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Sun Y, Shi D, Sun J, Zhang Y, Liu W, Luo B. Regulation mechanism of EBV-encoded EBER1 and LMP2A on YAP1 and the impact of YAP1 on the EBV infection status in EBV-associated gastric carcinoma. Virus Res 2024; 343:199352. [PMID: 38462175 PMCID: PMC10982081 DOI: 10.1016/j.virusres.2024.199352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/07/2024] [Accepted: 03/07/2024] [Indexed: 03/12/2024]
Abstract
This study aims to explore the role and regulatory mechanism of Yes-associated protein 1 (YAP1) in the development of Epstein-Barr virus-associated gastric cancer (EBVaGC). Here we showed that EBV can upregulate the expression and activity of YAP1 protein through its encoded latent products EBV-encoded small RNA 1 (EBER1) and latent membrane protein 2A (LMP2A), enhancing the malignant characteristics of EBVaGC cells. In addition, we also showed that overexpression of YAP1 induced the expression of EBV encoding latent and lytic phase genes and proteins in the epithelial cell line AGS-EBV infected with EBV, and increased the copy number of the EBV genome, while loss of YAP1 expression reduced the aforementioned indicators. Moreover, we found that YAP1 enhanced EBV lytic reactivation induced by two known activators, 12-O-tetradecanoylhorbol-13-acetate (TPA) and sodium butyrate (NaB). These results indicated a bidirectional regulatory mechanism between EBV and YAP1 proteins, providing new experimental evidence for further understanding the regulation of EBV infection patterns and carcinogenic mechanisms in gastric cancer.
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Affiliation(s)
- Yujie Sun
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, China
| | - Duo Shi
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, China
| | - Jiting Sun
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, China
| | - Yan Zhang
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, China; Department of Clinical Laboratory, Zibo Central Hospital, ZiBo 255036, China
| | - Wen Liu
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, China.
| | - Bing Luo
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, China.
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Kashyap D, Rele S, Bagde PH, Saini V, Chatterjee D, Jain AK, Pandey RK, Jha HC. Comprehensive insight into altered host cell-signaling cascades upon Helicobacter pylori and Epstein-Barr virus infections in cancer. Arch Microbiol 2023; 205:262. [PMID: 37310490 DOI: 10.1007/s00203-023-03598-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 06/14/2023]
Abstract
Cancer is characterized by mutagenic events that lead to disrupted cell signaling and cellular functions. It is one of the leading causes of death worldwide. Literature suggests that pathogens, mainly Helicobacter pylori and Epstein-Barr virus (EBV), have been associated with the etiology of human cancer. Notably, their co-infection may lead to gastric cancer. Pathogen-mediated DNA damage could be the first and crucial step in the carcinogenesis process that modulates numerous cellular signaling pathways. Altogether, it dysregulates the metabolic pathways linked with cell growth, apoptosis, and DNA repair. Modulation in these pathways leads to abnormal growth and proliferation. Several signaling pathways such RTK, RAS/MAPK, PI3K/Akt, NFκB, JAK/STAT, HIF1α, and Wnt/β-catenin are known to be altered in cancer. Therefore, this review focuses on the oncogenic roles of H. pylori, EBV, and its associated signaling cascades in various cancers. Scrutinizing these signaling pathways is crucial and may provide new insights and targets for preventing and treating H. pylori and EBV-associated cancers.
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Affiliation(s)
- Dharmendra Kashyap
- Lab No. POD 1B 602, Infection Bio-Engineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, 453552, India
| | - Samiksha Rele
- Lab No. POD 1B 602, Infection Bio-Engineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, 453552, India
| | - Pranit Hemant Bagde
- Lab No. POD 1B 602, Infection Bio-Engineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, 453552, India
| | - Vaishali Saini
- Lab No. POD 1B 602, Infection Bio-Engineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, 453552, India
| | | | | | - Rajan Kumar Pandey
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177, Solna, Sweden
| | - Hem Chandra Jha
- Lab No. POD 1B 602, Infection Bio-Engineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, 453552, India.
- Centre for Rural Development and Technology, Indian Institute of Technology Indore, Madhya Pradesh, 453552, Indore, India.
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3
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The lytic phase of Epstein-Barr virus plays an important role in tumorigenesis. Virus Genes 2023; 59:1-12. [PMID: 36242711 DOI: 10.1007/s11262-022-01940-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/02/2022] [Indexed: 01/13/2023]
Abstract
Epstein-Barr virus (EBV) is a recognized oncogenic virus that is related to the occurrence of lymphoma, nasopharyngeal carcinoma (NPC), and approximately 10% of gastric cancer (GC). EBV is a herpesvirus, and like other herpesviruses, EBV has a biphasic infection mode made up of latent and lytic infections. It has been established that latent infection promotes tumorigenesis in previous research, but in recent years, there has been new evidence that suggests that the lytic infection mode could also promote tumorigenesis. In this review, we mainly discuss the contribution of the EBV lytic phase to tumorigenesis, and graphically illustrate their relationship in detail. In addition, we described the relationship between the lytic cycle of EBV and autophagy. Finally, we also preliminarily explored the influence of the tumorigenesis effect of the EBV lytic phase on the future treatment of EBV-associated tumors.
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Cheng T, Zhang S, Xia T, Zhang Y, Ji Y, Pan S, Xie H, Ren Q, You Y, You B. EBV promotes vascular mimicry of dormant cancer cells by potentiating stemness and EMT. Exp Cell Res 2022; 421:113403. [PMID: 36336028 DOI: 10.1016/j.yexcr.2022.113403] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 10/15/2022] [Accepted: 10/22/2022] [Indexed: 11/06/2022]
Abstract
Vascular mimicry (VM) is defined as a vascular channel-like structure composed of tumor cells that correlates with the growth of cancer cells by providing blood circulation. However, whether VM can be formed in dormant cancer cells remains unclear. Our previous research revealed that polyploid giant cancer cells (PGCCs) are specific dormant cells related to the poor prognosis of head and neck cancer. Here, we demonstrated that EBV could promote VM formation by PGCCs in vivo and in vitro. Furthermore, we revealed that the activation of the ERK pathway partly mediated by LMP2A is responsible for stemness, and the acquisition of the stemness phenotype is crucial to the malignant biological behavior of PGCCs. The epithelial-to-mesenchymal transition (EMT) process plays a considerable role in PGCCs, and EMT progression is vital for EBV-positive PGCCs to form VM. This is the first study to reveal that EBV creates plasticity in PGCC-VM and provide a new strategy for targeted anti-tumor therapy.
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Affiliation(s)
- Tianyi Cheng
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Department of Otorhinolaryngology Head and Neck Surgery, The First People's Hospital of Yancheng, Yancheng, Jiangsu Province, China
| | - Siyu Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China
| | - Tian Xia
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China
| | - Yanshu Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, The First People's Hospital of Yancheng, Yancheng, Jiangsu Province, China
| | - Yan Ji
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China
| | - Si Pan
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China
| | - Haijing Xie
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China
| | - Qianqian Ren
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China
| | - Yiwen You
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China.
| | - Bo You
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China; Medical College of Nantong University, Nantong 226019, Jiangsu Province, China. Department of Pathology, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong, 226019, Jiangsu Province, China.
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van Bladel DAG, Stevens WBC, van den Brand M, Kroeze LI, Groenen PJTA, van Krieken JHJM, Hebeda KM, Scheijen B. Novel Approaches in Molecular Characterization of Classical Hodgkin Lymphoma. Cancers (Basel) 2022; 14:cancers14133222. [PMID: 35805000 PMCID: PMC9264882 DOI: 10.3390/cancers14133222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary The unique tumor composition of classical Hodgkin lymphoma (cHL), with only a small fraction of malignant Hodgkin and Reed–Sternberg cells within the tumor tissue, has created many challenges to characterize the genetic alterations that drive this lymphoid malignancy. Major advances in sequencing technologies and detailed analysis of circulating tumor DNA in blood samples of patients have provided important contributions to enhance our understanding of the pathogenesis of cHL. In this review, we provide an overview of the recent advances in genotyping the clonal and mutational landscape of cHL. In addition, we discuss different next-generation sequencing applications to characterize tumor tissue and cell-free DNA, which are now available to improve the diagnosis of cHL, and to monitor therapeutic response or disease progression during treatment and follow up of cHL patients. Abstract Classical Hodgkin lymphoma (cHL) represents a B-cell lymphoproliferative disease characterized by clonal immunoglobulin gene rearrangements and recurrent genomic aberrations in the Hodgkin Reed–Sternberg cells in a reactive inflammatory background. Several methods are available for the molecular analysis of cHL on both tissue and cell-free DNA isolated from blood, which can provide detailed information regarding the clonal composition and genetic alterations that drive lymphoma pathogenesis. Clonality testing involving the detection of immunoglobulin and T cell receptor gene rearrangements, together with mutation analysis, represent valuable tools for cHL diagnostics, especially for patients with an atypical histological or clinical presentation reminiscent of a reactive lesion or another lymphoma subtype. In addition, clonality assessment may establish the clonal relationship of composite or subsequent lymphoma presentations within one patient. During the last few decades, more insight has been obtained on the molecular mechanisms that drive cHL development, including recurrently affected signaling pathways (e.g., NF-κB and JAK/STAT) and immune evasion. We provide an overview of the different approaches to characterize the molecular composition of cHL, and the implementation of these next-generation sequencing-based techniques in research and diagnostic settings.
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Affiliation(s)
- Diede A. G. van Bladel
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
- Radboud Institute for Molecular Life Sciences, 6525 GA Nijmegen, The Netherlands
| | - Wendy B. C. Stevens
- Radboud University Medical Center, Department of Hematology, 6525 GA Nijmegen, The Netherlands;
| | - Michiel van den Brand
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
- Pathology-DNA, Rijnstate Hospital, 6815 AD Arnhem, The Netherlands
| | - Leonie I. Kroeze
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
| | - Patricia J. T. A. Groenen
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
| | - J. Han J. M. van Krieken
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
| | - Konnie M. Hebeda
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
| | - Blanca Scheijen
- Radboud University Medical Center, Department of Pathology, 6525 GA Nijmegen, The Netherlands; (D.A.G.v.B.); (M.v.d.B.); (L.I.K.); (P.J.T.A.G.); (J.H.J.M.v.K.); (K.M.H.)
