Yoshizaki T, Horikawa T, Qing-Chun R, Wakisaka N, Takeshita H, Sheen T S, Lee S Y, Sato H, Furukawa M
Department of Otolaryngology, School of Medicine, Kanazawa University, Kanazawa 920-8641, Japan.
Clin Cancer Res. 2001 Jul;7(7):1946-51.
The EBV latent membrane protein-1 (LMP-1) is a multifunctional protein. Recently, the contribution of LMP-1 to the metastasis of nasopharyngeal carcinoma (NPC) has been suggested. Angiogenesis is a key step for metastasis. Thus, the association of LMP-1 to neovascularization of NPC was examined in this study.
The association of LMP-1 to angiogenesis in 39 patients with NPC was evaluated by immunohistochemical study, and then induction of angiogenic factors by LMP-1 was examined by ELISA and luciferase reporter assay.
In an immunohistochemical study, the expression of LMP-1 was significantly correlated to microvessel counts (P = 0.0003), suggesting that LMP-1 may induce some angiogenic factors. Therefore, we studied the relationship between LMP-1 expression and interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) expression by immunohistochemical analysis. IL-8, VEGF, and bFGF expression were correlated to microvessel counts, but only IL-8 expression was significantly correlated to LMP-1 expression (P < 0.0001). Transfection with LMP-1 expression plasmid induced IL-8 protein expression in C33A cells. The expression of LMP-1 transactivated IL-8 promoter, as demonstrated by IL-8 promoter luciferase reporter assay. Mutation of the nuclear factor kappaB responsive element in the IL-8 promoter region completely abolished transactivation by LMP-1, whereas mutation of the activator protein responsive element did not affect promoter activity.
These results suggested that LMP-1 induces expression of IL-8 through the nuclear factor kappaB binding site, which may contribute in part to angiogenesis in NPC.
EB病毒潜伏膜蛋白1（LMP-1）是一种多功能蛋白。最近，有人提出LMP-1对鼻咽癌（NPC）转移有作用。血管生成是转移的关键步骤。因此，本研究检测了LMP-1与NPC新生血管形成的关系。
通过免疫组织化学研究评估39例NPC患者中LMP-1与血管生成的关系，然后通过酶联免疫吸附测定（ELISA）和荧光素酶报告基因检测法检测LMP-1对血管生成因子的诱导作用。
在免疫组织化学研究中，LMP-1的表达与微血管计数显著相关（P = 0.0003），提示LMP-1可能诱导某些血管生成因子。因此，我们通过免疫组织化学分析研究了LMP-1表达与白细胞介素8（IL-8）、血管内皮生长因子（VEGF）和碱性成纤维细胞生长因子（bFGF）表达之间的关系。IL-8、VEGF和bFGF的表达与微血管计数相关，但只有IL-8的表达与LMP-1的表达显著相关（P < 0.0001）。用LMP-1表达质粒转染可诱导C33A细胞中IL-8蛋白表达。如IL-8启动子荧光素酶报告基因检测所示，LMP-1的表达可反式激活IL-8启动子。IL-8启动子区域中核因子κB反应元件的突变完全消除了LMP-1的反式激活作用，而激活蛋白反应元件的突变不影响启动子活性。
这些结果提示LMP-1通过核因子κB结合位点诱导IL-8表达，这可能部分促成了NPC中的血管生成。
