Nuclear factor κB represses the expression of latent membrane protein 1 in Epstein-Barr virus transformed cells

AIM: To investigate the role of nuclear factor κB(NF-κB) in the regulation of Epstein-Barr virus(EBV) latent membrane protein 1(LMP1) in EBV transformed cells. METHODS: LMP1 expression was examined in EBV transformed human B lymphocytes with modulation of NF-κB activity. RESULTS: EBV infection is associated with several human cancers. EBV LMP1 is required for efficient transformation of adult primary B cells in vitro, and is expressed in several pathogenic stages of EBVassociated cancers. Regulation of EBV LMP1 involves both viral and cellular factors. LMP1 activates NF-κB signaling pathway that is a part of the EBV transformation program. However, the relation between NF-κB and LMP1 expression is not well established yet. In this report, we found that blocking the NF-κB activity by Inhibitor of κB stimulated LMP1 expression, while the overexpression of NF-κB repressed LMP1 expression in EBV-transformed IB4 cells. In addition, LMP1 repressed its own promoter activities in reporter assays, and the repression was associated with the activation of NF-κB. Moreover, NF-κB alone is sufficient to repress LMP1 promoter activities. CONCLUSION: Our data suggest LMP1 may repress its own expression through NF-κB in EBV transformed cells and shed a light on LMP1 regulation during EBV transformation.

Recombinant Vaccinia Virus is an Effective and Non-perturbing Vector for Human Dendritic Cells Transfected with Epstein-Barr Virus Latent Membrane Protein 2A

ObjectiveTo study the effects of dendritic cells (DC) transfected with recombinant vaccinia virus encoding Epstein Barr virus (EBV) latent membrane protein 2A(LMP2A) gene,and to provide evidence for further investigation on the therapeutic vaccines against EBV associated malignancies. MethodsMature DC were transfected with EBV LMP2A recombinant vaccinia virus (rVV LMP2A). Before and after the transfection,the expression of surface antigens on mature DC including CD1a,CD83,CD40,CD80,HLA DR was measured by fluorescence activated cell sorter (FACS) and the function of DC to stimulate allogeneic T cells proliferation was measured by mixed leukocyte reactions (MLR). ResultsLMP2A protein was highly expressed (66.1 %) in DC after the transfection of rVV LMP2A. No significant changes in the primary surface antigens expression and in the MLR were detected during the transfection. Transfected DC still had strong potential in stimulating the proliferation of allogeneic T cells. ConclusionRecombinant vaccinia virus was an effective and non perturbing vector to mediate the transfection of LMP2A into DC. The functions of mature DC were not affected significantly by the transfection of Vac LMP2A. This study could provide evidence for the further immunotherapy of EBV associated malignancies,e.g. nasopharyngeal carcinoma (NPC).

Computational Prediction and Identification of Epstein-Barr Virus Latent Membrane Protein 2A Antigen-Specific CD8^+ T-Cell Epitopes

Epstein-Barr virus （EBV） associated nasopharyngeal carcinoma （NPC） is a high incidence tumor in Southeast Asia. Among EBV encoded proteins, latent membrane protein 2A （LMP2A） is an important antigen for T cell therapy of EBV. In this study, we predicted six HLA-A2 restricted CTL candidate epitopes of LMP2A by SYFPEITHI, NetMHC and MHCPred methods combined with the polynomial method. Subsequently, biological functions of these peptides were tested by experiments in vitro. In ELISPOT assay, the positive response of the LMP2A specific CTL stimulated by three （LMP2A264.272, LMP2A426-434 and LMP2A3s6.364） of six peptides respectively showed that the numbers of spots forming cells （SFC） ranged from 55.7 to 80.6 SFC/5 x 104 CO8^＋ T cells and the responding index （RI） ranged from 5.4 to 7. These three epitope-specific CTLs could effectively kill specific HLA-A2- expressing target cells. As a result, LMP2A264.272 （QLSPLLGAV）, LMP2A426.434 （CLGGLLTMV） and LMP2A356.364 （FLYALALLL） were identified as LMP2A-specific CD8^＋ T-cell epitopes. It would be useful to clarify immune response toward EBV and to develop a vaccine against EBV-correlative NPC.

