The epithelial-to-mesenchymal transition (EMT) enables cells of epithelial phenotype to become motile and change to a migratory mesenchymal phenotype. EMT is known to be a fundamental requisite for tissue morphogenesis, and EMT-related pathways have been described in cancer metastasis and tissue fibrosis. Epithelial structures are marked by the presence of a sheet-like extracellular matrix, the basement membrane, which is assembled from two major proteins, laminin and collagen type IV. This specialized matrix is essential for tissue function and integrity, and provides an important barrier to the potential pathogenic migration of cells. The profound phenotypic transition in EMT involves the epithelial cells disrupting the basement membrane. Matrix metalloproteinases (MMPs) are known to cleave components of basement membranes, but MMP-basement membrane crosstalk during EMT in vivo is poorly understood. However, MMPs have been reported to play a role in EMT-related processes and a variety of basement membrane fragments have been shown to be released by specific MMPs in vitro and in vivo exhibiting distinct biological activities. This review discusses general considerations regarding the basement membrane in the context of EMT, a possible role for specific MMPs in EMT and highlights biologically active basement membrane fragments liberated by MMPs.

中文翻译：

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在上皮到间质转化的背景下，基底膜碎片。

上皮到间充质转变（EMT）使上皮表型的细胞能够活动并转变为迁移性间充质表型。已知EMT是组织形态发生的基本条件，并且在癌症转移和组织纤维化中已描述了与EMT相关的途径。上皮结构的特征是存在片状细胞外基质，即基底膜，该基底膜由两种主要蛋白质（层粘连蛋白和IV型胶原蛋白）组装而成。这种专门的基质对于组织功能和完整性必不可少，并为细胞潜在的病原性迁移提供了重要的屏障。EMT中深刻的表型转变涉及上皮细胞破坏基底膜。已知基质金属蛋白酶（MMP）可以裂解基底膜的成分，但是人们对体内EMT期间MMP基膜的串扰知之甚少。然而，据报道MMP在EMT相关过程中起作用，并且已证明各种基膜片段是由特异性MMP在体外和体内释放的，表现出独特的生物学活性。这篇综述讨论了EMT背景下有关基膜的一般考虑，EMT中特定MMP的可能作用，并强调了由MMP释放的生物活性基膜片段。