Activation of EDTA-resistant gelatinases in malignant human tumors
Activation of EDTA-resistant gelatinases in malignant human tumors
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DOI：
10.1158/0008-5472.can-06-1499
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发表时间：
2006-10-15
期刊：
影响因子：
11.2
通讯作者：
Chen, Wen-Tien
中科院分区：
文献类型：
--
作者：
Chen, Donghai;Kennedy, Alanna;Chen, Wen-Tien
在与人类癌症相关的许多蛋白酶中，seprase或成纤维细胞活化蛋白α（II型跨膜糖蛋白）具有两种类型的EDTA抗性蛋白酶活性：二肽基肽酶和170-kDa明胶酶活性。为了测试与seprase相关的明胶酶的活化是否可能参与恶性肿瘤，我们使用哺乳动物表达系统来产生可溶性重组seprase（r-seprase）。在假定的EDTA敏感的激活剂的存在下，r-seprase被转换成70- 50-kDa的缩短形式的seprase（S-seprase），表现出7倍的明胶酶活性增加，而二肽基肽酶活性水平保持不变。在人类恶性肿瘤中，如原位杂交和免疫组织化学所示，seprase主要在肿瘤细胞中表达。在5 mmol/L EDTA存在下，使用抗体或凝集素亲和柱从实验性异种移植物和恶性肿瘤中纯化的蛋白质测定seprase体内活化。Seprase的表达和激活最常见于卵巢癌，但也在其他四种恶性肿瘤类型中检测到，包括结肠和胃腺癌、乳腺浸润性导管癌和恶性黑色素瘤。总之，这些数据表明，在恶性肿瘤中，seprase被蛋白水解激活，以赋予其在胶原蛋白水解和肿瘤侵袭中的底物特异性。
Among the many proteases associated with human cancer, seprase or fibroblast activation protein alpha, a type II transmembrane glycoprotein, has two types of EDTA-resistant protease activities: dipeptidyl peptidase and a 170-kDa gelatinase activity. To test if activation of gelatinases associated with seprase could be involved in malignant tumors, we used a mammalian expression system to generate a soluble recombinant seprase (r-seprase). In the presence of putative EDTA-sensitive activators, r-seprase was converted into 70- to 50-kDa shortened forms of seprase (s-seprase), which exhibited a 7-fold increase in gelatinase activity, whereas levels of dipeptidyl peptidase activity remained unchanged. In malignant human tumors, seprase is expressed predominantly in tumor cells as shown by in situ hybridization and immunohistochemistry. Proteins purified from experimental xenografts and malignant tumors using antibody- or lectin-affinity columns in the presence of 5 mmol/L EDTA were assayed for seprase activation in vivo. Seprase expression and activation occur most prevalently in ovarian carcinoma but were also detected in four other malignant tumor types, including adenocarcinoma of the colon and stomach, invasive ductal carcinoma of the breast, and malignant melanoma. Together, these data show that, in malignant tumors, seprase is proteolytically activated to confer its substrate specificity in collagen proteolysis and tumor invasion.