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 与二丁基环(DBC)、环磷酸腺苷(AMP)和维甲酸(RA)鉴别。这个 用聚丙烯酰胺凝胶证实了上述ECM蛋白的合成 几种NB细胞条件培养液的电泳法 用~3H-亮氨酸和~3H-脯氨酸进行代谢性放射性标记。 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，从而促进分化 Nb.具体地说，Lm只存在于地表和 具有Schwannian特征的扁平细胞的细胞质 神经细胞，使我们相信：(1)具有雪旺特征的细胞 在培养中出现了细胞和神经元，以及(2)这些细胞可能 概述正常雪旺细胞神经元的相互作用。在这种情况下， 雪旺细胞上丰富的细胞表面LM可能是一种化学诱导剂 缺乏LM、富含LM受体的神经细胞。这种受体的存在 层粘连蛋白最近已经被几个研究人员证实对乳房有作用 癌、纤维肉瘤和肌肉细胞。此外，其他人已经表明， 神经元在层粘连蛋白底物上延伸神经突起。要评估…的有效性 这一假设，(1)我们已经搜索到了层粘连蛋白的存在 NB细胞中的受体及其在特定细胞中的准确定位 神经元和/或雪旺氏细胞分化前后的表型 使用抗LM受体的单抗和(2)我们有 寻找mRNA表达的可能差异，该基因是 参与了LM受体的合成。

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 dibutyrylcyclic (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 radiolabelling 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, others have shown that neurons extend neurites on laminin substrata. To evaluate the validity of this hypothesis, (1) we have searched for the presence of a laminin receptor in NB cell lines, its exact localization in specific cell phenotypes, before and after neuronal and/or Schwannian differentiation using a monoclonal antibody against the LM receptor and (2) we have searched for possible differences in the expression of the mRNA which is involved in the synthesis of the LM receptor.