Photocleavage Technology for Improved Serum-based Multi-Biomarker Cancer Assays

总结/摘要 基于血液的多生物标志物面板为有效的早期癌症检测和全人群癌症筛查提供了巨大的希望。 筛选例如，由三种或更多种表现出高灵敏度和特异性的生物标志物组成的组 已经报道了几种不同的癌症，包括卵巢癌、肺癌、乳腺癌和结肠直肠癌。各种 还开发了小型化固相免疫测定平台， 成本多重生物标志物检测和定量。这些包括基于微阵列的仪器， 微流体和微珠技术。 现在的一个高度优先事项是将有前途的基于血液的多生物标志物癌症面板过渡到多重平台 用于大规模生物标志物验证和临床最终使用。多重测定技术尤其是 重要的是提供人口范围筛查所需的成本效益和高通量能力。 然而，多重免疫测定的主要问题是所谓的“基质效应”。相比于大多数 常规的单重测定如ELISA、小型化的多重测定对干扰高度敏感 这是由于血液中存在更多的非靶向物质。这种干扰可能来自于 多种机制包括：i）低特异性嗜异性抗体; ii）基质诱导的珠聚集（例如， 和iii）非靶基质组分与任何组分的特异性或非特异性结合 生物标志物检测的结果。此外，样品基质的高粘度（例如，来自高总蛋白浓度） 可能干扰通常用于多重测定的微流体。重要的是，矩阵效应不仅 限制了测定灵敏度，但降低了线性和定量准确度。 在第一阶段，我们将评估一种称为PC-PURE™的多重血清学癌症检测新方法， 旨在消除矩阵效应。该技术基于使用新型光可裂解（PC）连接体 由AmberGen开发，其并入亲和捕获剂如适体或抗体中。的 然后将可光裂解的捕获剂系在微珠、亲和树脂或其它表面上， 目标生物标志物。生物标记物-[捕获剂]复合物在几分钟内温和而快速地光释放 在非变性条件下，通过低强度近紫外光进入明确定义的缓冲液， 在多重免疫测定之前预纯化和浓缩靶生物标志物。不同于常规 方法使用封闭缓冲液，稀释剂和选择的消耗，具体到特定的基质成分，PC- PURE™通过快速预纯化感兴趣的生物标志物来消除所有基质效应。 在第一阶段，我们将评估PC-PURE™的应用，以改善血液样本的多重检测 肿瘤脱落的蛋白质生物标志物。肿瘤脱落生物标志物具有高度癌症特异性的巨大潜力， 在血液中含量极低，因此受基质效应影响最大。模型5-生物标志物 将检测用于卵巢癌诊断的蛋白质组。两种已知浓度的加标样品 将在多路Luminex® MagPix®平台上分析生物标志物和卵巢癌患者血液样本 以及在为高通量临床测试设计的Bio-Bio 2200平台上进行的II期。 这项研究将与生物统计学副教授Gheorghe Doros博士合作进行， 波士顿大学公共卫生学院生物统计咨询小组主任， 数据统计分析的专家指导。我们还将与创始人兼CSO Bill杰克逊博士密切合作 碱基对生物技术公司的首席技术官，一位核酸适体领域的顶尖专家。为了加速PC-PURE™的商业化，我们将 与Luminex®密切合作，Luminex ®是多重检测平台的领先制造商之一（参见支持函）。

SUMMARY/ABSTRACT Blood-based multi-biomarker panels hold great promise for effective early cancer detection and population-wide screening. For example, panels consisting of three or more biomarkers which exhibit high sensitivity and specificity have been reported for several different cancers including ovarian, lung, breast and colorectal cancer. A variety of miniaturized solid-phase immunoassay platforms have also been developed to perform high throughput and low- cost multiplex biomarker detection and quantification. These include instruments based on microarrays, microfluidics and micro-bead technology. A high priority is now to transition promising blood-based multi-biomarker cancer panels to multiplex platforms for large-scale biomarker validation and ultimate use in the clinic. Multiplex assay technologies are especially important to provide the cost-effectiveness and high throughput capacity necessary for population-wide screening. However, a major problem with multiplex immunoassays is the so-called “matrix effect”. Compared to most conventional single-plex assays such as ELISA, miniaturized multiplex assays are highly susceptible to interference caused by the presence of the more abundant, non-target agents in blood. Such interference can originate from a variety of mechanisms including: i) low specificity heterophile antibodies; ii) matrix-induced bead aggregation (e.g. in Luminex® assays) and iii) specific or non-specific binding of non-target matrix components to any component of the biomarker assay. In addition, high viscosity of the sample matrix (e.g. from high total protein concentration) can interfere with the microfluidics commonly used for multiplex assays. Importantly, the matrix effect not only limits assay sensitivity, but reduces linearity and quantitative accuracy. During Phase I we will evaluate a new approach to multiplex serological cancer assays termed PC-PURE™ which is designed to eliminate the matrix effect. This technology is based on the use of novel photocleavable (PC) linkers developed by AmberGen which are incorporated into affinity capture agents such as aptamers or antibodies. The photocleavable capture agents are then tethered to micro-beads, affinity resins or other surfaces and used to isolate the target biomarker. The biomarker-[capture agent] complexes are gently and rapidly photo-released in minutes under non-denaturing conditions by low-intensity near-UV light into a well-defined buffer, enabling simultaneous pre-purification and concentration of the target biomarkers prior to multiplex immunoassay. Unlike conventional approaches using blocking buffers, diluents and selected depletion, specific to particular matrix components, PC- PURE™ eliminates all matrix effects by rapidly pre-purifying the biomarkers of interest. In Phase I we will evaluate the application of PC-PURE™ to improve the multiplex detection of blood-based panels of tumor-shed protein biomarkers. Tumor-shed biomarkers have great potential for high cancer specificity but are found at extremely low abundance in the blood and hence suffer most from the matrix effect. A model 5-biomarker protein panel for ovarian cancer diagnosis will be tested. Both spike-in samples with known concentrations of the biomarkers and ovarian cancer patient blood samples will be analyzed on a multiplex Luminex® MagPix® platform and in Phase II on a Bio-Plex 2200 platform designed for high-throughput clinical testing. This research will be conducted in collaboration with Dr. Gheorghe Doros, Associate Professor of Biostatistics and Director of the Biostatistics Consulting Group at the Boston University School of Public Health, who will provide expert guidance for statistical analysis of the data. We will also work closely with Dr. Bill Jackson, Founder and CSO of Base Pair Biotechnologies, a leading expert on aptamers. To accelerate commercialization of PC-PURE™, we will work closely with Luminex®, one of the leading manufacturers of multiplex assay platforms (see letters of support).