THE ROLE OF LAMININ AND ITS RECEPTOR IN DIFFERENTIATION OF NEUROBLASTOMA

我们最近研究了细胞外的合成和沉积。 基质(ECM)蛋白层粘连蛋白(LM)、纤维连接蛋白(FN)和IV型胶原 人神经母细胞瘤(NB)细胞体外培养前后的变化 与二丁酰环(DBC)AMP和维甲酸(RA)的鉴别。 用聚丙烯酰胺对上述ECM蛋白的合成进行了验证 几种细菌条件培养液的凝胶电泳(PAGE) 用~3H-亮氨酸和~3H-脯氨酸标记代谢后的细胞系。 蛋白质在细胞层上的沉积被证实为 免疫荧光(IF)，使用针对LM、FN和IV型胶原的抗血清 在细胞层上。上述蛋白的表达模式 特定的形态表型向我们暗示，这些蛋白质可能 在神经元-雪旺细胞相互作用中发挥作用，因此， Nb的分化。具体地说，LM只出现在 具有Schwannian特征的扁平细胞的表面和细胞质 而神经细胞的缺失使我们相信：(1)具有 雪旺细胞和神经元在培养中出现特征和(2) 这些细胞可能重现了正常的雪旺细胞-神经元相互作用。在……里面 这种情况下，雪旺细胞表面丰富的Lm可能是一种 对缺乏LM、富含LM受体的神经细胞的化学诱导剂。这个 层粘连蛋白的这种受体的存在最近已经被证实 几位研究乳腺癌、纤维肉瘤和肌肉细胞的研究人员。 此外，其他作者还表明，神经元在层粘连蛋白上延伸神经突起 底座。为了评估这一假设的有效性，我们将搜索 NB细胞中层粘连蛋白受体的存在，并将对其进行研究 量变与分化及其在特定物种上的定位 细胞表型。

We have recently studied the synthesis and deposition of the extracellular matrix (ECM) proteins laminin (LM), fibronectin (FN) and type IV collagen by human neuroblastoma (NB) cells in vitro, before and after differentiation with dibutyryl-cyclic (dbc) AMP and retinoic acid (RA). The synthesis of all the above ECM proteins was confirmed by polyacrylamide gel electrophoresis (PAGE) of the conditioned culture media of several NB cell lines, after metabolic radiolabeling with 3H-leucine and 3H-proline. Deposition of the proteins on the cell layers was confirmed by immunofluorescence (IF), using antisera against LM, FN and type IV collagen on the cell layers. The pattern of expression of the above proteins by specific morphologic phenotypes suggested to us that these proteins may play a role in neuronal-Schwann cell interaction and, hence, differentiation of NB. Specifically, the fact that LM was only present on the surface and the cytoplasm of flat cells with Schwannian characteristics and absent from neuronal cells led us to believe that: (1) cells with features of Schwann cells and neurones were appearing in culture and (2) these cells might recapitulate normal Schwann cell-neurone interaction. In this case, the abundant cell surface LM on Schwann cells might be a chemoattractant for LM-poor, LM-receptor-rich neuronal cells. The existence of such a receptor to laminin has been recently confirmed by several investigators for breast carcinoma, fibrosarcoma and muscle cells. Moreover, other authors have shown that neurons extend neurites on laminin substrata. To evaluate the validity of this hypothesis, we will search for the presence of a laminin receptor in NB cell lines and will study its quantitative changes with differentiation and its localization on specific cell phenotypes.