ADAM12 is selectively overexpressed in human glioblastomas and is associated with glioblastoma cell proliferation and shedding of heparin-binding epidermal growth factor
ADAM12 is selectively overexpressed in human glioblastomas and is associated with glioblastoma cell proliferation and shedding of heparin-binding epidermal growth factor
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DOI：
10.1016/s0002-9440(10)63429-3
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发表时间：
2004-11-01
影响因子：
6
通讯作者：
Okada, Y
中科院分区：
文献类型：
--
作者：
Kodama, T;Ikeda, E;Okada, Y
亚当斯（去整合素和金属蛋白酶）是参与细胞-细胞融合、细胞粘附、膜蛋白脱落和蛋白水解的多功能分子。在本研究中，我们研究了13个不同的ADAM物种的mRNA表达与假定的金属蛋白酶活性在人类星形细胞肿瘤，非肿瘤性脑组织，和其他颅内肿瘤，逆转录-聚合酶链反应，发现原型膜锚定的ADAM 12（ADAM 12 m）主要在胶质母细胞瘤中表达。实时荧光定量聚合酶链反应（PCR）结果显示，脑胶质母细胞瘤中ADAM 12 m的表达水平（16例）明显高于非肿瘤性脑组织（6例）、低级别星形细胞瘤（7例）、间变性星形细胞瘤（9例）（各组均P < 0.05）和颅内神经鞘瘤（5例）（P < 0.01）。原位杂交结果表明，胶质母细胞瘤细胞负责该基因的表达。通过免疫组化，ADAM 12 m主要免疫定位于胶质母细胞瘤细胞的细胞膜上。免疫印迹分析表明，在胶质母细胞瘤组织中，ADAM 12 m以类似于90 kd的活化的N-糖基化形式表达。胶质瘤中ADAM 12 m mRNA表达水平与增殖活性（MIB 1阳性细胞指数）呈正相关（r = 0.791，P < 0.0001; it = 32）。通过免疫印迹法在具有ADAM 12 m表达的胶质母细胞瘤样品中观察到与可溶性形式的肝素结合表皮生长因子（ADAM 12 m的底物）一致的蛋白条带，并且通过用胶质母细胞瘤的ADAM抑制剂处理来抑制。这些数据首次证明，在13种不同的ADAM物种中，ADAM 12 m在人胶质母细胞瘤中高度表达，并表明ADAM 12 m通过肝素结合表皮生长因子的脱落在胶质母细胞瘤的显著增殖中起作用的可能性。
ADAMs (a disintegrin and metalloproteinases) are multifunctional molecules involved in cell-cell fusion, cell adhesion, membrane protein shedding, and proteolysis. In the present study, we examined the mRNA expression of 13 different ADAM species with putative metalloproteinase activity in human astrocytic tumors, nonneoplastic brain tissues, and other intracranial tumors by, reverse transcriptase-polymerase chain reaction, and found that prototype membrane-anchored ADAM12 (ADAM12m) is predominantly expressed in glioblastomas. Real-time quantitative polymerase chain reaction indicated that the expression level of ADAM12m is remarkably at least 5.7-fold higher in ghoblastomas (it = 16) than in nonneoplastic brain tissues (it = 6), low grade (n = 7) and anaplastic astrocytic tumors (n = 9) (P < 0.05 for each group), and intracranial neurinomas (it = 5) (P < 0.01). In situ hybridization showed that glioblastoma cells are responsible for the gene expression. By immunohistochemistry, ADAM12m was predominantly immunolocalized on the cell membranes of glioblastoma cells. Immunoblotting analysis demonstrated that ADAM12m is expressed as an activated N-glycosylated form of similar to90 kd in glioblastoma tissues. There was a direct correlation between the mRNA expression levels of ADAM12m and proliferative activity (MIB1-positive cell index) of gliomas (r = 0.791, P < 0.0001; it = 32). Protein bands consistent with the soluble form of heparin-binding epidermal growth factor, a substrate of ADAM12m, were observed by immunoblotting in glioblastoma samples with the ADAM12m expression, and inhibited by treatment with ADAM inhibitor of the glioblastomas. These data demonstrate for the first time that among the 13 different ADAM species, ADAM12m is highly expressed in human glioblastomas, and suggest the possibility that ADAM12m plays a role in the prominent proliferation of the glioblastomas through shedding of heparin-binding epidermal growth factor.