1
|
Xu Y, Wu L, Hong J, Chi X, Zheng M, Wang L, Chen JL, Guo G. African swine fever virus A137R protein inhibits NF-κB activation via suppression of MyD88 signaling in PK15 and 3D4/21 cells in vitro. Vet Microbiol 2024; 292:110067. [PMID: 38564905 DOI: 10.1016/j.vetmic.2024.110067] [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: 12/19/2023] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024]
Abstract
African swine fever (ASF) is an infectious disease with high mortality caused by African swine fever virus (ASFV), which poses a great threat to the global swine industry. ASFV has evolved multiple strategies to evade host antiviral innate immunity by perturbing inflammatory responses and interferon production. However, the molecular mechanisms underlying manipulation of inflammatory responses by ASFV proteins are not fully understood. Here, we report that A137R protein of ASFV is a key suppressor of host inflammatory responses. Ectopic expression of ASFV A137R in HEK293T cells significantly inhibited the activation of IL-8 and NF-κB promoters triggered by Sendai virus (SeV), influenza A virus (IAV), or vesicular stomatitis virus (VSV). Accordingly, forced A137R expression caused a significant decrease in the production of several inflammatory cytokines such as IL-8, IL-6 and TNF-α in the cells infected with SeV or IAV. Similar results were obtained from experiments using A137R overexpressing PK15 and 3D4/21 cells infected with SeV or VSV. Furthermore, we observed that A137R impaired the activation of MAPK and NF-κB signaling pathways, as enhanced expression of A137R significantly decreased the phosphorylation of JNK, p38 and p65 respectively upon viral infection (SeV or IAV) and IL-1β treatment. Mechanistically, we found that A137R interacted with MyD88, and dampened MyD88-mediated activation of MAPK and NF-κB signaling. Together, these findings uncover a critical role of A137R in restraining host inflammatory responses, and improve our understanding of complicated mechanisms whereby ASFV evades innate immunity.
Collapse
Affiliation(s)
- Yang Xu
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Fujian-Taiwan Animal Pathogen Biology, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lei Wu
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Fujian-Taiwan Animal Pathogen Biology, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jinxuan Hong
- Key Laboratory of Fujian-Taiwan Animal Pathogen Biology, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaojuan Chi
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Meichun Zheng
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Liwei Wang
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ji-Long Chen
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Fujian-Taiwan Animal Pathogen Biology, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Guijie Guo
- Key Laboratory of Animal Pathogen Infection and Immunology of Fujian Province, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Fujian-Taiwan Animal Pathogen Biology, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
| |
Collapse
|
2
|
Ramaswami R, Polizzotto MN, Lurain K, Wyvill KM, Widell A, George J, Goncalves P, Steinberg SM, Whitby D, Uldrick TS, Yarchoan R. Safety, Activity, and Long-term Outcomes of Pomalidomide in the Treatment of Kaposi Sarcoma among Individuals with or without HIV Infection. Clin Cancer Res 2022; 28:840-850. [PMID: 34862247 PMCID: PMC8898289 DOI: 10.1158/1078-0432.ccr-21-3364] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 11/08/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022]
Abstract
PURPOSE Kaposi sarcoma (KS) is caused by Kaposi sarcoma herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8). KS, which develops most frequently among people with HIV, is generally treated with chemotherapy, but these drugs have acute and cumulative toxicities. We previously described initial results of a trial of pomalidomide, an oral immunomodulatory derivative of thalidomide, in patients with KS. Here, we present results on the full cohort and survival outcomes. PATIENTS AND METHODS Participants with KS with or without HIV were treated with pomalidomide 5 mg once daily for 21 days per 28-day cycle with aspirin 81 mg daily for thromboprophylaxis. Participants with HIV received antiretroviral therapy. Response was defined by modified version of the AIDS Clinical Trial Group KS criteria. We evaluated tumor responses (including participants who had a second course), adverse events, progression-free survival (PFS), and long-term outcomes. RESULTS Twenty-eight participants were enrolled. Eighteen (64%) were HIV positive and 21 (75%) had advanced (T1) disease. The overall response rate was 71%: 95% confidence interval (CI) 51%-87%. Twelve of 18 HIV-positive (67%; 95% CI, 41-87%) and 8 of 10 HIV-negative participants (80%; 95% CI, 44%-97%) had a response. Two of 4 participants who received a second course of pomalidomide had a partial response. The median PFS was 10.2 months (95% CI: 7.6-15.7 months). Grade 3 neutropenia was noted among 50% of participants. In the follow-up period, 3 participants with HIV had other KSHV-associated diseases. CONCLUSIONS Pomalidomide is a safe and active chemotherapy-sparing agent for the treatment of KS among individuals with or without HIV.
Collapse
Affiliation(s)
- Ramya Ramaswami
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Mark N Polizzotto
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Kathryn Lurain
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Kathleen M Wyvill
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Anaida Widell
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Jomy George
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Priscila Goncalves
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Seth M Steinberg
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institutes, National Institutes of Health
| | - Denise Whitby
- Viral Oncology Section, AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Thomas S Uldrick
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| | - Robert Yarchoan
- HIV/AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health
| |
Collapse
|
3
|
Choi YB, Cousins E, Nicholas J. Novel Functions and Virus-Host Interactions Implicated in Pathogenesis and Replication of Human Herpesvirus 8. Recent Results Cancer Res 2021; 217:245-301. [PMID: 33200369 DOI: 10.1007/978-3-030-57362-1_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human herpesvirus 8 (HHV-8) is classified as a γ2-herpesvirus and is related to Epstein-Barr virus (EBV), a γ1-herpesvirus. One important aspect of the γ-herpesviruses is their association with neoplasia, either naturally or in animal model systems. HHV-8 is associated with B-cell-derived primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD), endothelial-derived Kaposi's sarcoma (KS), and KSHV inflammatory cytokine syndrome (KICS). EBV is also associated with a number of B-cell malignancies, such as Burkitt's lymphoma, Hodgkin's lymphoma, and posttransplant lymphoproliferative disease, in addition to epithelial nasopharyngeal and gastric carcinomas. Despite the similarities between these viruses and their associated malignancies, the particular protein functions and activities involved in key aspects of virus biology and neoplastic transformation appear to be quite distinct. Indeed, HHV-8 specifies a number of proteins for which counterparts had not previously been identified in EBV, other herpesviruses, or even viruses in general, and these proteins are believed to play vital functions in virus biology and to be involved centrally in viral pathogenesis. Additionally, a set of microRNAs encoded by HHV-8 appears to modulate the expression of multiple host proteins to provide conditions conductive to virus persistence within the host and possibly contributing to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.
Collapse
Affiliation(s)
- Young Bong Choi
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA.
| | - Emily Cousins
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA
| | - John Nicholas
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA
| |
Collapse
|
4
|
Latent infection with Kaposi's sarcoma-associated herpesvirus enhances retrotransposition of long interspersed element-1. Oncogene 2019; 38:4340-4351. [PMID: 30770900 DOI: 10.1038/s41388-019-0726-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/18/2019] [Indexed: 12/14/2022]
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV), a gamma-2 herpesvirus, is the causative agent of KS, primary effusion lymphoma (PEL), and a plasma cell variant of multicentric Castleman's disease. Although KSHV latency is detected in KS-related tumors, oncogenic pathways activated by KSHV latent infection are not fully understood. Here, we found that retrotransposition of long interspersed element-1 (L1), a retrotransposon in the human genome, was enhanced in PEL cells. Among the KSHV latent genes, viral FLICE-inhibitory protein (vFLIP) enhanced L1 retrotransposition in an NF-κB-dependent manner. Intracellular cell adhesion molecule-1 (ICAM-1), an NF-κB target, regulated the vFLIP-mediated enhancement of L1 retrotransposition. Furthermore, ICAM-1 downregulated the expression of Moloney leukemia virus 10 (MOV10), an L1 restriction factor. Knockdown of ICAM-1 or overexpression of MOV10 relieved the vFLIP-mediated enhancement of L1 retrotransposition. Collectively, during KSHV latency, vFLIP upregulates ICAM-1 in an NF-κB-dependent manner, which, in turn, downregulates MOV10 expression and thereby enhances L1 retrotransposition. Because active L1 retrotransposition can lead to genomic instability, which is commonly found in KS and PEL, activation of L1 retrotransposition during KSHV latency may accelerate oncogenic processes through enhancing genomic instability. Our results suggest that L1 retrotransposition may be a novel target for impeding tumor development in KSHV-infected patients.
Collapse
|
5
|
Caspase-Dependent Suppression of Type I Interferon Signaling Promotes Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication. J Virol 2018. [PMID: 29514903 DOI: 10.1128/jvi.00078-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
An important component of lytic infection by Kaposi's sarcoma-associated herpesvirus (KSHV) is the ability of the virus to evade the innate immune response, specifically type I interferon (IFN) responses that are triggered by recognition of viral nucleic acids. Inhibition of type I IFN responses by the virus promotes viral replication. Here, we report that KSHV uses a caspase-dependent mechanism to block type I IFN, in particular IFN-β, responses during lytic infection. Inhibition of caspases during KSHV reactivation resulted in increased TBK1/IKKε-dependent phosphorylation of IRF3 as well as elevated levels of IFN-β transcription and secretion. The increased secretion of IFN-β upon caspase inhibition reduced viral gene expression, viral DNA replication, and virus production. Blocking IFN-β production or signaling restored viral replication. Overall, our results show that caspase-mediated regulation of pathogen sensing machinery is an important mechanism exploited by KSHV to evade innate immune responses.IMPORTANCE KSHV is the causative agent of Kaposi's sarcoma (KS), an AIDS-defining tumor that is one of the most common causes of cancer death in sub-Saharan Africa. In this study, we examined the role of a set of cellular proteases, called caspases, in the regulation of immune responses during KSHV infection. We demonstrate that caspases prevent the induction and secretion of the antiviral factor IFN-β during replicative KSHV infection. The reduced IFN-β production allows for high viral gene expression and viral replication. Therefore, caspases are important for maintaining KSHV replication. Overall, our results suggest that KSHV utilizes caspases to evade innate immune responses, and that inhibiting caspases could boost the innate immune response to this pathogen and potentially be a new antiviral strategy.