- Radboud Institute for Molecular Life Sciences, 6525 GA Nijmegen, The Netherlands
- Correspondence:
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6
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Zhu QY, Zhao GX, Li Y, Talakatta G, Mai HQ, Le QT, Young LS, Zeng MS. Advances in pathogenesis and precision medicine for nasopharyngeal carcinoma. MedComm (Beijing) 2021; 2:175-206. [PMID: 34766141 PMCID: PMC8491203 DOI: 10.1002/mco2.32] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/13/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a squamous carcinoma with apparent geographical and racial distribution, mostly prevalent in East and Southeast Asia, particularly concentrated in southern China. The epidemiological trend over the past decades has suggested a substantial reduction in the incidence rate and mortality rate due to NPC. These results may reflect changes in lifestyle and environment, and more importantly, a deeper comprehension of the pathogenic mechanism of NPC, leading to much progress in the preventing, screening, and treating for this cancer. Herein, we present the recent advances on the key signal pathways involved in pathogenesis of NPC, the mechanism of Epstein‐Barr virus (EBV) entry into the cell, and the progress of EBV vaccine and screening biomarkers. We will also discuss in depth the development of various therapeutic approaches including radiotherapy, chemotherapy, surgery, targeted therapy, and immunotherapy. These research advancements have led to a new era of precision medicine in NPC.
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Affiliation(s)
- Qian-Ying Zhu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Sun Yat-sen University Cancer Center (SYSUCC) Guangzhou China
| | - Ge-Xin Zhao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Sun Yat-sen University Cancer Center (SYSUCC) Guangzhou China
| | - Yan Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Sun Yat-sen University Cancer Center (SYSUCC) Guangzhou China
| | - Girish Talakatta
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Sun Yat-sen University Cancer Center (SYSUCC) Guangzhou China
| | - Hai-Qiang Mai
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Sun Yat-sen University Cancer Center (SYSUCC) Guangzhou China
| | - Quynh-Thu Le
- Department of Radiation Oncology Stanford California
| | - Lawrence S Young
- Warwick Medical School University of Warwick Coventry United Kingdom
| | - Mu-Sheng Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Sun Yat-sen University Cancer Center (SYSUCC) Guangzhou China
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7
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Dysregulation of Dual-Specificity Phosphatases by Epstein-Barr Virus LMP1 and Its Impact on Lymphoblastoid Cell Line Survival. J Virol 2020; 94:JVI.01837-19. [PMID: 31776277 DOI: 10.1128/jvi.01837-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 11/14/2019] [Indexed: 12/14/2022] Open
Abstract
The strongest evidence of the oncogenicity of Epstein-Barr virus (EBV) in vitro is its ability to immortalize human primary B lymphocytes into lymphoblastoid cell lines (LCLs). Yet the underlying mechanisms explaining how the virus tempers the growth program of the host cells have not been fully elucidated. The mitogen-activated protein kinases (MAPKs) are implicated in many cellular processes and are constitutively activated in LCLs. We questioned the expression and regulation of the dual-specificity phosphatases (DUSPs), the main negative regulator of MAPKs, during EBV infection and immortalization. Thirteen DUSPs, including 10 typical and 3 atypical types of DUSPs, were tested. Most of them were downregulated after EBV infection. Here, a role of viral oncogene latent membrane protein 1 (LMP1) in limiting DUSP6 and DUSP8 expression was identified. Using MAPK inhibitors, we found that LMP1 activates extracellular signal-regulated kinase (ERK) or p38 to repress the expression of DUSP6 and DUSP8, with corresponding substrate specificity. Morphologically, overexpression of DUSP6 and DUSP8 attenuates the ability of EBV-immortalized LCL cells to clump together. Mechanistically, apoptosis induced by restoring DUSP6 and DUSP8 in LCLs indicated a novel mechanism for LMP1 to provide a survival signal during EBV immortalization. Collectively, this report provides the first description of the interplay between EBV genes and DUSPs and contributes considerably to the interpretation of MAPK regulation in EBV immortalization.IMPORTANCE Infections by the ubiquitous Epstein-Barr virus (EBV) are associated with a wide spectrum of lymphomas and carcinomas. It has been well documented that activation levels of MAPKs are found in cancer cells to translate various external or intrinsic stimuli into cellular responses. Physiologically, the dual-specificity phosphates (DUSPs) exhibit great ability in regulating MAPK activities with respect to their capability of dephosphorylating MAPKs. In this study, we found that DUSPs were generally downregulated after EBV infection. EBV oncogenic latent membrane protein 1 (LMP1) suppressed DUSP6 and DUSP8 expression via MAPK pathway. In this way, LMP1-mediated MAPK activation was a continuous process. Furthermore, DUSP downregulation was found to contribute greatly to prevent apoptosis of EBV-infected cells. To sum up, this report sheds light on a novel molecular mechanism explaining how EBV maintains the unlimited proliferation status of the immortalized cells and provides a new link to understand EBV-induced B cell survival.
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8
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DuShane JK, Maginnis MS. Human DNA Virus Exploitation of the MAPK-ERK Cascade. Int J Mol Sci 2019; 20:ijms20143427. [PMID: 31336840 PMCID: PMC6679023 DOI: 10.3390/ijms20143427] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022] Open
Abstract
The extracellular signal-regulated kinases (ERKs) comprise a particular branch of the mitogen-activated protein kinase cascades (MAPK) that transmits extracellular signals into the intracellular environment to trigger cellular growth responses. Similar to other MAPK cascades, the MAPK-ERK pathway signals through three core kinases—Raf, MAPK/ERK kinase (MEK), and ERK—which drive the signaling mechanisms responsible for the induction of cellular responses from extracellular stimuli including differentiation, proliferation, and cellular survival. However, pathogens like DNA viruses alter MAPK-ERK signaling in order to access DNA replication machineries, induce a proliferative state in the cell, or even prevent cell death mechanisms in response to pathogen recognition. Differential utilization of this pathway by multiple DNA viruses highlights the dynamic nature of the MAPK-ERK pathway within the cell and the importance of its function in regulating a wide variety of cellular fates that ultimately influence viral infection and, in some cases, result in tumorigenesis.
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Affiliation(s)
- Jeanne K DuShane
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04401, USA
| | - Melissa S Maginnis
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04401, USA.
- Graduate School in Biomedical Sciences and Engineering, The University of Maine, Orono, ME 04401, USA.
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9
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LMP2A induces DNA methylation and expression repression of AQP3 in EBV-associated gastric carcinoma. Virology 2019; 534:87-95. [PMID: 31220652 DOI: 10.1016/j.virol.2019.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 05/14/2019] [Accepted: 06/11/2019] [Indexed: 12/27/2022]
Abstract
Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is a unique type of gastric carcinomas that promoter hypermethylation of tumor-related genes is extremely frequent to be found. Aquaporin 3 (AQP3) is a small membrane transport protein that plays a crucial role in cancer progression and metastasis. However, there is no experimental study on the expression of AQP3 in EBVaGC and the regulation mechanism of EBV on AQP3. In this study, the loss of AQP3 was contributed by the hypermethylation status of AQP3 promoter in EBVaGC which was caused by elevated expression of DNMT3a. In addition, stable and transient transfection system in SGC7901 showed that viral latent membrane protein 2A (LMP2A) activated phosphorylated ERK and up-regulated DNMT3a. Taken together, LMP2A induced the phosphorylation of ERK, which activated DNMT3a transcription and caused AQP3 expression loss through CpG island methylation of AQP3 promoter in EBVaGC.
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10
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Zhao CX, Zhu W, Ba ZQ, Xu HJ, Liu WD, Zhu B, Wang L, Song YJ, Yuan S, Ren CP. The regulatory network of nasopharyngeal carcinoma metastasis with a focus on EBV, lncRNAs and miRNAs. Am J Cancer Res 2018; 8:2185-2209. [PMID: 30555738 PMCID: PMC6291648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 10/16/2018] [Indexed: 06/09/2023] Open
Abstract
Metastasis of nasopharyngeal carcinoma (NPC) remains a main cause of death for NPC patients even though great advances have been made in therapeutic approaches. An in-depth study into the molecular mechanisms of NPC metastasis will help us combat NPC. Epstein-Barr virus (EBV) infection is an evident feature of nonkeratinizing NPC and is strongly associated with tumor metastasis. Recently, long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have become a hot topic of research due to their epigenetic regulatory roles in NPC metastasis. The EBV products, lncRNAs and miRNAs can target each other and share several common signaling pathways, which form an interconnected, complex molecular regulatory network. In this review, we discuss the features of this regulatory network and summarize the molecular mechanisms of NPC metastasis, focusing on EBV, lncRNAs and miRNAs with updated knowledge.
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Affiliation(s)
- Chen-Xuan Zhao
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Wei Zhu
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Zheng-Qing Ba
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Hong-Juan Xu
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Wei-Dong Liu
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Bin Zhu
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Lei Wang
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Yu-Jia Song
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Shuai Yuan
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
| | - Cai-Ping Ren
- The Key Laboratory of Carcinogenesis of The Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of The Chinese Ministry of Education, Xiangya Hospital, Central South UniversityChangsha 410008, Hunan, P. R. China
- Cancer Research Institute, Collaborative Innovation Center for Cancer Medicine, School of Basic Medical Science, Central South UniversityChangsha 410078, Hunan, P. R. China
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11
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El-Sharkawy A, Al Zaidan L, Malki A. Epstein-Barr Virus-Associated Malignancies: Roles of Viral Oncoproteins in Carcinogenesis. Front Oncol 2018; 8:265. [PMID: 30116721 PMCID: PMC6082928 DOI: 10.3389/fonc.2018.00265] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 06/27/2018] [Indexed: 12/19/2022] Open
Abstract
The Epstein–Barr virus (EBV) is the first herpesvirus identified to be associated with human cancers known to infect the majority of the world population. EBV-associated malignancies are associated with a latent form of infection, and several of the EBV-encoded latent proteins are known to mediate cellular transformation. These include six nuclear antigens and three latent membrane proteins (LMPs). In lymphoid and epithelial tumors, viral latent gene expressions have distinct pattern. In both primary and metastatic tumors, the constant expression of latent membrane protein 2A (LMP2A) at the RNA level suggests that this protein is the key player in the EBV-associated tumorigenesis. While LMP2A contributing to the malignant transformation possibly by cooperating with the aberrant host genome. This can be done in part by dysregulating signaling pathways at multiple points, notably in the cell cycle and apoptotic pathways. Recent studies also have confirmed that LMP1 and LMP2 contribute to carcinoma progression and that this may reflect the combined effects of these proteins on activation of multiple signaling pathways. This review article aims to investigate the aforementioned EBV-encoded proteins that reveal established roles in tumor formation, with a greater emphasis on the oncogenic LMPs (LMP1 and LMP2A) and their roles in dysregulating signaling pathways. It also aims to provide a quick look on the six members of the EBV nuclear antigens and their roles in dysregulating apoptosis.