Roles of the PI3K/Akt pathway in Epstein-Barr virusinduced cancers and therapeutic implications

Viruses have been shown to be responsible for 10%-15% of cancer cases. Epstein-Barr virus(EBV) is the first virus to be associated with human malignancies. EBV can cause many cancers, including Burkett's lymphoma, Hodgkin's lymphoma, post-transplant lymphoproliferative disorders, nasopharyngeal carcinoma and gastric cancer. Evidence shows that phosphoinositide 3-kinase/protein kinase B(PI3K/Akt) plays a key role in EBV-induced malignancies. The main EBV oncoproteins latent membrane proteins(LMP) 1 and LMP2 A can activate the PI3K/Akt pathway, which, in turn, affects cell survival, apoptosis, proliferation and genomic instability via its downstream target proteins to cause cancer. It has also been demonstrated that the activation of the PI3K/Akt pathway can result in drug resistance to chemotherapy. Thus, the inhibition of this pathway can increase the therapeutic efficacy of EBV-associated cancers. For example, PI3 K inhibitor Ly294002 has been shown to increase the effect of 5-fluorouracil in an EBV-associated gastric cancer cell line. At present, dual inhibitors of PI3 K and its downstream target mammalian target of rapamycin have been used in clinical trials and may be included in treatment regimens for EBV-associated cancers.

Nuclear translocation of EGF receptor regulated by Epstein-Barr virus encoded latent membrane protein 1

Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is considered to be the major oncogenic protein of EBV encoded proteins, and also it has always been the core of the oncogenic mechanism of EBV. Traditional receptor theory demonstrates that cell surface receptors exert biological functions on the membrane, which neither enter into the nucleus nor directly affect the transcription of the target genes. But, advanced studies on nuclear transloca-tion of the epidermal growth factor receptor (EGFR) family have greatly developed our knowl-edge of the biological function of cell surface receptors. In this study, we used Tet-on LMP1 HNE2 cell line as a cell model, which is a dual-stable LMP1 integrated NPC cell line and the ex-pression of LMP1 in which could be regulated by Tet system. We found that LMP1 could regulate the nuclear translocation of EGFR in a dose-dependent manner from both quantitative and qualitative levels through the Western blot analysis and the immunofluorescent analysis with a laser scanning confocal microscope. We further demonstrated that the nuclear localization se-quence of EGFR played some roles in the location of the protein within the nucleus under LMP1 regulation, and the nuclear accumulation of EGFR regulated by LMP1 was in a ligand-independent manner. These findings provide a novel view that the regulation of LMP1 on the nuclear translocation of EGFR is critical for the process of nasopharyngeal carcinoma.

Heterodimer formation between c-Jun and Jun B proteins mediated by Epstein Barr virus encoded latent membrane protein 1

Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) may trigger the transcription factor AP-1 including c-Jun and c-fos. In this report, using a Tet-on LMP1 HNE2 cell line which is a dual-stable LMP1 integrated nasopharyngeal carcinoma (NPC) cell line and the expression of LMP1 in which could be regulated by the Tet-on system, we show that Jun B can efficiently form a new heterodimeric complex with the c-Jun protein under the regulation of LMP1, phosphorylation of c-Jun (ser 63, ser 73) and Jun B is involved in the process of the new heterodimeric formation. We also find that this heterodimeric form can bind to the AP-1 consensus sequence. Transfection studies suggest that JNK interaction protein (JIP) could inhibit the heterodimer formation of c-Jun and Jun B through blocking the AP-1 signaling pathway triggered by LMP1. The interaction and function between c-Jun protein and Jun B protein increase the repertoire of possible regulatory complexes by LMP1 that could play an important role in the regulation of transcription of specific cellular genes in the process of genesis of nasopharyngeal carcinoma.

