Vascular Homeostasis Laboratory and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 200-701, Korea.
Angiogenesis. 2014 Jan;17(1):179-94. doi: 10.1007/s10456-013-9387-0. Epub 2013 Oct 5.
Solid tumors supply oxygen and nutrients required for angiogenesis by producing vascular endothelial growth factor (VEGF). Thus, inhibitors of VEGF signaling abrogate tumor angiogenesis, resulting in the suppression of tumor growth and metastasis. We here investigated the effects of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on VEGF-induced angiogenesis. TRAIL inhibited VEGF-induced in vitro angiogenesis of human umbilical vein endothelial cells (HUVECs) and in vivo neovascularization in chicken embryos and mice. TRAIL blocked VEGF-induced angiogenic signaling by inhibiting ERK, Src, FAK, paxillin, Akt, and eNOS. Further, TRAIL blocked intracellular Ca(2+) elevation and actin reorganization in HUVECs stimulated with VEGF, without inhibiting VEGF receptor-2 tyrosine phosphorylation. TRAIL increased caspase-8 activity, without inducing caspase-9/-3 activation and apoptosis. Moreover, TRAIL resulted in cleavage of FAK into FAK-related non-kinase-like fragments in VEGF-stimulated HUVECs, which was blocked by a caspase-8 inhibitor and cellular caspase-8-like inhibitory protein. Biochemical and pharmacological inhibition of caspase-8 and FAK blocked the inhibitory effects of TRAIL on VEGF-stimulated anti-angiogenic signaling and events. In addition, caspase-8 knockdown also suppressed VEGF-mediated signaling and angiogenesis, suggesting that procaspase-8 plays a role of a non-apoptotic modulator in VEGF-induced angiogenic signaling. These results suggest that TRAIL inhibits VEGF-induced angiogenesis by increasing caspase-8 activity and subsequently decreasing non-apoptotic signaling functions of procaspase-8, without inducing caspase-3 activation and endothelial cell cytotoxicity. These data indicate that caspase-8 may be used as an anti-angiogenic drug for solid tumors resistant to TRAIL and anti-tumor drugs.
实体瘤通过产生血管内皮生长因子 (VEGF) 来供应血管生成所需的氧气和营养物质。因此，VEGF 信号通路的抑制剂会阻断肿瘤血管生成，从而抑制肿瘤生长和转移。我们在这里研究了肿瘤坏死因子相关凋亡诱导配体 (TRAIL) 对 VEGF 诱导的血管生成的影响。TRAIL 抑制了 VEGF 诱导的人脐静脉内皮细胞 (HUVEC) 的体外血管生成和鸡胚和小鼠的体内新血管生成。TRAIL 通过抑制 ERK、Src、FAK、paxillin、Akt 和 eNOS，阻断了 VEGF 诱导的血管生成信号。此外，TRAIL 阻断了 VEGF 刺激的 HUVEC 中细胞内 Ca(2+) 的升高和肌动蛋白的重组，而不抑制 VEGF 受体-2 酪氨酸磷酸化。TRAIL 增加了 caspase-8 的活性，而没有诱导 caspase-9/-3 的激活和凋亡。此外，TRAIL 导致 FAK 在 VEGF 刺激的 HUVEC 中裂解成 FAK 相关的非激酶样片段，这被 caspase-8 抑制剂和细胞 caspase-8 样抑制蛋白阻断。caspase-8 和 FAK 的生化和药理学抑制阻断了 TRAIL 对 VEGF 刺激的抗血管生成信号和事件的抑制作用。此外，caspase-8 的敲低也抑制了 VEGF 介导的信号和血管生成，表明原 Caspase-8 在 VEGF 诱导的血管生成信号中起非凋亡调节剂的作用。这些结果表明，TRAIL 通过增加 caspase-8 的活性，随后降低原 Caspase-8 的非凋亡信号功能，来抑制 VEGF 诱导的血管生成，而不诱导 caspase-3 的激活和内皮细胞的细胞毒性。这些数据表明，caspase-8 可作为一种抗血管生成药物，用于治疗对 TRAIL 和抗肿瘤药物耐药的实体瘤。