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Affiliation(s)
- Ahmed El-Sharkawy
- Human Molecular Genetics Laboratory, Institute of Genetics and Biophysics "A. Buzzati-Traverso" (IGB)-CNR, Naples, Italy.,Biomolecular Science Programme, Università Degli Studi Della Campania "Luigi Vanvitelli", Naples, Italy
| | - Lobna Al Zaidan
- Biomedical Science Department, College of Health Sciences, Qatar University, Doha, Qatar
| | - Ahmed Malki
- Biomedical Science Department, College of Health Sciences, Qatar University, Doha, Qatar
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12
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Yin Q, Wang X, Roberts C, Flemington EK, Lasky JA. Methylation status and AP1 elements are involved in EBV-mediated miR-155 expression in EBV positive lymphoma cells. Virology 2016; 494:158-67. [PMID: 27110708 DOI: 10.1016/j.virol.2016.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/14/2016] [Accepted: 04/04/2016] [Indexed: 12/12/2022]
Abstract
The relationship between Epstein Barr Virus (EBV) and miR-155 is well established. EBV infection induces miR-155 expression, which is expressed at higher levels in EBV latency type III cells compared to EBV latency type I cells. However, the mechanism by which EBV latency genes activate miR-155 expression is still unclear. Here we present data showing that DNA methylation regulates miR-155 expression. We also provide evidence that the AP1 signaling pathway is involved in EBV-mediated miR-155 activation, and that Bay11 influences signaling of the miR-155 promoter AP1 element. Lastly, we show that LMP2A, LMP1 and EBNAs cannot activate miR-155 expression alone, indicating that the regulation of miR-155 by EBV is dependent on more than one EBV gene or cell signaling pathway. We conclude that the regulation of miR-155 in EBV-positive cells occurs through multiple cell signaling processes involving EBV-mediated chromatin remodeling, cell signaling regulation and transcription factor activation.
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Affiliation(s)
- Qinyan Yin
- Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Department of Medicine, SL9, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
| | - Xia Wang
- Department of Pathology and Laboratory Medicine, SL79, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
| | - Claire Roberts
- Department of Pathology and Laboratory Medicine, SL79, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
| | - Erik K Flemington
- Department of Pathology and Laboratory Medicine, SL79, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
| | - Joseph A Lasky
- Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Department of Medicine, SL9, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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13
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Epstein-Barr Virus (EBV) Tegument Protein BGLF2 Promotes EBV Reactivation through Activation of the p38 Mitogen-Activated Protein Kinase. J Virol 2015; 90:1129-38. [PMID: 26559845 DOI: 10.1128/jvi.01410-15] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 10/15/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Epstein-Barr virus (EBV) is a ubiquitous gammaherpesvirus associated with both B cell and epithelial cell malignancies. EBV infection of B cells triggers activation of several signaling pathways that are critical for cell survival, virus latency, and growth transformation. To identify EBV proteins important for regulating cell signaling, we used a proteomic approach to screen viral proteins for AP-1 and NF-κB promoter activity in AP-1- and NF-κB-luciferase reporter assays. We found that EBV BGLF2 activated AP-1 but not NF-κB reporter activity. Expression of EBV BGLF2 in cells activated p38 and c-Jun N-terminal kinase (JNK), both of which are important for mitogen-activated protein kinase (MAPK) signaling. Deletion of the carboxyl-terminal 66 amino acids of BGLF2 reduced the ability of BGLF2 to activate JNK and p38. Expression of BGLF2 enhanced BZLF1 expression in latently EBV-infected lymphoblastoid cell lines, and knockdown of BGLF2 reduced EBV reactivation induced by IgG cross-linking. Expression of BGLF2 induced BZLF1 expression and virus production in EBV-infected gastric carcinoma cells. BGLF2 enhanced BZLF1 expression and EBV production by activating p38; chemical inhibition of p38 and MAPK/ERK kinases 1 and 2 (MEK1/2) reduced expression of BZLF1 and virus production induced by BGLF2. In summary, the EBV tegument protein BGLF2, which is delivered to the cell at the onset of virus infection, activates the AP-1 pathway and enhances EBV reactivation and virus production. IMPORTANCE Epstein-Barr virus (EBV) is associated with both B cell and epithelial cell malignancies, and the virus activates multiple signaling pathways important for its persistence in latently infected cells. We identified a viral tegument protein, BGLF2, which activates members of the mitogen-activated protein kinase signaling pathway. Expression of BGLF2 increased expression of EBV BZLF1, which activates a switch from latent to lytic virus infection, and increased production of EBV. Inhibition of BGFL2 expression or inhibition of p38/MAPK, which is activated by BGLF2, reduced virus reactivation from latency. These results indicate that a viral tegument protein which is delivered to cells upon infection activates signaling pathways to enhance virus production and facilitate virus reactivation from latency.
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14
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Lin SJ, Wu SW, Chou YC, Lin JH, Huang YC, Chen MR, Ma N, Tsai CH. Novel expression and regulation of TIMP-1 in Epstein Barr virus-infected cells and its impact on cell survival. Virology 2015; 481:24-33. [DOI: 10.1016/j.virol.2015.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/25/2015] [Accepted: 02/10/2015] [Indexed: 11/26/2022]
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15
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Ahuja R, Kapoor NR, Kumar V. The HBx oncoprotein of hepatitis B virus engages nucleophosmin to promote rDNA transcription and cellular proliferation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1783-95. [PMID: 25918010 DOI: 10.1016/j.bbamcr.2015.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 12/31/2022]
Abstract
The pleiotropic HBx oncoprotein of hepatitis B virus is well known to promote the expression of ribosomal RNAs and several host proteins that are known to support the development and progression of hepatocellular carcinoma (HCC). While overexpression of the nucleolar phosphoprotein, nucleophosmin (NPM), correlates with HCC progression, its upregulation by viral HBx and the resulting impact on perturbed nucleolar functions remain enigmatic. The present study shows that HBx up-regulates NPM levels and hijacks its functions to promote cellular proliferation. We found that HBx expression stabilizes NPM through post-translational modifications. Enhanced CDK2-mediated phosphorylation of NPM at Thr199 upon HBx expression prevented its proteolytic cleavage and provided resistance to apoptosis. Further, HBx directly interacted with the C-terminal domain of NPM and got translocated into the nucleolus where it facilitated the recruitment of RNA polymerase I transcriptional machinery onto the rDNA promoter. Our results indicate that HBx enhances rDNA transcription via a novel regulatory mechanism involving acetylation of NPM and the subsequent depletion of histones from the rDNA promoter. Enhanced production of ribosomal RNA resulting from co-expression of HBx and NPM promoted ribosome biogenesis, cellular proliferation and transformation. Taken together, our study strongly suggests an important role of NPM in mediating the oncogenic effects of HBx and the corresponding nucleolar perturbations induced by this viral oncoprotein.
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Affiliation(s)
- Richa Ahuja
- Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Neetu Rohit Kapoor
- Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Vijay Kumar
- Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India.
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16
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Maintenance of Epstein-Barr Virus Latent Status by a Novel Mechanism, Latent Membrane Protein 1-Induced Interleukin-32, via the Protein Kinase Cδ Pathway. J Virol 2015; 89:5968-80. [PMID: 25810549 DOI: 10.1128/jvi.00168-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/16/2015] [Indexed: 01/14/2023] Open
Abstract
UNLABELLED Epstein-Barr virus (EBV), an oncogenic herpesvirus, has the potential to immortalize primary B cells into lymphoblastoid cell lines (LCLs) in vitro. During immortalization, several EBV products induce cytokines or chemokines, and most of these are required for the proliferation of LCLs. Interleukin-32 (IL-32), a recently discovered proinflammatory cytokine, is upregulated after EBV infection, and this upregulation is detectable in all LCLs tested. EBV latent membrane protein 1 (LMP1) is responsible for inducing IL-32 expression at the mRNA and protein levels. Mechanistically, we showed that this LMP1 induction is provided by the p65 subunit of NF-κB, which binds to and activates the IL-32 promoter. Furthermore, the short hairpin RNA (shRNA)-mediated depletion of endogenous LMP1 and p65 in LCLs suppressed IL-32 expression, further suggesting that LMP1 is the key factor that stimulates IL-32 in LCLs via the NF-κB p65 pathway. Functionally, knockdown of IL-32 in LCLs elicits viral reactivation and affects cytokine expression, but it has no impact on cell proliferation and apoptosis. Of note, we reveal the mechanism whereby IL-32 is involved in the maintenance of EBV viral latency by inactivation of Zta promoter activity. This atypical cytoplasmic IL-32 hijacks the Zta activator protein kinase Cδ (PKCδ) and inhibits its translocation from the cytoplasm to the nucleus, where PKCδ binds to the Zta promoter and activates lytic cycle progression. These novel findings reveal that IL-32 is involved in the maintenance of EBV latency in LCLs. This finding may provide new information to explain how EBV maintains latency, in addition to viral chromatin structure and epigenetic modification. IMPORTANCE EBV persists in two states, latency and lytic replication, which is a unique characteristic of human infections. So far, little is known about how herpesviruses maintain latency in particular tissues or cell types. EBV is an excellent model to study this question because more than 90% of people are latently infected. EBV can immortalize primary B cells into lymphoblastoid cell lines in vitro. Expression of IL-32, a novel atypical cytoplasmic proinflammatory cytokine, increased after infection. The expression of IL-32 was controlled by LMP1. In investigating the regulatory mechanism, we demonstrated that the p65 subunit of NF-κB is required for this upregulation. Of note, the important biological activity of IL-32 was to trap protein kinase Cδ in the cytoplasm and prevent it from binding to the Zta promoter, which is the key event for EBV reaction. So, the expression of LMP1-induced IL-32 plays a role in the maintenance of EBV latency.
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17
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Epstein-Barr virus LMP2A suppresses MHC class II expression by regulating the B-cell transcription factors E47 and PU.1. Blood 2015; 125:2228-38. [PMID: 25631773 DOI: 10.1182/blood-2014-08-594689] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 01/25/2015] [Indexed: 02/07/2023] Open
Abstract
Oncogenic Epstein-Barr virus (EBV) uses various approaches to escape host immune responses and persist in B cells. Such persistent infections may provide the opportunity for this virus to initiate tumor formation. Using EBV-immortalized lymphoblastoid cell lines (LCLs) as a model, we found that the expression of major histocompatibility complex (MHC) class II and CD74 in B cells is repressed after EBV infection. Class II transactivator (CIITA) is the master regulator of MHC class II-related genes. As expected, CIITA was downregulated in LCLs. We showed that downregulation of CIITA is caused by EBV latent membrane protein 2A (LMP2A) and driven by the CIITA-PIII promoter. Furthermore, we demonstrated that LMP2A-mediated E47 and PU.1 reduction resulted in CIITA suppression. Mechanistically, the LMP2A immunoreceptor tyrosine-based activation motif was critical for the repression of E47 and PU.1 promoter activity via Syk, Src, and the phosphatidylinositol 3-kinase/Akt pathway. Elimination of LMP2A in LCLs using a shLMP2A approach showed that the expression levels of E47, PU.1, CIITA, MHC class II, and CD74 are reversed. These data indicated that the LMP2A may reduce MHC class II expression through interference with the E47/PU.1-CIITA pathway. Finally, we demonstrated that MHC class II may be detected in tonsils and EBV-negative Hodgkin disease but not in EBV-associated posttransplant lymphoproliferative disease and Hodgkin disease.
