International Journal of Cancer, 2015, 136(11):2524–2534.

C/EBPb promotes angiogenesis through secretion of IL-6, which is inhibited by genistein, in EGFRvIII-positive glioblastoma

Xujie Liu, Kaiyu Liu, Jiazhen Qin, et al

Department of Cell Biology, Peking University Health Science Center, Beijing, People's Republic of China; Peking University Stem Cell Research Center, Beijing, People's Republic of China

To study the mechanisms underlying the IL-6-promoted angiogenic microenvironment in EGFRvIII-positive glioblastoma, VEGF expression in EGFRvIII-positive/negative tumors was determined by optical molecular imaging. Next, the HUVEC tube formation assay, Western blot, qPCR, RNA silencing, chromatin immunoprecipitation, luciferase reporter and ELISA assays were performed to examine the role of IL-6 and C/EBPβ in the formation of the angiogenic microenvironment in EGFRvIII-positive tumors. Finally, in vitro and in vivo genistein treatment experiments were conducted to challenge the interaction between the IL-6 promoter and C/EBPβ. Optical imaging revealed greater VEGF expression in EGFRvIII-positive tumor-bearing mice, suggesting an angiogenic microenvironment. In vitro experiments demonstrated that C/EBPβ-mediated regulation of IL-6 was indispensable for maintenance of this angiogenic microenvironment. In contrast, genistein-mediated upregulation of CHOP impeded C/EBPβ interaction with the IL-6 promoter, thus disturbing the angiogenic microenvironment. This more malignant microenvironment in EGFRvIII glioblastoma is generated, at least in part, by greater VEGF, IL-6 and C/EBPβ expression. Interaction of C/EBPβ with the IL-6 promoter maintains this angiogenic microenvironment, while disturbance of this dynamically balanced interaction inhibits EGFRvIII tumor proliferation by reducing both VEGF and IL-6 expression.

希腊《国际肿瘤学杂志》

在 EGFRvⅢ阳性胶质母细胞瘤中，金雀异黄素抑制了C/EBPb通过IL-6的分泌促进血管生成的作用

北京大学健康科学中心细胞生物学系，北京，中华人民共和国; 北京大学干细胞研究中心，北京，中华人民共和国

研究EGFRvIII阳性胶质母细胞瘤IL-6促进血管生成微环境的机制，通过光学分子成像测定EGFRvIII阳性/阴性肿瘤VEGF表达。接下来，进行HUVEC管形成测定，蛋白质印迹，qPCR，RNA沉默，染色质免疫沉淀，荧光素酶报告物和ELISA测定以检查IL-6和C /EBPβ在EGFRvIII阳性肿瘤中形成血管生成微环境中的作用。最后，进行体外和体内染料木素治疗实验以挑战IL-6启动子和C /EBPβ之间的相互作用。光学成像显示EGFRvIII阳性荷瘤小鼠VEGF表达较多，提示血管生成微环境。体外实验表明，C /EBPβ介导的IL-6调节对维持这种血管生成微环境是必不可少的。相比之下，染料木黄酮介导的CHOP上调阻碍了C /EBPβ与IL-6启动子的相互作用，从而影响血管生成微环境。 EGFRvIII胶质母细胞瘤中这种更恶性的微环境至少部分地由更大的VEGF，IL-6和C /EBPβ表达产生。 C /EBPβ与IL-6启动子的相互作用保持了这种血管生成微环境，而这种动态平衡相互作用的干扰通过降低VEGF和IL-6的表达来抑制EGFRvIII肿瘤的增殖。