Wewer U, Albrechtsen R, Ruoslahti E
Cancer Res. 1981 Apr;41(4):1518-24.
Laminin, a glycoprotein antigenically similar or identical to a component of epithelial basement membranes, was identified as a major component of the abundant extracellular matrix synthesized by an experimentally induced rat yolk sac tumor. Immunocytochemical staining revealed laminin in cultured tumor cells as well as in their extracellular matrix. The presence of soluble laminin in the culture media of the tumor cells was demonstrated using metabolic labeling followed by identification by immunoprecipitation and sodium dodecyl sulfate:polyacrylamide gel electrophoresis. This revealed two polypeptides with molecular weights of approximately 200,000 and 400,000. These comigrated with the polypeptides of mouse laminin isolated previously. The yolk sac tumor tissue grown in vivo contained laminin in the tumor cells and in the extracellular material as evidenced by immunofluorescence and immunoperoxidase staining. Immunization with the tumor matrix resulted in an antiserum that contained antilaminin and natifibronectin and was made specific for laminin by absorption with fibronectin. This antiserum precipitated laminin polypeptides from culture medium of yolk sac tumour cells and stained basement membranes in rat tissues in a manner indistinguishable from antilaminin. The presence of laminin in rat yolk sac cells, the presumed origin of our yolk sac tumor, was studied in some detail. Laminin was found to be present in normal cells of the visceral as well as the parietal yolk sac layer and in their basement membranes suggesting, but not proving, that both types of cells have ability to synthesize laminin. Production of laminin and the presence of laminin-containing basement membrane material may be important for the biological behavior of the yolk sac tumor. This tumor will also be a useful source of laminin for chemical and biological characterization of this basement membrane protein.
层粘连蛋白是一种糖蛋白，在抗原性上与上皮基底膜的一种成分相似或相同，它被鉴定为实验诱导的大鼠卵黄囊肿瘤合成的丰富细胞外基质的主要成分。免疫细胞化学染色显示，培养的肿瘤细胞及其细胞外基质中均存在层粘连蛋白。利用代谢标记，随后通过免疫沉淀和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳进行鉴定，证明肿瘤细胞培养基中存在可溶性层粘连蛋白。这揭示了两条分子量约为200,000和400,000的多肽。这些多肽与先前分离的小鼠层粘连蛋白的多肽迁移情况相同。通过免疫荧光和免疫过氧化物酶染色证明，体内生长的卵黄囊肿瘤组织在肿瘤细胞和细胞外物质中均含有层粘连蛋白。用肿瘤基质免疫产生了一种抗血清，该抗血清含有抗层粘连蛋白和抗纤连蛋白，通过用纤连蛋白吸收使其对层粘连蛋白具有特异性。这种抗血清从卵黄囊肿瘤细胞培养基中沉淀出层粘连蛋白多肽，并以与抗层粘连蛋白无法区分的方式对大鼠组织中的基底膜进行染色。我们对大鼠卵黄囊细胞（我们的卵黄囊肿瘤的假定起源）中层粘连蛋白的存在进行了较为详细的研究。发现层粘连蛋白存在于脏层和壁层卵黄囊层的正常细胞及其基底膜中，这表明但未证明这两种类型的细胞都有合成层粘连蛋白的能力。层粘连蛋白的产生以及含层粘连蛋白的基底膜物质的存在可能对卵黄囊肿瘤的生物学行为很重要。这种肿瘤也将是用于这种基底膜蛋白化学和生物学特性研究的层粘连蛋白的有用来源。
