Rewiring ERBB Signaling in Cancer Cells

重新连接癌细胞中的 ERBB 信号

基本信息

批准号：
7375348
负责人：
RALF LANDGRAF
金额：
$ 27.3万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-07-01 至 2008-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7375348
关键词：
Adopted Agonist Amplifiers Anoikis Antineoplastic Agents Apoptosis Apoptotic Avidity Behavior Binding Sites Biological Assay Braces-Orthopedic appliances Buffers Cancer Center Cell Adhesion Cell Death Cell Line Cell Survival Cells Cellular Structures Characteristics Chimera organism Clinical Collaborations Complement Complex Data Disruption Dissociation Docking Doctor of Philosophy Drug resistance EGFR gene ERBB2 gene ERBB3 gene Engineering Ensure Equilibrium Evaluation Exclusion Face Fluorescence Microscopy Focal Adhesion Kinase 1 Foundations Generations Goals Growth Lead Ligands Light MAP Kinase Gene Maintenance Malignant Neoplasms Mediating Methodology Modeling Modification Molecular Conformation Nature Outcome Pathway interactions Pattern Phenotype Phosphorylation Phosphotransferases Probability Property Protein Overexpression Proteins Proteomics Publishing Range Reagent Receptor Signaling Relative (related person)Residual state Roche brand of trastuzumab Role Scheme Signal Transduction Signaling Molecule Site Solid Neoplasm Spatial Behavior Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Staging System Testing Therapeutic Uses Therapeutic antibodies Tyrosine Phosphorylation Variant Work aptamer base cancer cell cytotoxic density dimer dosage gel electrophoresis inhibitor/antagonist insight killings kinase inhibitor malignant breast neoplasm novel receptor receptor density response scaffold size therapeutic target tumorigenic

项目摘要

DESCRIPTION (provided by applicant): In several solid tumors, but especially in breast cancers, overexpression of ERBB2 results in more aggressive growth, and enhanced metastatic potential and probability of emergence of drug resistance. An important aspect in this response is the interaction between ERBB2 and ERBB3. Simultaneously elevated levels of ERBB3 phosphorylation (and in many cases receptor levels) result in enhanced anti-apoptotic signaling since several PI3K binding sites reside in the kinase-deficient ERBB3. Unless ERBB2 inhibition is quantitative (which is currently not feasible), steady state levels of phospho-ERBB3 rapidly return to pre-inhibition levels after kinase inhibitor treatment through stabilization of the residual activated ERBB3, regardless of sustained and substantial inhibition of ERBB2. This seriously undercuts ERBB2 directed therapy, but it also reflects on intrinsic aspects of ERBB2-ERBB3 signaling. ERBB2 has apparently evolved to avoid stable self-association and is constitutively activated in very transient interactions. Our preliminary data suggest that ERBB2 has built-in control mechanisms to further suppress "accidental activation" in such transient complexes. ERBB2 overexpression results in high levels of activated ERBB2 but at a state of spatial separation and low fraction of activation. We propose that this reflects efforts by the cancer cell to ensure a low spatial density of activated receptors, because the combination of spatial density and exclusion of ERBB3 in stable ERBB2 dimers would favor a cytotoxic signaling outcome. We have investigated this by using chimeric receptor constructs with altered intrinsic control and association behavior as well as ligand variants that differ in their degree of disruption of ERBB3 clusters. In contrast to ERBB2, self-association and orderly dissociation of clusters during activation appears to be required for ERBB3. Perturbing this system causes cell death in a manner that appears to be related to changes in cell adhesion characteristics, possibly because the cells progress towards a more pro-metastatic path without sufficient signaling to "brace" against the onset of anoikis like apoptosis. The avoidance of ERBB2 clustering and maintenance of ERBB3 clusters are important in getting a balanced signaling response and are very accessible targets for deliberate system perturbation. We will evaluate the nature of cell death in different cellular contexts, adopt existing and novel methodology for direct assessment of receptor clustering and spatial proximity of activated receptors to evaluate their contribution to signaling outcomes, and determine the nature of signaling that emanates from out-of-context and cell-death promoting activation. It is our long range goal to capitalize on this understanding to enforce out-of-context activation of ERBB2 by engineered therapeutics (antibodies or aptamers). The studies proposed here are also likely to shed light on the mechanisms of currently used therapeutics (such as Herceptin) which may, albeit without mechanistic foundation, already utilize part of this response. We also expect to better understand why previous attempts to actively enforce ERBB2 mediated apoptosis have not been more successful.

描述（由申请人提供）：在几种实体瘤中，尤其是在乳腺癌中，ERBB2的过度表达导致更积极的生长，并增强转移潜力和出现耐药性的可能性。该反应的一个重要方面是 ERBB2 和 ERBB3 之间的相互作用。同时，ERBB3 磷酸化水平（在许多情况下是受体水平）升高会导致抗凋亡信号增强，因为激酶缺陷的 ERBB3 中存在多个 PI3K 结合位点。除非 ERBB2 抑制是定量的（目前不可行），否则磷酸化 ERBB3 的稳态水平在激酶抑制剂处理后通过稳定残留的活化 ERBB3 迅速恢复到抑制前水平，无论 ERBB2 是否持续和实质性抑制。这严重削弱了 ERBB2 定向治疗，但也反映了 ERBB2-ERBB3 信号传导的内在方面。 ERBB2 显然已进化为避免稳定的自关联，并在非常短暂的相互作用中被组成型激活。我们的初步数据表明，ERBB2 具有内置的控制机制，可以进一步抑制此类瞬态复合物中的“意外激活”。 ERBB2 过度表达导致高水平的激活 ERBB2，但处于空间分离和低激活比例的状态。我们认为这反映了癌细胞为确保激活受体的低空间密度所做的努力，因为空间密度和稳定 ERBB2 二聚体中 ERBB3 的排除相结合将有利于细胞毒性信号转导结果。我们通过使用具有改变的内在控制和关联行为的嵌合受体构建体以及对 ERBB3 簇的破坏程度不同的配体变体对此进行了研究。与 ERBB2 相比，ERBB3 似乎需要激活过程中簇的自缔合和有序解离。扰乱该系统会导致细胞死亡，其方式似乎与细胞粘附特性的变化有关，可能是因为细胞朝着更利于转移的路径发展，而没有足够的信号来“支撑”细胞凋亡等失巢凋亡的发生。避免 ERBB2 聚类和维护 ERBB3 聚类对于获得平衡的信号响应非常重要，并且是故意系统扰动的非常容易实现的目标。我们将评估不同细胞环境中细胞死亡的性质，采用现有的和新颖的方法来直接评估受体聚类和激活受体的空间邻近性，以评估它们对信号传导结果的贡献，并确定从外部发出的信号传导的性质。 -环境和细胞死亡促进激活。我们的长期目标是利用这种理解，通过工程疗法（抗体或适体）强制 ERBB2 的断言激活。这里提出的研究也可能揭示目前使用的治疗药物（例如赫赛汀）的机制，尽管没有机制基础，但可能已经利用了这种反应的一部分。我们还希望更好地理解为什么之前积极执行 ERBB2 介导的细胞凋亡的尝试没有取得更大的成功。