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 transforme...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.展开更多
Epstein-Barr virus （EBV）-encoded latent membrane protein 1 （LMPI） has been known to have oncogenic properties during latent infection in nasopharyngeal carcinoma （NPC）. Our studies focused on the role of LMP1 in...Epstein-Barr virus （EBV）-encoded latent membrane protein 1 （LMPI） has been known to have oncogenic properties during latent infection in nasopharyngeal carcinoma （NPC）. Our studies focused on the role of LMP1 in NPC, and showed that LMP1 triggers the NF-κB, AP-1 and STAT signaling pathways. Strikingly, LMP1 was found to mediate the formation of a new heterodimer between c-Jun and JunB. Also, we have identified JAK/STAT and PI-PLC-PKC activation triggered by LMP1 through upregulating the expression of JAK3 and enhancing the phosphorylation of STATo The constitutive activation of these signaling cascades explains LMP1＇s ability to induce such a diverse array of morphological and phenotypic effects in cells and provides insight into how LMP1 may induce cell transformation, in which multihit targeted genes in the downstream play an essential role. All signaling cascades triggered by LMP1 ultimately lead to the disruption of the cell cycle： the acceleration of G1/S phase and the arrest of G2/M phase. We also found that LMP1 induced the expression of hTERT and promoted cell immortalization. Importantly, by intervening physical intracellular signal transduction pathways and disturbing the progression of the cell cycle, LMP1, an important oncoprotein encoded by EBV, is thought to be a key modulator in the pathogenesis of NPC. Interfering LMP1 signaling could be a promising strategy to target the malignant phenotype of NPC. Cellular ＆ Molecular Immunology.展开更多
In our recent studies, we found that LMP1 encoded by Epstein-Barr virus could accelerate the formation of active c-Jun/Jun B heterodimer. We studied the regulation of cyclinD1 by c-Jun/Jun B heterodimers by laser scan...In our recent studies, we found that LMP1 encoded by Epstein-Barr virus could accelerate the formation of active c-Jun/Jun B heterodimer. We studied the regulation of cyclinD1 by c-Jun/Jun B heterodimers by laser scanning confocal influorescence microscopy, Western blot, luciferase activity assay, super-EMSA and flow cytometry in the Tet-on-LMP1 HNE2 cell line, in which LMP1 expression was regulated by Tet-on system. c-Jun/Jun B heterodimers induced by LMP1 could up regulate cyclin D1 promoter activity and expression. Overexpression of cy-clinD1 accelerated the progression of cell cycle.展开更多
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 s...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.展开更多
Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is considered as the major oncogenic protein of EBV encoded proteins, which could transactivate many transcription factors including activator protein ...Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is considered as the major oncogenic protein of EBV encoded proteins, which could transactivate many transcription factors including activator protein 1 (AP-1). Transcription factor plays its role in biological effects through binding to the target gene promoter,transactivating the transcription of target gene, regulating the target gene expression, etc. Recently, we found that LMP1 could mediate a new heterodimer form of c-Jun and JunB, which could bind to AP1 DNA sequence. In this report,we confirmed p16 as a putative target gene of c-Jun/JunB using bioinformatics. We used Tet-on-LMP1 HNE2 cell line as a cell model, which is a dual-stable LMP1 integrated HNE2 cell line and the expression of LMP1 could be regu-lated by the Tet system, and we wanted to explore whether c-Jun/JunB heterodimers mediated by LMP1 could regulate p16. Data demonstrated that c-Jun/Jun B heterodimers me-diated by LMP1 downregulated both the promoter activity and p16 expression, and accelerated the cell cycle progression. These findings established a new direct connection between the AP-I singnal pathway and the cell cycle, and provided a new model for the carcinogenesis mechanism.展开更多
Latent membrane protein 1 （LMP1）, an important protein encoded by Epstein Barr virus （EBV）, has been implied to link with the pathogenesis of nasopharyngeal carcinoma （NPC）. Its dual effects of increasing cell p...Latent membrane protein 1 （LMP1）, an important protein encoded by Epstein Barr virus （EBV）, has been implied to link with the pathogenesis of nasopharyngeal carcinoma （NPC）. Its dual effects of increasing cell proliferation and inhibiting cell apoptosis have been confirmed. In this study, we showed that the expression of Survivin and CDK4 protein in CNE-LMP1, a LMP1 positive NPC epithelial cell line, is higher than in LMP1 negative NPC epithelial cell line- CNE1, and the expression is LMP1 dosage-dependent. Although it was reported that Survivin specifically expressed in cell cycle G2/M phase, our studies suggested that LMP1 could promote the expression of Survivin in G0/G1, S and G2/ M phase. It also showed that Survivin and CDK4 could be accumulated more in the nuclei triggered by LMP1. More interestingly, Survivin and CDK4 could form a protein complex in the nuclei of CNE-LMP1 rather than in that of CNE1, which demonstrated that the interaction between these two proteins could be promoted by LMPI. These results strongly suggested that the role of LMP1 in the regulation of Survivin and CDK4 may also shed some light on the mechanism research of LMP1 in NPC.展开更多
基金Supported by Grants from the NIH CA138213,RR15635Department of Defense W81XWH-12-1-0225(Luwen Zhang)Qianli Wang was partially supported by Undergraduate Creative Activities and Research Experiences and Beckman Scholars Program
文摘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.
