融合蛋白EGFP-PPA原核表达及标记肿瘤细胞研究

Mannose-Exposing Tumor Cells Detected by the EGFP-PPA Fusion Protein

肿瘤细胞糖基化改变是非常普遍的现象,与恶性肿瘤的发生发展有着密切的关系。掌叶半夏凝集素(Pinellia pedatisecta agglutinin,PPA)是一种甘露糖特异性结合凝集素,与增强型绿色荧光蛋白(enhanced green fluorescent protein EGFP),通过基因工程技术形成融合基因,并在大肠杆菌中表达纯化了EGFP-PPA融合蛋白。实验结果表明,此融合蛋白可以识别实体肿瘤细胞表面的一部分标志,如Hep3B、Hu7、PLC、BEL-7404以及A549,而不能识别肝正常细胞L02,提示实体瘤细胞表面显露的甘露糖残基被此融合蛋白所识别,说明PPA识别具有甘露糖表型的实体瘤细胞表面的一部分,这些实验结果为进一步阐明甘露糖显露细胞在肿瘤发生发展中的作用提供了新的研究手段。

Altered glycosylation may be a hallmark of malignant transformation and cancer progression.In the work described,a specific mannose-binding lectin,Pinellia pedatisecta agglutinin（PPA）,is genetically fused with enhanced green fluorescent proteins（EGFP） to generate the EGFP-PPA fusion protein.Results show that the fusion protein EGFP-PPA recognizes a small fraction of solid tumor cells,including Hep3B,Hu7,PLC,BEL-7404 and A549,however,the same phenomenon is not observed in normal liver cell line L02,indicating that a fraction of solid tumor cells exposing mannose residues is detected by EGFP-PPA.The authors,herein,report that PPA recognizes a fraction of solid tumor cells showing mannose-exposing phenotype.Taken together,these results provide a new method to elucidate the function of these mannose-exposing solid tumor cells in tumor development.