EB病毒LMP1在鼻咽癌细胞中调控核转录因子κB活性研究

The Epstein-Barr Virus Encoded Latent Membrane Protein 1 Promotes Nuclear Factor-kappa B Activity in a Nasopharyngeal Carcinoma Cell Line

为了探讨EB病毒潜伏膜蛋白 1(LMP1)的致瘤机制 ,对鼻咽癌细胞中LMP1通过核转录因子κB(NFκB)介导的信号传导途径在鼻咽癌变中的意义进行了研究。利用LMP1受四环素衍生物强力霉素诱导表达的鼻咽癌细胞Tet on LMP1HNE2 ,通过NFκB报道基因分析法、凝胶迁移率分析 (EMSA)及细胞集落形成率等方法 ,结合硫代磷酸反义寡核苷酸阻断技术 ,证实LMP1增强鼻咽癌细胞NFκB的DNA结合活性和反式激活活性 ,这种增强的活性可被LMP1及NFκBp6 5硫代磷酸反义寡核苷酸阻断 ,而NFκBp5 0仅阻断DNA结合活性 ,对反式激活活性无影响。同时 ,LMP1及NFκBp6 5硫代磷酸反义寡核苷酸可部分逆转鼻咽癌细胞的恶性表型 ,而反义 p5 0这种效应不显著。这些结果表明 ,LMP1在鼻咽癌中通过NFκB信号传导途径可能参与了鼻咽癌变 ,NFκBp6 5可能是主要的效应者。

As an oncogenic protein, the Epstein-Barr virus encoded latent membrane protein 1(LMP1)may play a key role in nasopharyngeal carcinogenesis through its signal transduction pathway, especially NF-κB pathway. In order to attest this hypothesis, a dual-stable LMP1 integrated nasopharyngeal carcinoma cell line with Tet-on regulating system designated Tet-on-LMP1 HNE2, in which expression of LMP1 could be dose-dependent regulated by doxycycline, was used. It was found that NFκB activity was 3-10 folds high at LMP1 induced statement by reporter gene analysis, and this result was further confirmed by electrophoresis mobility shift assay which showed NFκB accumulated in nuclear when LMP1 expression was induced. When Tet-on-LMP1 HNE2 cells were co-incubated with phosphorothioate oligonucleotides (PS-ODNs) to antisense LMP1, NFκB p65 and NFκB p50 at various times, NFκB activity curves showed that antisense LMP1 blocked NFκB activity at earlier time than antisense p65 did, and p50 showed no block effect. What's more, PS-ODNs to antisense LMP1 and NFκB p65, but not p50, partially reversed malignant phenotype of Tet-on-LMP1 HNE2 boosted by LMP1 expression. All of these deduced that LMP1 could participate in the nasopharyngeal carcinogenesis by improving NFκB activity in NPC, and NFκB, of which p65 in particular, has the potency used as a molecular target to NPC gene therapy.