ErbB2 Downregulation Through HSP90 Inhibition

通过 HSP90 抑制下调 ErbB2

• 批准号: 7212882
• 负责人: Hamid Band
• 金额: $ 4.92万
• 依托单位: NORTHSHORE UNIVERSITY HEALTHSYSTEM
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2007-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7212882
• 关键词: Animals; Ansamycin Antineoplastic Antibiotic; Antibodies; Antineoplastic Agents; Area; Biochemical; Bioinformatics; Biological; Biology; Breast; Breast Cancer Cell; Cancer Etiology; Cancer Patient; Cancer cell line; Cell Proliferation; Cell surface; Cells; Clinical; Clinical Research; Dominant-Negative Mutation; Down-Regulation; ERBB2 gene; Enzymes; Epidermal Growth Factor Receptor; Family; Family member; Geldanamycin; Growth; HSP 90 inhibition; Heat-Shock Proteins 90; Her2/erbb2/neu Staining Method; Heregulin; Heterodimerization; Human; Knowledge; Lead; Ligands; Lysosomes; Malignant Neoplasms; Mediating; Modification; Molecular; Molecular Chaperones; Mono-S; Nude Mice; Pathway interactions; Patients; Pharmaceutical Preparations; Phase; Play; Polyubiquitin; Process; Protein Overexpression; Protein Tyrosine Kinase; Proteins; Proteomics; Public Health; RNA Interference; Recruitment Activity; Recycling; Relapse; Relative (related person); Rifabutin; Role; Signal Transduction; Signaling Protein; Surface; Testing; Therapeutic; Therapeutic Effect; Translating; Trastuzumab; Ubiquitin; Ubiquitination; Variant; Work; Xenograft procedure; Yeasts; anticancer activity; attenuation; base; hormone therapy; human SGTA protein; improved; in vivo; inhibitor/antagonist; insight; malignant breast neoplasm; member; multicatalytic endopeptidase complex; novel; novel therapeutics; outcome forecast; receptor; response; success; therapeutic target; trafficking; tumor; ubiquitin ligase; ubiquitin-protein ligase; yeast two hybrid system

DESCRIPTION (provided by applicant): Technical Description: ErbB2 (Her2/Neu) overexpression is found in 20-30% of breast cancer patients as well as other cancers, and signifies poor prognosis. Success with humanized anti-ErbB2 antibodies has further validated ErbB2 as a therapeutic target. Ansamycin HSP90 inhibitors, such as 17AAG, are in phase l/ll clinical studies as novel anticancer agents as they target ErbB2 and other signaling proteins for ubiquitin-dependent degradation. Based on recent studies by us and others, we hypothesize that CHIP (C-terminus of HSP70-lnteracting Protein) and additional hitherto unknown ubiquitin ligases mediate 17AAG-induced ErbB2 downregulation either through proteasomal or through lysosomal degradation. Here, we propose comprehensive strategies to test these hypotheses. We will carry out cell biological, molecular and biochemical studies to distinguish whether HSP90 inhibitor-driven ErbB2 downregulation is mediated through degradation in the proteasome, lysosome or both. We will examine the role of CHIP and several candidate proteins identified through bioinformatics in 17AAG-induced ErbB2 ubiquitinylation and degradation, proliferation and survival of ErbB2 overexpressing breast cancer cell lines and in their in vivo growth in nude mice, using overexpression, dominant-negative mutant expression and RNAi knockdown strategies. If additional unknown ubiquitin ligases appear likely to mediate 17AAG-induced ErbB2 degradation, we will employ proteomics and yeast two-hybrid approaches to identify these proteins and characterize them functionally as for CHIP and other candidates. Through this comprehensive approach, we hope to elucidate the biological basis of ErbB2 downregulation by HSP90 inhibitory drugs and their anticancer activity. Success of these studies will open new therapeutic avenues for ErbB2-driven cancers as well those caused by EGFRvlll, an ErbB1 variant with biological similarities with ErbB2. Relevance to Public Health: This proposal will investigate new means of interfering with a cancer-causing protein Her2/Neu that is highly increased in 20-30% breast cancers with worst prognosis. The proposed studies could provide a basis for newer, more effective targeted therapies against breast and other cancers.

描述(申请人提供)：技术描述：ERBB2(Her2/Neu)在20-30%的乳腺癌患者以及其他癌症患者中发现过度表达，并表明预后不良。人源化抗ErbB2抗体的成功进一步证实了ErbB2是一种治疗靶点。安山霉素HSP90抑制剂，如17AAG，作为新型抗癌药物正处于L/11期临床研究阶段，因为它们针对ErbB2和其他信号蛋白进行泛素依赖的降解。根据我们和其他人最近的研究，我们假设CHIP(HSP70相互作用蛋白的C末端)和其他迄今未知的泛素连接酶通过蛋白酶体或溶酶体降解介导17AAG诱导的ErbB2下调。在这里，我们提出了全面的策略来检验这些假设。 我们将进行细胞生物学、分子和生化研究，以区分HSP90抑制剂驱动的ErbB2下调是否是通过蛋白酶体、溶酶体或两者的降解来介导的。我们将利用过表达、显性-阴性突变表达和RNAi敲除策略，研究CHIP和通过生物信息学确定的几个候选蛋白在17AAG诱导的ErbB2泛素化和ErbB2高表达乳腺癌细胞株的降解、增殖和存活以及它们在裸鼠体内生长中的作用。如果其他未知的泛素连接酶可能介导17AAG诱导的ErbB2降解，我们将使用蛋白质组学和酵母双杂交方法来鉴定这些蛋白质，并像CHIP和其他候选蛋白质一样对它们进行功能鉴定。通过这一综合途径，我们希望阐明HSP90抑制药物下调ErbB2的生物学基础及其抗癌活性。这些研究的成功将为ErbB2驱动的癌症以及由EGFRvlll引起的癌症开辟新的治疗途径。EGFRvlll是一种ErbB1变体，与ErbB2具有生物学上的相似性。 与公共卫生相关：这项提案将调查干扰一种致癌蛋白Her2/Neu的新方法，这种蛋白在预后最差的乳腺癌中高达20%-30%。拟议的研究可能为更新、更有效的针对乳腺癌和其他癌症的靶向治疗提供基础。