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18
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Abstract
LMP2A is an EBV-encoded protein with three domains: (a) an N-terminal cytoplasmic domain, which has PY motifs that bind to WW domain-containing E3 ubiquitin ligases and an ITAM that binds to SH2 domain-containing proteins, (b) a transmembrane domain with 12 transmembrane segments that localizes LMP2A in cellular membranes, and (c) a 27-amino acid C-terminal domain which mediates homodimerization and heterodimerization of LMP2 protein isoforms. The most prominent two isoforms of the protein are LMP2A and LMP2B. The LMP2B isoform lacks the 19-amino acid N-terminal domain found in LMP2A, which modulates cellular signaling resulting in a baseline activation of B cells and degradation of cellular kinases leading to the downregulation of normal B cell signaling pathways. These two seemingly contradictory processes allow EBV to establish and maintain latency. LMP2 is expressed in many EBV-associated malignancies. While its antigenic properties may be useful in developing LMP2-specific immunity, the LMP2A N-terminal motifs also provide a basis to target LMP2A-modulated cellular kinases for the development of treatment strategies.
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19
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Cho M, Eze O, Xu R. Molecular genetics of gastric adenocarcinoma in clinical practice. World J Med Genet 2014; 4:58-68. [DOI: 10.5496/wjmg.v4.i3.58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 05/16/2014] [Indexed: 02/06/2023] Open
Abstract
The molecular genetics of gastric carcinoma (GC) dictates their biology and clinical behavior. The two morphologically distinct types of gastric carcinoma by Lauren classification, i.e., intestinal and diffuse cell types, have a significant difference in clinical outcome. These two types of GC have different molecular pathogenetic pathways with unique genetic alterations. In addition to environmental and other etiologies, intestinal type GC is associated with Helicobacter pylori (H. pylori) infection and involves a multistep molecular pathway driving the normal epithelium to intestinal metaplasia, dysplasia, and malignant transformation by chromosomal and/or microsatellite instability (MSI), mutation of tumor suppressor genes, and loss of heterozygosity among others. Diffuse type shows no clear causal relationship with H. pylori infection, but is commonly associated with deficiency of cell-cell adhesion due to mutation of the E-cadherin gene (CDH1), and a manifestation of the hereditary gastric cancer syndrome. Thus, detection of CDH1 mutation or loss of expression of E-cadherin may aid in early diagnosis or screening of diffuse type GC. Detection of certain genetic markers, for example, MSI and matrix metalloproteinases, may provide prognostic information, particularly for intestinal type. The common genetic alterations may offer therapeutic targets for treatment of GC. Polymorphisms in Thymidylate synthase to metabolize 5-fluorouracil, glutathione S-transferase for degradation of Cisplatin, and amplification/overexpression of human epidermal growth factor receptor 2 targeted by monoclonal antibody Trastuzumab, are a few examples. P13K/Akt/mTOR pathway, c-Met pathways, epidermal growth factor receptor, insulin-like growth factor receptor, vascular endothelial growth factor receptor fibroblast growth factor receptor, and micro RNAs are several potential therapeutic biomarkers for GC under investigation.
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20
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Fukuda M, Kawaguchi Y. Role of the immunoreceptor tyrosine-based activation motif of latent membrane protein 2A (LMP2A) in Epstein-Barr virus LMP2A-induced cell transformation. J Virol 2014; 88:5189-94. [PMID: 24554661 PMCID: PMC3993816 DOI: 10.1128/jvi.03714-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/13/2014] [Indexed: 01/08/2023] Open
Abstract
Latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) is widely expressed in EBV-associated malignancies. We demonstrate that LMP2A has a transformation ability. This study shows that LMP2A-induced transformation in several human nonhematopoietic cell lines was blocked in those cells expressing an immunoreceptor tyrosine-based activation motif (ITAM) LMP2A mutant. The Syk inhibitor or Syk-specific small interfering RNA (siRNA) inhibited LMP2A-induced transformation. These results indicate that the interaction of the LMP2A ITAM with Syk is a key step for LMP2A-mediated transformation.
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Affiliation(s)
| | - Yasushi Kawaguchi
- Division of Viral Infection, Department of Infectious Disease Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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21
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Identification of protein kinase inhibitors with a selective negative effect on the viability of Epstein-Barr virus infected B cell lines. PLoS One 2014; 9:e95688. [PMID: 24759913 PMCID: PMC3997413 DOI: 10.1371/journal.pone.0095688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 03/29/2014] [Indexed: 01/21/2023] Open
Abstract
Epstein-Barr virus (EBV) is a human herpesvirus, which is causally associated with the development of several B lymphocytic malignancies that include Burkitt's lymphomas, Hodgkin's disease, AIDS and posttransplant associated lymphomas. The transforming activity of EBV is orchestrated by several latent viral proteins that mimic and modulate cellular growth promoting and antiapoptotic signaling pathways, which involve among others the activity of protein kinases. In an effort to identify small molecule inhibitors of the growth of EBV-transformed B lymphocytes a library of 254 kinase inhibitors was screened. This effort identified two tyrosine kinase inhibitors and two MEK inhibitors that compromised preferentially the viability of EBV-infected human B lymphocytes. Our findings highlight the possible dependence of EBV-infected B lymphocytes on specific kinase-regulated pathways underlining the potential for the development of small molecule-based therapeutics that could target selectively EBV-associated human B lymphocyte malignancies.
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22
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Abstract
Epstein-Barr virus (EBV), a ubiquitous human double stranded DNA virus, is associated with a variety of malignancies including Burkitt's lymphoma, Hodgkin's lymphoma, nasopharyngeal carcinoma (NPC) and gastric carcinoma (GC). These EBV-associated cancers are characterized by the proliferation of monoclonal EBV-infected cells, and viral gene expression in these cells is limited to a subset of latent genes, indicating that EBV latent genes contribute to carcinogenesis. Here I describe the mechanisms of carcinogenesis by EBV, focusing on the function of two EBV latent gens, latent membrane protein 2A (LMP2A) and EBV-encoded small RNA (EBER). LMP2A, which is known to mimic the B cell receptor (BCR) signaling, has been reported to contribute to malignant lymphoma development through the modulation of immune signals. Also, it has been demonstrated that LMP2A-mediated intracellular signaling plays significant roles in epithelial carcinogenesis. On the other hand, it has been demonstrated that EBER, which is expected to form double stranded RNA (dsRNA) structure, triggers a signal transduction from host viral RNA sensors RIG-I and TLR3. Activation of innate immune signals by EBER has been reported to contribute to the pathogenesis of EBV-associated diseases, including cancers.
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Affiliation(s)
- Dai Iwakiri
- Institute for Genetic Medicine Hokkaido University
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23
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Salgado APC, Soares-Martins JAP, Andrade LG, Albarnaz JD, Ferreira PCP, Kroon EG, Bonjardim CA. Study of vaccinia and cowpox viruses' replication in Rac1-N17 dominant-negative cells. Mem Inst Oswaldo Cruz 2013; 108:554-62. [PMID: 23903969 DOI: 10.1590/s0074-02762013000500004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/13/2013] [Indexed: 11/22/2022] Open
Abstract
Interfering with cellular signal transduction pathways is a common strategy used by many viruses to create a propitious intracellular environment for an efficient replication. Our group has been studying cellular signalling pathways activated by the orthopoxviruses Vaccinia (VACV) and Cowpox (CPXV) and their significance to viral replication. In the present study our aim was to investigate whether the GTPase Rac1 was an upstream signal that led to the activation of MEK/ERK1/2, JNK1/2 or Akt pathways upon VACV or CPXV' infections. Therefore, we generated stable murine fibroblasts exhibiting negative dominance to Rac1-N17 to evaluate viral growth and the phosphorylation status of ERK1/2, JNK1/2 and Akt. Our results demonstrated that VACV replication, but not CPXV, was affected in dominant-negative (DN) Rac1-N17 cell lines in which viral yield was reduced in about 10-fold. Viral late gene expression, but not early, was also reduced. Furthermore, our data showed that Akt phosphorylation was diminished upon VACV infection in DN Rac1-N17 cells, suggesting that Rac1 participates in the phosphoinositide-3 kinase pathway leading to the activation of Akt. In conclusion, our results indicate that while Rac1 indeed plays a role in VACV biology, perhaps another GTPase may be involved in CPXV replication.
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Affiliation(s)
- Ana Paula Carneiro Salgado
- Grupo de Transdução de Sinal/Orthopoxvirus e Flavivírus - LABVÍRUS, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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24
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Salgado APC, Soares-Martins JAP, Andrade LG, Albarnaz JD, Ferreira PCP, Kroon EG, Bonjardim CA. Study of vaccinia and cowpox viruses' replication in Rac1-N17 dominant-negative cells. Mem Inst Oswaldo Cruz 2013; 108. [PMID: 23903969 PMCID: PMC3970603 DOI: 10.1590/0074-0276108052013004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Interfering with cellular signal transduction pathways is a common strategy used by many viruses to create a propitious intracellular environment for an efficient replication. Our group has been studying cellular signalling pathways activated by the orthopoxviruses Vaccinia (VACV) and Cowpox (CPXV) and their significance to viral replication. In the present study our aim was to investigate whether the GTPase Rac1 was an upstream signal that led to the activation of MEK/ERK1/2, JNK1/2 or Akt pathways upon VACV or CPXV' infections. Therefore, we generated stable murine fibroblasts exhibiting negative dominance to Rac1-N17 to evaluate viral growth and the phosphorylation status of ERK1/2, JNK1/2 and Akt. Our results demonstrated that VACV replication, but not CPXV, was affected in dominant-negative (DN) Rac1-N17 cell lines in which viral yield was reduced in about 10-fold. Viral late gene expression, but not early, was also reduced. Furthermore, our data showed that Akt phosphorylation was diminished upon VACV infection in DN Rac1-N17 cells, suggesting that Rac1 participates in the phosphoinositide-3 kinase pathway leading to the activation of Akt. In conclusion, our results indicate that while Rac1 indeed plays a role in VACV biology, perhaps another GTPase may be involved in CPXV replication.