Collapse
|
6
|
Yao S, Hu M, Hao T, Li W, Xue X, Xue M, Zhu X, Zhou F, Qin D, Yan Q, Zhu J, Gao SJ, Lu C. MiRNA-891a-5p mediates HIV-1 Tat and KSHV Orf-K1 synergistic induction of angiogenesis by activating NF-κB signaling. Nucleic Acids Res 2015; 43:9362-78. [PMID: 26446987 PMCID: PMC4627096 DOI: 10.1093/nar/gkv988] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 09/19/2015] [Indexed: 12/03/2022] Open
Abstract
Co-infection with HIV-1 and Kaposi's sarcoma-associated herpesvirus (KSHV) is the cause of aggressive AIDS-related Kaposi's sarcoma (AIDS-KS) characterized by abnormal angiogenesis. The impact of HIV-1 and KSHV interaction on the pathogenesis and extensive angiogenesis of AIDS-KS remains unclear. Here, we explored the synergistic effect of HIV-1 Tat and KSHV oncogene Orf-K1 on angiogenesis. Our results showed that soluble Tat or ectopic expression of Tat enhanced K1-induced cell proliferation, microtubule formation and angiogenesis in chorioallantoic membrane and nude mice models. Mechanistic studies revealed that Tat promoted K1-induced angiogenesis by enhancing NF-κB signaling. Mechanistically, we showed that Tat synergized with K1 to induce the expression of miR-891a-5p, which directly targeted IκBα 3′ untranslated region, leading to NF-κB activation. Consequently, inhibition of miR-891a-5p increased IκBα level, prevented nuclear translocation of NF-κB p65 and ultimately suppressed the synergistic effect of Tat- and K1-induced angiogenesis. Our results illustrate that, by targeting IκBα to activate the NF-κB pathway, miR-891a-5p mediates Tat and K1 synergistic induction of angiogenesis. Therefore, the miR-891a-5p/NF-κB pathway is important in the pathogenesis of AIDS-KS, which could be an attractive therapeutic target for AIDS-KS.
Collapse
Affiliation(s)
- Shuihong Yao
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, P.R. China Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, P.R. China Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China Medical School, Quzhou College of Technology, Quzhou 324000, P.R. China
| | - Minmin Hu
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Tingting Hao
- Department of Medical Laboratory, The Affiliated Hospital of Xuzhou Medical College, Xuzhou 221000, P.R. China
| | - Wan Li
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Xue Xue
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Min Xue
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Xiaofei Zhu
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Feng Zhou
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Di Qin
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Qin Yan
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Jianzhong Zhu
- Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Chun Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, P.R. China Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, P.R. China Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| |
Collapse
|
7
|
Othman Z, Sulaiman MK, Willcocks MM, Ulryck N, Blackbourn DJ, Sargueil B, Roberts LO, Locker N. Functional analysis of Kaposi's sarcoma-associated herpesvirus vFLIP expression reveals a new mode of IRES-mediated translation. RNA (NEW YORK, N.Y.) 2014; 20:1803-1814. [PMID: 25246653 PMCID: PMC4201831 DOI: 10.1261/rna.045328.114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 08/26/2014] [Indexed: 06/03/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus, the etiological agent of Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). One of the key viral proteins that contributes to tumorigenesis is vFLIP, a viral homolog of the FLICE inhibitory protein. This KSHV protein interacts with the NFκB pathway to trigger the expression of antiapoptotic and proinflammatory genes and ultimately leads to tumor formation. The expression of vFLIP is regulated at the translational level by an internal ribosomal entry site (IRES) element. However, the precise mechanism by which ribosomes are recruited internally and the exact location of the IRES has remained elusive. Here we show that a 252-nt fragment directly upstream of vFLIP, within a coding region, directs translation. We have established its RNA structure and demonstrate that IRES activity requires the presence of eIF4A and an intact eIF4G. Furthermore, and unusually for an IRES, eIF4E is part of the complex assembled onto the vFLIP IRES to direct translation. These molecular interactions define a new paradigm for IRES-mediated translation.
Collapse
Affiliation(s)
- Zulkefley Othman
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Mariam K Sulaiman
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Margaret M Willcocks
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Nathalie Ulryck
- Faculté des Sciences Pharmaceutiques et Biologiques, UMR8015, Université Paris Descartes, 75270 Paris, France
| | - David J Blackbourn
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Bruno Sargueil
- Faculté des Sciences Pharmaceutiques et Biologiques, UMR8015, Université Paris Descartes, 75270 Paris, France
| | - Lisa O Roberts
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU27HE, United Kingdom
| |
Collapse
|
8
|
OWEN CHRISTOPHERB, HUGHES DAVIDJ, BAQUERO-PEREZ BELINDA, BERNDT ANJA, SCHUMANN SOPHIE, JACKSON BRIANR, WHITEHOUSE ADRIAN. Utilising proteomic approaches to understand oncogenic human herpesviruses (Review). Mol Clin Oncol 2014; 2:891-903. [PMID: 25279171 PMCID: PMC4179824 DOI: 10.3892/mco.2014.341] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 06/10/2014] [Indexed: 12/16/2022] Open
Abstract
The γ-herpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus are successful pathogens, each infecting a large proportion of the human population. These viruses persist for the life of the host and may each contribute to a number of malignancies, for which there are currently no cures. Large-scale proteomic-based approaches provide an excellent means of increasing the collective understanding of the proteomes of these complex viruses and elucidating their numerous interactions within the infected host cell. These large-scale studies are important for the identification of the intricacies of viral infection and the development of novel therapeutics against these two important pathogens.
Collapse
Affiliation(s)
- CHRISTOPHER B. OWEN
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - DAVID J. HUGHES
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - BELINDA BAQUERO-PEREZ
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - ANJA BERNDT
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - SOPHIE SCHUMANN
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - BRIAN R. JACKSON
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - ADRIAN WHITEHOUSE
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| |
Collapse
|
9
|
Interplay between Kaposi's sarcoma-associated herpesvirus and the innate immune system. Cytokine Growth Factor Rev 2014; 25:597-609. [PMID: 25037686 DOI: 10.1016/j.cytogfr.2014.06.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 06/16/2014] [Indexed: 02/04/2023]
Abstract
Understanding of the innate immune response to viral infections is rapidly progressing, especially with regards to the detection of DNA viruses. Kaposi's sarcoma-associated herpesvirus (KSHV) is a large dsDNA virus that is responsible for three human diseases: Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease. The major target cells of KSHV (B cells and endothelial cells) express a wide range of pattern recognition receptors (PRRs) and play a central role in mobilizing inflammatory responses. On the other hand, KSHV encodes an array of immune evasion genes, including several pirated host genes, which interfere with multiple aspects of the immune response. This review summarizes current understanding of innate immune recognition of KSHV and the role of immune evasion genes that shape the antiviral and inflammatory responses.
Collapse
|
10
|
Popiolek-Barczyk K, Makuch W, Rojewska E, Pilat D, Mika J. Inhibition of intracellular signaling pathways NF-κB and MEK1/2 attenuates neuropathic pain development and enhances morphine analgesia. Pharmacol Rep 2014; 66:845-51. [PMID: 25149989 DOI: 10.1016/j.pharep.2014.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 04/30/2014] [Accepted: 05/05/2014] [Indexed: 01/26/2023]
Abstract
BACKGROUND Neuropathic pain is clinically challenging because it is resistant to alleviation by morphine. The nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways may be involved in the development of neuropathic pain. The aim of our study was to examine the influence of a chronic, intrathecal administration of parthenolide (PTL, inhibitor of NF-κB) and U0126 (inhibitor of MEK1/2) on nociception and morphine effectiveness in a rat model of neuropathy. METHODS The chronic constriction injury of the sciatic nerve in Wistar rats was performed. PTL and U0126 were injected chronic intrathecally and morphine was injected once at day 7. To evaluate allodynia and hyperalgesia, the von Frey and cold plate tests were used, respectively. The experiments were carried out according to IASP rules. Using qRT-PCR we analyzed mRNAs of μ-(mor), δ-(dor) and κ-(kor)-opioid receptors in the lumbar spinal cord after drugs administration. RESULTS The administration of PTL and U0126 decreased allodynia and hyperalgesia and significantly potentiated morphine effect. The mor, dor and kor mRNAs were down-regulated 7 days after injury in the ipsilateral spinal cord. The PTL and U0126 significantly up-regulated the mRNA levels of all opioid receptors. The levels of mor and dor mRNAs were much higher compared to those in naïve, but only the kor levels returned to control values. CONCLUSIONS These results indicate that the inhibition of the NF-κB pathway has better analgesic effects. Both inhibitors similarly potentiate morphine analgesia, which parallels the up-regulation of both mor and dor mRNAs expression spinal levels of the model of neuropathy.