Chimerically fused antigen rich of overlapped epitopes from latent membrane protein 2 （LMP2） of Epstein-Barr virus as a potential vaccine and diagnostic agent

Epstein-Barr virus （EBV） is prevalent throughout the world and is associated with several malignant diseases in humans. Latent membrane protein 2 （LMP2） of EBV plays a crucial role in the pathogenesis of EBV-associated tumors; therefore, LMP2 has been considered to be a potential immunodiagnostic and immunotherapeutic target. A multi-epitope-based antigen is a promising option for therapeutic vaccines and diagnoses of such malignancies. In this study, we systematically screened cytotoxic T lymphocyte （CTL）, helper T cell （Th） and B-cell epitopes within EBV-LMP2 using bioinformatics. Based on the screen, two peptides rich in overlapping epitopes of both T cells and B cells were selected to construct a plasmid containing the sequence for a chimeric multi-epitope protein referred to as EBV-LMP2m, which is composed of LMP2aa195-232 and LMP2aa419-436. The EBV-LMP2m protein was expressed in E. coil BL21 （DE3） after prokaryotic codon optimization. Inoculation of the purified chimeric antigen in BALB/c mice induced not only high levels of specific IgG in the serum and secretory IgA in the vaginal mucus but also a specific CTL response. By using purified EBV-LMP2m as an antigen, the presence of specific IgG in the serum specimens of 202 nasopharyngeal carcinoma （NPC） patients was effectively detected with 52.84% sensitivity and 95.40% specificity, which represents an improvement over the traditional detection method based on VCA-IgA （60.53% sensitivity and 76.86% specificity）. The above results indicate that EBV-LMP2m may be used not only as a potential target antigen for EBV-associated tumors but also a diagnostic agent for NPC patients.

Establishment of Novel Monoclonal Fabs Specific for Epstein-Barr Virus Encoded Latent Membrane Protein 1

Dear Editor,Epstein-Barr virus(EBV,also termed human herpesvirus-4)was the first identified human tumor virus.Since its discovery in 1964,studies have shown that EBV infects over 90%of all people by the time they are adults(Williams and Crawford 2006).EBV infection can result in mucocutaneous and systemic diseases,ranging from selflimited illnesses to aggressive malignancies,including B cell Hodgkin lymphoma and nasopharyngeal carcinoma.In vitro,EBV transforms resting B cells into proliferating blast cells(Pope et al.1968).

Construction and humoral immune response of Epstein-Barrvirus latent membrane protein 2 DNA vaccine in mice

We constructed a eukaryotic expression plas-mid encoding Epstein-Barr virus latent membrane protein 2(EBV,LMP2)and evaluated its effects on humoral immunity.First,the encoding sequence of the EBV LMP2 was amplified from B95-8 cell RNA by reverse transcrip-tion polymerase chain reaction(RT-PCR)and then was directionally cloned into eukaryotic expression vector pcDNA3.1.It was employed to evaluate immune response of the mice inoculated doubly with the DNA vaccine.The serum antibody against LMP2 was detected with enzyme-linked immunosorbent assay(ELISA).The recombinant plasmid pcDNA3.1-LMP2 was confirmed by the restrictive endonuclease analysis and sequence analysis.The serum titer of IgG antibody against LMP2 epitope in the mice immunized with the DNA vaccine encoding LMP2 was up to 1∶4000.In conclusion,the EBV LMP2 DNA vaccine can induce a strong humoral immune response in mice.

