Giavazzi Raffaella, Sennino Barbara, Coltrini Daniela, Garofalo Angela, Dossi Romina, Ronca Roberto, Tosatti Maria Pia Molinari, Presta Marco
Laboratory of the Biology and Treatment of Metastasis, Mario Negri Institute for Pharmacological Research, Bergamo, Italy.
Am J Pathol. 2003 Jun;162(6):1913-26. doi: 10.1016/S0002-9440(10)64325-8.
Tumors express more than a single angiogenic growth factor. To investigate the relative impact of fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) on tumor growth and neovascularization, we generated tumor cell transfectants differing for VEGF and/or FGF-2 expression. Human endometrial adenocarcinoma HEC-1-B-derived Tet-FGF-2 cells that express FGF-2 under the control of the tetracycline-responsive promoter (Tet-off system) were further transfected with a VEGF(121) anti-sense (AS-VEGF) cDNA. Next, Tet-FGF-2 and AS-VEGF/Tet-FGF-2 cells were transplanted subcutaneously in nude mice that received tetracycline or not in the drinking water. Simultaneous expression of FGF-2 and VEGF in Tet-FGF-2 cells resulted in fast-growing lesions characterized by high blood vessel density, patency and permeability, and limited necrosis. Blood vessels were highly heterogeneous in size and frequently associated with pericytes. Inhibition of FGF-2 production by tetracycline caused a significant decrease in tumor burden paralleled by a decrease in blood vessel density and size. AS-VEGF expression resulted in a similar reduction in blood vessel density associated with a significant decrease in pericyte organization, vascular patency, and permeability. The consequent decrease in tumor burden was paralleled by increased tumor hypoxia and necrosis. A limited additional inhibitory effect was exerted by simultaneous down-regulation of FGF-2 and VEGF expression. These findings demonstrate that FGF-2 and VEGF stimulate vascularization synergistically but with distinctive effects on vessel functionality and tumor survival. Blockade of either one of the two growth factors results in a decrease in blood vessel density and, consequently, in tumor burden. However, inhibition of the expression of VEGF, but not of FGF-2, affects also vessel maturation and functionality, leading to tumor hypoxia and necrosis. Our experimental model represents an unique tool to investigate anti-neoplastic therapies in different angiogenic environments.
肿瘤表达的血管生成生长因子不止一种。为了研究成纤维细胞生长因子-2（FGF-2）和血管内皮生长因子（VEGF）对肿瘤生长和新生血管形成的相对影响，我们构建了VEGF和/或FGF-2表达不同的肿瘤细胞转染子。在四环素反应性启动子（Tet-off系统）控制下表达FGF-2的人子宫内膜腺癌HEC-1-B来源的Tet-FGF-2细胞，再用VEGF(121)反义（AS-VEGF）cDNA进行转染。接下来，将Tet-FGF-2和AS-VEGF/Tet-FGF-2细胞皮下移植到饮用水中添加或不添加四环素的裸鼠体内。Tet-FGF-2细胞中FGF-2和VEGF的同时表达导致病变快速生长，其特征为血管密度高、通畅且具有通透性，坏死有限。血管大小高度不均一，且常与周细胞相关联。四环素抑制FGF-2产生导致肿瘤负荷显著降低，同时血管密度和大小也降低。AS-VEGF表达导致血管密度有类似降低，同时周细胞组织、血管通畅性和通透性显著降低。随之而来的肿瘤负荷降低伴随着肿瘤缺氧和坏死增加。FGF-2和VEGF表达的同时下调产生了有限的额外抑制作用。这些发现表明，FGF-2和VEGF协同刺激血管生成，但对血管功能和肿瘤存活有不同影响。阻断这两种生长因子中的任何一种都会导致血管密度降低，进而导致肿瘤负荷降低。然而，抑制VEGF的表达而非FGF-2的表达，也会影响血管成熟和功能，导致肿瘤缺氧和坏死。我们的实验模型是研究不同血管生成环境中抗肿瘤治疗的独特工具。
