Heckman C A, Oravecz K I, Schwab D, Pontén J
Department of Biological Sciences, Bowling Green State University, Ohio 43403.
J Cell Physiol. 1993 Mar;154(3):554-65. doi: 10.1002/jcp.1041540314.
It has long been known that the growth rate of cells in vitro can be retarded by providing substrates of restricted area. Such experiments were performed with adhesive islets, made by depositing metals onto agarose layers through templates of various sizes. Since normal cells are unable to adhere to agarose, they become confined to the metallic surface. Using such haptotactic islets, we have studied the role of membrane ruffling and cell locomotion in the resistance of AG1523 human fibroblasts to growth factor-induced mitogenesis. Cells plated on small substrates, i.e., 2,150 microns 2 in area, initially showed vigorous ruffling, which was suppressed by 8 h after plating but had resumed again by 12 h. In contrast, cells on larger-size islets showed a rapid decline and stabilization of ruffling activity. When the growth rate was measured for single cells cultured on haptotactic islets, it was found to increase linearly from areas of 4,280 microns 2 up to 425,000 microns 2. Since the area needed to saturate the growth response was approximately 50-fold larger than the area occupied by a single cell, the growth inhibition was attributed in part to an interference with locomotion. The implication that locomotion provided positive input into growth control mechanisms was subjected to a direct test by evaluating the effect of nine polypeptide growth factors on the motility of serum-starved cells. All except TGF-beta 1 stimulated movement. Finally, the mitogenic effect of growth factors was measured by [3H]thymidine incorporation and found to be proportional to motile activities, as quantitatively assayed. We conclude that locomotion suppression is a factor in AG1523 cell resistance to growth factor-induced mitogenesis.
长期以来，人们一直知道，通过提供面积受限的底物，可以抑制体外细胞的生长速度。此类实验是用粘附胰岛进行的，粘附胰岛是通过各种尺寸的模板将金属沉积到琼脂糖层上制成的。由于正常细胞无法粘附到琼脂糖上，它们被限制在金属表面。利用这种趋触性胰岛，我们研究了膜皱褶和细胞运动在AG1523人成纤维细胞对生长因子诱导的有丝分裂抗性中的作用。接种在小底物（即面积为2150平方微米）上的细胞最初显示出强烈的皱褶，接种后8小时受到抑制，但在12小时时又恢复了。相比之下，接种在较大尺寸胰岛上的细胞显示出皱褶活性迅速下降并稳定。当测量在趋触性胰岛上培养的单细胞的生长速度时，发现其从4280平方微米到425000平方微米的面积范围内呈线性增加。由于使生长反应饱和所需的面积比单个细胞占据的面积大约大50倍，因此生长抑制部分归因于对运动的干扰。通过评估九种多肽生长因子对血清饥饿细胞运动性的影响，对运动为生长控制机制提供正向输入这一观点进行了直接测试。除TGF-β1外，所有因子均刺激细胞运动。最后，通过[3H]胸腺嘧啶核苷掺入法测量生长因子的促有丝分裂作用，发现其与定量测定的运动活性成正比。我们得出结论，运动抑制是AG1523细胞对生长因子诱导的有丝分裂产生抗性的一个因素。
