癌胚抗原特异性寡核苷酸适配子的体外筛选及其意义

目的:通过体外筛选获得癌胚抗原(CEA)特异性适配子,为高表达CEA肿瘤的靶向奠定基础。方法:构建长度为81 bp的随机ssDNA文库,体外筛选、富集CEA特异性适配子,通过配体介导的靶蛋白纯化实验检测经筛选的适配子与纯化蛋白结合;提取LS174T细胞总蛋白,免疫共沉淀检测经筛选的适配子与细胞总蛋白的结合。结果:经体外7轮筛选富集及筛选条件的优化,配体介导的靶标分离实验证实了筛选出的适配子与纯化CEA蛋白的结合;免疫沉淀及Westem blot证实了其识别并特异性结合天然状态的CEA。结论:经过体外7轮筛选,证实了所获得的CEA适配子可特异性地与纯化CEA和天然状态的CEA蛋白结合,为后续高表达的CEA肿瘤的靶向诊断和治疗奠定了初步的实验基础。

In vitro selection of specific binding DNA aptamer to human carcinoembryonic antigen

Objective: Given many advantages over antibodies,the aptamer has shown its potential in therapeutic and commercial applications during the past decades.Carcinoembryonic antigen(CEA),one of the most widely studied human tumor-associated antigens(TAA),has been considered as an attractive molecule for cancer target therapy and imaging.This paper focuses on the screening of the CEA-specific aptamer in vitro.Methods: Seven rounds of in vitro selection were performed against the purified CEA protein.Ligand-mediated target purification and co-immunoprecipitation were adopted to verify the specific binding of the aptamer to the purified and native protein separately.Results:We obtained the CEA-specific aptamer that could bind both the purified and the native protein with high specificity.Conclusion: The CEA-specific apatmer was produced.The results in this study may provide preliminary base for further investigation of the CEA-aptamer.Given the great advantages of the aptamer,one can expect a development of tumor associated antigen-aptamer applications in the future.