Microtubule depolymerization rapidly collapses capillary tube networks in vitro and angiogenic vessels in vivo through the small GTPase Rho
Microtubule depolymerization rapidly collapses capillary tube networks in vitro and angiogenic vessels in vivo through the small GTPase Rho
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DOI：
10.1074/jbc.m308373200
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发表时间：
2004-03-19
影响因子：
4.8
通讯作者：
Davis, GE
中科院分区：
文献类型：
--
作者：
Bayless, KJ;Davis, GE
内皮细胞管完整性的维持依赖于完整的细胞骨架。我们目前的数据表明，快速崩溃的内皮细胞在体外发生的微管解聚剂，但不是在肌动蛋白解聚后，管理后的剂量依赖性方式。用C3外切酶或表达显性负性RhoA的重组腺病毒预处理内皮细胞网络导致管塌陷的完全阻断，表明RhoA在这些事件中的作用。微管解聚也导致RhoA的激活，而组成性活性RhoA的表达增加诱导细胞变圆和内皮细胞凋亡。此外，用化疗剂长春碱治疗后，发生快速毛细血管网络塌陷，随后发生内皮细胞凋亡。长春碱（而非对照药物）诱导了半胱天冬酶原-3、半胱天冬酶原-9和半胱天冬酶原-8的裂解，沿着已知的半胱天冬酶靶点p21活化激酶-2和凝溶胶蛋白，表明管塌陷引起了明确的凋亡反应。使用血管内皮生长因子刺激的体内血管生成模型，长春碱治疗也导致血管生成血管的塌陷和凋亡。凋亡的内皮细胞染色强烈裂解的caspase-3，和终端dUTP缺口末端标记染色显示，在长春碱治疗，但不控制血管生成领域的核碎片。总之，这些研究结果表明，微管解聚剂直接诱导内皮网络崩溃在体外和体内导致内皮细胞凋亡的方式依赖于小GTdR，RhoA。此外，这些发现揭示了微管破坏化疗药物的新功能，即它们快速塌陷新形成的血管生成血管的能力，这可能有助于它们限制血管生成和肿瘤生长的有效性。
Maintenance of endothelial cell tube integrity is dependent on an intact cytoskeleton. We present data indicating that rapid collapse of endothelial tubular networks in vitro occurs in a dose-dependent manner after administration of microtubule-depolymerizing reagents but not after actin depolymerization. Pretreatment of endothelial cell networks with C3 exoenzyme or recombinant adenoviruses expressing dominant negative RhoA resulted in complete blockade of tube collapse, indicating a role for RhoA in these events. Microtubule depolymerization also resulted in activation of RhoA, whereas increased expression of constitutively active RhoA induced cell rounding and apoptosis of endothelial cells. Furthermore, following treatment with the chemotherapeutic agent vinblastine, rapid capillary tube network collapse occurred followed by endothelial cell apoptosis. Vinblastine, but not control agents, induced cleavage of procaspase-3, procaspase-9, and procaspase-8, along with the known caspase targets p21-activated kinase-2 and gelsolin, indicating that tube collapse caused a defined apoptotic response. Using a model of vascular endothelial growth factor-stimulated angiogenesis in vivo, vinblastine treatment also resulted in collapse and apoptosis of angiogenic blood vessels. Apoptotic endothelial cells stained strongly for cleaved caspase-3, and terminal dUTP nick-end labeling staining revealed fragmented nuclei in vinblastine-treated but not control angiogenic areas. Together, these findings indicate that microtubule-depolymerizing agents directly induce endothelial network collapse in vitro and in vivo leading to endothelial cell apoptosis in a manner dependent on the small GTPase, RhoA. In addition, these findings reveal a novel function for microtubule disrupting chemotherapeutic agents, namely their ability to rapidly collapse newly formed angiogenic vessels, which may contribute to their effectiveness in limiting angiogenesis and tumor growth.