Pippia P, Cogoli A, Sciola L, Tilloca G, Meloni M A, Barni S
Istituto di Fisiologia Generale e Chimica Biologica, Università di Sassari.
Boll Soc Ital Biol Sper. 1990 Oct;66(10):945-52.
In a study performed to identify the molecular mechanisms which regulate cell to cell adhesion and contact inhibition in neoplastic and syngeneic normal cells of the rat we have observed that the adhesive capacity depends on the reagents used, either EDTA or trypsin, to release the cells from monolayer. Taking profit of this last property and of the possibility of blocking free -NH2 groups on membrane proteins with specific cross-linking reagents "in vitro", we have studied in this work the behaviour of the proteins of the cell coat involved in cell to cell adhesion of rat fibroblasts FG/2. The cross-linking reagents used were dimethyladipimidate (DMA) and dimethylsuberimidate (DMS). The cells were exposed to the reagents at 0 degrees C for 30'. Cell to cell adhesion was measured by determining the percentage of single cells labeled with 3H-leucine, adhering to a confluent monolayer at different incubation times. The inhibitory effect on cell to cell adhesion brought about by cross-linking reagents indicates that a) EDTA-released cells are more sensitive to both imides than those released with trypsin, b) DMA is more effective on trypsin-released cells and c) DMS is more effective on EDTA-released cells. Therefore, we conclude that the inhibition of adhesion by reaction with the two cross-linking reagents is more likely due to a stiffening of the molecules of the cell coat involved in the adhesion, rather than to the modification of -NH2 residues which should specifically participate to adhesive process.
在一项旨在确定调节大鼠肿瘤细胞和同基因正常细胞间细胞黏附及接触抑制的分子机制的研究中，我们观察到黏附能力取决于用于从单层释放细胞的试剂，即乙二胺四乙酸（EDTA）或胰蛋白酶。利用这一特性以及用特定交联试剂在“体外”封闭膜蛋白上游离氨基的可能性，我们在这项工作中研究了参与大鼠成纤维细胞FG/2细胞间黏附的细胞被膜蛋白的行为。所用的交联试剂是己二酰亚胺二甲酯（DMA）和辛二酰亚胺二甲酯（DMS）。细胞在0℃下暴露于试剂30分钟。通过测定在不同孵育时间黏附于汇合单层的用³H-亮氨酸标记的单细胞百分比来测量细胞间黏附。交联试剂对细胞间黏附的抑制作用表明：a）EDTA释放的细胞比胰蛋白酶释放的细胞对两种亚胺更敏感；b）DMA对胰蛋白酶释放的细胞更有效；c）DMS对EDTA释放的细胞更有效。因此，我们得出结论，与两种交联试剂反应导致的黏附抑制更可能是由于参与黏附的细胞被膜分子变硬，而不是由于应特异性参与黏附过程的氨基残基的修饰。
