Synergistic anti-hepatoma effect of bufalin combined with sorafenib via mediating the tumor vascular microenvironment by targeting mTOR/VEGF signaling.
Synergistic anti-hepatoma effect of bufalin combined with sorafenib via mediating the tumor vascular microenvironment by targeting mTOR/VEGF signaling.
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DOI：
10.3892/ijo.2018.4351
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发表时间：
2018-06
影响因子：
5.2
通讯作者：
Haiyong Wang;Chenyue Zhang;Hui-ying Chi;Z. Meng
中科院分区：
文献类型：
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作者：
Haiyong Wang;Chenyue Zhang;Hui-ying Chi;Z. Meng
索拉非尼主要通过抑制血管形成来抑制肿瘤生长，然而，其功效需要改进，因此，开发增强其抗血管生成作用的策略是首要关注的。蟾毒灵抑制肿瘤细胞增殖和转移，并诱导细胞凋亡。在我们以前的研究中，已经证明蟾蜍灵可以增强索拉非尼对人脐静脉内皮细胞（HUVECs）的抗血管生成作用。然而，蟾蜍灵是否通过影响肿瘤血管微环境与索拉非尼协同作用仍有待阐明。在本研究中，发现蟾蜍灵或索拉非尼孵育24 h后抑制肝细胞癌（HCC）细胞增殖，并用两者联合治疗后抑制作用增强。从每个处理组收集包含来自HCC细胞的上清液的条件培养基（CM）。CM对HUVECs迁移和小管形成的抑制作用最强。血管生成阵列，酶联免疫吸附试验（ELISA）和蛋白质印迹分析确定，血管内皮生长因子（VEGF）的分泌减少在HCC细胞与CM的组合处理。与VEGF一起孵育可逆转用组合-CM处理的HUVEC中管形成的抑制。体内实验证明，来自用组合治疗处理的小鼠的皮下HCC细胞肿瘤表达最低水平的VEGF，如通过免疫组织化学和ELISA证明的。此外，在用磷酸肌醇3-激酶抑制剂PI 103预处理的HUVEC中，雷帕霉素的磷酸化机制靶点（mTOR）的水平降低。此外，PI 103预处理可减弱HCC细胞的迁移和HUVEC管形成。总之，结果显示蟾蜍灵联合索拉非尼通过靶向mTOR/VEGF信号传导影响肿瘤血管微环境而具有协同抗肝癌作用。
Sorafenib inhibits tumor growth primarily by inhibiting vessel formation, however, its efficacy requires improvement, therefore, the development of strategies which augment its antiangiogenic effect are of primary concern. Bufalin inhibits tumor cell proliferation and metastasis, and induces apoptosis. In our previous study, it was demonstrated that the antiangiogenic effect of sorafenib was improved by bufalin in human umbilical vein endothelial cells (HUVECs). However, whether bufalin synergizes with sorafenib by affecting the tumor vascular microenvironment remains to be elucidated. In the present study, it was found that hepatocellular carcinoma (HCC) cell proliferation was inhibited by either bufalin or sorafenib following incubation for 24 h, and the inhibition was enhanced upon treatment with a combination of the two. Conditioned medium (CM), comprising supernatant from HCC cells was collected from each of the treatment groups. The migration and tubule formation were suppressed the most in the combination-CM treated HUVECs. The secretion of vascular endothelial growth factor (VEGF) was decreased in HCC cells treated with the combination-CM, as determined by an angiogenesis array, enzyme-linked immunosorbent assay (ELISA) and western blot analysis. The inhibition of tube formation in HUVECs treated with the combination-CM was reversed by incubation with VEGF. The in vivo experiments demonstrated that subcutaneous HCC cell tumors from mice treated with the combination treatment expressed the lowest levels of VEGF, as evidenced by immunohistochemistry and ELISA. Additionally, the level of phosphorylated mechanistic target of rapamycin (mTOR) was reduced in HUVECs pretreated with the phosphoinositide 3-kinase inhibitor PI103. Furthermore, the migration of HCC cells and HUVEC tube formation were attenuated by PI103 pretreatment. In conclusion, the results revealed a synergistic anti-hepatoma effect of bufalin combined with sorafenib via affecting the tumor vascular microenvironment by targeting mTOR/VEGF signaling.