Department of Neurology, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany.
J Neurooncol. 2011 Oct;105(1):57-65. doi: 10.1007/s11060-011-0561-1. Epub 2011 Mar 11.
Tumor angiogenesis is of central importance in the malignancy of glioblastoma multiforme (GBM). As previously shown, human mesenchymal stem cells (hMSC) migrate towards GBM and are incorporated into tumor microvessels. However, phenotype and function of recruited hMSC remain unclear. We evaluated the differentiation and angiogenic potential of hMSC after stimulation with glioblastoma-conditioned medium in vitro. Immunostaining with endothelial, smooth muscle cell and pericyte markers was used to analyze hMSC differentiation in different concentrations of tumor-conditioned medium (CM), and the angiogenic potential was evaluated by matrigel-based tube-formation assay (TFA). Immunofluorescence staining revealed that tumor-conditioned hMSC (CM-hMSC) expressed CD 151, VE-cadherin, desmin, α-smooth muscle actin, nestin, and nerval/glial antigen 2 (NG2) in a CM concentration-dependent manner, whereas no expression of von-Willebrand factor (vWF) and smooth myosin could be detected. These findings are indicative of GBM-dependent differentiation of hMSC into pericyte-like cells, rather than endothelial or smooth muscle cells. Furthermore, TFA of hMSC and CM-hMSC revealed CM-dependent formation of capillary-like networks, which differed substantially from those formed by human endothelial cells (HUVEC), also implying pericyte-like tube formation. These results are indicative of GBM-derived differentiation of hMSC into pericyte-like mural cells, which might contribute to the neovascularization and stabilization of tumor vessels.
肿瘤血管生成在多形性胶质母细胞瘤（GBM）的恶性程度中具有核心重要性。如前所述，人间质干细胞（hMSC）向 GBM 迁移并被纳入肿瘤微血管中。然而，招募的 hMSC 的表型和功能仍不清楚。我们评估了 hMSC 在体外接受胶质母细胞瘤条件培养基刺激后的分化和血管生成潜力。用内皮细胞、平滑肌细胞和成纤维细胞标志物的免疫染色来分析不同浓度肿瘤条件培养基（CM）中 hMSC 的分化，并通过基质胶管形成测定（TFA）评估血管生成潜力。免疫荧光染色显示，肿瘤条件培养的 hMSC（CM-hMSC）以 CM 浓度依赖性方式表达 CD151、VE-钙粘蛋白、结蛋白、α-平滑肌肌动蛋白、巢蛋白和神经胶质抗原 2（NG2），而 von-Willebrand 因子（vWF）和平滑肌肌球蛋白的表达则无法检测到。这些发现表明 hMSC 依赖于 GBM 分化为周细胞样细胞，而不是内皮细胞或平滑肌细胞。此外，hMSC 和 CM-hMSC 的 TFA 显示 CM 依赖性形成毛细血管样网络，与由人内皮细胞（HUVEC）形成的网络有很大不同，这也暗示了周细胞样管形成。这些结果表明 hMSC 依赖于 GBM 分化为周细胞样壁细胞，这可能有助于肿瘤血管的新生和稳定。