Collapse
Affiliation(s)
| | - Wioletta Makuch
- Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| | - Ewelina Rojewska
- Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| | - Dominika Pilat
- Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| | - Joanna Mika
- Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| |
Collapse
|
11
|
NEMO is essential for Kaposi's sarcoma-associated herpesvirus-encoded vFLIP K13-induced gene expression and protection against death receptor-induced cell death, and its N-terminal 251 residues are sufficient for this process. J Virol 2014; 88:6345-54. [PMID: 24672029 DOI: 10.1128/jvi.00028-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 was originally believed to protect virally infected cells against death receptor-induced apoptosis by interfering with caspase 8/FLICE activation. Subsequent studies revealed that K13 also activates the NF-κB pathway by binding to the NEMO/inhibitor of NF-κB (IκB) kinase gamma (IKKγ) subunit of an IKK complex and uses this pathway to modulate the expression of genes involved in cellular survival, proliferation, and the inflammatory response. However, it is not clear if K13 can also induce gene expression independently of NEMO/IKKγ. The minimum region of NEMO that is sufficient for supporting K13-induced NF-κB has not been delineated. Furthermore, the contribution of NEMO and NF-κB to the protective effect of K13 against death receptor-induced apoptosis remains to be determined. In this study, we used microarray analysis on K13-expressing wild-type and NEMO-deficient cells to demonstrate that NEMO is required for modulation of K13-induced genes. Reconstitution of NEMO-null cells revealed that the N-terminal 251 amino acid residues of NEMO are sufficient for supporting K13-induced NF-κB but fail to support tumor necrosis factor alpha (TNF-α)-induced NF-κB. K13 failed to protect NEMO-null cells against TNF-α-induced cell death but protected those reconstituted with the NEMO mutant truncated to include only the N-terminal 251 amino acid residues [the NEMO(1-251) mutant]. Taken collectively, our results demonstrate that NEMO is required for modulation of K13-induced genes and the N-terminal 251 amino acids of NEMO are sufficient for supporting K13-induced NF-κB. Finally, the ability of K13 to protect against TNF-α-induced cell death is critically dependent on its ability to interact with NEMO and activate NF-κB. IMPORTANCE Kaposi's sarcoma-associated herpesvirus-encoded vFLIP K13 is believed to protect virally infected cells against death receptor-induced apoptosis and to activate the NF-κB pathway by binding to adaptor protein NEMO/IKKγ. However, whether K13 can also induce gene expression independently of NEMO and the minimum region of NEMO that is sufficient for supporting K13-induced NF-κB remain to be delineated. Furthermore, the contribution of NEMO and NF-κB to the protective effect of K13 against death receptor-induced apoptosis is not clear. We demonstrate that NEMO is required for modulation of K13-induced genes and its N-terminal 251 amino acids are sufficient for supporting K13-induced NF-κB. The ability of K13 to protect against TNF-α-induced cell death is critically dependent on its ability to interact with NEMO and activate NF-κB. Our results suggest that K13-based gene therapy approaches may have utility for the treatment of patients with NEMO mutations and immunodeficiency.
Collapse
|
12
|
Yeudall WA, Miyazaki H. Chemokines and squamous cancer of the head and neck: targets for therapeutic intervention? Expert Rev Anticancer Ther 2014; 7:351-60. [PMID: 17338654 DOI: 10.1586/14737140.7.3.351] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The biological properties of squamous carcinoma cells are intimately regulated by a multitude of cytokines and growth factors; the most well studied of these include epidermal growth factor receptor agonists and members of the transforming growth factor-beta family. The recent explosion of research in the field of chemokine function as a mediator of tumor progression has led to the possibility that these small, immunomodulatory proteins also play key roles in squamous carcinogenesis and may, therefore, be potential targets for novel therapeutic approaches.
Collapse
MESH Headings
- Amino Acid Motifs
- Amino Acid Sequence
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Carcinoma, Squamous Cell/blood supply
- Carcinoma, Squamous Cell/drug therapy
- Carcinoma, Squamous Cell/physiopathology
- Cell Survival
- Cell Transformation, Neoplastic
- Chemokines/antagonists & inhibitors
- Chemokines/physiology
- Chemokines, CXC/antagonists & inhibitors
- Chemokines, CXC/physiology
- Disease Progression
- Drug Design
- ErbB Receptors/antagonists & inhibitors
- ErbB Receptors/physiology
- Head and Neck Neoplasms/blood supply
- Head and Neck Neoplasms/drug therapy
- Head and Neck Neoplasms/physiopathology
- Humans
- Molecular Sequence Data
- Neoplasm Invasiveness
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/physiology
- Neovascularization, Pathologic/drug therapy
- Neovascularization, Pathologic/physiopathology
- Receptors, Chemokine/drug effects
- Receptors, Chemokine/physiology
- Sequence Alignment
- Sequence Homology, Amino Acid
- Signal Transduction
- Transforming Growth Factor beta/antagonists & inhibitors
- Transforming Growth Factor beta/physiology
Collapse
Affiliation(s)
- W Andrew Yeudall
- Virginia Commonwealth University School of Dentistry, Philips Institute for Oral & Craniofacial Molecular Biology, Department of Biochemistry and Massey Cancer Center, Richmond, VA 23298, USA.
| | | |
Collapse
|
13
|
Abstract
Development of metastatic cancer is a complex series of events that includes genesis of tumor-related vascular and lymphatic systems, enhanced cellular motility, and the capacity to invade and survive at distant sites, as well as evasion of host defences. The wild-type p53 protein plays key roles in controlling these facets of tumor progression, and loss of normal p53 function can be sufficient to predispose tumor cells to gain metastatic properties. In contrast, dominant p53 mutants that have gained oncogenic functions can actively drive metastasis through a variety of mechanisms. This chapter aims to highlight these processes.
Collapse
Affiliation(s)
- W A Yeudall
- Department of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, 980566, Richmond, VA, 23298, USA,
| |
Collapse
|
14
|
Cousins E, Nicholas J. Molecular biology of human herpesvirus 8: novel functions and virus-host interactions implicated in viral pathogenesis and replication. Recent Results Cancer Res 2014; 193:227-68. [PMID: 24008302 PMCID: PMC4124616 DOI: 10.1007/978-3-642-38965-8_13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the second identified human gammaherpesvirus. Like its relative Epstein-Barr virus, HHV-8 is linked to B-cell tumors, specifically primary effusion lymphoma and multicentric Castleman's disease, in addition to endothelial-derived KS. HHV-8 is unusual in its possession of a plethora of "accessory" genes and encoded proteins in addition to the core, conserved herpesvirus and gammaherpesvirus genes that are necessary for basic biological functions of these viruses. The HHV-8 accessory proteins specify not only activities deducible from their cellular protein homologies but also novel, unsuspected activities that have revealed new mechanisms of virus-host interaction that serve virus replication or latency and may contribute to the development and progression of virus-associated neoplasia. These proteins include viral interleukin-6 (vIL-6), viral chemokines (vCCLs), viral G protein-coupled receptor (vGPCR), viral interferon regulatory factors (vIRFs), and viral antiapoptotic proteins homologous to FLICE (FADD-like IL-1β converting enzyme)-inhibitory protein (FLIP) and survivin. Other HHV-8 proteins, such as signaling membrane receptors encoded by open reading frames K1 and K15, also interact with host mechanisms in unique ways and have been implicated in viral pathogenesis. Additionally, a set of micro-RNAs encoded by HHV-8 appear to modulate expression of multiple host proteins to provide conditions conducive to virus persistence within the host and could also contribute to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.
Collapse
Affiliation(s)
- Emily Cousins
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, 1650 Orleans Street, Baltimore, MD, 21287, USA,
| | | |
Collapse
|
15
|
The Kaposi's sarcoma-associated herpesvirus (KSHV)-induced 5-lipoxygenase-leukotriene B4 cascade plays key roles in KSHV latency, monocyte recruitment, and lipogenesis. J Virol 2013; 88:2131-56. [PMID: 24335295 DOI: 10.1128/jvi.02786-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). KS lesions are characterized by endothelial cells with multiple copies of the latent KSHV episomal genome, lytic replication in a low percentage of infiltrating monocytes, and inflammatory cytokines plus growth factors. We demonstrated that KSHV utilizes inflammatory cyclooxygenase 2/prostaglandin E2 to establish and maintain latency (Sharma-Walia, N., A. G. Paul, V. Bottero, S. Sadagopan, M. V. Veettil, N. Kerur, and B. Chandran, PLoS Pathog 6:e1000777, 2010 [doi:10.1371/journal.ppat.1000777]). Here, we evaluated the role of 5-lipoxygenase (5LO) and its chemotactic metabolite leukotriene B4 (LTB4) in KSHV biology. Abundant staining of 5LO was detected in human KS tissue sections. We observed elevated levels of 5LO and high levels of secretion of LTB4 during primary KSHV infection of endothelial cells and in PEL B cells (BCBL-1 and BC-3 cells). Blocking the 5LO/LTB4 cascade inhibited viral latent ORF73, immunomodulatory K5, viral macrophage inflammatory protein 1 (MIP-1), and viral MIP-2 gene expression, without much effect on lytic switch ORF50, immediate early lytic K8, and viral interferon-regulatory factor 2 gene expression. 5LO inhibition significantly downregulated latent viral Cyclin and latency-associated nuclear antigen 2 levels in PEL cells. 5LO/LTB4 inhibition downregulated TH2-related cytokine secretion, elevated TH1-related cytokine secretion, and reduced human monocyte recruitment, adhesion, and transendothelial migration. 5LO/LTB4 inhibition reduced fatty acid synthase (FASN) promoter activity and its expression. Since FASN, a key enzyme required in lipogenesis, is important in KSHV latency, these findings collectively suggest that 5LO/LTB4 play important roles in KSHV biology and that effective inhibition of the 5LO/LTB4 pathway could potentially be used in treatment to control KS/PEL.