Potent Dendritic Cell Vaccine Loaded with Latent Membrane Protein 2A (LMP2A)

Epstein-Barr virus （EBV）, a potential oncogenic herpesvirus, has been found to be associated with several malignancies. It＇s critical to elicit cellular immunity of the body to fight against EBV-associated tumor development. Using dendritic cells （DCs） loaded with latent membrane protein 2A （LMP2A） to elicit T cell response against tumor may be one of the most direct and safest immunotherapy approaches. The present study aimed to develop DCs-based cancer vaccine （DC loaded with LMP2A protein） and study its biological characteristics and immune functions. Purified LMP2A protein was extracted from a cell line L929/LMP2A stably expressing LMP2A. LMP2A could be loaded on DCs with no significant changes of the DC surface markers and cytomorphology. The percentage of DCs loaded with LMP2A was above 80%. LMP2A-loaded DCs markedly enhanced the proliferation of antigen-specific CD8^＋ T and CD4^＋ T cells by 3H-TdR incorporation assay. Besides, the specific cytotoxicity of the CTLs against LMP2A target cells was also significantly increased. These results indicated that DC-based vaccine loaded with virus antigen could elicit potent CTL response and provide a foundation for further study on the DC-based immunotherapy for nasopharygeal carcinoma and other EBV associated tumors. Cellular ＆ Molecular Immunology.

IL-2Rα up-regulation is mediated by latent membrane protein 1 and promotes lymphomagenesis and chemotherapy resistance in natural killer/T-cell lymphoma

Background:Natural killer/T-cell lymphoma(NKTCL)is a highly aggressive non-Hodgkin lymphoma often resistant to chemotherapy.Serum level of soluble IL-2 receptorα(IL-2Rα)is elevated in NKTCL patients and correlates signifi-cantly with treatment response and survival.In the current study we examined the potential role of IL-2Rαby over-expressing IL-2Rαin representative cell lines.Methods:Levels of IL-2Rαwere evaluated in the human natural killer cell line NK-92 and the NKTCL cell line SNK-6.Lentiviral vectors were used to express latent membrane protein 1(LMP1)in NK-92 cells,and IL-2Rαin both NK-92 and SNK-6 cells.The biological effects of these genes on proliferation,apoptosis,cell cycle distribution,and chemosensitiv-ity were analyzed.Results:Expression of IL-2Rαwas significantly higher in SNK-6 cells than in NK-92 cells.Expressing LMP1 in NK-92 cells remarkably up-regulated IL-2Rαlevels,whereas selective inhibitorss of the proteins in the MAPK/NF-κB pathway significantly down-regulated IL-2Rα.IL-2Rαoverexpression in SNK-6 cells promoted cell proliferation by altering cell cycle distribution,and induced resistance to gemcitabine,doxorubicin,and asparaginase.These effects were reversed by an anti-IL-2Rαantibody.Conclusions:Our results suggest that LMP1 activates the MAPK/NF-κB pathway in NKTCL cells,up-regulating IL-2Rαexpression.IL-2Rαoverexpression promotes growth and chemoresistance in NKTCL,making this interleukin receptor a potential therapeutic target.

Immunotherapy of Epstein-Barr Virus Associated Malignancies Using Mycobacterial HSP70 and LMP2A356-364 Epitope Fusion Protein

Epstein-Barr virus infection is strongly associated with a number of malignancies.The EBV latent membrane protein 2A has been implicated as one of the most attractive candidates for immunotherapy of related malignancies.In previous studies,the T cell epitopes of LMP2A have been identified systematically.However,the epitope-based vaccine generally meets inefficient immunogenicity when used in vivo directly,which could be overcome by combination with appropriate adjuvants.Heat shock protein is a natural chaperon,which is able to activate the classical major histocompatibility complex class I antigen-processing pathway(cross-presentation).In this study,a minigene encoding LMP2A356-364(FLYALALLL)was genetically fused to the carboxy-terminal of mycobacterial heat shock protein 70.The epitope fusion protein was expressed and purified,and the cross-presentation of LMP2A_(356-364) by monocyte-derived dendritic cells pulsed with the epitope fusion protein was evaluated.Results showed that the epitope fusion protein-pulsed mDCs were much more efficient than the single peptide-pulsed mDCs on CTL activation.Immunization of HLA-A2.1 transgenic mice with MtHsp70-LMP2A_(356-364) generated peptide specific CTL more effectively than a single peptide plus incomplete Freund's adjuvant(IFA).Growth of LMP2A expressing B16 melanoma tumor cells was suppressed in the vaccinated groups.Our results suggested that MtHsp70-LMP2A_(356-364) fusion protein was more effective than the CD8^(+)T cell epitope alone on anti-tumor immunity.As a result,the MtHsp70-LMP2A_(356-364) fusion protein is considered to be a promising candidate vaccine for EBV related malignancies.

