Kenigsberg R L, Hong Y, Yao H, Lemieux N, Michaud J, Tautu C, Théorêt Y
Department of Pediatrics, Ste-justine's Hospital, Montreal, Quebec, Canada.
Am J Pathol. 1997 Sep;151(3):867-81.
We presently report the effects of human recombinant basic fibroblast growth factor (bFGF) on a newly established medulloblastoma cell line, UM-MB1. This predominantly adherent cell line has a mean doubling time of 39.3 hours and was found, by karyotypic analysis, to be near triploid. UM-MB1 consists of undifferentiated cells expressing markers of neuronal lineage such as the three neurofilament subunits as well as neuron-specific enolase, synaptophysin, and microtubule-associated proteins 1 and 5. In contrast, no immunoreactivity for glial fibrillary acidic protein was evident. When exposed to nanomolar amounts of bFGF, UM-MB1 cells began to extend neurite-like processes with arborizations and growth-cone-like structures. In addition, UM-MB1 cells treated with bFGF exhibited ultrastructural alterations that reflect their enhanced differentiation as well as the increased expression of at least one of the neurofilament subunits as evidenced both immunocytochemically and on Western blots. Furthermore, bFGF significantly decreased UM-MB1 cell growth as well as induced their death. UM-MB1 cells treated with bFGF for several days displayed DNA cleavage, nuclear shrinkage, and chromatin condensation while retaining their cytoplasmic and mitochondrial membrane integrity, all early indices of apoptosis. After this, cell death was evident with the concomitant appearance of the classical apoptotic bodies. By flow cytometry, bFGF was found to increase the proportion of cells in G1 before inducing their death by apoptosis. In conclusion, UM-MB1 cells can, when appropriately stimulated, be induced to differentiate along their neuronal lineage pathway. Their differentiation induced by bFGF, although incomplete, appears to promote or inhibit the expression of apoptotic effectors or suppressors in these cells, respectively, so to induce their death by an apoptotic-like mechanism.
我们目前报告了人重组碱性成纤维细胞生长因子（bFGF）对新建立的髓母细胞瘤细胞系UM-MB1的影响。这个主要贴壁生长的细胞系平均倍增时间为39.3小时，通过核型分析发现接近三倍体。UM-MB1由未分化细胞组成，这些细胞表达神经元谱系的标志物，如三种神经丝亚基以及神经元特异性烯醇化酶、突触素和微管相关蛋白1和5。相比之下，胶质纤维酸性蛋白没有明显的免疫反应性。当暴露于纳摩尔量的bFGF时，UM-MB1细胞开始伸出具有分支和生长锥样结构的神经突样突起。此外，用bFGF处理的UM-MB1细胞表现出超微结构改变，这反映了它们增强的分化以及至少一种神经丝亚基表达的增加，免疫细胞化学和蛋白质印迹均证明了这一点。此外，bFGF显著降低UM-MB1细胞的生长并诱导其死亡。用bFGF处理数天的UM-MB1细胞显示出DNA裂解、核收缩和染色质浓缩，同时保持其细胞质和线粒体膜的完整性，这些都是凋亡的早期指标。在此之后，细胞死亡明显，同时出现了典型的凋亡小体。通过流式细胞术发现，bFGF在诱导细胞凋亡死亡之前增加了G1期细胞的比例。总之，UM-MB1细胞在受到适当刺激时，可以被诱导沿着其神经元谱系途径分化。bFGF诱导的它们的分化虽然不完全，但似乎分别促进或抑制这些细胞中凋亡效应器或抑制因子的表达，从而通过类似凋亡的机制诱导它们死亡。
