Meerovitch Karen, Bergeron Frédéric, Leblond Lorraine, Grouix Brigitte, Poirier Cathy, Bubenik Monica, Chan Laval, Gourdeau Henriette, Bowlin Terry, Attardo Giorgio
Department of Cancer Biology, Shire-BioChem Inc., 275 Armand Frappier Boulevard, Laval, Quebec, Canada H7V 4A7.
Vascul Pharmacol. 2003 Feb;40(2):77-89. doi: 10.1016/s1537-1891(02)00339-7.
Integrin-mediated cell adhesion is necessary for endothelial cell proliferation and apoptosis, which is a major determinant in tumor-induced angiogenesis. In this study, we compared two novel, structurally similar, Arg-Gly-Asp (RGD) peptidomimetic compounds having different integrin selectivities, for their inhibition of endothelial cell proliferation and induction of apoptosis on functionally relevant extracellular matrices (ECM) for angiogenesis. BCH-14661 was specific for integrin alphavbeta3, whereas BCH-15046 nonselectively antagonized integrins alphavbeta3, alphavbeta5, and alpha5beta1. Both compounds were potent inducers of endothelial cell apoptosis when plated on RGD-dependent ECM (vitronectin, VN), which was dependent on the ability to induce cell detachment. However, with endothelial cells plated on RGD-independent ECM (type I collagen, COL), only BCH-15046 was able to significantly prevent growth and induce apoptosis. This effect was not dependent on the induction of detachment. Experiments using the matrix metalloproteinase (MMP) inhibitor GM 6001 revealed that cleavage of COL was not required for the ability of BCH-15046 to induce apoptosis. However, the inhibition of growth factor-stimulated endothelial cell proliferation, required MMPs, and correlated with BCH-15046s' potent inhibition of endothelial cell attachment to denatured collagen. Antibody inhibition experiments showed that adhesion to denatured collagen required integrins alphavbeta3 and beta1, but not alphavbeta5. In addition, BCH-15046 exerted a significant inhibition of VEGF-stimulated angiogenesis in the chick chorioallontoic membrane in vivo. These results suggest that integrin antagonism of both alphavbeta3 and alpha5beta1 are important for MMP-independent induction of apoptosis on COL and MMP-dependent inhibition of endothelial cell-denatured collagen interactions required for proliferation.
整合素介导的细胞黏附对于内皮细胞增殖和凋亡是必需的，而内皮细胞增殖和凋亡是肿瘤诱导血管生成的主要决定因素。在本研究中，我们比较了两种新型的、结构相似的、具有不同整合素选择性的精氨酸-甘氨酸-天冬氨酸（RGD）肽模拟物，研究它们对内皮细胞增殖的抑制作用以及在血管生成功能相关的细胞外基质（ECM）上诱导凋亡的能力。BCH-14661对整合素αvβ3具有特异性，而BCH-15046则非选择性地拮抗整合素αvβ3、αvβ5和α5β1。当接种在依赖RGD的ECM（玻连蛋白，VN）上时，这两种化合物都是内皮细胞凋亡的有效诱导剂，这取决于诱导细胞脱离的能力。然而，对于接种在不依赖RGD的ECM（I型胶原，COL）上的内皮细胞，只有BCH-15046能够显著抑制其生长并诱导凋亡。这种效应不依赖于细胞脱离的诱导。使用基质金属蛋白酶（MMP）抑制剂GM 6001的实验表明，BCH-15046诱导凋亡的能力不需要COL的裂解。然而，生长因子刺激的内皮细胞增殖的抑制需要MMPs，并且与BCH-15046对内皮细胞黏附变性胶原的有效抑制相关。抗体抑制实验表明，黏附变性胶原需要整合素αvβ3和β1，但不需要αvβ5。此外，BCH-15046在体内对鸡胚绒毛尿囊膜中血管内皮生长因子（VEGF）刺激的血管生成具有显著抑制作用。这些结果表明，整合素αvβ3和α5β1的拮抗作用对于在COL上不依赖MMP诱导凋亡以及在增殖所需的内皮细胞-变性胶原相互作用中依赖MMP抑制是重要的。