鼻咽癌细胞中EB病毒编码的潜伏膜蛋白1活化cyclinD1的表达

为了探讨EB病毒编码的潜伏膜蛋白 1(EBV LMP1)促进细胞增殖 ,参与EBV相关疾病致瘤的分子机制 ,研究了LMP1在鼻咽癌细胞中调节cyclinD1表达 ,进而影响细胞周期行进及细胞恶性表型改变 ,并初步确定了LMP1发挥该功能的结构域 .利用已建株的Tet on LMP1 HNE2鼻咽癌细胞系 ,蛋白质印迹实验分析LMP1诱导cyclinD1蛋白质表达的表达动力学 ,包括时间效应及剂量效应 ;利用三种LMP1功能区缺失的突变体及野生型LMP1,以载体型细胞为对照 ,确定LMP1活化cyclinD1表达的结构域 .同时结合基因诱导表达及反义寡聚核酸技术阻断基因表达的实验方法 ,进一步确定LMP1上调的cyclinD1功能 ,即对细胞周期行进及细胞恶性表型的影响 .结果表明LMP1确实可以诱导cyclinD1的表达 (2～ 4倍 ) ,且诱导具有时间依赖性及剂量依赖性 ;利用三种LMP1功能区缺失的突变体及野生型LMP1,以载体型细胞为对照 ,结合报道基因分析法 ,确定与空白载体细胞系比较 ,野生型LMP1从转录水平可反式激活cyclinD1报道基因活性约 11 2倍 ,其中CTAR1及CTAR2均可活化cyclinD1表达 ,但以CTAR2为主 ,与野生型LMP1诱导cyclinD1反式激活活性比较 ,CTAR1缺失导致cyclinD1报道基因活性下降 2 3 6 % ,CTAR2缺失导致cyclinD1活性下降约 80 7% ,C端均缺失时cyclinD1活性只?

EBV-LMP1上调Ezrin表达对鼻咽癌细胞转移潜能的影响

背景与目的:细胞骨架相关蛋白Ezrin的异常表达与肿瘤侵袭转移密切相关,既往研究已证实EB病毒潜伏膜蛋白1(Epstein-Barr virus latent membrane protein1,EBV-LMP1)可促进鼻咽癌细胞的转移能力。本研究旨在进一步探讨EBV-LMP1是否通过改变Ezrin的表达来影响鼻咽癌细胞的转移能力。方法:采用免疫细胞化学和Western blot检测两种鼻咽癌细胞株-CNE1细胞(EBV阴性)和CNE1-GL细胞(稳定转染EBV-LMP1)中LMP1和Ezrin的表达;细胞-基质粘附实验检测CNE1、CNE1-GL和经Ezrin抗体预处理的CNE1-GL细胞(AntiEzrin-CNE1-GL)对细胞外基质的粘附力;Transwell小室法检测上述3种细胞的运动和对重组基底膜侵袭能力。结果:CNE1细胞中Ezrin阴性表达,而CNE1-GL细胞中Ezrin强阳性表达。CNE1-GL细胞对细胞外基质的粘附率[(89.38±6.12)%]强于CNE1细胞[(49.42±5.37)%](P<0.001),而AntiEzrin-CNE1-GL细胞对基质的粘附率[(56.94±4.08)%]明显下降,与CNE1-GL相比,差异有统计学意义(P<0.05)。运动实验和侵袭实验均提示CNE1-GL细胞运动、侵袭能力(107±11和179±25)强于CNE1细胞(27±3和46±6),差异均有统计学意义(P<0.001),而AntiEzrin-CNE1-GL细胞的运动、侵袭能力(38±4和51±5)较CNE1-GL细胞显均显著下降(P<0.001)。结论:CNE1细胞中EBV-LMP1可通过上调Ezrin表达来促进细胞转移。

