Ogier-Denis E, Codogno P, Chantret I, Trugnan G
Unité de Recherches sur la Biologie et la Pathologie Moléculaire des Glycoproteines, Institut National de la Santé et de la Recherche Médicale U180, Paris, France.
J Biol Chem. 1988 May 5;263(13):6031-7.
Studies on the regulation of the enterocytic differentiation of the human colon cancer cell line HT-29, which is differentiated in the absence (Glc-) but not in the presence of glucose (Glc+), have recently shown that the post-translational processing of sucrase-isomaltase and particularly its glycosylation vary as a function of cell differentiation (Trugnan G., Rousset, M., Chantret, I., Barbat, A., and Zweibaum, A. (1987) J. Cell Biol. 104, 1199-1205). Other studies indicate that in undifferentiated HT-29 Glc+ cells there is an accumulation of UDP-N-acetylhexosamine, which is involved in the glycosylation process (Wice, B. M., Trugnan, G., Pinto, M., Rousset, M., Chevalier, G., Dussaulx, E., Lacroix, B., and Zweibaum, A. (1985) J. Biol. Chem. 260, 139-146). The purpose of the present work is to investigate whether an overall alteration of protein glycosylation is associated with the inability of HT-29 cells to differentiate. At least three alterations are detected: (i) after a 10-min pulse, the incorporation of D-[2-3H]mannose in undifferentiated cells is severely reduced, compared to differentiated cells. (ii) After a 24-h period of labeling with D-[2-3H]mannose, undifferentiated cells accumulate more than 60% of the radioactivity in the high mannose glycopeptides, whereas differentiated HT-29 Glc- cells accumulate only 38%. (iii) The analysis of the high mannose oligosaccharides transferred "en bloc" from the lipid precursor shows that Man9,8-GlcNAc2 species accumulate in undifferentiated cells, whereas no such accumulation can be detected in differentiated cells. This glycosylation pattern is consistent with an impairment of the trimming of high mannose into complex glycans. It is concluded that N-glycan processing is correlated with the state of enterocytic differentiation of HT-29 cells.
对人结肠癌细胞系HT - 29肠细胞分化调控的研究表明，该细胞系在无葡萄糖（Glc -）条件下可分化，但在有葡萄糖（Glc +）时则不能分化。最近的研究显示，蔗糖酶 - 异麦芽糖酶的翻译后加工，尤其是其糖基化，会随细胞分化而变化（Trugnan G.，Rousset, M.，Chantret, I.，Barbat, A.，和Zweibaum, A.（1987年）《细胞生物学杂志》104卷，1199 - 1205页）。其他研究表明，在未分化的HT - 29 Glc +细胞中，参与糖基化过程的UDP - N - 乙酰己糖胺会积累（Wice, B. M.，Trugnan, G.，Pinto, M.，Rousset, M.，Chevalier, G.，Dussaulx, E.，Lacroix, B.，和Zweibaum, A.（1985年）《生物化学杂志》260卷，139 - 146页）。本研究的目的是调查蛋白质糖基化的整体改变是否与HT - 29细胞无法分化有关。至少检测到三种改变：（i）经过10分钟的脉冲标记后，与分化细胞相比，未分化细胞中D - [2 - 3H]甘露糖的掺入量严重减少。（ii）用D - [2 - 3H]甘露糖标记24小时后，未分化细胞在高甘露糖糖肽中积累了超过60%的放射性，而分化的HT - 29 Glc -细胞仅积累38%。（iii）对从脂质前体“整体”转移的高甘露糖寡糖的分析表明，Man9,8 - GlcNAc2种类在未分化细胞中积累，而在分化细胞中未检测到这种积累。这种糖基化模式与高甘露糖修剪成复杂聚糖的受损情况一致。结论是，N - 聚糖加工与HT - 29细胞的肠细胞分化状态相关。