Collapse
|
16
|
Yamin R, Kaynan NS, Glasner A, Vitenshtein A, Tsukerman P, Bauman Y, Ophir Y, Elias S, Bar-On Y, Gur C, Mandelboim O. The viral KSHV chemokine vMIP-II inhibits the migration of Naive and activated human NK cells by antagonizing two distinct chemokine receptors. PLoS Pathog 2013; 9:e1003568. [PMID: 23966863 PMCID: PMC3744409 DOI: 10.1371/journal.ppat.1003568] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 07/05/2013] [Indexed: 12/14/2022] Open
Abstract
Natural killer (NK) cells are innate immune cells able to rapidly kill virus-infected and tumor cells. Two NK cell populations are found in the blood; the majority (90%) expresses the CD16 receptor and also express the CD56 protein in intermediate levels (CD56Dim CD16Pos) while the remaining 10% are CD16 negative and express CD56 in high levels (CD56Bright CD16Neg). NK cells also reside in some tissues and traffic to various infected organs through the usage of different chemokines and chemokine receptors. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human virus that has developed numerous sophisticated and versatile strategies to escape the attack of immune cells such as NK cells. Here, we investigate whether the KSHV derived cytokine (vIL-6) and chemokines (vMIP-I, vMIP-II, vMIP-III) affect NK cell activity. Using transwell migration assays, KSHV infected cells, as well as fusion and recombinant proteins, we show that out of the four cytokine/chemokines encoded by KSHV, vMIP-II is the only one that binds to the majority of NK cells, affecting their migration. We demonstrate that vMIP-II binds to two different receptors, CX3CR1 and CCR5, expressed by naïve CD56Dim CD16Pos NK cells and activated NK cells, respectively. Furthermore, we show that the binding of vMIP-II to CX3CR1 and CCR5 blocks the binding of the natural ligands of these receptors, Fractalkine (Fck) and RANTES, respectively. Finally, we show that vMIP-II inhibits the migration of naïve and activated NK cells towards Fck and RANTES. Thus, we present here a novel mechanism in which KSHV uses a unique protein that antagonizes the activity of two distinct chemokine receptors to inhibit the migration of naïve and activated NK cells. NK cells belong to the innate immune system, able to rapidly kill tumors and various pathogens. They reside in the blood and in various tissues and traffic to different infected organs through the usage of different chemokines and chemokine receptors. KSHV is a master of immune evasion, and around a quarter of the KSHV encoded genes are dedicated to interfere with immune cell recognition. Here, we investigate the role played by the KSHV derived cytokine and chemokines (vIL-6, vMIP-I, vMIP-II, vMIP-III) in modulating NK cell activity. We show that vMIP-II binds and inhibits the activity of two different receptors, CX3CR1 and CCR5, expressed by naïve NK cells and by activated NK cells, respectively. Thus, we demonstrate here a novel mechanism in which KSHV uses a unique protein that antagonizes the activity of two distinct chemokine receptors to inhibit the migration of naïve and activated NK cells.
Collapse
MESH Headings
- Anti-HIV Agents/pharmacology
- CCR5 Receptor Antagonists
- CX3C Chemokine Receptor 1
- Cell Movement/drug effects
- Cells, Cultured
- Chemokine CCL5/metabolism
- Chemokine CX3CL1/metabolism
- Chemokines/pharmacology
- Cytokines/genetics
- Cytokines/metabolism
- Herpesvirus 8, Human/chemistry
- Humans
- Immunoblotting
- Interleukin-6
- Killer Cells, Natural/cytology
- Killer Cells, Natural/drug effects
- Killer Cells, Natural/metabolism
- Polymerase Chain Reaction
- Receptors, CCR5/genetics
- Receptors, CCR5/metabolism
- Receptors, Chemokine/antagonists & inhibitors
- Receptors, Chemokine/genetics
- Receptors, Chemokine/metabolism
Collapse
Affiliation(s)
- Rachel Yamin
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Noa S. Kaynan
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Ariella Glasner
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Alon Vitenshtein
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Pinchas Tsukerman
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Yoav Bauman
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Yael Ophir
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Shlomo Elias
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Yotam Bar-On
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Chamutal Gur
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Ofer Mandelboim
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, Jerusalem, Israel
- * E-mail:
| |
Collapse
|
17
|
Paul AG, Chandran B, Sharma-Walia N. Cyclooxygenase-2-prostaglandin E2-eicosanoid receptor inflammatory axis: a key player in Kaposi's sarcoma-associated herpes virus associated malignancies. Transl Res 2013; 162:77-92. [PMID: 23567332 PMCID: PMC7185490 DOI: 10.1016/j.trsl.2013.03.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 02/13/2013] [Accepted: 03/15/2013] [Indexed: 12/28/2022]
Abstract
The role of cyclooxygenase-2 (COX-2), its lipid metabolite prostaglandin E2 (PGE2), and Eicosanoid (EP) receptors (EP; 1-4) underlying the proinflammatory mechanistic aspects of Burkitt's lymphoma, nasopharyngeal carcinoma, cervical cancer, prostate cancer, colon cancer, and Kaposi's sarcoma (KS) is an active area of investigation. The tumorigenic potential of COX-2 and PGE2 through EP receptors forms the mechanistic context underlying the chemotherapeutic potential of nonsteroidal anti-inflammatory drugs (NSAIDs). Although role of the COX-2 is described in several viral associated malignancies, the biological significance of the COX-2/PGE2/EP receptor inflammatory axis is extensively studied only in Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) associated malignancies such as KS, a multifocal endothelial cell tumor and primary effusion lymphoma (PEL), a B cell-proliferative disorder. The purpose of this review is to summarize the salient findings delineating the molecular mechanisms downstream of COX-2 involving PGE2 secretion and its autocrine and paracrine interactions with EP receptors (EP1-4), COX-2/PGE2/EP receptor signaling regulating KSHV pathogenesis and latency. KSHV infection induces COX-2, PGE2 secretion, and EP receptor activation. The resulting signal cascades modulate the expression of KSHV latency genes (latency associated nuclear antigen-1 [LANA-1] and viral-Fas (TNFRSF6)-associated via death domain like interferon converting enzyme-like- inhibitory protein [vFLIP]). vFLIP was also shown to be crucial for the maintenance of COX-2 activation. The mutually interdependent interactions between viral proteins (LANA-1/vFLIP) and COX-2/PGE2/EP receptors was shown to play key roles in the biological mechanisms involved in KS and PEL pathogenesis such as blockage of apoptosis, cell cycle regulation, transformation, proliferation, angiogenesis, adhesion, invasion, and immune-suppression. Understanding the COX-2/PGE2/EP axis is very important to develop new safer and specific therapeutic modalities for KS and PEL. In addition to COX-2 being a therapeutic target, EP receptors represent ideal targets for pharmacologic agents as PGE2 analogues and their blockers/antagonists possess antineoplastic activity, without the reported gastrointestinal and cardiovascular toxicity observed with few a NSAIDs.
Collapse
MESH Headings
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Antineoplastic Agents/pharmacology
- Cyclooxygenase 2/metabolism
- Dinoprostone/metabolism
- Gene Expression Regulation, Viral
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/pathogenicity
- Humans
- Lymphoma, Primary Effusion/drug therapy
- Lymphoma, Primary Effusion/metabolism
- Receptors, Eicosanoid/metabolism
- Sarcoma, Kaposi/drug therapy
- Sarcoma, Kaposi/metabolism
- Sarcoma, Kaposi/virology
- Signal Transduction
- Virus Latency/genetics
Collapse
Affiliation(s)
- Arun George Paul
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Ill
| | - Bala Chandran
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Ill
| | - Neelam Sharma-Walia
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Ill
| |
Collapse
|
18
|
Dai L, Bai L, Lu Y, Xu Z, Reiss K, Del Valle L, Kaleeba J, Toole BP, Parsons C, Qin Z. Emmprin and KSHV: new partners in viral cancer pathogenesis. Cancer Lett 2013; 337:161-6. [PMID: 23743354 PMCID: PMC3728473 DOI: 10.1016/j.canlet.2013.05.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/24/2013] [Accepted: 05/27/2013] [Indexed: 01/15/2023]
Abstract
Emmprin regulates pathogenic elements relevant to virus-associated cancer, including drug resistance and cell migration. Kaposi's sarcoma-associated herpesvirus (KSHV) regulates emmprin expression and downstream function. Targeting emmprin or its interacting proteins at the cell surface suppresses KSHV-induced pathogenesis in vitro.
