生物选择性代谢和正交反应介导的靶向标记策略：唾液酸糖蛋白定量和肿瘤细胞成像示踪分析

蛋白质糖基化是一类重要的蛋白质翻译后修饰方式,糖蛋白在生命过程中发挥着重要作用.我们针对唾液酸糖蛋白,设计合成新靶向多功能信号（质谱、顺磁共振造影和荧光）报告分子，利用叠氮修饰的非天然唾液酸糖苷可通过细胞自身代谢组装到糖链末端的特点,进一步通过生物正交反应将所设计合成的多功能信号报告分子一维靶向标记到肿瘤细胞表面唾液酸糖蛋白上,不仅可实现唾液酸糖蛋白和肿瘤细胞的ICP-MS定量和计数分析，而且可进行肿瘤细胞表面唾液酸糖蛋白和肿瘤细胞的顺磁共振造影和荧光成像；此外，标签分子中集成了生物素单元，可用于唾液酸糖蛋白的富集分离，便于生物质谱进行结构鉴定。这一生物自身代谢和生物正交反应介导的靶向一维标记多维检测方法可以提供唾液酸糖蛋白含量变化和肿瘤细胞转移的示踪信息，为进一步研究肿瘤细胞表面唾液酸化的糖蛋白在肿瘤发生和转移过程中的作用机制提供了新的研究工具，可望为肿瘤治疗药物的设计提供有力的信息。

Protein glycolisation is one of the most important ways of post translational protein modification, and glycoproteins play a crucile role during life process. We will design and synthesize a new reporting molecule of multiple functions including ICP-MS readout, MRI and fluorescence imaging.It can be labeled specifically onto the N3-Sia at the end of sugur chain of sialoglycoproteins, which are biometabolized into the sialoglycoproteins,via the so-called bio-orthogonal reaction. This specifc labling enable one not only to quantify and count the sialoglycoproteins and tumor cells on which sialoglycoproteins are overexpressed, but also to be subjected to MRI and fluorescence imaging of the sialoglycoproteins and tumor cells. Besides, because of a biotin unit has been binded into the reporting molecule, the sialoglycoproteins can be enriched and separated out of the proteins bulk. This makes it easy to further characterize the sialoglycoproteins using ESI- and/or MALDI-based mass spectrometry.The bioselective metabolism and bio-orthogonal mediated target-labeling strategy with multiplex detection ability will offer ever more information on the concentration change of the sialoglycoproteins and the translocation of the tumor cells, presenting a new tool for studying the behavor and mechnism of sialoglycoproteins during cancer development.It is very much expected that such information obtained will benefit the design of drugs towards cancer.