Amano J, Oshima M
Division of Biochemistry and Nutrition, Research Institute, International Medical Center of Japan, Tokyo 162-8655, Japan.
J Biol Chem. 1999 Jul 23;274(30):21209-16. doi: 10.1074/jbc.274.30.21209.
We made a comparative study of the structures of the oligosaccharides on the glycoproteins from Caco-2 human colonic adenocarcinoma cells, before and after differentiation. Enterocytic differentiated Caco-2 cells highly express H type 1 blood group antigen on the cell surface as well as activities of brush border membrane hydrolases, such as dipeptidyl peptidase IV and alkaline phosphatase. A strong correlation was observed between the amounts of H type 1 blood group antigen and the degrees of differentiation. Structural analysis with use of lectin affinity high performance liquid chromatography revealed that typical mucin-type sugar chains of the glycoproteins from undifferentiated cells have H type 2 group, linear polylactosamines, and core 1 structure. On the other hand, differentiated cells newly contain H type 1 and Le(b) groups and core 2 structure. Mucins with H type 1 group make contact with brush border membrane enzymes on differentiated cells. Furthermore benzyl 2-acetamide-2-deoxy-alpha-D-galactopyranoside inhibited both expression of H type 1 group on the cell surface and enhancement of brush border membrane enzyme activities even in the presence of a differentiating inducer. These results suggest that the mucin-type sugar chains with H type 1 group have important functions regarding differentiation of Caco-2 cells.
我们对人结肠腺癌细胞系Caco-2在分化前后糖蛋白上寡糖的结构进行了比较研究。肠细胞分化的Caco-2细胞在细胞表面高表达1型H血型抗原以及刷状缘膜水解酶的活性，如二肽基肽酶IV和碱性磷酸酶。观察到1型H血型抗原的量与分化程度之间存在很强的相关性。利用凝集素亲和高效液相色谱进行结构分析表明，未分化细胞糖蛋白的典型粘蛋白型糖链具有2型H基团、线性多乳糖胺和核心1结构。另一方面，分化细胞新含有1型H和Le(b)基团以及核心2结构。具有1型H基团的粘蛋白与分化细胞上的刷状缘膜酶接触。此外，即使在存在分化诱导剂的情况下，苄基2-乙酰氨基-2-脱氧-α-D-吡喃半乳糖苷也能抑制细胞表面1型H基团的表达以及刷状缘膜酶活性的增强。这些结果表明，具有1型H基团的粘蛋白型糖链在Caco-2细胞的分化中具有重要功能。
