MODULATION OF CELL BEHAVIORS BY PROTEOGLYCANS WITH ANTI-CELL-SUBSTRATE ADHESION ACTIVITY-STUDIES ON INVOLVING MOLECULES AND THE MECHANISM

细胞与基质或细胞的粘附是调节各种销售行为的关键步骤。我们之前发现PG-M，一种大型硫酸软骨素蛋白多糖，对任何类型的细胞粘附到ECM都有抑制活性，并提出了它在调节sell-ECM相互作用中的一般作用（J.Biol.）。化学。一些证据表明，这种活性可能是由于硫酸软骨素链通过核心蛋白片段固定在ECM上。为了获得PG-M作用的直接证据，我们研究了反义特异性抑制PG-M合成对人骨肉瘤细胞癌性粘附的影响。这种抑制抑制了恶性细胞粘附表型，这与PG-M控制sell-ECM粘附的观点一致。为了深入了解其机制，我们假设硫酸软骨素诱导的sell粘附抑制可能是由于sell表面受体能够特异性地与硫酸软骨素链相互作用，从而影响ECM分子受体的聚类或构象变化。目前的结果表明，存在一个58 kda的蛋白，该蛋白与PG-M- OR硫酸软骨素固定化凝胶柱具有亲和力。蛋白质与色谱柱的相互作用需要Ca^<2+>的存在。根据这些特性，58-kDa蛋白现在被指定为糖小牛蛋白，可以用含有洗涤剂的溶液从培养成纤维细胞的膜部分和碎胚体的匀浆中提取。纯化的硫酸软骨素氨基酸序列表明该分子属于膜联蛋白vi家族，对该蛋白的进一步研究将回答我们所假设的硫酸软骨素链抗黏附活性机制是否可行的问题。

Cell adhesion to substrate or cell is a crucial step that regulates a variety of sell behavior. We previously showed that PG-M, a large chondroitin sulfate proteoglycan had an jnhibitory activity for any types of cell-adhesion to ECM and proposed its general role in modulating sell-ECM interactions (J.Biol. Chem., 264, 8012, 1989) Several lines of evidence suggested that the activity could be due to the chondroitin sulfate chains immobilized onto ECM via the core protein moiety. To obtain the direct evidence for the role of PG-M, we investigated the effect of the anitisense specific inhibition of PG-M synthesis on the oncogenic adhesion of human osteosarcoma cells. The inhibition suppressed the malignant cell-adhesive phenotype, consistent with the idea that PG-M controls sell-ECM adhesion. To gain insight into the mechanism, we postulated that the chondroitin sulfate-induced inhibition of sell adhesion might be due to a sell surface receptor capable of intercing specifically with chondroitin sulfate chains, thereby influencing the clustering or conformational change of receptors for ECM molecules. The present results have indicated the occurrence of a 58-kDa protein which had an affinity to the PG-M- OR chondroitin sulfate-immobilized gel column. The interaction of the protein with the column required the presence of Ca^<2+>. According to these properties, 58-kDa protein is now designated glycocalfin could be extracted with a detergent-contergent-containing solution from the membrane fractions of cultured fibroblasts and from the homogenate of minced embryo bodirs. The amino asid sequences of purified of gycocolfin have shown that this molecule is a famiry of annexin VI.Further studies of the protein will answer the question whether our postulated mechanism for the anti-adhesion actibity of immobilized chondroitin sulfate chains could be operative or not.