Zagzag D, Friedlander D R, Dosik J, Chikramane S, Chan W, Greco M A, Allen J C, Dorovini-Zis K, Grumet M
Department of Pathology, New York University Medical Center, New York 10016, USA.
Cancer Res. 1996 Jan 1;56(1):182-9.
The expression of the extracellular matrix glycoprotein tenascin-C (TN) is enhanced in human astrocytomas and correlates with angiogenesis. To determine whether vascular cells are able to synthesize TN, we investigated the expression of TN protein and mRNA in nine astrocytomas. Immunogold electron microscopy in two glioblastomas multiforme detected the presence of TN in an extracellular perivascular location and to a lesser extent among tumor cells, confirming light microscopy immunohistochemical findings. In situ hybridization of astrocytomas using a digoxigenin-labeled antisense riboprobe detected strong staining for TN mRNA in vascular cells, especially in hyperplastic vessels, including those at the invasive edge of the tumors but not in vessels of normal brains. We observed weaker staining in tumor cells indicating a higher level of TN mRNA in vascular than in tumor cells. No staining was detected with the sense probe. Moreover, we investigated the ability of human brain microvessel endothelial cells (HBMECs) in primary culture to synthesize TN in vitro. Western blot analysis of the culture supernatants from HBMECs detected large amounts of TN. Immunogold silver staining demonstrated the presence of TN on the surface of HBMECs and in the subendothelial matrix. The distribution of TN mRNA in vascular cells of astrocytomas and the ability of HBMECs to synthesize TN in vitro demonstrate that vascular cells, including endothelial cells, are a major source of TN associated with angiogenesis. Furthermore, our results suggest that TN expression may be associated with endothelial cell activation and may play an important role in angiogenesis.
细胞外基质糖蛋白腱生蛋白-C（TN）在人类星形细胞瘤中的表达增强，且与血管生成相关。为了确定血管细胞是否能够合成TN，我们研究了9例星形细胞瘤中TN蛋白和mRNA的表达。在两个多形性胶质母细胞瘤中进行免疫金电子显微镜检查，发现在血管周围细胞外位置存在TN，在肿瘤细胞中含量较少，这证实了光学显微镜免疫组织化学的结果。使用地高辛标记的反义核糖探针对星形细胞瘤进行原位杂交，检测到血管细胞中TN mRNA有强烈染色，特别是在增生血管中，包括肿瘤侵袭边缘的血管，但正常脑组织血管中未检测到。我们观察到肿瘤细胞中的染色较弱，表明血管中TN mRNA水平高于肿瘤细胞。正义探针未检测到染色。此外，我们研究了原代培养的人脑微血管内皮细胞（HBMECs）在体外合成TN的能力。对HBMECs培养上清液进行蛋白质印迹分析，检测到大量TN。免疫金银染色显示HBMECs表面和内皮下基质中存在TN。星形细胞瘤血管细胞中TN mRNA的分布以及HBMECs在体外合成TN的能力表明，包括内皮细胞在内的血管细胞是与血管生成相关的TN的主要来源。此外，我们的结果表明TN表达可能与内皮细胞活化有关，并且可能在血管生成中起重要作用。