EB病毒潜伏膜蛋白1通过TRAF/TRADD激活JNK信号途径

为了探讨在鼻咽癌细胞中EB病毒编码的潜伏膜蛋白 1(LMP1)激活c Jun氨基端激酶 (JNK)信号途径的分子机制 ,利用可调控表达LMP1的鼻咽癌细胞系L7,蛋白质印迹检测 ,发现LMP1能够促进JNK的活化 ;利用稳定表达LMP1的鼻咽癌细胞系HNE2 LMP1及其三种突变体HNE2 LMP1ΔCTAR 1、HNE2 LMP1ΔCTAR2、HNE2 LMP1ΔCTAR 1,2及LMP1阴性的HNE2 为材料 ,采用蛋白质印迹和报告基因法分析JNK和活化蛋白 1(AP1)活化情况 ,结果显示HNE2 LMP1和HNE2 LMP1ΔCTAR1中磷酸化JNK蛋白表达量和AP1活性都无显著差异 ,而与HNE2 LMP1ΔCTAR2、HNE2 LMP1ΔCTAR1,2、阴性对照HNE2及空白载体转染细胞的JNK蛋白表达和AP1活性具有显著差异 ;进一步比较转染TRAF、TRADD显性负性突变体鼻咽癌细胞系HNE2 LMP1中磷酸化的JNK量和AP1活性 ,结果显示 :TRAF DN和TRADD DN的导入使活化的JNK蛋白和AP 1活性显著降低 ,二者间无显著差异 ,提示TRAF和TRADD可能参与了LMP1对JNK和AP 1的活化 .以上结果提示在鼻咽癌细胞系中LMP1功能结构域CTAR2通过结合TRAF/TRADD激活JNK从而活化重要的转录因子AP1.

EB病毒LMP1-CTAR3对NP69细胞增殖和蛋白质表达的影响

为了探讨EB病毒潜伏性膜蛋白1(LMP1)第三个功能活性区域(CTAR3)在鼻咽上皮细胞NP69中的转化作用机制,采用逆病毒感染的方法,将浓缩的逆病毒RV-LMP1和RV-LMP1△232～351分别感染鼻咽上皮细胞NP69,建立NP69-LMP1与NP69-LMP1△232～351稳定表达细胞系.通过绘制生长曲线、平皿克隆形成试验和软琼脂集落形成试验比较野生型和突变型LMP1对NP69细胞增殖的影响,运用蛋白质组学方法鉴定NP69-LMP1与NP69-LMP1△232～351细胞间的差异表达蛋白,选用实时荧光定量RT-PCR与Western blot对其中部分蛋白质点差异表达进行验证.结果发现:a.突变型LMP1△232～351促NP69细胞增殖的能力较野生型LMP1明显降低(n=3,P<0.05);b.鉴定了LMP1-CTAR3在NP69细胞中参与调节的16个蛋白质(表达上调的蛋白质8个,下调的8个).c.实时荧光定量RT-PCR和Westernblot证实了部分上述蛋白质的差异表达.以上结果说明,LMP1-CTAR3是其发挥促细胞增殖的重要活性部位,可能通过参与调节G蛋白和异柠檬酸脱氢酶等蛋白质的表达而起作用.

