佛波酯能改变细胞表面糖蛋白N－糖链的结构

利用标记Ｎ－糖链的凝集素亲和层析法研究了佛波醇肉桂酸乙酸酯（ＰＭＡ）对人肝癌细胞ＳＭＭＣ－７７２１表面糖蛋白上Ｎ－糖链结构的影响，发现１００ｎｍｏｌ／Ｌ的ＰＭＡ处理５天后，可使细胞表面Ｎ－糖链中高甘露糖型和杂合型以及四天线、Ｃ２Ｃ２，６三天线复杂型的比例增高，而二天线复杂型降低。此结果与我们曾报道的视黄酸（ＲＡ）和双丁配环磷酸腺苷（ｄｂ－ｃＡＭＰ）对该细胞表面Ｎ－糖链的影响相反。因ＲＡ和ｄｂ－ｃＡＭＰ是ＳＭＭＣ－７７２１细胞的分化诱导剂，可抑制细胞生长；而ＰＭＡ是该细胞的增殖促进剂，故细胞表面Ｎ－糖链的变化与细胞的分化和增殖密切相关。

Phorbol Ester Changes the Structure of N-linked Glycans in the Cell Surface Glycoproteins

Using serial lectin affinity chromatography of 3H-lebeled N-glycans,the effects of phorbol myriatate acetate(PMA)on the structure of N-glycans from SMMC-7721 cell surface were studied. It was found that after treatment with 100 AM PMA for 5 days,the percentage of the high-mannose type and the hybrid type,as well as the tetraantennary and the C2C2.6 triantennary complex type in the N-glycans were increased.Whereas the percentage of biantennary complex type was decreased.These changes were just opposite to that observed for the effect of retinoic acid and dibutyryl cyclic adenolsine monophosphate(db-cAMP)on the N-glycan from the same cell line.Considering that retinoic acid and db-cAMP are the differentiation-inducers and PMA is a proliferative stimutator of SMMO-7721 cells,the present results suggest that there is a close relationship between the structure of N-glycan and the differentiation or proliferation of the cells.