Emmprin (CD147; basigin) is a multifunctional glycoprotein expressed at higher levels by cancer cells and stromal cells in the tumor microenvironment. Through direct effects within tumor cells and promotion of tumor–stroma interactions, emmprin participates in induction of tumor cell invasiveness, angiogenesis, metastasis and chemoresistance. Although its contribution to cancer progression has been widely studied, the role of emmprin in viral oncogenesis still remains largely unclear, and only a small body of available literature implicates emmprin-associated mechanisms in viral pathogenesis and tumorigenesis. We summarize these data in this review, focusing on the role of emmprin in pathogenesis associated with the Kaposi sarcoma-associated herpesvirus (KSHV), a common etiology for cancers arising in the setting of immune suppression. We also discuss future directions for mechanistic studies exploring roles for emmprin in viral cancer pathogenesis.
Collapse
Affiliation(s)
- Lu Dai
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Knowlton ER, Lepone LM, Li J, Rappocciolo G, Jenkins FJ, Rinaldo CR. Professional antigen presenting cells in human herpesvirus 8 infection. Front Immunol 2013; 3:427. [PMID: 23346088 PMCID: PMC3549500 DOI: 10.3389/fimmu.2012.00427] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 12/24/2012] [Indexed: 12/18/2022] Open
Abstract
Professional antigen presenting cells (APC), i.e., dendritic cells (DC), monocytes/macrophages, and B lymphocytes, are critically important in the recognition of an invading pathogen and presentation of antigens to the T cell-mediated arm of immunity. Human herpesvirus 8 (HHV-8) is one of the few human viruses that primarily targets these APC for infection, altering their cytokine profiles, manipulating their surface expression of MHC molecules, and altering their ability to activate HHV-8-specific T cells. This could be why T cell responses to HHV-8 antigens are not very robust. Of these APC, only B cells support complete, lytic HHV-8 infection. However, both complete and abortive virus replication cycles in APC could directly affect viral pathogenesis and progression to Kaposi's sarcoma (KS) and HHV-8-associated B cell cancers. In this review, we discuss the effects of HHV-8 infection on professional APC and their relationship to the development of KS and B cell lymphomas.
Collapse
Affiliation(s)
- Emilee R Knowlton
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh Pittsburgh, PA, USA
| | | | | | | | | | | |
Collapse
|
20
|
Kaposi's sarcoma-associated herpesvirus oncoprotein K13 protects against B cell receptor-induced growth arrest and apoptosis through NF-κB activation. J Virol 2012; 87:2242-52. [PMID: 23236068 DOI: 10.1128/jvi.01393-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has been linked to the development of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease (MCD). We have characterized the role of KSHV-encoded viral FLICE inhibitory protein (vFLIP) K13 in the modulation of anti-IgM-induced growth arrest and apoptosis in B cells. We demonstrate that K13 protects WEHI 231, an immature B-cell line, against anti-IgM-induced growth arrest and apoptosis. The protective effect of K13 was associated with the activation of the NF-κB pathway and was deficient in a mutant K13 with three alanine substitutions at positions 58 to 60 (K13-58AAA) and a structural homolog, vFLIP E8, both of which lack NF-κB activity. K13 upregulated the expression of NF-κB subunit RelB and blocked the anti-IgM-induced decline in c-Myc and rise in p27(Kip1) that have been associated with growth arrest and apoptosis. K13 also upregulated the expression of Mcl-1, an antiapoptotic member of the Bcl2 family. Finally, K13 protected the mature B-cell line Ramos against anti-IgM-induced apoptosis through NF-κB activation. Inhibition of anti-IgM-induced apoptosis by K13 may contribute to the development of KSHV-associated lymphoproliferative disorders.
Collapse
|
21
|
Croci DO, Salatino M, Rubinstein N, Cerliani JP, Cavallin LE, Leung HJ, Ouyang J, Ilarregui JM, Toscano MA, Domaica CI, Croci MC, Shipp MA, Mesri EA, Albini A, Rabinovich GA. Disrupting galectin-1 interactions with N-glycans suppresses hypoxia-driven angiogenesis and tumorigenesis in Kaposi's sarcoma. ACTA ACUST UNITED AC 2012; 209:1985-2000. [PMID: 23027923 PMCID: PMC3478924 DOI: 10.1084/jem.20111665] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Disrupting Gal-1 interactions with N-glycans prevents hypoxia-driven angiogenesis to suppress tumorigenesis of Kaposi’s sarcoma Kaposi’s sarcoma (KS), a multifocal vascular neoplasm linked to human herpesvirus-8 (HHV-8/KS-associated herpesvirus [KSHV]) infection, is the most common AIDS-associated malignancy. Clinical management of KS has proven to be challenging because of its prevalence in immunosuppressed patients and its unique vascular and inflammatory nature that is sustained by viral and host-derived paracrine-acting factors primarily released under hypoxic conditions. We show that interactions between the regulatory lectin galectin-1 (Gal-1) and specific target N-glycans link tumor hypoxia to neovascularization as part of the pathogenesis of KS. Expression of Gal-1 is found to be a hallmark of human KS but not other vascular pathologies and is directly induced by both KSHV and hypoxia. Interestingly, hypoxia induced Gal-1 through mechanisms that are independent of hypoxia-inducible factor (HIF) 1α and HIF-2α but involved reactive oxygen species–dependent activation of the transcription factor nuclear factor κB. Targeted disruption of Gal-1–N-glycan interactions eliminated hypoxia-driven angiogenesis and suppressed tumorigenesis in vivo. Therapeutic administration of a Gal-1–specific neutralizing mAb attenuated abnormal angiogenesis and promoted tumor regression in mice bearing established KS tumors. Given the active search for HIF-independent mechanisms that serve to couple tumor hypoxia to pathological angiogenesis, our findings provide novel opportunities not only for treating KS patients but also for understanding and managing a variety of solid tumors.
Collapse
Affiliation(s)
- Diego O Croci
- Laboratorio de Inmunopatología, Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Narayanan A, Kehn-Hall K, Senina S, Lundberg L, Van Duyne R, Guendel I, Das R, Baer A, Bethel L, Turell M, Hartman AL, Das B, Bailey C, Kashanchi F. Curcumin inhibits Rift Valley fever virus replication in human cells. J Biol Chem 2012; 287:33198-214. [PMID: 22847000 DOI: 10.1074/jbc.m112.356535] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Rift Valley fever virus (RVFV) is an arbovirus that is classified as a select agent, an emerging infectious virus, and an agricultural pathogen. Understanding RVFV-host interactions is imperative to the design of novel therapeutics. Here, we report that an infection by the MP-12 strain of RVFV induces phosphorylation of the p65 component of the NFκB cascade. We demonstrate that phosphorylation of p65 (serine 536) involves phosphorylation of IκBα and occurs through the classical NFκB cascade. A unique, low molecular weight complex of the IKK-β subunit can be observed in MP-12-infected cells, which we have labeled IKK-β2. The IKK-β2 complex retains kinase activity and phosphorylates an IκBα substrate. Inhibition of the IKK complex using inhibitors impairs viral replication, thus alluding to the requirement of an active IKK complex to the viral life cycle. Curcumin strongly down-regulates levels of extracellular infectious virus. Our data demonstrated that curcumin binds to and inhibits kinase activity of the IKK-β2 complex in infected cells. Curcumin partially exerts its inhibitory influence on RVFV replication by interfering with IKK-β2-mediated phosphorylation of the viral protein NSs and by altering the cell cycle of treated cells. Curcumin also demonstrated efficacy against ZH501, the fully virulent version of RVFV. Curcumin treatment down-regulated viral replication in the liver of infected animals. Our data point to the possibility that RVFV infection may result in the generation of novel versions of host components (such as IKK-β2) that, by virtue of altered protein interaction and function, qualify as unique therapeutic targets.
Collapse
Affiliation(s)
- Aarthi Narayanan
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Punj V, Matta H, Chaudhary PM. A computational profiling of changes in gene expression and transcription factors induced by vFLIP K13 in primary effusion lymphoma. PLoS One 2012; 7:e37498. [PMID: 22624040 PMCID: PMC3356309 DOI: 10.1371/journal.pone.0037498] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 04/23/2012] [Indexed: 01/08/2023] Open
Abstract
Infection with Kaposi's sarcoma associated herpesvirus (KSHV) has been linked to the development of primary effusion lymphoma (PEL), a rare lymphoproliferative disorder that is characterized by loss of expression of most B cell markers and effusions in the body cavities. This unique clinical presentation of PEL has been attributed to their distinctive plasmablastic gene expression profile that shows overexpression of genes involved in inflammation, adhesion and invasion. KSHV-encoded latent protein vFLIP K13 has been previously shown to promote the survival and proliferation of PEL cells. In this study, we employed gene array analysis to characterize the effect of K13 on global gene expression in PEL-derived BCBL1 cells, which express negligible K13 endogenously. We demonstrate that K13 upregulates the expression of a number of NF-κB responsive genes involved in cytokine signaling, cell death, adhesion, inflammation and immune response, including two NF-κB subunits involved in the alternate NF-κB pathway, RELB and NFKB2. In contrast, CD19, a B cell marker, was one of the genes downregulated by K13. A comparison with K13-induced genes in human vascular endothelial cells revealed that although there was a considerable overlap among the genes induced by K13 in the two cell types, chemokines genes were preferentially induced in HUVEC with few exceptions, such as RANTES/CCL5, which was induced in both cell types. Functional studies confirmed that K13 activated the RANTES/CCL5 promoter through the NF-κB pathway. Taken collectively, our results suggest that K13 may contribute to the unique gene expression profile, immunophenotype and clinical presentation that are characteristics of KSHV-associated PEL.
