The response to brain tumor-derived growth factors is altered in radioresistant human brain endothelial cells
The response to brain tumor-derived growth factors is altered in radioresistant human brain endothelial cells
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DOI：
10.4161/cbt.5.11.3459
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发表时间：
2006-11
影响因子：
3.6
通讯作者：
N. Mclaughlin;B. Annabi;K. Kim;J. Bahary;R. Moumdjian;R. Béliveau
中科院分区：
文献类型：
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作者：
N. Mclaughlin;B. Annabi;K. Kim;J. Bahary;R. Moumdjian;R. Béliveau
导读：人们认为脑肿瘤血管的耐辐射性阻碍了辅助癌症治疗的效率。然而，辐照人脑微血管内皮细胞（HBMEC）对脑肿瘤源性生长因子的血管生成反应的信号通路所知甚少。本研究的目的是评估电离辐射（IR）对HBMEC存活、迁移和小管形成的影响。方法：培养HBMEC，单次亚致死剂量辐照。采用核细胞计数和流式细胞术检测细胞存活率。HBMEC迁移对脑肿瘤源性生长因子（U-87 GF）和小管形成的响应分别采用改良Boyden chambers和Matrigel检测。结果：我们观察到单次给药3-10 Gy IR剂量仅使细胞存活率降低30%。耐辐射HBMEC过表达RhoA和RhoA激酶，RhoA是一种调节细胞粘附和迁移的小GTPase蛋白，RhoA的主要靶点之一是丝氨酸-苏氨酸蛋白激酶。血管内皮生长因子（VEGF）可诱导HBMEC迁移，但鞘氨醇-1-磷酸（S1P）和U-87 GF对HBMEC迁移的影响更大。IR暴露后，HBMEC基础迁移增加了两倍以上，而对S1P和U-87 GF的反应明显减弱。同样，ROK Y-27632抑制剂响应于S1P和U-87 GF降低HBMEC迁移。RhoA的过表达减少了小管的形成，在辐照的HBMEC中也观察到这种效应。结论：我们的研究结果表明，放射耐药HBMEC对肿瘤分泌生长因子和小管发生的迁移反应在IR后发生改变。RhoA/ROK信号通路参与了ir改变的血管生成功能，可能是增强放疗对肿瘤相关内皮细胞影响的潜在分子靶点。
Introduction: Radioresistant brain tumor vasculature is thought to hamper the efficiency of adjuvant cancer therapies. However, little is known regarding the signalling pathways involved in the angiogenic response to brain tumor-derived growth factors in irradiated human brain microvascular endothelial cells (HBMEC). The goal of this study is to assess the effect of ionizing radiation (IR) on HBMEC survival, migration and tubulogenesis. Methods: HBMEC were cultured and irradiated at sublethal single doses. Cell survival was assessed by nuclear cell counting and flow cytometry. HBMEC migration in response to brain tumor-derived growth factors (U-87 GF) and tubulogenesis were assayed using modified Boyden chambers and Matrigel, respectively. Results: We observed that single administration of 3-10 Gy IR doses only reduced cell survival by 30%. Radioresistant HBMEC overexpressed RhoA, a small GTPase protein regulating cellular adhesion and migration, and Rho-kinase (ROK), a serine-threonine protein kinase and one of RhoA’s major targets. HBMEC migration was induced by vascular endothelial growth factor (VEGF), but even more so in response to sphingosine-1-phosphate (S1P) and to U-87 GF. Following IR exposure, HBMEC basal migration increased more than two-fold, whereas the response to S1P and to U-87 GF was significantly diminished. Similarly, the inhibitor of ROK Y-27632 decreased HBMEC migration in response to S1P and U-87 GF. Overexpression of RhoA decreased tubulogenesis, an effect also observed in irradiated HBMEC. Conclusion: Our results suggest that radioresistant HBMEC migration response to tumor-secreted growth factors and tubulogenesis are altered following IR. The RhoA/ROK signalling pathway is involved in the IR-altered angiogenic functions and may represent a potential molecular target for enhancing the impact of radiotherapy on tumor-associated endothelial cells.