Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
FASEB J. 2011 Aug;25(8):2528-37. doi: 10.1096/fj.10-178590. Epub 2011 Apr 14.
Cell surface glycans are involved in numerous physiological processes that involve cell-cell interactions and migration, including lymphocyte trafficking and cancer metastasis. We have used a bioorthogonal metabolic labeling strategy to detect cell surface glycans and demonstrate, for the first time, fluorescence and radionuclide imaging of sialylated glycans in a murine tumor model in vivo. Peracetylated azido-labeled N-acetyl-mannosamine, injected intraperitoneally, was used as the metabolic precursor for the biosynthesis of 5-azidoneuraminic, or azidosialic acid. Azidosialic acid-labeled cell surface glycans were then reacted, by Staudinger ligation, with a biotinylated phosphine injected intraperitoneally, and the biotin was detected by subsequent intravenous injection of a fluorescent or radiolabeled avidin derivative. At 24 h after administration of NeutrAvidin, labeled with either a far-red fluorophore or (111)In, there was a significant azido-labeled N-acetyl-mannosamine-dependent increase in tumor-to-tissue contrast, which was detected using optical imaging or single-photon-emission computed tomography (SPECT), respectively. The technique has the potential to translate to the clinic, where, given the prognostic relevance of altered sialic acid expression in cancer, it could be used to monitor disease progression.
细胞表面聚糖参与众多生理过程，包括细胞-细胞相互作用和迁移、淋巴细胞迁移和癌症转移。我们使用生物正交代谢标记策略来检测细胞表面聚糖，并首次在体内鼠肿瘤模型中荧光和放射性核素成像检测唾液酸化聚糖。将乙酰化叠氮标记的 N-乙酰甘露糖胺腹膜内注射作为 5-叠氮唾液酸或叠氮唾液酸的生物合成的代谢前体。然后，通过 Staudinger 连接反应，将叠氮唾液酸化的细胞表面聚糖与腹膜内注射的生物素化膦反应，随后通过静脉内注射荧光或放射性标记的亲和素衍生物检测生物素。在给予中性亲和素 24 小时后，用远红荧光团或 (111)In 标记，肿瘤与组织之间的对比有明显的依赖于叠氮乙酰甘露糖胺的增加，分别使用光学成像或单光子发射计算机断层扫描 (SPECT) 检测到。该技术具有转化为临床的潜力，鉴于癌症中唾液酸表达改变的预后相关性，它可用于监测疾病进展。