Collapse
Affiliation(s)
- Vasu Punj
- From Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California Keck School of Medicine, Los Angeles, California, United States of America
- Bioinformatics Core, Norris Comprehensive Cancer Center at USC Epigenome Center, University of Southern California Keck School of Medicine, Los Angeles, California, United States of America
| | - Hittu Matta
- From Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California Keck School of Medicine, Los Angeles, California, United States of America
| | - Preet M. Chaudhary
- From Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California Keck School of Medicine, Los Angeles, California, United States of America
- * E-mail:
| |
Collapse
|
24
|
Kaposi's sarcoma associated herpesvirus encoded viral FLICE inhibitory protein K13 activates NF-κB pathway independent of TRAF6, TAK1 and LUBAC. PLoS One 2012; 7:e36601. [PMID: 22590573 PMCID: PMC3348130 DOI: 10.1371/journal.pone.0036601] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/11/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Kaposi's sarcoma associated herpesvirus encoded viral FLICE inhibitory protein (vFLIP) K13 activates the NF-κB pathway by binding to the NEMO/IKKγ subunit of the IκB kinase (IKK) complex. However, it has remained enigmatic how K13-NEMO interaction results in the activation of the IKK complex. Recent studies have implicated TRAF6, TAK1 and linear ubiquitin chains assembled by a linear ubiquitin chain assembly complex (LUBAC) consisting of HOIL-1, HOIP and SHARPIN in IKK activation by proinflammatory cytokines. METHODOLOGY/PRINCIPAL FINDINGS Here we demonstrate that K13-induced NF-κB DNA binding and transcriptional activities are not impaired in cells derived from mice with targeted disruption of TRAF6, TAK1 and HOIL-1 genes and in cells derived from mice with chronic proliferative dermatitis (cpdm), which have mutation in the Sharpin gene (Sharpin(cpdm/cpdm)). Furthermore, reconstitution of NEMO-deficient murine embryonic fibroblast cells with NEMO mutants that are incapable of binding to linear ubiquitin chains supported K13-induced NF-κB activity. K13-induced NF-κB activity was not blocked by CYLD, a deubiquitylating enzyme that can cleave linear and Lys63-linked ubiquitin chains. On the other hand, NEMO was required for interaction of K13 with IKK1/IKKα and IKK2/IKKβ, which resulted in their activation by "T Loop" phosphorylation. CONCLUSIONS/SIGNIFICANCE Our results demonstrate that K13 activates the NF-κB pathway by binding to NEMO which results in the recruitment of IKK1/IKKα and IKK2/IKKβ and their subsequent activation by phosphorylation. Thus, K13 activates NF-κB via a mechanism distinct from that utilized by inflammatory cytokines. These results have important implications for the development of therapeutic agents targeting K13-induced NF-κB for the treatment of KSHV-associated malignancies.
Collapse
|
25
|
Uldrick TS, Wyvill KM, Kumar P, O'Mahony D, Bernstein W, Aleman K, Polizzotto MN, Steinberg SM, Pittaluga S, Marshall V, Whitby D, Little RF, Yarchoan R. Phase II study of bevacizumab in patients with HIV-associated Kaposi's sarcoma receiving antiretroviral therapy. J Clin Oncol 2012; 30:1476-83. [PMID: 22430271 PMCID: PMC3383119 DOI: 10.1200/jco.2011.39.6853] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 01/06/2012] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Alternatives to cytotoxic agents are desirable for patients with HIV-associated Kaposi's sarcoma (KS). Vascular endothelial growth factor-A (VEGF-A) contributes to KS pathogenesis. We evaluated the humanized anti-VEGF-A monoclonal antibody, bevacizumab, in patients with HIV-KS. PATIENTS AND METHODS Patients with HIV-KS who either experienced progression while receiving highly active antiretroviral therapy (HAART) for at least 1 month or did not regress despite HAART for at least 4 months were administered bevacizumab 15 mg/kg intravenously on days 1 and 8 and then every 3 weeks. The primary objective was assessment of antitumor activity using modified AIDS Clinical Trial Group (ACTG) criteria for HIV-KS. HIV-uninfected patients were also eligible and observed separately. RESULTS Seventeen HIV-infected patients were enrolled. Fourteen patients had been receiving effective HAART for at least 6 months (median, 1 year). Thirteen patients had advanced disease (ACTG T(1)), 13 patients had received prior chemotherapy for KS, and seven patients had CD4 count less than 200 cells/μL. Median number of cycles was 10 (range, 1 to 37 cycles); median follow-up was 8.3 months (range, 3 to 36 months). Of 16 assessable patients, best tumor responses observed were complete response (CR) in three patients (19%), partial response (PR) in two patients (12%), stable disease in nine patients (56%), and progressive disease in two patients (12%). Overall response rate (CR + PR) was 31% (95% CI, 11% to 58.7%). Four of five responders had received prior chemotherapy for KS. Over 202 cycles, grade 3 to 4 adverse events at least possibly attributed to therapy included hypertension (n = 7), neutropenia (n = 5), cellulitis (n = 3), and headache (n = 2). CONCLUSION Bevacizumab is tolerated in patients with HIV-KS and has activity in a subset of patients.
Collapse
MESH Headings
- Adult
- Aged
- Angiogenesis Inhibitors/administration & dosage
- Angiogenesis Inhibitors/adverse effects
- Angiogenesis Inhibitors/therapeutic use
- Anti-Retroviral Agents/therapeutic use
- Antibodies, Monoclonal, Humanized/administration & dosage
- Antibodies, Monoclonal, Humanized/adverse effects
- Antibodies, Monoclonal, Humanized/therapeutic use
- Antiretroviral Therapy, Highly Active
- Bevacizumab
- Cytokines/blood
- Disease-Free Survival
- Drug Administration Schedule
- Female
- HIV Infections/complications
- HIV Infections/diagnosis
- HIV Infections/drug therapy
- Humans
- Kaplan-Meier Estimate
- Male
- Maryland
- Middle Aged
- Sarcoma, Kaposi/blood
- Sarcoma, Kaposi/blood supply
- Sarcoma, Kaposi/drug therapy
- Sarcoma, Kaposi/virology
- Time Factors
- Treatment Outcome
- Vascular Endothelial Growth Factor A/antagonists & inhibitors
- Vascular Endothelial Growth Factor A/blood
- Young Adult
Collapse
Affiliation(s)
- Thomas S. Uldrick
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Kathleen M. Wyvill
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Pallavi Kumar
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Deirdre O'Mahony
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Wendy Bernstein
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Karen Aleman
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Mark N. Polizzotto
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Seth M. Steinberg
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Stefania Pittaluga
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Vickie Marshall
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Denise Whitby
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Richard F. Little
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| | - Robert Yarchoan
- Thomas S. Uldrick, Kathleen M. Wyvill, Pallavi Kumar, Deirdre O'Mahony, Wendy Bernstein, Karen Aleman, Mark N. Polizzotto, Seth M. Steinberg, Stefania Pittaluga, Richard F. Little, and Robert Yarchoan, Center for Cancer Research, National Cancer Institute (NCI), Bethesda; Vickie Marshall and Denise Whitby, SAIC-Frederick, NCI, Frederick, MD
| |
Collapse
|
26
|
Abstract
Kaposi's sarcoma herpesvirus (KSHV) latent oncoprotein viral FLICE (FADD-like interferon converting enzyme)-like inhibitory protein (v-FLIP) or K13, a potent activator of NF-κB, has well-established roles in KSHV latency and oncogenesis. KSHV-induced COX-2 represents a novel strategy employed by KSHV to promote latency and inflammation/angiogenesis/invasion. Here, we demonstrate that v-FLIP/K13 promotes tumorigenic effects via the induction of host protein COX-2 and its inflammatory metabolite PGE2 in an NF-κB-dependent manner. In addition to our previous studies demonstrating COX-2/PGE2's role in transcriptional regulation of KSHV latency promoter and latent gene expression, the current study adds to the complexity that though LANA-1 (latency associated nuclear antigen) is utilizing COX-2/PGE2 as critical factors for its transcriptional regulation, it is the v-FLIP/K13 gene in the KSHV latency cluster that maintains continuous COX-2/PGE2 levels in the infected cells. We demonstrate that COX-2 inhibition, via its chemical inhibitors (NS-398 or celecoxib), reduced v-FLIP/K13-mediated NF-κB induction, and extracellular matrix (ECM) interaction-mediated signaling, mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) levels, and subsequently downregulated detachment-induced apoptosis (anoikis) resistance. vFLIP expression mediated the secretion of cytokines, and spindle cell differentiation activated the phosphorylation of p38, RSK, FAK, Src, Akt and Rac1-GTPase. The COX-2 inhibition in v-FLIP/K13-HMVECs reduced inflammation and invasion/metastasis-related genes, along with reduced anchorage-independent colony formation via modulating ‘extrinsic' as well as ‘intrinsic' cell death pathways. COX-2 blockade in v-FLIP/K13-HMVEC cells drastically augmented cell death induced by removal of essential growth/survival factors secreted in the microenvironment. Transformed cells obtained from anchorage-independent colonies of COX-2 inhibitor-treated v-FLIP/K13-HMVEC cells expressed lower levels of endothelial–mesenchymal transition genes such as slug, snail and twist, and higher expression of the tumor-suppressor gene, E-cadherin. Taken together, our study provides strong evidences that FDA-approved COX-2 inhibitors have great potential in blocking tumorigenic events linked to KSHV's oncogenic protein v-FLIP/K13.