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Affiliation(s)
- Ana Paula Carneiro Salgado
- Grupo de Transdução de Sinal/Orthopoxvirus e Flavivírus - LABVÍRUS , Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil
| | - Jamária Adriana Pinheiro Soares-Martins
- Grupo de Transdução de Sinal/Orthopoxvirus e Flavivírus - LABVÍRUS , Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil , Department of Microbiology and Molecular Genetics, Medical College
of Wisconsin, Milwaukee, WI, USA
| | - Luciana Garcia Andrade
- Grupo de Transdução de Sinal/Orthopoxvirus e Flavivírus - LABVÍRUS , Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil
| | - Jonas Dutra Albarnaz
- Grupo de Transdução de Sinal/Orthopoxvirus e Flavivírus - LABVÍRUS , Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil
| | - Paulo César Peregrino Ferreira
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil
| | - Erna Geessien Kroon
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil
| | - Cláudio Antônio Bonjardim
- Grupo de Transdução de Sinal/Orthopoxvirus e Flavivírus - LABVÍRUS , Laboratório de Vírus, Departamento de Microbiologia, Instituto de
Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG,
Brasil , Corresponding author:
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Epstein-Barr virus latent membrane protein 2A contributes to anoikis resistance through ERK activation. J Virol 2013; 87:8227-34. [PMID: 23698301 DOI: 10.1128/jvi.01089-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus (EBV) is associated with various malignancies, including epithelial cancers. In this study, we analyzed the effect of EBV infection on epithelial cells by using EBV-converted epithelial cells. In EBV-positive cells, the extracellular signal-regulated kinase (ERK) pathway is constitutively activated. Inhibition of ERK activity leads to reduced anoikis resistance; therefore, EBV-positive cells are more resistant to anoikis, a type of apoptosis induced by cell detachment, than are EBV-negative cells. Among the viral genes expressed in EBV-positive cells, the latent membrane protein 2A (LMP2A) is responsible for induction of ERK-mediated anoikis resistance, although the expression level of LMP2A is much lower in EBV-positive cells than in EBV-transformed B cells. Further analysis demonstrated that LMP2A downregulation of the proanoikis mediator Bim through proteasomal degradation is dependent on the immunoreceptor tyrosine-based activation motif (ITAM). These findings suggest that LMP2A-mediated ERK activation is involved in the generation of EBV-associated epithelial malignancies.
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Enrichment of stem-like cell population comprises transformation ability of Epstein-Barr virus latent membrane protein 2A for non-transformed cells. Virus Res 2013; 174:108-15. [PMID: 23524324 DOI: 10.1016/j.virusres.2013.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 03/09/2013] [Accepted: 03/11/2013] [Indexed: 12/11/2022]
Abstract
Epstein-Barr virus (EBV) is a representative human oncogenic virus that causes malignancies of various cell lineages. LMP2A, an EBV-encoded latent membrane protein, is expressed in EBV-associated malignancies of various cell lineages. LMP2A caused visible tumor formation transplanted in nude mice when transferred to immortalized non-transformed fibroblasts, NIH3T3. LMP2A-expressing cells showed higher ability of colony formation in soft agar than empty vector-transfected control cells, although the expression of LMP2A did not cause focus transformation in low serum concentrations. LMP2A expression increased the size of Hoechst 33,342 dye excreting side population (SP), in which cancer-initiating cells or cancer stem-like cells were enriched. SP increase by LMP2A was also responsible for colony formation in soft agar. The LMP2A-mediated SP increase depended on the activations of Stat3, MEK/ERK, and PI3K pathways, and on upregulation of HMGA2. Enrichment of SP, stem-like cells, by LMP2A promoted the transformation capability of LMP2A from non-transformed cells. The enrichment of stem-like cell population by a virus-encoded factor might explain the oncogenic functions of oncogenic viruses.
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Dergai O, Dergai M, Skrypkina I, Matskova L, Tsyba L, Gudkova D, Rynditch A. The LMP2A protein of Epstein-Barr virus regulates phosphorylation of ITSN1 and Shb adaptors by tyrosine kinases. Cell Signal 2012; 25:33-40. [PMID: 22975684 DOI: 10.1016/j.cellsig.2012.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 09/04/2012] [Indexed: 01/20/2023]
Abstract
Latent Membrane Protein 2A (LMP2A) is an Epstein-Barr virus-encoded protein that is important for the maintenance of latent infection. Its activity affects cellular differentiation, migration, proliferation and B cell survival. LMP2A resembles a constitutively activated B cell antigen receptor and exploits host kinases to activate a set of downstream signaling pathways. In the current study we demonstrate the interaction of LMP2A with intersectin 1 (ITSN1), a key endocytic adaptor protein. This interaction occurs via both the N- and C-tails of LMP2A and is mediated by the SH3 domains of ITSN1. Additionally, we identified the Shb adaptor and the Syk kinase as novel binding ligands of ITSN1. The Shb adaptor interacts simultaneously with the phosphorylated tyrosines of LMP2A and the SH3 domains of ITSN1 and mediates indirect interaction of ITSN1 to LMP2A. Syk kinase promotes phosphorylation of both ITSN1 and Shb adaptors in LMP2A-expressing cells. In contrast to ITSN1, Shb phosphorylation depends additionally on Lyn kinase activity. Considering that Shb and ITSN1 are implicated in various receptor tyrosine kinase signaling, our results indicate that LMP2A can affect a number of signaling pathways by regulating the phosphorylation of the ITSN1 and Shb adaptors.
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Affiliation(s)
- Oleksandr Dergai
- State Key Laboratory of Molecular and Cellular Biology, Institute of Molecular Biology and Genetics, 150 Zabolotnogo Street, Kyiv 03680, Ukraine
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28
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Noch E, Khalili K. Oncogenic viruses and tumor glucose metabolism: like kids in a candy store. Mol Cancer Ther 2012; 11:14-23. [PMID: 22234809 DOI: 10.1158/1535-7163.mct-11-0517] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Oncogenic viruses represent a significant public health burden in light of the multitude of malignancies that result from chronic or spontaneous viral infection and transformation. Although many of the molecular signaling pathways that underlie virus-mediated cellular transformation are known, the impact of these viruses on metabolic signaling and phenotype within proliferating tumor cells is less well understood. Whether the interaction of oncogenic viruses with metabolic signaling pathways involves enhanced glucose uptake and glycolysis (both hallmark features of transformed cells) or dysregulation of molecular pathways that regulate oxidative stress, viruses are adept at facilitating tumor expansion. Through their effects on cell proliferation pathways, such as the PI3K and MAPK pathways, the cell cycle regulatory proteins p53 and ATM, and the cell stress response proteins HIF-1α and AMPK, viruses exert control over critical metabolic signaling cascades. Additionally, oncogenic viruses modulate the tumor metabolomic profile through direct and indirect interactions with glucose transporters, such as GLUT1, and specific glycolytic enzymes, including pyruvate kinase, glucose 6-phosphate dehydrogenase, and hexokinase. Through these pathways, oncogenic viruses alter the phenotypic characteristics and energy-use methods of transformed cells; therefore, it may be possible to develop novel antiglycolytic therapies to target these dysregulated pathways in virus-derived malignancies.
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Affiliation(s)
- Evan Noch
- Department of Neuroscience and Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Lan YY, Hsiao JR, Chang KC, Chang JSM, Chen CW, Lai HC, Wu SY, Yeh TH, Chang FH, Lin WH, Su IJ, Chang Y. Epstein-Barr virus latent membrane protein 2A promotes invasion of nasopharyngeal carcinoma cells through ERK/Fra-1-mediated induction of matrix metalloproteinase 9. J Virol 2012; 86:6656-67. [PMID: 22514348 PMCID: PMC3393536 DOI: 10.1128/jvi.00174-12] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 04/04/2012] [Indexed: 01/31/2023] Open
Abstract
Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) is highly metastatic, and this malignant feature may be promoted by an EBV oncoprotein, latent membrane protein 2A (LMP2A). Acting as a signal regulator, LMP2A can enhance invasiveness and motility of epithelial cells. Downstream from the LMP2A-triggered signaling events, it is largely unknown what key effector proteins are induced and essentially promote cell invasion. In the present study, we found that in NPC cells, LMP2A upregulated matrix metalloproteinase 9 (MMP9), a metastasis-associated protease. LMP2A increased MMP9 expression at both the mRNA and protein levels. It also activated the MMP9 promoter, in which two AP-1 elements were required for the promoter activation. Among AP-1 transcription factors, Fra-1 was induced by LMP2A and is essential for LMP2A-triggered MMP9 expression. Induction of Fra-1 was dependent on the LMP2A-activated ERK1/2 pathway, and induction of the ERK1/2-Fra-1-MMP9 axis required PY motifs in the amino-terminal domain of LMP2A. Notably, LMP2A-promoted invasion of NPC cells was blocked when MMP9 expression, Fra-1 induction, or ERK1/2 activation was inhibited. In addition, we found an association of LMP2A with MMP9 expression in NPC tumor biopsy specimens, where Fra-1 was a major mediation factor. This study reveals an underlying mechanism of LMP2A-induced cell invasion, from signal transduction to upregulation of a critical protease. Considering that MMP9 can also be upregulated by another EBV oncoprotein, LMP1, this protease may be a pivotal effector at which the EBV-induced, invasion-promoting mechanisms converge, serving as an attractive therapeutic target for NPC treatment.
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Affiliation(s)
- Yu-Yan Lan
- National Institute of Infectious Diseases and Vaccinology
- Graduate Institute of Basic Medical Science
| | | | | | - Jeffrey Shu-Ming Chang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Chaio-Wei Chen
- National Institute of Infectious Diseases and Vaccinology
| | - Hsiao-Ching Lai
- National Institute of Infectious Diseases and Vaccinology
- Graduate Institute of Basic Medical Science
| | - Shih-Yi Wu
- National Institute of Infectious Diseases and Vaccinology
| | - Tzu-Hao Yeh
- National Institute of Infectious Diseases and Vaccinology
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Fang-Hsin Chang
- National Institute of Infectious Diseases and Vaccinology
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Hung Lin
- National Institute of Infectious Diseases and Vaccinology
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Ih-Jen Su
- National Institute of Infectious Diseases and Vaccinology
| | - Yao Chang
- National Institute of Infectious Diseases and Vaccinology
- Graduate Institute of Basic Medical Science
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
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Pereira ACTC, Soares-Martins JAP, Leite FGG, Da Cruz AFP, Torres AA, Souto-Padrón T, Kroon EG, Ferreira PCP, Bonjardim CA. SP600125 inhibits Orthopoxviruses replication in a JNK1/2 -independent manner: Implication as a potential antipoxviral. Antiviral Res 2011; 93:69-77. [PMID: 22068148 PMCID: PMC7114308 DOI: 10.1016/j.antiviral.2011.10.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/15/2011] [Accepted: 10/24/2011] [Indexed: 11/24/2022]
Abstract
The pharmacological inhibitor SP600125 [anthra(1,9-cd)pyrazol-6(2H)-one 1,9-pyrazoloanthrone] has been largely employed as a c-JUN N-terminal kinase (JNK1/2) inhibitor. In this study, we evaluated whether pretreatment with SP600125 was able to prevent Orthopoxviruses Vaccinia virus (VACV), Cowpox virus (CPXV) and modified Vaccinia virus Ankara (MVA) replication. We found that incubation with SP600125 not only blocked virus-stimulated JNK phosphorylation, but also, significantly reduced virus production. We observed 1-3 log decline in viral yield depending on the cell line infected (A31, BSC-40 or BHK-21). The reduction in viral yield correlated with a dramatic impact on virus morphogenesis progress, intracellular mature viruses (IMV) were barely detected. Despite the fact that SP600125 can act as an efficient anti-orthopoxviral compound, we also provide evidence that this antiviral effect is not specifically exerted through JNK1/2 inhibition. This conclusion is supported by the fact that viral titers measured after infections of JNK1/2 knockout cells were not altered as compared to those of wild-type cells. In contrast, a decline in viral titers was verified when the infection of KO cells was carried out in the presence of the pharmacological inhibitor. SP600125 has been the focus of recent studies that have evaluated its action on diverse viral infections including DNA viruses. Our data support the notion that SP600125 can be regarded as a potential antipoxviral compound.