EB病毒LMP1基因和蛋白在结外鼻型NK/T细胞淋巴瘤中的表达及与预后的关系

目的 从蛋白和DNA两个水平初步检测成都地区结外鼻型NK/T细胞淋巴瘤中L MP1的表达,并探讨与预后的关系。方法 应用免疫组化和PCR技术检测6 7例结外鼻型NK/T细胞淋巴瘤L MP1的表达,并应用Kaplan- Meier曲线分别比较L MP1蛋白和L MP1DNA阳性表达组与阴性表达组的生存率。结果 L MP1蛋白阳性表达10例(14 .93% ) ,L MP1DNA阳性表达5 6例(83.5 8% ) ,L MP1总检出率83.5 8%。L MP1蛋白(P=0 .6 78)和L MP1DNA (P=0 .94 3)表达均与预后无明显关系。结论 L MP1与成都地区结外鼻型NK/T细胞淋巴瘤关系密切;结外鼻型NK/T细胞淋巴瘤中L MP1蛋白水平和DNA水平表达不一致;L MP1的表达与预后无明显关系。

EB病毒潜伏膜蛋白1在鼻咽癌细胞中通过STAT3促进VEGF表达

探讨了EB病毒编码的潜伏膜蛋白 1(LMP1)是否通过STAT3调控诱导血管内皮细胞生长因子 (VEGF)的表达 .利用蛋白质印迹的方法对HNE2、HNE2 LMP1以及瞬时转染STAT3显性负性突变体STAT3β的HNE2 LMP1细胞中VEGF含量进行检测 ,发现LMP1可以上调VEGF的表达 ,而STAT3β可以抑制VEGF的上调 ;利用LMP1可控表达细胞系tet on LMP1 HNE2进行LMP1时间和剂量诱导表达研究 ,发现VEGF可以随LMP1的动态表达而表达 ;将VEGF野生型报告基因和VEGF潜在的STAT3转录因子突变体报告基因与LMP1表达载体分别共转染研究发现 ,LMP1可以激活VEGF的转录 ,这种转录通过VEGF启动子区STAT3转录因子的结合位点发挥作用 ;电泳迁移率变动分析 (EMSA)确证了STAT3的这种DNA位点的特异性活性 .结果表明 :EB病毒编码的LMP1在鼻咽癌细胞中可以增加VEGF的转录和表达 。

EB病毒LMP1促鼻咽上皮细胞增殖的蛋白分子鉴定

目的:探讨EB病毒潜伏性膜蛋白1(LMP1)促鼻咽上皮细胞增殖的分子机制。方法:采用逆病毒感染的方法,将浓缩的逆病毒RV-pLNSX(空载体)和RV-LMP1分别感染鼻咽上皮细胞NP69,建立NP69-pLN-SX与NP69-LMP1稳定表达细胞系,通过绘制细胞生长曲线、平皿克隆形成实验和软琼脂集落形成实验检测LMP1对NP69细胞增殖的影响;运用比较蛋白质组学方法鉴定LMP1在NP69细胞中参与调节的蛋白,并对部分蛋白表达进行验证。结果:(1)LMP1具有促鼻咽上皮细胞NP69增殖的作用(n=3,P<0.05)。(2)鉴定了22个LMP1参与调节NP69细胞的蛋白(表达上调的蛋白9个,下调的13个),实时荧光定量RT-PCR和Western blotting证实了部分上述蛋白的差异表达。结论:LMP1可能通过参与调节keratin19和vimentin等蛋白的表达促鼻咽上皮细胞NP69增殖。

鼻咽癌细胞系 SUNE 中 EBV-LMP1 基因对上皮细胞增殖的影响

目的研究鼻咽癌细胞系ＳＵＮＥ中ＥＢＶ┐ＬＭＰ１基因对上皮细胞增殖的影响，探索ＬＭＰ１在鼻咽癌发生中所起的作用。方法用ＬＭＰ１基因真核表达质粒转染人胚肾上皮细胞，检测ＬＭＰ１的表达，观察细胞在软琼脂中的集落形成能力，ＭＴＴ吸收能力以及ＰＣＮＡ的表达情况。结果被ＬＭＰ１基因转染的细胞生长旺盛，能在软琼脂中形成多个集落，ＭＴＴ吸收能力增强，ＰＣＮＡ的表达水平增高。结论ＬＭＰ１基因能明显改变上皮细胞的生物学行为，促进细胞的生长、增殖和转化，使转染的上皮细胞获得肿瘤细胞的生长特征。