Tamaki M, McDonald W, Del Maestro R F
Division of Neurosurgery, Victoria Hospital Research Institute, University of Western Ontario, London, Canada.
J Neurosurg. 1996 Jun;84(6):1013-9. doi: 10.3171/jns.1996.84.6.1013.
Type IV collagen is a major protein component of the vascular basement membrane and its degradation is crucial to the initiation of tumor-associated angiogenesis. The authors have investigated the influence of cell density on the release of collagen type IV degrading activity by C6 astrocytoma cells in monolayer culture. The release of collagen type IV degrading activity was assessed biochemically, immunocytochemically, and by Western blot analysis. The results demonstrate that increasing plating density and increasing cell density are associated with decreased collagen type IV degrading activity released per tumor cell. These findings indicate the existence of regulatory mechanisms dependent on cell-cell communication, which modulate release of collagen type IV degrading activity. The extrapolation of these results to the in vivo tumor microenvironment would suggest that individual and/or small groups of invading tumor cells, distant from the main tumor mass, would release substantial collagen type IV degrading activity, which may be crucial to their continued invasion and to angiogenesis.
IV型胶原蛋白是血管基底膜的主要蛋白质成分，其降解对于肿瘤相关血管生成的启动至关重要。作者研究了细胞密度对单层培养的C6星形细胞瘤细胞释放IV型胶原降解活性的影响。通过生化、免疫细胞化学和蛋白质印迹分析评估IV型胶原降解活性的释放。结果表明，接种密度增加和细胞密度增加与每个肿瘤细胞释放的IV型胶原降解活性降低有关。这些发现表明存在依赖细胞间通讯的调节机制，该机制调节IV型胶原降解活性的释放。将这些结果外推至体内肿瘤微环境表明，远离主要肿瘤块的单个和/或小群侵袭性肿瘤细胞会释放大量IV型胶原降解活性，这可能对它们的持续侵袭和血管生成至关重要。