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Affiliation(s)
- Anna C T C Pereira
- Grupo de Transdução de Sinal/Orthopoxvirus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
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31
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Viral induction and targeted inhibition of galectin-1 in EBV+ posttransplant lymphoproliferative disorders. Blood 2011; 117:4315-22. [PMID: 21300977 DOI: 10.1182/blood-2010-11-320481] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Posttransplant lymphoproliferative disorders (PTLDs) are potentially fatal, EBV-driven B-cell malignancies that develop in immunocompromised solid organ or hematopoietic stem cell recipients. In PTLD, the expression of EBV proteins, including latent membrane protein 1 (LMP1) and LMP2A, viral immune evasion strategies, and impaired host immune surveillance foster the proliferation of EBV-transformed B cells. Current PTLD treatment strategies include reduction of immunosuppression, which increases the risk of graft rejection, anti-CD20 treatment, combination chemotherapy, and administration of EBV-specific cytotoxic T cells. In the present study, we report that EBV-transformed lymphoblastoid B-cell lines (LCLs) and primary PTLDs overexpress galectin-1 (Gal1), a carbohydrate-binding lectin that induces tolerogenic dendritic cells and triggers the selective apoptosis of CD4(+) Th1 and Th17 cells and cytotoxic T cells. In transcriptional reporter assays, LMP2A and LMP1 each increased Gal1-driven luciferase expression, and the combination of LMP2A and LMP1 was additive. In addition, small interfering RNA (siRNA)-mediated depletion of LMP2A decreased Gal1 protein abundance in EBV-transformed LCLs. Gal1 expression in LCLs was dependent on both activating protein 1 (AP-1) and PI3K. A newly developed neutralizing Gal1 mAb selectively inhibited Gal1-mediated apoptosis of EBV-specific CD8(+) T cells. Given the tolerogenic and immunosuppressive function of Gal1, antibody-mediated Gal1 neutralization may represent a novel immunotherapeutic strategy for PTLD and other Gal1-expressing tumors.
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Abstract
NF-κB is a pivotal transcription factor that controls cell survival and proliferation in diverse physiological processes. The activity of NF-κB is tightly controlled through its cytoplasmic sequestration by specific inhibitors, IκBs. Various cellular stimuli induce the activation of an IκB kinase, which phosphorylates IκBs and triggers their proteasomal degradation, causing nuclear translocation of activated NF-κB. Under normal conditions, the activation of NF-κB occurs transiently, thus ensuring rapid but temporary induction of target genes. Deregulated NF-κB activation contributes to the development of various diseases, including cancers and immunological disorders. Accumulated studies demonstrate that the NF-κB signaling pathway is a target of several human oncogenic viruses, including the human T cell leukemia virus type 1, the Kaposi sarcoma-associated herpesvirus, and the Epstein-Bar virus. These viruses encode specific oncoproteins that target different signaling components of the NF-κB pathway, leading to persistent activation of NF-κB. This chapter will discuss the molecular mechanisms by which NF-κB is activated by the viral oncoproteins.
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Affiliation(s)
- Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065
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Huang YT, Liu MY, Tsai CH, Yeh TH. Upregulation of interleukin-1 by Epstein-Barr virus latent membrane protein 1 and its possible role in nasopharyngeal carcinoma cell growth. Head Neck 2010; 32:869-76. [PMID: 19827118 DOI: 10.1002/hed.21270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is associated with Epstein-Barr virus (EBV) infection. We previously found that interleukin (IL)-1alpha and IL-1beta significantly increased in NPC tissues. This study investigated what EBV-encoded proteins were involved in such IL-1 production. METHODS AND RESULTS IL-1alpha and IL-1beta messenger ribonucleic acids (mRNAs) were detected in the EBV latent membrane protein 1 (LMP1) transfectant (LMP135) only by reverse transcriptase-polymerase chain reaction (RT-PCR). LMP1-mediated IL-1alpha and IL-1beta production could be enhanced by tumor necrosis factor alpha (TNF-alpha), determined by enzyme-linked immunosorbent assay (ELISA). Moreover, IL-1alpha and IL-1beta mRNAs and proteins were increased in a dose-dependent manner in epithelial cells transiently transfected by an LMP1 plasmid. Besides, immortalized human epidermal keratinocyte (RHEK-1) epithelial cells could be enhanced to proliferate by IL-1alpha and IL-1beta determined by water-soluble tetrazolium salt (WST-1) assay. CONCLUSIONS EBV LMP1 is capable of upregulating IL-1alpha and IL-1beta secretions from epithelial cells and positively modulated by TNF-alpha. This may consequently contribute to tumor growth in patients with NPC.
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Affiliation(s)
- Yu-Tzu Huang
- School of Medicine, Fu Jen Catholic University, Hsin-Chuang, Taipei Hsien, Taiwan, Republic of China
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Abstract
Epstein-Barr virus (EBV) has been accepted as an infective agent causing gastric carcinoma (GC). Epstein-Barr virus-associated GC, comprising nearly 10% of all cases of GC, is the monoclonal growth of EBV-infected epithelial cells, which express several EBV-latent genes (latency I program). Sequential events in the gastric mucosa could be traced from EBV infection of the pit cells to fully developed carcinomas by EBV encoded small RNA (EBER)-in situ hybridization. The histological features of the carcinoma consist of a lace pattern of carcinoma cells within the mucosa and the dense infiltration of lymphocytes and macrophages at the invasive site, which might be due to cytokines produced by neoplastic cells. The primary molecular abnormality in EBV-associated GC is global and non-random CpG island methylation in the promoter region of many cancer-related genes. The experimental system of recombinant EBV infection using GC cell lines demonstrated that viral latent membrane protein 2A (LMP2A) is responsible for the promotion of DNA methylation. LMP2A up-regulates cellular DNMT1 through the phosphorylation of STAT3, causing CpG methylation of a tumor suppressor gene, PTEN. DNA methylation in EBV-infected stomach cells may be due to overdrive of the cellular defense against foreign DNA, which eventually leads to the development of EBV-associated GC.
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Affiliation(s)
- Masashi Fukayama
- Department of Pathology and Diagnostic Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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Epstein-Barr virus-encoded LMP2A induces an epithelial-mesenchymal transition and increases the number of side population stem-like cancer cells in nasopharyngeal carcinoma. PLoS Pathog 2010; 6:e1000940. [PMID: 20532215 PMCID: PMC2880580 DOI: 10.1371/journal.ppat.1000940] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 05/05/2010] [Indexed: 12/29/2022] Open
Abstract
It has been recently reported that a side population of cells in nasopharyngeal carcinoma (NPC) displayed characteristics of stem-like cancer cells. However, the molecular mechanisms underlying the modulation of such stem-like cell populations in NPC remain unclear. Epstein-Barr virus was the first identified human tumor virus to be associated with various malignancies, most notably NPC. LMP2A, the Epstein-Barr virus encoded latent protein, has been reported to play roles in oncogenic processes. We report by immunostaining in our current study that LMP2A is overexpressed in 57.6% of the nasopharyngeal carcinoma tumors sampled and is mainly localized at the tumor invasive front. We found also in NPC cells that the exogenous expression of LMP2A greatly increases their invasive/migratory ability, induces epithelial-mesenchymal transition (EMT)-like cellular marker alterations, and stimulates stem cell side populations and the expression of stem cell markers. In addition, LMP2A enhances the transforming ability of cancer cells in both colony formation and soft agar assays, as well as the self-renewal ability of stem-like cancer cells in a spherical culture assay. Additionally, LMP2A increases the number of cancer initiating cells in a xenograft tumor formation assay. More importantly, the endogenous expression of LMP2A positively correlates with the expression of ABCG2 in NPC samples. Finally, we demonstrate that Akt inhibitor (V) greatly decreases the size of the stem cell side populations in LMP2A-expressing cells. Taken together, our data indicate that LMP2A induces EMT and stem-like cell self-renewal in NPC, suggesting a novel mechanism by which Epstein-Barr virus induces the initiation, metastasis and recurrence of NPC.
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CUX1/Wnt signaling regulates epithelial mesenchymal transition in EBV infected epithelial cells. Exp Cell Res 2009; 315:1819-31. [PMID: 19361498 DOI: 10.1016/j.yexcr.2009.04.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 03/06/2009] [Accepted: 04/02/2009] [Indexed: 02/07/2023]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a refractory and lethal interstitial lung disease characterized by alveolar epithelial cells apoptosis, fibroblast proliferation and extra-cellular matrix protein deposition. EBV, localised to alveolar epithelial cells of pulmonary fibrosis patients is associated with a poor prognosis. A strategy based on microarray-differential gene expression analysis to identify molecular drivers of EBV-associated lung fibrosis was utilized. Alveolar epithelial cells were infected with EBV to identify genes whose expression was altered following TGFbeta1-mediated lytic phase. EBV lytic reactivation by TGFbeta1 drives a selective alteration in CUX1 variant (a) (NCBI accession number NM_181552) expression, inducing activation of non-canonical Wnt pathway mediators, implicating it in Epithelial Mesenchymal Transition (EMT), the molecular event underpinning scar production in tissue fibrosis. The role of EBV in EMT can be attenuated by antiviral strategies and inhibition of Wnt signaling by using All-Trans Retinoic Acids (ATRA). Activation of non-canonical Wnt signaling pathway by EBV in epithelial cells suggests a novel mechanism of EMT via CUX1 signaling. These data present a framework for further description of the link between infectious agents and fibrosis, a significant disease burden.
