Bagley Rebecca G, Walter-Yohrling Jennifer, Cao Xiaohong, Weber William, Simons Betsy, Cook Brian P, Chartrand Scott D, Wang Clarence, Madden Stephen L, Teicher Beverly A
Genzyme Corp., Framingham, Massachusetts 01701-9322, USA.
Cancer Res. 2003 Sep 15;63(18):5866-73.
Human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells (HMVEC) have been the standards for cell-based assays in the field of angiogenesis research and in antiangiogenic drug discovery. These normal mature endothelial cells may not be most representative of human tumor endothelial cells. Human AC133+/CD34+ bone marrow progenitor cells were established in cell culture media containing vascular endothelial growth factor, basic fibroblast growth factor (bFGF), and heparin to drive differentiation toward the endothelial phenotype. The resulting cells designated endothelial precursor cells (EPC) have many of the same functional properties as mature endothelial cells represented by HUVEC and HMVEC. By SAGE analysis, the genes expressed by EPC are more similar to the genes expressed by endothelial cells isolated from fresh surgical specimens of human tumors than are the genes expressed by HUVEC and HMVEC. Analysis of several cell surface markers by flow cytometry showed that EPC, HUVEC, and HMVEC have similar expression of P1H12, vascular endothelial growth factor 2, and endoglin but that EPC have much lower expression of ICAM1, ICAM2, VCAM1, and thrombomodulin than do HUVEC and HMVEC. The EPC generated can form tubes/networks on Matrigel, migrate through porous membranes, and invade through thin layers of Matrigel similarly to HUVEC and HMVEC. However, in a coculture assay using human SKOV3 ovarian cancer cell clusters in collagen as a stimulus for invasion through Matrigel, EPC were able to invade into the malignant cell cluster, whereas HMVEC were not able to invade the malignant cell cluster. In vivo, a Matrigel plug assay where human EPC were suspended in the Matrigel allowed tube/network formation by human EPC to be carried out in a murine host. EPC may be a better model of human tumor endothelial cells than HUVEC and HMVEC and, thus, may provide an improved cell-based model for second generation antineoplastic antiangiogenic drug discovery.
人脐静脉内皮细胞（HUVEC）和人微血管内皮细胞（HMVEC）一直是血管生成研究领域和抗血管生成药物研发中基于细胞检测的标准细胞。这些正常成熟的内皮细胞可能并非最能代表人类肿瘤内皮细胞。人AC133+/CD34+骨髓祖细胞在含有血管内皮生长因子、碱性成纤维细胞生长因子（bFGF）和肝素的细胞培养基中培养，以驱动其向内皮表型分化。由此产生的细胞被称为内皮祖细胞（EPC），具有许多与以HUVEC和HMVEC为代表的成熟内皮细胞相同的功能特性。通过SAGE分析，与HUVEC和HMVEC所表达的基因相比，EPC所表达的基因与从人类肿瘤新鲜手术标本中分离出的内皮细胞所表达的基因更为相似。通过流式细胞术对几种细胞表面标志物进行分析表明，EPC、HUVEC和HMVEC对P1H12、血管内皮生长因子2和内皮糖蛋白的表达相似，但EPC对细胞间黏附分子1（ICAM1）、细胞间黏附分子2（ICAM2）、血管细胞黏附分子1（VCAM1）和血栓调节蛋白的表达远低于HUVEC和HMVEC。所产生的EPC能够在基质胶上形成管/网络，通过多孔膜迁移，并与HUVEC和HMVEC类似地穿过薄层基质胶进行侵袭。然而，在一项共培养试验中，使用人SKOV3卵巢癌细胞簇在胶原蛋白中作为穿过基质胶侵袭的刺激物，EPC能够侵袭到恶性细胞簇中，而HMVEC则无法侵袭恶性细胞簇。在体内，将人EPC悬浮在基质胶中的基质胶栓试验能够在小鼠宿主体内进行人EPC的管/网络形成。与HUVEC和HMVEC相比，EPC可能是更好的人类肿瘤内皮细胞模型，因此，可能为第二代抗肿瘤抗血管生成药物研发提供改进的基于细胞的模型。
