Magnusson K E, Gustafsson M, Holmgren K, Johansson B
Department of Medical Microbiology, Faculty of Health Sciences, University of Linköping, Sweden.
J Cell Physiol. 1990 May;143(2):381-90. doi: 10.1002/jcp.1041430224.
We have studied the effect of maturation to small intestinal-like epithelial cells of the human colonic carcinoma cell line HT29 on the lateral mobility of different representative membrane components (lipid, proteins), as assessed with fluorescence recovery after photobleaching (FRAP). Maturation was induced in vitro in the HT29 cells by replacing glucose (Glu) with galactose (Gal) in the growth medium (DMEM) during a 21-day period. Scanning electron microscopy revealed an increased number of microvilli in the apical cell membrane, and enzyme analyses (alkaline phosphatase, aminopeptidase) in combination with aqueous countercurrent distribution, indicated that maturation was induced with DMEM-Gal. In comparison to control cells grown in DMEM-Glu medium, the more small intestinal-like cells grown in DMEM-Gal displayed no alteration of the lateral mobility of either cholera toxin (B subunit)-labelled ganglioside GM1 (diffusion coefficient, D [x 10(8)] = 0.8-0.9 cm2s-1; mobile fraction, R = 50-60%) or antibody-stained Class 2 histocompatibility (HLA-DR) antigen (D [x 10(9)] = 2 cm2s-1; R = 60-70%). However, antibody-labelled beta 2-microglobulin of HLA Class 1 antigen displayed increased mobility in HT29-Gal cells; D was x 1.4 and R x 1.8 larger in the HT29-Gal cells. By contrast, the mobility of a neoplastic antigen was reduced; D and R were x0.60 and x0.69 of the values seen in HT29-Glu cells. It is thus concluded that DMEM-Gal-induced differentiation in confluent HT29 cells is accompanied by specific rather than general effects on the lateral mobility of different membrane components.
我们研究了人结肠癌细胞系HT29向小肠样上皮细胞成熟过程中，不同代表性膜成分（脂质、蛋白质）侧向流动性的变化，采用光漂白后荧光恢复（FRAP）技术进行评估。在21天的时间里，通过在生长培养基（DMEM）中用半乳糖（Gal）替代葡萄糖（Glu），在体外诱导HT29细胞成熟。扫描电子显微镜显示顶端细胞膜微绒毛数量增加，酶分析（碱性磷酸酶、氨肽酶）结合水相逆流分布表明，DMEM-Gal诱导了细胞成熟。与在DMEM-Glu培养基中生长的对照细胞相比，在DMEM-Gal中生长的更具小肠样特征的细胞，霍乱毒素（B亚基）标记的神经节苷脂GM1（扩散系数，D [x 10(8)] = 0.8 - 0.9 cm2s-1；移动分数，R = 50 - 60%）或抗体染色的2类组织相容性（HLA-DR）抗原（D [x 10(9)] = 2 cm2s-1；R = 60 - 70%）的侧向流动性均未改变。然而，HLA 1类抗原的抗体标记β2-微球蛋白在HT29-Gal细胞中的流动性增加；在HT29-Gal细胞中，D增大了1.4倍，R增大了1.8倍。相比之下，一种肿瘤抗原的流动性降低；D和R分别为HT29-Glu细胞中所见值的0.60倍和0.69倍。因此得出结论，DMEM-Gal诱导汇合的HT29细胞分化时，对不同膜成分的侧向流动性产生了特异性而非一般性的影响。