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Bultema R, Longnecker R, Swanson-Mungerson M. Epstein-Barr virus LMP2A accelerates MYC-induced lymphomagenesis. Oncogene 2009; 28:1471-6. [PMID: 19182823 DOI: 10.1038/onc.2008.492] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Despite the identification of Epstein-Barr virus (EBV) in tumors of Burkitt's lymphoma (BL) over 40 years ago, the exact contribution of EBV to BL is undefined. EBV encodes for multiple proteins in latent B cells that affect B cell survival and activation. One such protein, latent membrane protein 2A (LMP2A), protects B cells from numerous pro-apoptotic stimuli. Therefore, we tested whether LMP2A protects B cells from apoptosis induced by aberrant c-MYC expression that precedes and dominates BL. We crossed LMP2A-transgenic mice (LMP2A-Tg), in which all B cells express LMP2A, to a transgenic mouse that expresses a BL translocation of myc (lambda-MYC-Tg mice). LMP2A promotes proliferation and protects B cells from MYC-induced apoptosis in lambda-MYC-Tg mice. LMP2A also accelerates the development of lymphoma in LMP2A/lambda-MYC-Tg mice. Finally, LMP2A increases the expression of Bcl-X(L) in both pre-tumor B cells and tumor cells, suggesting a mechanism for LMP2A-mediated B cell survival in the presence of MYC. These results support a hypothesis that EBV LMP2A promotes tumor development by protecting pre-tumor B cells that would normally apoptose after the c-myc translocation.
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Affiliation(s)
- R Bultema
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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The M type K15 protein of Kaposi's sarcoma-associated herpesvirus regulates microRNA expression via its SH2-binding motif to induce cell migration and invasion. J Virol 2008; 83:622-32. [PMID: 18971265 DOI: 10.1128/jvi.00869-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Kaposi's sarcoma (KS) associated herpesvirus (KSHV) is the etiological agent of KS. In vivo, KS is a tumor capable of spreading throughout the body, and pulmonary metastasis is observed clinically. In vitro, KSHV induces the invasiveness of endothelial cells. The KSHV open reading frame K15 is a KSHV-specific gene encoding a transmembrane protein. Two highly divergent forms of K15, the predominant (P) and minor (M) forms (K15P and K15M, respectively), have been identified in different KSHV strains. The two K15 alleles resemble the latent membrane protein 2A (LMP2A) gene of Epstein-Barr virus (EBV) in their genomic locations and protein topology. Also, both K15 proteins have motifs similar to those found in the EBV LMP1 protein. K15 therefore appears to be a hybrid of a distant evolutionary relative of EBV LMP1 and LMP2A. Since both LMP1 and LMP2A proteins are capable of inducing cell motility, we sought to determine whether K15 has similar abilities. In this study, we show that K15M is latently expressed in KSHV-positive PEL cells and knockdown of K15M in PEL cells reduces cell motility. K15M localizes to lysosomal membranes and induces cell migration, invasion, and NF-kappaB (but not AP-1) activity via its conserved SH2-binding motif. K15M also induces the expression of microRNAs miR-21 and miR-31 via this conserved motif, and knocking down both these microRNAs eliminates K15M-induced cell motility. Therefore, K15M may contribute to KSHV-mediated tumor metastasis and angiogenesis via regulation of miR-21 and miR-31, which we show here for the first time to be a specific regulator of cell migration. In light of these findings, the targeting of K15 or the downstream microRNAs regulated by it may represent novel therapies for treatment of KSHV-associated neoplasia.
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40
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Shair KHY, Schnegg CI, Raab-Traub N. EBV latent membrane protein 1 effects on plakoglobin, cell growth, and migration. Cancer Res 2008; 68:6997-7005. [PMID: 18757414 DOI: 10.1158/0008-5472.can-08-1178] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Latent membrane protein 1 (LMP1), the major oncoprotein of EBV, is likely responsible for many of the altered cellular growth properties in EBV-associated cancers, including nasopharyngeal carcinoma (NPC). In this study, the effects of LMP1 on cell growth and migration were studied in the context of the EBV-positive C666-1 NPC cell line. In the soft agar transformation and Transwell metastasis assays, LMP1 enhanced cell growth and migration through activation of phosphatidylinositol 3-kinase (PI3K)/Akt and nuclear factor-kappaB (NF-kappaB) signaling. Inhibitors of PI3K, Akt, and NF-kappaB signaling dramatically reduced these enhanced properties. An IkappaBalpha super-repressor also blocked these effects. However, constitutive activation of Akt alone did not alter cell growth, suggesting that both PI3K/Akt and NF-kappaB activation are required by LMP1. These enhanced effects required the full-length LMP1 encompassing both the PI3K/Akt-activating COOH-terminal activation region (CTAR) 1 and the nonredundant NF-kappaB-activating regions CTAR1 and CTAR2. LMP2A, a latent protein that is also frequently expressed in NPC, similarly activates the PI3K/Akt pathway; however, its overexpression in C666-1 cells did not affect cell growth or migration. LMP1 also decreased expression of the junctional protein plakoglobin, which was shown to be partially responsible for enhanced migration induced by LMP1. This study reveals that in epithelial cells the transforming properties of LMP1 require activation of both PI3K/Akt and NF-kappaB and shows that the loss of plakoglobin expression by LMP1 is a significant factor in the enhanced migration.
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Affiliation(s)
- Kathy H Y Shair
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, NC 27599, USA
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Pan YR, Vatsyayan J, Chang YS, Chang HY. Epstein-Barr virus latent membrane protein 2A upregulates UDP-glucose dehydrogenase gene expression via ERK and PI3K/Akt pathway. Cell Microbiol 2008; 10:2447-60. [PMID: 18717819 DOI: 10.1111/j.1462-5822.2008.01221.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Epstein-Barr virus latent membrane protein 2A (LMP2A) is frequently detected in nasopharyngeal carcinoma (NPC), a tumour of high metastatic capacity. A recent microarray assay notes that expression of the UDP-glucose dehydrogenase (UGDH) gene, participating in glycosaminoglycan synthesis, shows high correlation with LMP2A levels in NPC biopsies. This study extends the finding and demonstrates that the UGDH transcript and protein quantities, the enzyme activity, and glycosaminoglycan contents increase in LMP2A overexpressed human embryonic kidney 293 (HEK293) cells. The luciferase reporter gene assay demarcates that a region from 630 to 486 bp upstream of the transcription start is critical for LMP2A-mediated gene expression. Moreover, a specificity protein 1 (Sp1) binding site mutation in this region reduces the LMP2A-responsive expression of the UGDH gene. Consistent with these findings, cell motility enhancement by LMP2A diminishes by treating the cells with Sp1-specific inhibitor and small interference RNA (siRNA). Using a signalling pathway-specific inhibitor, it is revealed that phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK), not c-Jun N-terminal kinase (JNK) and p38, participate in LMP2A-induced UGDH expression. This study provides a model for molecular mechanism participating in LMP2A-mediated UGDH gene activation.
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Affiliation(s)
- Yun-Ru Pan
- Institute of Molecular Medicine, National Tsing Hua University, Hsin Chu, 300, Taiwan
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42
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Anderson LJ, Longnecker R. EBV LMP2A provides a surrogate pre-B cell receptor signal through constitutive activation of the ERK/MAPK pathway. J Gen Virol 2008; 89:1563-1568. [PMID: 18559925 DOI: 10.1099/vir.0.2008/001461-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) provides developmental and survival signals that mimic those of a B-cell receptor (BCR). Expression of LMP2A during B-cell development results in the ability of B cells to exit the bone marrow in the absence of a BCR and persist in the periphery, where they would normally undergo apoptosis. This study extends the current knowledge of LMP2A function by examining the growth properties of bone marrow B cells from TgE LMP2A mice. Despite the lack of pre-BCR expression, bone marrow B cells from TgE LMP2A mice proliferate and survive in low concentrations of interleukin 7, similar to wild-type cells. Constitutive phosphorylation of ERK/MAPK and PI3K/Akt in TgE LMP2A bone marrow B cells is also reminiscent of signalling through the pre-BCR, altogether demonstrating that LMP2A provides a pre-BCR-like signal to developing B cells.
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Affiliation(s)
- Leah J Anderson
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL 60611, USA
| | - Richard Longnecker
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL 60611, USA
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EBV LMP2A affects LMP1-mediated NF-kappaB signaling and survival of lymphoma cells by regulating TRAF2 expression. Blood 2008; 111:3813-20. [PMID: 18230756 DOI: 10.1182/blood-2007-03-080309] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A mechanism used by Epstein-Barr virus (EBV) for in vitro transformation of B cells into lymphoblastoid cell lines (LCLs) is activation of the NF-kappaB pathway, which is largely mediated by the EBV latent membrane protein 1 (LMP1). LMP1 is coexpressed with LMP2A in many EBV-associated lymphoid malignancies. Since inhibition of NF-kappaB leads to apoptosis of EBV-infected LCLs and lymphoma cell lines, we sought to determine whether LMP1 alone, or in combination with other viral proteins, is responsible for initiating NF-kappaB activation in these cells, thereby playing a role in cell survival. We found that suppression of LMP1 by RNA interference results in inhibition of basal NF-kappaB and induction of apoptosis. Unexpectedly, knockdown of LMP2A also resulted in comparable decrease of NF-kappaB activity and apoptosis. We report that LMP2A protein controls the expression of TRAF2 mRNA, which in turn is necessary for signaling by LMP1. Our data contrast with previous studies showing that transfected LMP1 can signal in the absence of LMP2A or TRAF2, and demonstrate that both LMP2A and TRAF2 are required for survival in naturally infected lymphoma cells and LCLs. These results also support LMP1, LMP2A, and TRAF2 as potential therapeutic targets in a subset of EBV-associated lymphoid malignancies.
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Grande SM, Bannish G, Fuentes-Panana EM, Katz E, Monroe JG. Tonic B-cell and viral ITAM signaling: context is everything. Immunol Rev 2007; 218:214-34. [PMID: 17624955 DOI: 10.1111/j.1600-065x.2007.00535.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The presence of an immunoreceptor tyrosine-based activation motif (ITAM) makes immunoreceptors different from other signaling receptors, like integrins, G-coupled protein receptors, chemokine receptors, and growth factor receptors. This unique motif has the canonical sequence D/Ex(0-2)YxxL/Ix(6-8)YxxL/I, where x represents any amino acid and is present at least once in all immunoreceptor complexes. Immunoreceptors can promote survival, activation, and differentiation by transducing signals through these highly conserved motifs. Traditionally, ITAM signaling is thought to occur in response to ligand-induced aggregation, although evidence indicates that ligand-independent tonic signaling also provides functionally relevant signals. The majority of proteins containing ITAMs are transmembrane proteins that exist as part of immunoreceptor complexes. However, oncogenic viruses also have ITAM-containing proteins. In this review, we discuss what is known about tonic signaling by both cellular and viral ITAM-containing proteins and speculate what we might learn from each context.
