Salomon D S, Liotta L A, Rennard S I, Foidart J M, Terranova V, Yaar M
Coll Relat Res. 1982 Mar;2(2):93-110. doi: 10.1016/s0174-173x(82)80026-5.
The effect of retinoic acid on the synthesis and degradation of basement membrane components by endoderm cells derived from mouse embryonal carcinoma (EC) cells was studied in a serum-free, defined medium. By immunofluorescence these cells accumulate type IV collagen, laminin, and fibronectin after growth in media containing epidermal growth factor (EGF), fibroblast growth factor (FGF), insulin, transferrin, and Pedersen fetuin. Collagen accounted for 2 to 4% of the newly synthesized proteins, of which 90% were found in the culture media. This collagen was identified as Pro-type IV be gel electrophoresis and enzymatic susceptibility. The EC cells preferentially attached to type IV collagen in vitro and such attachment was mediated by laminin. Treatment of EC cells with retinoic acid caused an increased accumulation of collagen (10 to 15% of secreted proteins) and also stimulated the elaboration of latent protease which degraded laminin and type IV collagen. The laminin-degrading activity was plasminogen dependent. The type IV collagen-degrading activity was a metal protease which could be activated by trypsin or plasmin. It is likely that at least part of the laminin degrading activity is plasmin (mediated through plasminogen activator), since highly purified plasmin is shown to degrade native laminin.
在无血清的特定培养基中，研究了视黄酸对源自小鼠胚胎癌（EC）细胞的内胚层细胞合成和降解基底膜成分的影响。通过免疫荧光法发现，这些细胞在含有表皮生长因子（EGF）、成纤维细胞生长因子（FGF）、胰岛素、转铁蛋白和佩德森胎球蛋白的培养基中生长后，会积累IV型胶原、层粘连蛋白和纤连蛋白。胶原占新合成蛋白质的2%至4%，其中90%存在于培养基中。通过凝胶电泳和酶敏感性鉴定，这种胶原被确定为Pro-IV型。EC细胞在体外优先附着于IV型胶原，这种附着由层粘连蛋白介导。用视黄酸处理EC细胞会导致胶原积累增加（占分泌蛋白的10%至15%），还会刺激产生降解层粘连蛋白和IV型胶原的潜在蛋白酶。层粘连蛋白降解活性依赖于纤溶酶原。IV型胶原降解活性是一种金属蛋白酶，可被胰蛋白酶或纤溶酶激活。很可能至少部分层粘连蛋白降解活性是由纤溶酶介导的（通过纤溶酶原激活剂），因为高度纯化的纤溶酶显示可降解天然层粘连蛋白。
