美国韦克福雷斯特大学26日发布消息说，该校医学院的研究人员日前通过动物实验发现，一种名为血管紧缩素（1－7）的小肽可以通过抑制血管形成的方式阻止癌细胞生长。
研究人员首先在两组实验鼠体内培育了肺癌细胞，其中一组注射血管紧缩素（1－7）进行治疗，另一组注射生理盐水作为对照。6周后，研究人员发现，接受血管紧缩素（1－7）治疗的实验鼠体内肿瘤明显缩小，大小只有对照组实验鼠体内肿瘤的40％。此外，前者体内肿瘤中血管的数量也明显少于后者。
研究人员通过鸡胚实验进一步研究了血管紧缩素（1－7）对血管形成的影响。他们发现，注射生理盐水的鸡胚血管正常生长，而注射血管紧缩素（1－7）的鸡胚血管数量下降了一半以上。
研究人员指出，血管是肿瘤获取营养从而不断增殖的重要渠道，抑制肿瘤内血管的形成对治疗癌症具有重要意义。他们的实验表明，血管紧缩素（1－7）可能不仅对肺癌有效，或许还可以抑制乳腺癌、结肠癌等癌症的发展。这项研究成果已刊登在美国《分子癌症治疗学》杂志上。（生物谷Bioon.com）
生物谷推荐原始出处：
Mol Cancer Ther June 1, 2009 8, 1676 doi: 10.1158/1535-7163.MCT-09-0161
Angiotensin-(1-7) inhibits tumor angiogenesis in human lung cancer xenografts with a reduction in vascular endothelial growth factor
David R. Soto-Pantoja1,2, Jyotsana Menon1,3, Patricia E. Gallagher1,3 and E. Ann Tallant1,2,3
1Hypertension and Vascular Research Center, 2Molecular Genetics and Genomics Program, and 3Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston Salem, North Carolina
Angiotensin-(1-7) [Ang-(1-7)] is an endogenous seven-amino acid peptide hormone with antiproliferative properties. Our previous studies showed that Ang-(1-7) inhibits the growth of human lung cancer cells in vitro and reduces the size of human lung tumor xenografts in vivo. In the current study, s.c. injection of Ang-(1-7) not only caused a significant reduction in human A549 lung tumor growth but also markedly decreased vessel density, suggesting that the heptapeptide inhibits angiogenesis to reduce tumor size. A decrease in human endothelial cell tubule formation in Matrigel was observed following a 16 h incubation with Ang-(1-7), with a maximal reduction at a 10 nmol/L concentration. Ang-(1-7) had similar antiangiogenic effects in the chick chorioallantoic membrane, causing a >50% decrease in neovascularization. The Ang-(1-7)-induced reduction in both endothelial cell tubule formation and vessel formation in the chick was completely blocked by the specific Ang-(1-7) receptor antagonist [d-proline7]-Ang-(1-7), suggesting that these biological actions are mediated by an AT(1-7) receptor. Ang-(1-7) significantly reduced vascular endothelial growth factor-A protein and mRNA in tumors from mice treated with the heptapeptide compared with saline controls as well as in the parent A549 human lung cancer cells in culture. These results suggest that Ang-(1-7) may attenuate tumor angiogenesis by reducing vascular endothelial growth factor-A, a primary proangiogenic protein. Taken together, this study shows that Ang-(1-7) exhibits significant antiangiogenic activity and may be a novel therapeutic agent for lung cancer treatment targeting a specific AT(1-7) receptor.