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Affiliation(s)
- Shannon M Grande
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
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45
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Noguchi K, Fukazawa H, Murakami Y, Takahashi N, Yamagoe S, Uehara Y. Gamma-herpesviruses and cellular signaling in AIDS-associated malignancies. Cancer Sci 2007; 98:1288-96. [PMID: 17640300 PMCID: PMC11158765 DOI: 10.1111/j.1349-7006.2007.00555.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2007] [Revised: 04/24/2007] [Accepted: 04/30/2007] [Indexed: 11/29/2022] Open
Abstract
gamma-Herpesviruses, Epstein-Barr virus (EBV/HHV-4) and Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8), are involved in human carcinogenesis, particularly in immunocompromised patients. Virus-associated malignancies are becoming of significant concern for the mortality of long-lived immunocompromised patients, and therefore, research of advanced strategies for AIDS-related malignancies is an important field in cancer chemotherapy. Detailed understanding of the EBV and KSHV lifecycle and related cancers at the molecular level is required for novel strategies of molecular-targeted cancer chemotherapy. The present review gives a simple outline of the functional interactions between KSHV- and EBV-viral gene products and host cell deregulated signaling pathways as possible targets of chemotherapy against AIDS-related malignancies.
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MESH Headings
- Animals
- Apoptosis/genetics
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/pathogenicity
- Herpesvirus 4, Human/physiology
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/pathogenicity
- Herpesvirus 8, Human/physiology
- Humans
- Lymphoma, AIDS-Related/drug therapy
- Lymphoma, AIDS-Related/metabolism
- Lymphoma, AIDS-Related/pathology
- Lymphoma, AIDS-Related/virology
- Sarcoma, Kaposi/drug therapy
- Sarcoma, Kaposi/metabolism
- Sarcoma, Kaposi/pathology
- Sarcoma, Kaposi/virology
- Signal Transduction/genetics
- Signal Transduction/physiology
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Affiliation(s)
- Kohji Noguchi
- Department of Bioactive Molecules, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
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Fukuda M, Longnecker R. Epstein-Barr virus latent membrane protein 2A mediates transformation through constitutive activation of the Ras/PI3-K/Akt Pathway. J Virol 2007; 81:9299-306. [PMID: 17582000 PMCID: PMC1951437 DOI: 10.1128/jvi.00537-07] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) is widely expressed in EBV-infected cells within the infected human host and EBV-associated malignancies, suggesting that LMP2A is important for EBV latency, persistence, and EBV-associated tumorigenesis. Previously, we demonstrated that LMP2A provides an antiapoptotic signal through the activation of phosphatidylinositol 3-kinase (PI3-K)/Akt pathway in vitro. However, the exact function of LMP2A in tumor progression is not well understood. In this study, we found that LMP2A did not induce anchorage-independent cell growth in a human keratinocyte cell line, HaCaT, but did in a human gastric carcinoma cell line, HSC-39. In addition, LMP2A activated the PI3-K/Akt pathway in both HaCaT and HSC-39 cells; however, LMP2A did not activate Ras in HaCaT cells but did in HSC-39 cells. Furthermore, the Ras inhibitors manumycin A and a dominant-negative form of Ras (RasN17) and the PI3-K inhibitor LY294002 blocked LMP2A-mediated Akt phosphorylation and anchorage-independent cell growth in HSC-39 cells. These results suggest that constitutive activation of the Ras/PI3-K/Akt pathway by LMP2A is a key factor for LMP2A-mediated transformation.
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Affiliation(s)
- Makoto Fukuda
- Department of Microbiology-Immunology, Northwestern University Medical School, 303 E. Chicago Ave., Chicago, IL 60611, USA
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Iwakiri D, Samanta M, Takada K. [Mechanisms of EBV-mediated oncogenesis]. Uirusu 2007; 56:201-8. [PMID: 17446669 DOI: 10.2222/jsv.56.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Epstein-Barr virus (EBV) is the DNA tumor virus, which is known to be relevant to various cancers. EBV maintains latent infection in cancer cells, and there are three types of latent infection (type I-III) according to the patterns of viral latent genes expression. EBV has the ability to transform B cells into immortalized lymphoblastoid cell lines (LCL) showing type III latency, in which all latent genes are expressed. The mechanism of B-cell transformation has provided a model of EBV-associated lymphomas in immunosuppressed individuals. In type I and II latency, the limited numbers of latent genes are expressed. Previous studies have demonstrated the oncogenic functions of latent EBV genes including nuclear antigen EBNA1, membrane protein LMP1 and LMP2A. In addition, we have demonstrated that EBV-encoded small RNA EBERs play a significant role in oncogenesis. Here we summarize recent progresses in the studies on molecular mechanisms of EBV-mediated oncogenesis.
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Affiliation(s)
- Dai Iwakiri
- Department of Tumor Virology, Institute for Genetic Medicine, Hokkaido University, Kita-ku, Sapporo, Japan.
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48
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Rovedo M, Longnecker R. Epstein-barr virus latent membrane protein 2B (LMP2B) modulates LMP2A activity. J Virol 2007; 81:84-94. [PMID: 17035319 PMCID: PMC1797235 DOI: 10.1128/jvi.01302-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Accepted: 09/28/2006] [Indexed: 12/14/2022] Open
Abstract
Latent membrane protein 2A (LMP2A) and LMP2B are viral proteins expressed during Epstein-Barr virus (EBV) latency in EBV-infected B cells both in cell culture and in vivo. LMP2A has important roles in modulating B-cell receptor (BCR) signal transduction by associating with the cellular tyrosine kinases Lyn and Syk via specific phosphotyrosine motifs found within the LMP2A N-terminal tail domain. LMP2A has been shown to alter normal BCR signal transduction in B cells by reducing levels of Lyn and by blocking tyrosine phosphorylation and calcium mobilization following BCR cross-linking. Although little is currently known about the function of LMP2B in B cells, the similarity in structure between LMP2A and LMP2B suggests that they may localize to the same cellular compartments. To investigate the function of LMP2B, B-cell lines expressing LMP2A, LMP2B, LMP2A/LMP2B, and the relevant vector controls were analyzed. As was previously shown, cells expressing LMP2A had a dramatic block in normal BCR signal transduction as measured by calcium mobilization and tyrosine phosphorylation. There was no effect on BCR signal transduction in cells expressing LMP2B. Interestingly, when LMP2B was expressed in conjunction with LMP2A, there was a restoration of normal BCR signal transduction upon BCR cross-linking. The expression of LMP2B did not alter the cellular localization of LMP2A but did bind to and prevent the phosphorylation of LMP2A. A restoration of Lyn levels, but not a change in LMP2A levels, was also observed in cells coexpressing LMP2B with LMP2A. From these results, we conclude that LMP2B modulates LMP2A activity.
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Affiliation(s)
- Mark Rovedo
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Ward 6-231, 303 E. Chicago Avenue, Chicago, IL 60611, USA
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Zapata HJ, Nakatsugawa M, Moffat JF. Varicella-zoster virus infection of human fibroblast cells activates the c-Jun N-terminal kinase pathway. J Virol 2006; 81:977-90. [PMID: 17079291 PMCID: PMC1797429 DOI: 10.1128/jvi.01470-06] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The transcription factors ATF-2 and c-Jun are important for transactivation of varicella-zoster virus (VZV) genes. c-Jun is activated by the c-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase pathway that responds to stress and cytokines. To study the effects of VZV on this pathway, confluent human foreskin fibroblasts were infected with cell-associated VZV for 1 to 4 days. Immunoblots showed that phosphorylated JNK and c-Jun levels increased in VZV-infected cells, and kinase assays determined that phospho-JNK was active. Phospho-JNK was detected after 24 h, and levels rose steadily over 4 days in parallel with accumulation of VZV antigen. The two main activators of JNK are MKK4 and MKK7, and levels of their active, phosphorylated forms also increased. The competitive inhibitor of JNK, SP600125, caused a dose-dependent reduction in VZV yield (50% effective concentration, congruent with 8 microM). Specificity was verified by immunoblotting; phospho-c-Jun was eliminated by 18 microM SP600125 in VZV-infected cells. Immunofluorescent confocal microscopy showed that phospho-c-Jun and most of phospho-JNK were in the nuclei of VZV-infected cells; some phospho-JNK was in the cytoplasm. MKK4, MKK7, JNK, and phospho-JNK were detected by immunoblotting in purified preparations of VZV virions, but c-Jun was absent. JNK was located in the virion tegument, as determined by biochemical fractionation and immunogold transmission electron microscopy. Overall, these results demonstrate the importance of the JNK pathway for VZV replication and advance the idea that JNK is a useful drug target against VZV.
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Affiliation(s)
- Heidi J Zapata
- Department of Microbiology and Immunology, State University of New York Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
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50
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Nandi S, Reinert LS, Hachem A, Mazan-Mamczarz K, Hagner P, He H, Gartenhaus RB. Phosphorylation of MCT-1 by p44/42 MAPK is required for its stabilization in response to DNA damage. Oncogene 2006; 26:2283-9. [PMID: 17016429 DOI: 10.1038/sj.onc.1210030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We discovered a novel oncogene in a T-cell lymphoma cell line, multiple copies in T-cell lymphoma-1 (MCT-1), that has been shown to decrease cell-doubling time, shorten the duration of G(1) transit time and/or G(1)-S transition, and transform NIH3T3 fibroblasts. We subsequently demonstrated that there were significantly increased levels of MCT-1 protein in a subset of primary diffuse large B-cell lymphomas. Levels of MCT-1 protein were shown to be increased after exposure to DNA damaging agents. This increase did not require new protein synthesis, suggesting that post-translational mechanisms were involved. Phosphorylation is one potential mechanism by which the activity of molecules involved in cell cycle/survival is rapidly modulated. The RAS/mitogen-activated/extracellular-regulated kinase (MEK)/extracellular signal-regulated kinases (ERK) pathway plays a prominent role in the regulation of cell growth and proliferation through phosphorylation-dependent regulation of several substrates. The MCT-1 protein is predicted to have numerous putative phosphorylation sites. Using a combination of genetic and pharmacological approaches, we established that phosphorylation of MCT-1 protein by p44/p42 mitogen-activated protein kinases is critical for stabilization of MCT-1 protein and for its ability to promote cell proliferation. Our data suggests that targeting the RAS/MEK/ERK signal transduction cascade may provide a potential therapeutic approach in lymphomas and related malignancies that exhibit high levels of MCT-1 protein.
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Affiliation(s)
- S Nandi
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
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