Metabolism of Proteoglycans in the Extracellular Matrix

细胞外基质是结缔组织的主要成分之一，是一种分子复合体，为细胞的发育、分化和代谢提供必要的环境。与胶原蛋白一起，蛋白多糖在细胞外基质中起着主要的构成作用。我们研究了细胞外基质的代谢调节，特别是硫酸乙酰肝素蛋白多糖的分解代谢和这一过程所必需的降解酶--乙酰肝素酶。我们从大鼠甲状旁腺细胞系(PTR)的细胞培养物中大量分离出该酶，并对其酶学性质进行了详细的研究。我们已经测定了编码乙酰肝素酶的mRNA的核苷酸序列。我们还利用肺癌、口腔鳞癌和食管鳞癌的临床标本，研究了乙酰肝素酶降解细胞外基质在癌细胞侵袭和转移机制中的作用。主要研究结果总结如下：1.本文的主要研究成果。本论文的主要研究内容如下：1.分离了一种降解硫酸乙酰肝素蛋白多糖的特异酶--肝素酶，并对其酶学性质，包括底物结构要求进行了详细的研究。测定了编码乙酰肝素酶基因的核苷酸序列。已制备抗乙酰肝素酶的单抗和多克隆抗体。通过免疫组织化学和免疫印迹方法对这些抗体进行鉴定。肺癌、口腔鳞状细胞癌和食道鳞状细胞癌的侵袭性与乙酰肝素酶的产生之间已经建立了良好的相关性。乙酰肝素酶在癌症侵袭机制中的作用的研究正在进行中。

The extracellular matrix is one of the major constituents of connective tissues and functions as a molecular complex providing proper environments necessary for cell development, differentiation and metabolism. Together with collagens, proteoglycans play major constitutive roles in the extracellular matrix. We have studied the metabolic regulation of extracellular matrix, especially focusing on the catabolism of heparan sulfate proteoglycans and a degrading enzyme, heparanase, necessary for this process. We have isolated a large quantity of the enzyme from cell cultures of rat parathyroid cell line (PTr) and characterized its enzymatic properties in detail. We have determined the nucleotide sequence of the mRNA encoding heparanase. We also investigated roles of extracellular matrix degradation by heparanase in the mechanism of cancer cell invasion and metastasis, using clinical specimens of lung cancers, oral squamous cell carcinomas and esophageal squamous cell carcinomas. The major results are summarized as follow.1. Heparanase, a specific enzyme which degrades heparan sulfate proteoglycans, was isolated and its enzymatic properties, including the substrate structural requirements were studied in detail.2. Nucleotide sequence of the gene encoding heparanase was determined.3. Monoclonal and polyclonal antibodies against heparanase have been prepared. Characterization of these antibodies is still under way by immunohistochemical and Western blot procedures.4. Good correlation between the invasiveness and the production of heparanase in lung cancers, oral squamous cell carcinomas and esophageal squamous cell carcinomas has been established. Studies on roles of heparanase in the mechanism of cancer invasion are under way.