基金grants from State Key Basic Research and Development Plan （973） of the Ministry of Science and Technology of China （2004CB518703） National High Technology Research and Development Program （863） of China （N0.2006AA02Z481）+1 种基金 National Science Fund for Distinguished Young Scholars 0verseas （30428008） Hong Kong Cooperation Fund Project of National Natural Science Foundation of China （30418004）.
文摘Epstein-Barr virus （EBV）-encoded latent membrane protein 1 （LMPI） has been known to have oncogenic properties during latent infection in nasopharyngeal carcinoma （NPC）. Our studies focused on the role of LMP1 in NPC, and showed that LMP1 triggers the NF-κB, AP-1 and STAT signaling pathways. Strikingly, LMP1 was found to mediate the formation of a new heterodimer between c-Jun and JunB. Also, we have identified JAK/STAT and PI-PLC-PKC activation triggered by LMP1 through upregulating the expression of JAK3 and enhancing the phosphorylation of STATo The constitutive activation of these signaling cascades explains LMP1＇s ability to induce such a diverse array of morphological and phenotypic effects in cells and provides insight into how LMP1 may induce cell transformation, in which multihit targeted genes in the downstream play an essential role. All signaling cascades triggered by LMP1 ultimately lead to the disruption of the cell cycle： the acceleration of G1/S phase and the arrest of G2/M phase. We also found that LMP1 induced the expression of hTERT and promoted cell immortalization. Importantly, by intervening physical intracellular signal transduction pathways and disturbing the progression of the cell cycle, LMP1, an important oncoprotein encoded by EBV, is thought to be a key modulator in the pathogenesis of NPC. Interfering LMP1 signaling could be a promising strategy to target the malignant phenotype of NPC. Cellular ＆ Molecular Immunology.
基金This work was supported by the StateKey Basic Research Program,Foundational Investigation on Human Carcinogenes is of China(Grant No.G1998051201)National Natural Science Foundat ion for Distinguished Young Scholars of China(Grant No.39525022)National Natural Science Foundation of China(Grant Nos.30300403,30100005&30000087).
文摘In our recent studies, we found that LMP1 encoded by Epstein-Barr virus could accelerate the formation of active c-Jun/Jun B heterodimer. We studied the regulation of cyclinD1 by c-Jun/Jun B heterodimers by laser scanning confocal influorescence microscopy, Western blot, luciferase activity assay, super-EMSA and flow cytometry in the Tet-on-LMP1 HNE2 cell line, in which LMP1 expression was regulated by Tet-on system. c-Jun/Jun B heterodimers induced by LMP1 could up regulate cyclin D1 promoter activity and expression. Overexpression of cy-clinD1 accelerated the progression of cell cycle.
基金the National Natural Science Foundation of China(81400159,81873450,81700196,81672686)Pearl River Nova Program of Guangzhou(201710010161)+1 种基金Sister Institution Net-work Fund of the MD Anderson Cancer Center(to Qingqing Cai)the Fundamental Research Funds for the Central Universities(17ykpy77).
文摘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.
文摘Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is considered as the major oncogenic protein of EBV encoded proteins, which could transactivate many transcription factors including activator protein 1 (AP-1). Transcription factor plays its role in biological effects through binding to the target gene promoter,transactivating the transcription of target gene, regulating the target gene expression, etc. Recently, we found that LMP1 could mediate a new heterodimer form of c-Jun and JunB, which could bind to AP1 DNA sequence. In this report,we confirmed p16 as a putative target gene of c-Jun/JunB using bioinformatics. We used Tet-on-LMP1 HNE2 cell line as a cell model, which is a dual-stable LMP1 integrated HNE2 cell line and the expression of LMP1 could be regu-lated by the Tet system, and we wanted to explore whether c-Jun/JunB heterodimers mediated by LMP1 could regulate p16. Data demonstrated that c-Jun/Jun B heterodimers me-diated by LMP1 downregulated both the promoter activity and p16 expression, and accelerated the cell cycle progression. These findings established a new direct connection between the AP-I singnal pathway and the cell cycle, and provided a new model for the carcinogenesis mechanism.
基金National Nature Science Foundation for Distinguished Young Scholar of China (No.39525022)National Basic Research Program(No.2004CB518703) National Nature Science Foundation of China (No.30570085).
文摘Latent membrane protein 1 （LMP1）, an important protein encoded by Epstein Barr virus （EBV）, has been implied to link with the pathogenesis of nasopharyngeal carcinoma （NPC）. Its dual effects of increasing cell proliferation and inhibiting cell apoptosis have been confirmed. In this study, we showed that the expression of Survivin and CDK4 protein in CNE-LMP1, a LMP1 positive NPC epithelial cell line, is higher than in LMP1 negative NPC epithelial cell line- CNE1, and the expression is LMP1 dosage-dependent. Although it was reported that Survivin specifically expressed in cell cycle G2/M phase, our studies suggested that LMP1 could promote the expression of Survivin in G0/G1, S and G2/ M phase. It also showed that Survivin and CDK4 could be accumulated more in the nuclei triggered by LMP1. More interestingly, Survivin and CDK4 could form a protein complex in the nuclei of CNE-LMP1 rather than in that of CNE1, which demonstrated that the interaction between these two proteins could be promoted by LMPI. These results strongly suggested that the role of LMP1 in the regulation of Survivin and CDK4 may also shed some light on the mechanism research of LMP1 in NPC.
