Reversible disruption of cell-matrix and cell-cell interactions by overexpression of sialomucin complex
Reversible disruption of cell-matrix and cell-cell interactions by overexpression of sialomucin complex
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DOI：
10.1074/jbc.272.52.33245
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发表时间：
1997-12-26
影响因子：
4.8
通讯作者：
Carraway, KL
中科院分区：
文献类型：
--
作者：
Komatsu, M;Carraway, CAC;Carraway, KL
唾液酸粘蛋白复合物（Sialomucin complex，SMC）是由粘蛋白（mucin，ASGP-1）和跨膜蛋白（transmembrane，ASGP-2）两个亚基组成的一种大的异二聚体糖蛋白复合物，在腹水型13762大鼠乳腺癌细胞表面大量表达。我们已经分离出含有不同数目的ASGP-1粘蛋白重复序列的重组cDNA，其可以表达为具有可变长度的蛋白产物。为研究SMC的抗粘附作用，将这些cDNA转染人癌细胞系。使用四环素反应，诱导型表达系统，我们证明了SMC的过度表达诱导的形态学变化，细胞脱落，和细胞-细胞分离的转染A375人黑色素瘤细胞在培养中。细胞的粘附和悬浮状态之间的转变是完全可逆的，并且依赖于SMC表达水平。通过测量转染的A375黑色素瘤和MCF-7乳腺癌细胞系与纤连蛋白、层粘连蛋白和胶原IV的细胞粘附，进一步从动力学上分析SMC的抗粘附作用，证明SMC破坏整合素介导的细胞与细胞外基质蛋白的粘附。这种抗粘附作用的程度取决于SMC分子中粘蛋白重复序列的数量以及细胞表面表达的水平。
Sialomucin complex (SMC) is a large, heterodimeric glycoprotein complex composed of mucin (ASGP-1) and transmembrane (ASGP-2) subunits and expressed abundantly on the cell surface of ascites 13762 rat mammary adenocarcinoma cells. We have isolated recombinant cDNAs containing different numbers of ASGP-1 mucin repeats, which can be expressed as protein products with variable lengths. To study the anti adhesive effect of SMC, these cDNAs were transfected into human cancer cell lines. Using a tetracycline-responsive, inducible expression system, we demonstrated that the overexpression of SMC induces morphology changes, cell detachment, and cell-cell dissociation of transfected A375 human melanoma cells in culture. The transition between the adherent and suspension states of the cells is fully reversible and dependent on the SMC expression level. The anti-adhesion effect of SMC was further analyzed kinetically by measuring the cell adhesion of transfected A375 melanoma and MCF-7 breast cancer cell lines to fibronectin, laminin, and collagen IV, demonstrating that SMC disrupts integrin-mediated cell adhesion to extracellular matrix proteins. The degree of this anti-adhesion effect was dependent on the number of mucin repeats in the SMC molecule as well as the level of cell surface expression.