Tsg101 - a Modulator of ErbB2 Signaling in Breast Cancer

Tsg101 - 乳腺癌中 ErbB2 信号传导的调节剂

• 批准号: 7934238
• 负责人: Kay-Uwe Wagner
• 金额: $ 19.73万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7934238
• 关键词: Ablation; Address; Advanced Development; Affect; Amino Acid Motifs; Binding; Biochemical; Biological; Breast Cancer Cell; Cell Culture Techniques; Cell Death; Cell Surface Receptors; Cell Survival; Complex; Data; Development; Down-Regulation; ERBB2 gene; Engineering; Epidermal Growth Factor Receptor; Epithelial; Epithelial Cells; Event; Exhibits; Gene Amplification; Growth; Her2/erbb2/neu Staining Method; Heterodimerization; Human; In Vitro; Individual; Knock-out; Lead; Ligase; Lysosomes; Malignant Neoplasms; Mammary Neoplasms; Mammary Tumorigenesis; Mammary gland; Mediating; Modeling; Molecular; Molecular Genetics; Mus; N-terminal; Oncogene Proteins; Oncogenic; Outcome; Pathway interactions; Pharmaceutical Preparations; Pharmacologic Substance; Prevention therapy; Property; Proteins; Proteomics; Publishing; Receptor Protein-Tyrosine Kinases; Research; Resistance; Roche brand of trastuzumab; Role; Signal Transduction; Small Interfering RNA; Sorting - Cell Movement; Testing; Tetracyclines; Transducers; Trastuzumab; Treatment Efficacy; Tsg101 protein; Tyrosine Kinase Inhibitor; Ubiquitination; Work; base; breast tumorigenesis; cancer cell; human TSG101 protein; in vivo; interest; malignant breast neoplasm; mammary gland development; member; mutant; neoplastic; neoplastic cell; novel; novel therapeutic intervention; outcome forecast; overexpression; preclinical study; prevent; public health relevance; receptor; receptor downregulation; therapeutic target; tool; tumor progression; ubiquitin ligase; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Our long-term objective is to elucidate how growth-regulatory signaling networks regulate the multiplication and survival of normal and neoplastic mammary epithelial cells. Our current studies focus on biological and biochemical functions of the oncoprotein encoded by the Tumor Susceptibility Gene 101 (Tsg101). Tsg101 is a key member of the endosomal sorting complex required for transport (ESCRT). This pathway is crucial for the transport, sorting, and lysosomal degradation of ubiquitinated cell surface receptors, in particular such as the EGFR and ErbB2 (Her2/neu) that are important receptor tyrosine kinases implicated in breast tumorigenesis and other human malignancies. A primary objective of our current research is to examine how Tsg101 engages with and modifies active ErbB-signaling complexes. In particular, we are interested in the function of Tsg101's intrinsic PTAP amino acid motif to regulate the activity of Tsg101 and its effect on the downregulation of oncogenic Her2/neu in normal and neoplastic mammary epithelial cells. Our central hypothesis is that altering the expression of Tsg101 or modifying its activity through inhibition of its self-regulatory PTAP domain will affect the onset and progression of Her2/neu-mediated mammary tumorigenesis. In the first specific aim of this proposal, we will determine how altering the expression level of wildtype Tsg101 modifies the growth properties of mouse and human mammary cancer cells in culture as well as tumor progression in vivo. We will also examine whether Tsg101 deficiency affects the survival of Trastuzumab-resistant human breast cancer cells. The second specific aim focuses on the mechanisms of the activation of Tsg101 that mediate an accelerated ubiquitination and degradation of the Tsg101 protein and its cargo (i.e. ErbB2). We will study the interaction of constitutively active Tsg101 with the ubiquitin ligase Tal as well as known members of the ESCRT complex. Additionally, we will use a proteomics approach to identify novel regulators for the activation of Tsg101. In the third specific aim, we will address whether activating Tsg101 will result in a more efficient downregulation of oncogenic ErbB2 in mammary cancer cells in vitro and in vivo. We propose the development of advanced genetically engineered models to predict the outcome of a possible targeted therapy against Her2/neu-mediated breast cancer by modifying the activity of Tsg101. Using these tools we might be able to herald the efficacy of this therapeutic strategy before pharmaceutical agents become available. PUBLIC HEALTH RELEVANCE: A significant subset of invasive breast cancers exhibit Her2/neu gene amplification with an unfavorable prognosis. The objective of this proposal is to elucidate how altering the expression of Tsg101 or modifying its activity will affect the onset and progression of Her2/neu-mediated breast cancer. The genetic and molecular studies outlined in this application will help to predict the potential value of Tsg101 as a therapeutic target before a drug will be developed and tested in preclinical trials.

描述（由申请人提供）：我们的长期目标是阐明生长调节信号网络如何调节正常和肿瘤性乳腺上皮细胞的增殖和存活。我们目前的研究重点是肿瘤易感基因 101 (Tsg101) 编码的癌蛋白的生物学和生化功能。 Tsg101 是运输所需的内体分选复合体 (ESCRT) 的关键成员。该通路对于泛素化细胞表面受体的运输、分选和溶酶体降解至关重要，特别是 EGFR 和 ErbB2 (Her2/neu)，它们是与乳腺肿瘤发生和其他人类恶性肿瘤有关的重要受体酪氨酸激酶。我们当前研究的主要目标是研究 Tsg101 如何参与并修饰活跃的 ErbB 信号复合物。我们特别感兴趣的是 Tsg101 的内在 PTAP 氨基酸基序调节 Tsg101 活性的功能及其对正常和肿瘤性乳腺上皮细胞中致癌 Her2/neu 下调的影响。我们的中心假设是，改变 Tsg101 的表达或通过抑制其自我调节 PTAP 结构域改变其活性将影响 Her2/neu 介导的乳腺肿瘤发生的发生和进展。在该提案的第一个具体目标中，我们将确定改变野生型 Tsg101 的表达水平如何改变小鼠和人类乳腺癌细胞在培养物中的生长特性以及体内肿瘤进展。我们还将检查 Tsg101 缺陷是否会影响曲妥珠单抗耐药的人乳腺癌细胞的存活。第二个具体目标侧重于 Tsg101 的激活机制，该机制介导 Tsg101 蛋白及其货物（即 ErbB2）的加速泛素化和降解。我们将研究组成型活性 Tsg101 与泛素连接酶 Tal 以及 ESCRT 复合体的已知成员的相互作用。此外，我们将使用蛋白质组学方法来识别 Tsg101 激活的新型调节因子。在第三个具体目标中，我们将解决激活 Tsg101 是否会导致体外和体内乳腺癌细胞中致癌 ErbB2 更有效的下调。我们建议开发先进的基因工程模型，通过改变 Tsg101 的活性来预测针对 Her2/neu 介导的乳腺癌的可能靶向治疗的结果。使用这些工具，我们也许能够在药物可用之前预示这种治疗策略的功效。公共健康相关性：浸润性乳腺癌的一个重要子集表现出 Her2/neu 基因扩增，预后不良。该提案的目的是阐明改变 Tsg101 的表达或改变其活性将如何影响 Her2/neu 介导的乳腺癌的发病和进展。本申请中概述的遗传和分子研究将有助于在临床前试验中开发和测试药物之前预测 Tsg101 作为治疗靶点的潜在价值。