Collapse
|
27
|
Lee HR, Brulois K, Wong L, Jung JU. Modulation of Immune System by Kaposi's Sarcoma-Associated Herpesvirus: Lessons from Viral Evasion Strategies. Front Microbiol 2012; 3:44. [PMID: 22403573 PMCID: PMC3293256 DOI: 10.3389/fmicb.2012.00044] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Accepted: 01/27/2012] [Indexed: 12/14/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), a member of the herpesvirus family, has evolved to establish a long-term, latent infection of cells such that while they carry the viral genome gene expression is highly restricted. Latency is a state of cryptic viral infection associated with genomic persistence in their host and this hallmark of KSHV infection leads to several clinical-epidemiological diseases such as KS, a plasmablastic variant of multicentric Castleman's disease, and primary effusion lymphoma upon immune suppression of infected hosts. In order to sustain efficient life-long persistency as well as their life cycle, KSHV dedicates a large portion of its genome to encode immunomodulatory proteins that antagonize its host's immune system. In this review, we will describe our current knowledge of the immune evasion strategies employed by KSHV at distinct stages of its viral life cycle to control the host's immune system.
Collapse
Affiliation(s)
- Hye-Ra Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | | | | | | |
Collapse
|
28
|
Tang Q, Qin D, Lv Z, Zhu X, Ma X, Yan Q, Zeng Y, Guo Y, Feng N, Lu C. Herpes simplex virus type 2 triggers reactivation of Kaposi's sarcoma-associated herpesvirus from latency and collaborates with HIV-1 Tat. PLoS One 2012; 7:e31652. [PMID: 22347501 PMCID: PMC3276581 DOI: 10.1371/journal.pone.0031652] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 01/16/2012] [Indexed: 01/23/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) infection was necessary but not sufficient for Kaposi's sarcoma (KS) development without other cofactors. Previously, we identified that both human immunodeficiency type 1 (HIV-1) Tat and herpes simplex virus 1 (HSV-1) were important cofactors reactivating KSHV from latency. Here, we further investigated the potential of herpes simplex virus 2 (HSV-2) to influence KSHV replication and examined the role of Tat in this procedure. We demonstrated that HSV-2 was a potentially important factor in the pathogenesis of KS, as determined by production of lytic phase mRNA transcripts, viral proteins and infectious viral particles in BCBL-1 cells. These results were further confirmed by an RNA interference experiment using small interfering RNA targeting KSHV Rta and a luciferase reporter assay testing Rta promoter-driven luciferase activity. Mechanistic studies showed that HSV-2 infection activated nuclear factor-kappa B (NF-κB) signaling pathway. Inhibition of NF-κB pathway enhanced HSV-2-mediated KSHV activation, whereas activation of NF-κB pathway suppressed KSHV replication in HSV-2-infected BCBL-1 cells. Additionally, ectopic expression of Tat enhanced HSV-2-induced KSHV replication. These novel findings suggest a role of HSV-2 in the pathogenesis of KS and provide the first laboratory evidence that Tat may participate HSV-2-mediated KSHV activation, implying the complicated pathogenesis of acquired immunodeficiency syndrome (AIDS)-related KS (AIDS-KS) patients.
Collapse
Affiliation(s)
- Qiao Tang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People's Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Clinical Laboratory, the Affiliated Nanjing First Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Di Qin
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Zhigang Lv
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Clinical Laboratory, Jiangsu Province Official Hospital, Nanjing, People's Republic of China
| | - Xiaolei Zhu
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xinting Ma
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qin Yan
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yi Zeng
- Department of Microbiology and Immunology, Youjiang Medical College for Nationalities, Bose, People's Republic of China
| | - Yuanyuan Guo
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Ninghan Feng
- Department of Urology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Chun Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People's Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
- * E-mail:
| |
Collapse
|
29
|
Everly D, Sharma-Walia N, Sadagopan S, Chandran B. Herpesviruses and Cancer. CANCER ASSOCIATED VIRUSES 2012:133-167. [DOI: 10.1007/978-1-4614-0016-5_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
|
30
|
Qazi BS, Tang K, Qazi A. Recent advances in underlying pathologies provide insight into interleukin-8 expression-mediated inflammation and angiogenesis. Int J Inflam 2011; 2011:908468. [PMID: 22235381 PMCID: PMC3253461 DOI: 10.4061/2011/908468] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 08/15/2011] [Accepted: 09/06/2011] [Indexed: 12/24/2022] Open
Abstract
Interleukin-8 has long been recognized to have anti-inflammatory activity, which has been established in various models of infection, inflammation, and cancer. Several cell types express the receptor for the cytokine IL-8 and upon its recognition produce molecules that are active both locally and systemically. Many different types of cells, in particular monocytes, neutrophils, epithelial, fibroblast, endothelial, mesothelial, and tumor cells, secrete IL-8. Increased expression of IL-8 and/or its receptors has been characterized in many chronic inflammatory conditions, including psoriasis, ARDS, COPD, and RA as well as many cancers, and its upregulation often correlates with disease activity. IL-8 constitutes the CXC class of chemokines, a potent chemoattractant and activator of neutrophils and other immune cells. It is a proangiogenic cytokine that is overexpressed in many human cancers. Therefore, inhibiting the effects of IL-8 signaling may be a significant therapeutic intervention.
Collapse
Affiliation(s)
- Basit Saleem Qazi
- Department of Orthopedic Surgery Spine Unit, First Affiliated Hospital of Dalian Medical University, 222 Zhongshan Road, Dalian, Liaoning 116011, China
| | | | | |
Collapse
|
31
|
Dai L, Bratoeva M, Toole BP, Qin Z, Parsons C. KSHV activation of VEGF secretion and invasion for endothelial cells is mediated through viral upregulation of emmprin-induced signal transduction. Int J Cancer 2011; 131:834-43. [PMID: 21918972 DOI: 10.1002/ijc.26428] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 08/29/2011] [Indexed: 11/08/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma (KS)-one of the most common tumors arising in the setting of immune suppression. Hallmarks of KS lesions include KSHV-infected cells of endothelial lineage and neoangiogenesis. Promigratory factors secreted in the tumor microenvironment by KSHV-infected cells promote endothelial cell (EC) migration and angiogenesis but existing therapies targeting these pathways are not widely utilized. This underscores the need for additional characterization of KSHV-host interactions relevant to EC pathogenesis to identify new therapeutic targets. We recently demonstrated that de novo infection by KSHV promotes EC invasion through upregulation of extracellular matrix metalloproteinase inducer (emmprin)-a multifunctional glycoprotein previously shown to induce tumor cell invasion and regional angiogenesis through upregulation of signal transduction and promotion of tumor-stroma interactions. This study was undertaken to determine whether EC invasion for KSHV-infected cells is induced through activation of specific signal transduction pathways and proangiogenic factors by emmprin. We found that KSHV activation of emmprin induces PI3K/Akt- and mitogen-activated protein kinase (MAPK)-dependent secretion of vascular endothelial growth factor (VEGF). Functionally, EC invasion following de novo infection is induced by emmprin-dependent PI3K/Akt and MAPK activation of VEGF. These findings support the potential utility of targeting emmprin for reducing VEGF secretion and EC migration in the KS microenvironment.
Collapse
Affiliation(s)
- Lu Dai
- Department of Regenerative Medicine & Cell Biology, Medical University of South Carolina, Charleston, SC, USA
| | | | | | | | | |
Collapse
|
32
|
Deletion of Kaposi's sarcoma-associated herpesvirus FLICE inhibitory protein, vFLIP, from the viral genome compromises the activation of STAT1-responsive cellular genes and spindle cell formation in endothelial cells. J Virol 2011; 85:10375-88. [PMID: 21795355 DOI: 10.1128/jvi.00226-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Kaposi's sarcoma herpesvirus (KSHV) Fas-associated death domain (FADD)-like interleukin-1 beta-converting enzyme (FLICE)-inhibitory protein, vFLIP, has antiapoptotic properties, is a potent activator of the NF-κB pathway, and induces the formation of endothelial spindle cells, the hallmark of Kaposi's sarcoma, when overexpressed in primary endothelial cells. We used a reverse genetics approach to study several functions of KSHV vFLIP in the context of the whole viral genome. Deletion of the gene encoding vFLIP from a KSHV genome cloned in a bacterial artificial chromosome (BAC) reduced the ability of the virus to persist and induce spindle cell formation in primary human umbilical vein endothelial cells (HUVECs). Only a few, mainly interferon (IFN)-responsive, genes were expressed in wild-type KSHV (KSHV-wt)-infected endothelial cells at levels higher than those in KSHV-ΔFLIP-infected endothelial cells, in contrast to the plethora of cellular genes induced by overexpressed vFLIP. In keeping with this observation, vFLIP induces the phosphorylation of STAT1 and STAT2 in an NF-κB-dependent manner in endothelial cells. vFLIP-dependent phosphorylation of STAT1 and STAT2 could be demonstrated after endothelial cells were infected with KSHV-wt, KSHV-ΔFLIP, and a KSHV-vFLIP revertant virus. These findings document the impact of KSHV vFLIP on the transcriptome of primary endothelial cells during viral persistence and highlight the role of vFLIP in the activation of STAT1/STAT2 and STAT-responsive cellular genes by KSHV.
