Role of decorin and diffusion MRI in anti-VEGF efficacy for recurrent glioblastoma

项目摘要/摘要 胶质母细胞瘤(GBM)是一种几乎没有临床选择的致命疾病。尽管外科手术取得了一定的进步 手术、放疗和化疗，确诊后的中位生存期仅为14个月左右。在复发时，很少有 存在有效的治疗选择。贝伐单抗，一种人源化的抑制血管内皮生长因子-A的单抗，收到了 2009年5月加快了FDA对用于复发性GBM的批准，并迅速成为复发性GBM的标准护理 在美国的GBM。几乎所有的患者在治疗过程中都会接受贝伐单抗治疗。因为贝伐单抗 在GBM的管理中发挥着如此重要的作用，开发成像生物标记物来提高风险 分层和预测患者的利益是非常理想的。这样的生物标记物将在临床上用于识别 将受益于贝伐单抗并对下一阶段的队列浓缩有科学意义的患者 针对高危患者的联合疗法或探索性研究，其中常规疗法如贝伐单抗 都有可能失败。 广泛的初步数据(在400名患者中进行的7项试验)表明，弥散磁共振特征是一种强烈的、独立的 复发肾小球基底膜患者抗血管内皮生长因子治疗效果的预测指标，如果患者 在对比剂增强的肿瘤中表现为高表观扩散系数(ADC)。数据还表明，这些扩散 MR信号可能是由于核心蛋白(DCN)的表达升高所致，核心蛋白是一种具有多种功能的糖蛋白。我们 假设生存优势和成像特征来自DCN的多方面功能，包括 抗血管生成特性和细胞外基质的软化，我们理论上会导致增加 抗血管内皮生长因子治疗的有效性和ADC的增加。 目前的研究将探索DCN表达、弥散磁共振成像和抗血管内皮生长因子抗体之间的因果和机制联系 治疗效果。首先，目标1将涉及对弥散磁共振表型和 图像引导活检检测DCN蛋白在人GBM中的表达 免疫组织化学和原位杂交法检测基因表达。弥散磁共振成像与弥散张量成像的关系 表达，以及使用完整外显子组分析的相应的基因类型，使用批量RNA测序的遗传亚型， 使用单细胞RNA测序的细胞状态和循环DCN的血浆水平也将被执行。 同时，Aim 2将建立DCN表达、弥散磁共振测量、 和抗血管内皮生长因子治疗通过复合钙，基因修饰的患者来源的原位异种移植(Pdx)。 临床前试验。为了实现这一点，一系列患者来源的细胞系将被编辑为沉默过表达的DCN PDX模型使用四环素控制的基因表达系统。DCN的表达在改变中的直接作用 磁共振弥散成像测量和通过开启或关闭DCN表达来提高抗血管内皮生长因子治疗后的生存率 使用多西环素将被确定。

PROJECT SUMMARY/ABSTRACT Glioblastoma (GBM) is a uniformly fatal disease with very few clinical options. Despite modest advancements in surgical procedures, radiation and chemotherapy, median survival from diagnosis is only around 14 months. Upon recurrence, few effective treatment options exist. Bevacizumab, a humanized monoclonal antibody that inhibits VEGF-A, received accelerated FDA approval in May 2009 for use in recurrent GBM and quickly became the standard of care for recurrent GBM in the United States. Almost all patients receive bevacizumab at some point in their treatment. Because bevacizumab plays such an important role in the management of GBM, the development of imaging biomarkers to improve risk stratification and predict patient benefit is highly desired. Such a biomarker would be clinically useful for identifying patients that will benefit from bevacizumab as well as scientifically useful for cohort enrichment in the next phase of combination therapies or exploratory studies aimed at high-risk patients, where conventional therapies like bevacizumab are likely to fail. Extensive preliminary data (>7 trials in >400 patients) suggests diffusion MRI characteristics are a strong, independent predictor of anti-VEGF therapeutic efficacy in recurrent GBM, with patients exhibiting a significant survival benefit if they present with a high apparent diffusion coefficient (ADC) within contrast enhancing tumor. Data also suggests these diffusion MR signatures may result from an elevated expression of decorin (DCN), a glycoprotein with a variety of functions. We hypothesize that the survival advantage and imaging signatures arise from the multifaceted functions of DCN, which include anti-angiogenic characteristics and softening of the extracellular matrix, which we theorize would result in increased effectiveness of anti-VEGF therapies and an increase in ADC. The current study will explore the causal, mechanistic links between DCN expression, diffusion MRI, and anti-VEGF treatment efficacy. First, Aim 1 will involve a deep exploration into the association between diffusion MR phenotypes and DCN expression in human GBM using image-guided biopsies and examining DCN protein expression using immunohistochemistry and gene expression using in-situ hybridization. The relationship between diffusion MRI, DCN expression, and corresponding genotypes using whole exome analysis, genetic subtypes using bulk RNA sequencing, cellular states using single-cell RNA sequencing, and blood plasma levels of circulating DCN will also be performed. Concurrently, Aim 2 will establish the causal, mechanistic links between DCN expression, diffusion MRI measurements, and anti-VEGF treatment in GBM through ca complex, genetically modified patient-derived orthotopic xenograft (PDX) preclinical trial. To accomplish this, a series of patient-derived cell lines will be edited to silence of overexpress DCN within PDX models using a tetracycline-controlled gene expression system. The direct role of DCN expression in changing diffusion MRI measurements and increasing survival following anti-VEGF therapy by turning on or off DCN expression using doxycycline will be determined.