Reichert Fanny, Barak Vivian, Tarshis Marc, Prindull Gregor, Tarshis Elizabeth, Ben-Ishay Zina
Hebrew University Hadassah Medical School and Hadassah University Hospital, Jerusalem 91120, Israel.
Eur J Haematol. 2005 Jul;75(1):41-6. doi: 10.1111/j.1600-0609.2005.00436.x.
Reducing the blood supply of tumors is one modality to combat cancer. The objective of this study was to evaluate such an approach in the treatment of localized murine AML (acute myelogenous leukemia). For this purpose we designed an experimental model in which leukemic cells were embedded in 1% agar discs before subcutaneous implantation in C57Bl female mice. The C-1498 AML cell line (Frederick Inst., NCI, MD, USA) was used. Thirty experimental mice received on alternate days injections of 5 x 2.5 microg anti-VEGF (vascular endothelial growth factor) and 5 x 2.5 microg anti-Flk-1 (VEGFR2) antibodies to the site of cell implantation over a period of 10 d. Fifteen control mice received daily PBS injections. All mice were sacrificed 16 d after AML implantation. Of the 30 experimental animals, macroscopic examination showed in 21 animals (70%) small sized, pale tumors (0.5 g); in six mice (20%) the tumors were replaced completely by necrotic tissue, while in three mice (10%), there were large (2.5 g), highly vascularized tumors. In all 15 control mice large highly vascularized tumors were seen. A separate group of mice was studied for total survival following AML implantation. While 12 mice in the control group not treated with antibodies survived for 16 d post-implantation, survival was prolonged in 15 antibody treated mice by approximate 30 d to a total survival time of 48 d. Tumor specimens were processed for histology, immunohistochemistry (IHC) for CD31 endothelial cell antigen, and tube-like formation assay. The small, pale tumors of antibody treated animals consisted of degenerate hyaline material with remnant nests of leukemic cells, whereas large tumors showed sheets of leukemic cells and numerous blood vessels. Specimens processed for CD31 antigen showed scarce or absence of blood vessels in the small, pale tumors in contrast to intensive staining from a rich network of blood vessels in the large, highly vascularized tumors. Tube-like formation assays disclosed rudimentary Grade 1 endothelial cell tubes in the small, pale tumors as opposed to polygonal Grade 4 tube formation in control animals. In conclusion, this murine model of localized AML allows assessment of anti-angiogenic tumor regression. Anti-angiogenic antibodies against VEGF and Flk-1 have therapeutic effects in murine AML.
减少肿瘤的血液供应是对抗癌症的一种方式。本研究的目的是评估这种方法在治疗局部性小鼠急性髓性白血病（AML）中的效果。为此，我们设计了一个实验模型，将白血病细胞包埋在1%的琼脂圆盘中，然后皮下植入C57Bl雌性小鼠体内。使用的是C-1498 AML细胞系（美国国立癌症研究所弗雷德里克研究所，马里兰州）。30只实验小鼠在10天内每隔一天在细胞植入部位注射5×2.5微克抗血管内皮生长因子（VEGF）抗体和5×2.5微克抗Flk-1（VEGFR2）抗体。15只对照小鼠每天注射磷酸盐缓冲盐水（PBS）。所有小鼠在植入AML 16天后处死。在30只实验动物中，肉眼检查显示，21只动物（70%）有小的、浅色的肿瘤（0.5克）；6只小鼠（20%）的肿瘤完全被坏死组织取代，而3只小鼠（10%）有大的（2.5克）、血管丰富的肿瘤。在所有15只对照小鼠中都观察到了大的、血管丰富的肿瘤。对另一组小鼠进行了AML植入后的总生存期研究。对照组中未用抗体治疗的12只小鼠在植入后存活了16天，而15只接受抗体治疗的小鼠生存期延长了约30天，总生存期达到48天。对肿瘤标本进行组织学处理、针对CD31内皮细胞抗原的免疫组织化学（IHC）检测以及管状结构形成试验。接受抗体治疗的动物的小的、浅色的肿瘤由退化的透明物质和残留的白血病细胞巢组成，而大的肿瘤则显示有大片的白血病细胞和大量血管。针对CD31抗原处理的标本显示，小的、浅色的肿瘤中血管稀少或没有血管，与之形成对比的是，大的、血管丰富的肿瘤中有丰富的血管网络密集染色。管状结构形成试验显示，小的、浅色的肿瘤中有初级的1级内皮细胞管，而对照动物中有多边形的4级管状结构形成。总之，这种局部性AML的小鼠模型允许评估抗血管生成的肿瘤消退情况。针对VEGF和Flk-1的抗血管生成抗体在小鼠AML中有治疗作用。
