Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, China.
Eur J Pharmacol. 2011 Sep 30;667(1-3):136-43. doi: 10.1016/j.ejphar.2011.06.013. Epub 2011 Jun 23.
Riccardin D is a novel macrocyclic bisbibenzyl compound extracted from Chinese liverwort plant Dumortiera hirsuta. Our previous studies showed that riccardin D is a DNA topo II inhibitor and has therapeutic potential for treatment of cancers. In this combined in vitro and in vivo study, we examined the inhibitory effects of riccardin D on tumor angiogenesis and the subsequent effect of anticancer activity was evaluated. Incubation with riccardin D weakly inhibited the proliferation of human umbilical vascular endothelial cells (HUVEC) as estimated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The scratch wound experiment showed that riccardin D effectively decreased the motility and migration of HUVEC cells. Riccardin D inhibited the formation of capillary tube as demonstrated by decrease of branch points formed by HUVEC cells on 3-D Matrigel. We examined the levels of angiogenic factors including vascular endothelial growth factor (VEGF), VEGF receptor 2, epidermal growth factor receptor (EGF receptor), and matrix metalloproteinase (MMPs) in HUVEC cells. The expressions of VEGF, phospho-VEGF receptor 2, EGF receptor and MMP-2 were significantly reduced by riccardin D as estimated by Western blot assay and real-time quantitative PCR analysis. The decrease of VEGF was also detected in riccardin D-treated human lung cancer H460 cells. The anticancer activity of riccardin D was then evaluated in a mouse model in which riccardin D delayed the growth of H460 xenografts without obvious toxicity to animals after three weeks injection. To evaluate the role of antiangiogenesis of riccardin D in mice, CD34 immunohistochemical staining was employed to analyze the mean vascular density in H460 xenograft tissues. The number of blood vessels was significantly decreased after riccardin D treatment. These results suggest that riccardin D display the inhibitory effect on growth of human lung carcinoma cells and that the inhibition of angiogenesis may involve in anticancer activity of riccardin D.
瑞卡汀 D 是一种从中国土生土长的鹿蹄草植物中提取的新型大环双苄基化合物。我们之前的研究表明，瑞卡汀 D 是一种 DNA 拓扑异构酶 II 抑制剂，具有治疗癌症的潜力。在这项体外和体内相结合的研究中，我们研究了瑞卡汀 D 对肿瘤血管生成的抑制作用，并评估了随后的抗癌活性。通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐 (MTT) 测定法估计，瑞卡汀 D 对人脐静脉内皮细胞 (HUVEC) 的增殖有微弱的抑制作用。划痕实验表明，瑞卡汀 D 能有效降低 HUVEC 细胞的运动和迁移能力。瑞卡汀 D 抑制了由 HUVEC 细胞在 3-D Matrigel 上形成的毛细血管管腔的形成，这一点从分支点的形成减少得到了证明。我们检测了血管内皮生长因子 (VEGF)、VEGF 受体 2、表皮生长因子受体 (EGF 受体) 和基质金属蛋白酶 (MMPs) 等血管生成因子在 HUVEC 细胞中的水平。通过 Western blot 分析和实时定量 PCR 分析，瑞卡汀 D 显著降低了 VEGF、磷酸化 VEGF 受体 2、EGF 受体和 MMP-2 的表达。瑞卡汀 D 处理的人肺癌 H460 细胞中也检测到 VEGF 的减少。然后，在小鼠模型中评估了瑞卡汀 D 的抗癌活性，结果表明，在三周的注射后，瑞卡汀 D 延缓了 H460 异种移植物的生长，而对动物没有明显的毒性。为了评估瑞卡汀 D 对小鼠的抗血管生成作用，采用 CD34 免疫组织化学染色分析 H460 异种移植物组织中的平均血管密度。瑞卡汀 D 处理后，血管数量明显减少。这些结果表明，瑞卡汀 D 对人肺癌细胞的生长有抑制作用，而血管生成的抑制可能涉及瑞卡汀 D 的抗癌活性。
