STRUCTURE/FUNCTION OF METALLOPROTEINASE MT3/MMP

这项建议的长期目标是了解 恶性肿瘤细胞所使用的蛋白质分解机制 细胞外基质在体内形成致密的结构屏障 侵袭和转移过程。尽管外科手术有了改进 针对原发肿瘤的技术，未能控制肿瘤的扩散 癌细胞是当今与癌症相关的死亡的主要原因。 癌细胞通过以下途径侵袭局部组织并向远处器官转移 调节蛋白水解酶的表达，使它们能够 降解它们周围的细胞外基质屏障。一个家庭 被称为基质降解金属蛋白酶的蛋白水解酶一直是 与癌症进展有关，因为它们具有降解能力 细胞外基质的所有蛋白质成分，包括 胶原蛋白、弹性蛋白和蛋白多糖。而大多数MMP 都是分泌酶，最近发现的MT-MMP亚群包含 其C末端的潜在跨膜结构域，因此能够 锚定在细胞表面并形成局部蛋白水解区 在入侵细胞和它们周围的细胞外基质屏障之间。这个 这个亚群的发现澄清了早先的怀疑，即肿瘤细胞 利用固定在细胞表面的特殊蛋白质分解机制 在局部侵袭和转移过程中清除一条通路。MT3-基质金属蛋白酶，a 最近加入这个亚群的，最近从一个 逆转录-聚合酶链式反应检测口腔恶性黑色素瘤组织 由其他细胞和组织表达。此外，它一直是 提出在侵袭性疾病的发展中发挥重要作用 肿瘤的表型。建立MT3-MMPs之间的因果关系 表达与侵袭性表型的关系，综合策略是 在本申请中提出的1)阐明(S)治理机制 它从酶原到活性形式的转化，2)它的酶的特性 通过以重组形式表达和分离酶的性质， 3)评估MT3-MMPs对侵袭潜能的调节能力 在体外构建的细胞外基质中的肿瘤细胞。 MT3-基质金属蛋白酶蛋白水解性的研究 激活机制及其赋予侵袭性潜能的能力 不仅应该提供关于肿瘤细胞的全面知识基础 该细胞膜相关金属蛋白酶在人体内的作用 恶性肿瘤，但它作为一种诊断标记物或 新的癌症疗法的靶点。

The long term objective of this proposal is to understand the proteolytic machinery employed by malignant tumor cells to traverse the dense structural barriers established by the extracellular matrix during the invasive and metastatic process. Despite improved surgical techniques against the primary tumors, failure to control the spread of cancer cells contributes to most of the cancer related death today. Cancer cells invade local tissues and metastasize to distant organs by regulating the expression of proteolytic enzymes that allow them to degrade their surrounding extracellular matrix barriers. One family of proteinases, known as the matrix-degrading metalloproteinases, have been implicated in cancer progression by virtue of their ability to degrade all proteinaceous components of the extracellular matrix including collagens, elastin and proteoglycans. While the majority of the MMPs are secreted enzymes, the recently identified MT-MMP subgroup contain potential transmembrane domains at their C-termini and therefore be able to anchor on the cell surface and form a localized proteolytic zone between the invading cells and their surrounding ECM barrier. The discovery of this subgroup clarified earlier suspicion that tumor cells utilize special proteolytic machinery anchored on their cell surfaces to clear a pathway during local invasion and metastasis. MT3-MMP, a recent addition to this subgroup, was recently identified from an malignant oral melanoma tissue by degeneraate RT-PCR strategy and found to be expressed by other cells and tissues. Furthermore, it has been proposed to play an important role in the development of invasive phenotype of tumor. To establish a causal relationship between MT3-MMP expression and the invasive phenotype, a comprehensive strategy is proposed in this application to 1) elucidate the mechanism(s) governing its conversion from zymogen to active form, 2) characterize its enzymic properties by expressing and isolating the enzyme in recombinant forms, and 3) assess the ability of MT3-MMP to regulate the invasive potential of tumor cells in an in vitro construct of the extracellular matrix. Insights from the characterization of MT3-MMP proteolytic activity, its activation mechanism as well as its ability to confer invasive potential on tumor cells should not only provide a thorough knowledge base on the role of this cell membrane associated metalloproteinase in human malignancies, but also its potential utility as a diagnotic marker or a target for new cancer therapies.