Instituto de Micro y Nanotecnología(IMN-CNM), CSIC, Tres Cantos, Madrid, Spain.
Instituto de Micro y Nanotecnología(IMN-CNM), CSIC, Tres Cantos, Madrid, Spain.
Semin Cancer Biol. 2018 Oct;52(Pt 1):26-38. doi: 10.1016/j.semcancer.2017.08.011. Epub 2017 Sep 1.
Most of the cancer deaths could be avoided by early detection of the tumor when it is confined to its primary site and it has not metastasized. To this aim, one of the most promising strategies is the discovery and detection of protein biomarkers shed by the young tumor to the bloodstream. Proteomic technologies, mainly mass spectrometry and multiplexed immunoassays, have rapidly developed during last years with improved limits of detection and multiplexing capability. Unfortunately, these developments together major investments and large international efforts have not resulted into new useful protein biomarkers. Here, we analyze the potential and limitations of current proteomic technologies for detecting protein biomarkers released into circulation by the tumor. We find that these technologies can hardly probe the deepest region of the plasma proteome, at concentrations below the pg/mL level, where protein biomarkers for early cancer detection may exist. This clearly indicates the need of incorporating novel ultrasensitive techniques to the proteomic tool-box that can cover the inaccessible regions of the plasma proteome. We here propose biological detectors based on nanomechanical systems for discovery and detection of cancer protein biomarkers in plasma. We review the modes of operation of these devices, putting our focus on recent developments on nanomechanical sandwich immunoassays and nanomechanical spectrometry. The first technique enables reproducible immunodetection of proteins at concentrations well below the pg/mL level, with a limit of detection on the verge of 10 ag/mL. This technology can potentially detect low abundance tumor-associated proteins in plasma at the very early stages of the tumor. The second technique enables the identification of individual intact proteins by two physical coordinates, the mass and stiffness, instead of the mass-to-charge ratio of the protein constituents. This technology enormously simplifies the identification of proteins and it can provide useful information on interactions and posttranslational modifications, that otherwise is lost in mass spectrometry.
大多数癌症死亡可以通过早期发现肿瘤来避免，当肿瘤局限于原发部位且尚未转移时。为此，最有前途的策略之一是发现和检测由年轻肿瘤分泌到血液中的蛋白质生物标志物。蛋白质组学技术，主要是质谱和多重免疫分析，近年来随着检测限和多重检测能力的提高而迅速发展。不幸的是，这些进展以及大量的投资和大型国际努力并没有产生新的有用的蛋白质生物标志物。在这里，我们分析了当前用于检测肿瘤释放到循环中的蛋白质生物标志物的蛋白质组学技术的潜力和局限性。我们发现，这些技术很难探测到血浆蛋白质组最深的区域，即浓度低于 pg/mL 水平的区域，而这些区域可能存在用于早期癌症检测的蛋白质生物标志物。这清楚地表明，需要将新的超灵敏技术纳入蛋白质组学工具包中，以覆盖血浆蛋白质组中无法到达的区域。在这里，我们提出了基于纳米机械系统的生物探测器，用于发现和检测血浆中的癌症蛋白质生物标志物。我们回顾了这些设备的操作模式，重点关注最近在纳米机械三明治免疫分析和纳米机械光谱学方面的进展。第一种技术能够在 pg/mL 以下的浓度下重复检测蛋白质，检测限接近 10 ag/mL。这项技术有可能在肿瘤的早期阶段检测到血浆中低丰度的肿瘤相关蛋白。第二种技术可以通过质量和刚度这两个物理坐标来识别单个完整的蛋白质，而不是蛋白质成分的质荷比。这项技术极大地简化了蛋白质的鉴定，并且可以提供关于相互作用和翻译后修饰的有用信息，否则在质谱中会丢失这些信息。
