Kollmar Otto, Scheuer Claudia, Menger Michael D, Schilling Martin K
Department of General, Visceral, Vascular and Pediatric Surgery, University of Saarland, D-66421 Homburg-Saar, Germany.
Ann Surg Oncol. 2006 Feb;13(2):263-75. doi: 10.1245/ASO.2006.03.096. Epub 2006 Jan 20.
In a mouse model of hepatic metastasis, we herein analyzed whether the CXC chemokine macrophage inflammatory protein (MIP)-2, a functional analogue of the human interleukin 8, stimulates tumor cell migration in vitro and angiogenesis and tumor growth in vivo.
By using chemotaxis chambers, CT26.WT colorectal tumor cell adhesion and migration were studied under stimulation with different concentrations of MIP-2. To evaluate angiogenesis and tumor growth in vivo, 1 x 10(5) CT26.WT cells were implanted into the left liver lobe of syngeneic BALB/c mice, and 10, 100, and 1000 nM of MIP-2 or phosphate-buffered saline (controls) was injected into the peritumoral area. After 7 days, angiogenesis, proliferation, tumor growth, apoptosis, cleaved caspase 3, and CXCR-2 expression were analyzed by using intravital fluorescence microscopy, histology, immunohistochemistry, and fluorescence-activated cell sorting.
In vitro, 98.8% of unstimulated CT26.WT cells showed CXCR-2 receptor expression. In the chemotaxis assays, MIP-2 provoked a dose-dependent increase of cell migration and a most pronounced cell adhesion at a dose of 100 nM. In vivo, MIP-2, in particular in a dose of 100 or 1000 nM, induced a significant increase of tumor capillary density and a marked widening of the angiogenic front at the tumor margin. Capillaries of the angiogenic front, but not of the tumor center, showed significant dilation, thus indicating a pronounced action of vascular endothelial growth factor. Tumor volume was significantly increased, in particular after 100 nM of MIP-2 stimulation, when compared with phosphate-buffered saline-treated controls, whereas only 1000 nM of MIP-2-treated animals additionally showed a higher frequency of apoptotic cell death within the tumor margin.
Our study indicates for the first time that the CXC chemokine MIP-2 promotes angiogenesis and growth of colorectal CT26.WT hepatic metastasis.
在肝转移小鼠模型中，我们在此分析了CXC趋化因子巨噬细胞炎性蛋白（MIP）-2（人类白细胞介素8的功能类似物）是否在体外刺激肿瘤细胞迁移以及在体内刺激血管生成和肿瘤生长。
使用趋化小室，研究不同浓度MIP-2刺激下CT26.WT结肠直肠肿瘤细胞的黏附和迁移。为了评估体内血管生成和肿瘤生长，将1×10⁵个CT26.WT细胞植入同基因BALB/c小鼠的左肝叶，并在肿瘤周围区域注射10、100和1000 nM的MIP-2或磷酸盐缓冲盐水（对照）。7天后，通过活体荧光显微镜检查、组织学、免疫组织化学和荧光激活细胞分选分析血管生成、增殖、肿瘤生长、细胞凋亡、裂解的半胱天冬酶3和CXCR-2表达。
体外，98.8%未受刺激的CT26.WT细胞显示CXCR-2受体表达。在趋化试验中，MIP-2引起细胞迁移的剂量依赖性增加，在100 nM剂量时细胞黏附最为明显。在体内，MIP-2，特别是100或1000 nM剂量，导致肿瘤毛细血管密度显著增加，肿瘤边缘血管生成前沿明显增宽。血管生成前沿的毛细血管而非肿瘤中心的毛细血管显示出明显扩张，从而表明血管内皮生长因子的显著作用。与磷酸盐缓冲盐水处理的对照相比，肿瘤体积显著增加，特别是在100 nM MIP-2刺激后，而只有1000 nM MIP-2处理的动物在肿瘤边缘还显示出更高频率的凋亡细胞死亡。
我们的研究首次表明CXC趋化因子MIP-2促进结肠直肠CT26.WT肝转移的血管生成和生长。
