我们计划： [1]解读LRIG1胞外域在抑制EGFR活性中的作用机理，[2]通过EGFR确定LRIG1诱发的信号传导的机制及其抑制细胞生长的能力，[3]研究LRIG1的体内LRIG1 ectodomain的体内功能。这些协同的研究线应牢固确定LRIG1在肿瘤性中的功能作用，并阐明其作用机理。预期的结果可能会为基本癌症研究开辟新的观点，并通过使用天然肿瘤细胞生长的天然抑制剂来导致未来的癌症治疗方法。