EB病毒LMP1在鼻咽癌细胞系中通过NF-κB、AP-1促进MMP9表达

Matrix metalloproteinase 9 expression is induced by Epstein-Barr virus LMP1 via NF-κB or AP-1 signaling pathway in nasopharyngeal carcinoma cells

目的 探讨EB病毒 (Epstein BarrVirus,EBV)LMP1是否通过NF κB和AP 1促进MMP9表达 ,为全面阐明LMP1的分子致瘤机制提供实验依据。方法 将MMP9 CAT表达质粒导入HNE2 pSG5、HNE2 LMP1、HNE2 LMP1(1 185 )、HNE2 LMP1(1 2 31)、HNE2 LMP1Δ187 35 1鼻咽癌 (nasopharyngealcarcinoma ,NPC)细胞系 ,比较各组细胞系的氯霉素乙酰转移酶 (CAT)活性 ,以确定LMP1或其不同的结构域是否上调MMP9转录 ;采用明胶Zymography法检测上述细胞产生MMP9的活性 ,以确定LMP1或其不同的结构域是否促进MMP9蛋白表达 ;借助报道基因分析法确定在NPC中野生型LMP1能否激活NF κB和AP 1的活性 ,进一步将突变了NF κB或AP 1结合位点的MMP9 CAT表达质粒导入上述细胞系 ;比较相应的CAT活性 ,以确定LMP1或其不同的结构域是否通过NF κB或AP 1上调MMP9表达。结果 与导入载体pCDNA3比较 ,HNE2 LMP1、HNE2 LMP1(1 185 )、HNE2 LMP1(1 2 31)和HNE2 LMP1Δ187 35 1NPC细胞系CAT活性分别提高 7.2 ,1.3,3.3和 4.0倍。明胶Zymography法检测显示 ,在HNE2 LMP1、HNE2 LMP1(1 2 31)和HNE2 LMP1Δ187 35 1细胞系中 ,均可检测到 92 0 0 0MMP9活性 ,而HNE2 pSG5、HNE2 LMP1(1 2 31)几乎均为阴性。较之母细胞 ,野生型LMP1活化NF

Objective To clarify if Epstein-Barr virus encoded LMP1 induces matrix metalloproteinase 9 expression via NF-κB or AP-1 signaling pathway, which gives evidence to the elucidation of the mechanism of LMP1- mediated carcinogenesis.Methods To determine whether LMP1 or its mutants contribute to MMP9 production via NF-κB or AP-1 transcription factor, MMP9- chloramphenicol acetyl transferase (CAT), NF-κB mut 9-CAT, AP-1 mut MMP9-CAT were transfected into human nasopharyngeal carcinoma cells stably expressing LMP1 (HNE2-LMP1) or its mutants, [HNE2-LMP1 (1-185), HNE2-LMP1(1-231), HNE2-LMP1 Δ187-351] by electroporation technic. The difference of MMP9 reporter activity among those cell lines was detected by CAT assay and expression of MMP9 was determined in nasopharyngeal carcinoma cells stably expressing LMP1 or its mutants by zymographic analysis. In the meantime, efforts were made to demonstrate if LMP1 regulates NF-κB or AP-1 activation using reporter gene analysis.Results In contrast with vector-transfected cells, MMP9 CAT activity in HNE2-LMP1, HNE2-LMP1 (1-185), HNE2-LMP1(1-231), HNE2-LMP1 Δ187-351 increased 7.2, 1.3, 3.3, 4.0 times respectively. Zymographic analysis demonstrated that the 92 kDa MMP9 expression was induced in HNE2-LMP1, HNE2-LMP1(1-231) and HNE2-LMP1 Δ187-351 cells, whereas it was negtive in HNE2-pSG5 and HNE2-LMP1 (1-185) cells. As compared to the HNE2 cells, NF-κB or AP-1 reporter activity in HNE2-LMP1 cells were increased 13.8, 8.4 fold respectively. Moreover, In contrast with MMP9 CAT-transfected cells, MMP9 CAT activity in NF-κB mut MMP9-CAT or AP-1 mut MMP9-CAT transfected HNE2-LMP1, HNE2-LMP1 (1-185), HNE2-LMP1(1-231) and HNE2-LMP1 Δ187-351 cells were significantly decreased by 18.1% or 16.3%, 35.0% or 33.3%, 29.1% or 26.1% from the original level. However, there was no difference in NF-κB mut MMP9-CAT or AP-1 mut MMP9-CAT transfected HNE2-pSG5, HNE2-LMP1 (1-185) cells.Conclusion In nasophargyngeal carcinoma, Epstein-Barr virus-encoded LMP1 induces MMP9 transcription and enzymatic activity via an NF-κB or AP-1 signaling pathway, which may contribute to invasiveness and metastasis.