Collapse
|
33
|
Boss IW, Renne R. Viral miRNAs and immune evasion. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:708-14. [PMID: 21757042 DOI: 10.1016/j.bbagrm.2011.06.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/27/2011] [Accepted: 06/28/2011] [Indexed: 11/29/2022]
Abstract
Viral miRNAs, ~22nt RNA molecules which post-transcriptionally regulate gene expression, are emerging as important tools in immune evasion. Viral infection is a complex process that requires immune evasion in order to establish persistent life-long infection of the host. During this process viruses express both protein-coding and non-coding genes, which help to modulate the cellular environment making it more favorable for infection. In the last decade, it was uncovered that DNA viruses express a diverse and abundant pool of small non-coding RNA molecules, called microRNAs (miRNAs). These virally encoded miRNAs are non-immunogenic and therefore are important tools used to evade both innate and adaptive immune responses. This review aims to summarize our current knowledge of herpesvirus- and polyomavirus-encoded miRNAs, and how they contribute to immune evasion by targeting viral and/or host cellular genes. This article is part of a Special Issue entitled: MicroRNAs in viral gene regulation.
Collapse
Affiliation(s)
- Isaac W Boss
- Department of Molecular Genetics and Microbiology, University of Florida, Gainsville, FL, USA.
| | | |
Collapse
|
34
|
Yang Y, Groshong JS, Matta H, Gopalakrishnan R, Yi H, Chaudhary PM. Constitutive NF-kappaB activation confers interleukin 6 (IL6) independence and resistance to dexamethasone and Janus kinase inhibitor INCB018424 in murine plasmacytoma cells. J Biol Chem 2011; 286:27988-97. [PMID: 21705340 DOI: 10.1074/jbc.m110.213363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Myeloma cells are dependent on IL6 for their survival and proliferation during the early stages of disease, and independence from IL6 is associated with disease progression. The role of the NF-κB pathway in the IL6-independent growth of myeloma cells has not been studied. Because human herpesvirus 8-encoded K13 selectively activates the NF-κB pathway, we have used it as a molecular tool to examine the ability of the NF-κB pathway to confer IL6 independence on murine plasmacytomas. We demonstrated that ectopic expression of K13, but not its NF-κB-defective mutant or a structural homolog, protected plasmacytomas against IL6 withdrawal-induced apoptosis and resulted in emergence of IL6-independent clones that could proliferate long-term in vitro in the absence of IL6 and form abdominal plasmacytomas with visceral involvement when injected intraperitoneally into syngeneic mice. These IL6-independent clones were dependent on NF-κB activity for their survival and proliferation but were resistant to dexamethasone and INCB018424, a selective Janus kinase 1/2 inhibitor. Ectopic expression of human T cell leukemia virus 1-encoded Tax protein, which resembles K13 in inducing constitutive NF-κB activation, similarly protected plasmacytoma cells against IL6 withdrawal-induced apoptosis. Although K13 is known to up-regulate IL6 gene expression, its protective effect was not due to induction of endogenous IL6 production but instead was associated with sustained expression of several antiapoptotic members of the Bcl2 family upon IL6 withdrawal. Collectively, these results demonstrate that NF-κB activation cannot only promote the emergence of IL6 independence during myeloma progression but can also confer resistance to dexamethasone and INCB018424.
Collapse
Affiliation(s)
- Yanqiang Yang
- Department of Medicine, Division of Hematology-Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA
| | | | | | | | | | | |
Collapse
|
35
|
Kaposi's sarcoma-associated herpesvirus infection of endothelial cells inhibits neutrophil recruitment through an interleukin-6-dependent mechanism: a new paradigm for viral immune evasion. J Virol 2011; 85:7321-32. [PMID: 21543487 DOI: 10.1128/jvi.00021-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), an endothelial cell (EC) neoplasm characterized by dysregulated angiogenesis and inflammation. KSHV infection of EC causes production of proinflammatory mediators, regarded as possible initiators of the substantial mononuclear leukocyte recruitment seen in KS. Conversely, KSHV immune evasion strategies exist, such as degradation of EC leukocyte adhesion receptors by viral proteins. Here, we report the effects of KSHV infection of primary EC on recruitment of flowing leukocytes. Infection did not initiate adhesion of any leukocyte subset per se. However, on cytokine-stimulated EC, KSHV specifically inhibited neutrophil, but not PBL or monocyte, transmigration, an observation consistent with the inflammatory cell profile found in KS lesions in vivo. This inhibition could be recapitulated on uninfected EC using supernatant from infected cultures. These supernatants contained elevated levels of human interleukin 6 (hIL-6), and both the KSHV- and the supernatant-induced inhibitions of neutrophil transmigration were abrogated in the presence of a hIL-6 neutralizing antibody. Furthermore, preconditioning of EC with hIL-6 mimicked the effect of KSHV. Using RNA interference (RNAi), we show that upregulation of suppressor of cytokine signaling 3 (SOCS3) was necessary for this effect of hIL-6. These studies reveal a novel paracrine mode of KSHV immune evasion, resulting in reduced recruitment of neutrophils, a cell type whose antiviral and antitumor roles are becoming increasingly appreciated. Moreover, the findings have implications for our understanding of the contribution of hIL-6 to the pathogenesis of other inflammatory disorders and tumors in which this cytokine is abundant.
Collapse
|
36
|
Amplification of the angiogenic signal through the activation of the TSC/mTOR/HIF axis by the KSHV vGPCR in Kaposi's sarcoma. PLoS One 2011; 6:e19103. [PMID: 21559457 PMCID: PMC3084756 DOI: 10.1371/journal.pone.0019103] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 03/16/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Kaposi's sarcoma (KS) is a vascular neoplasm characterized by the dysregulated expression of angiogenic and inflammatory cytokines. The driving force of the KS lesion, the KSHV-infected spindle cell, secretes elevated levels of vascular endothelial growth factor (VEGF), essential for KS development. However, the origin of VEGF in this tumor remains unclear. METHODOLOGY/PRINCIPAL FINDINGS Here we report that the KSHV G protein-coupled receptor (vGPCR) upregulates VEGF in KS through an intricate paracrine mechanism. The cytokines secreted by the few vGPCR-expressing tumor cells activate in neighboring cells multiple pathways (including AKT, ERK, p38 and IKKβ) that, in turn, converge on TSC1/2, promoting mTOR activation, HIF upregulation, and VEGF secretion. Conditioned media from vGPCR-expressing cells lead to an mTOR-dependent increase in HIF-1α and HIF-2α protein levels and VEGF upregulation. In a mouse allograft model for KS, specific inhibition of the paracrine activation of mTOR in non-vGPCR-expressing cells was sufficient to inhibit HIF upregulation in these cells, and abolished the ability of the vGPCR-expressing cells to promote tumor formation in vivo. Similarly, pharmacologic inhibition of HIF in this model blocked VEGF secretion and also lead to tumor regression. CONCLUSIONS/SIGNIFICANCE Our findings provide a compelling explanation for how the few tumor cells expressing vGPCR can contribute to the dramatic amplification of VEGF secretion in KS, and further provide a molecular mechanism for how cytokine dysregulation in KS fuels angiogenesis and tumor development. These data further suggest that activation of HIF by vGPCR may be a vulnerable target for the treatment of patients with KS.
Collapse
|
37
|
Matta H, Gopalakrishnan R, Punj V, Yi H, Suo Y, Chaudhary PM. A20 is induced by Kaposi sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 and blocks K13-induced nuclear factor-kappaB in a negative feedback manner. J Biol Chem 2011; 286:21555-64. [PMID: 21531730 DOI: 10.1074/jbc.m111.224048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of A20, a negative regulator of the NF-κB pathway, is frequently lost in several subtypes of Hodgkin and non-Hodgkin lymphoma. We report that A20 is expressed in Kaposi sarcoma-associated herpesvirus (KSHV)-infected primary effusion lymphoma cell lines, and its expression correlates closely with the expression of KSHV-encoded viral FLICE inhibitory protein K13. Ectopic expression of K13 induced A20 expression through NF-κB-mediated activation of A20 promoter. In turn, A20 blocked K13-induced NF-κB activity and up-regulation of proinflammatory cytokines CCL20 and IL-8 in a negative feedback fashion. Both the N-terminal deubiquitinating domain and the C-terminal zinc finger domain of A20 were involved in the inhibition of K13-induced NF-κB activity. Overexpression of A20 blocked K13-induced IκBα phosphorylation, NF-κB nuclear translocation, and cellular transformation. Consistent with the above, K13-induced IκBα phosphorylation and NF-κB transcriptional activation were enhanced in A20-deficient cells. Finally, A20 was found to interact physically with K13. Taken collectively, these results demonstrate that K13 is a key determinant of A20 expression in KSHV-infected cells, and A20 is a key negative regulator of K13-induced NF-κB activity. A20 might serve to control the inflammatory response to KSHV infection and protect KSHV-infected cells from apoptosis.
Collapse
Affiliation(s)
- Hittu Matta
- Jane Ann Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA
| | | | | | | | | | | |
Collapse
|
38
|
Regulation of Nm23-H1 and cell invasiveness by Kaposi's sarcoma-associated herpesvirus. J Virol 2011; 85:3596-606. [PMID: 21270158 DOI: 10.1128/jvi.01596-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), and the induction of an invasive cellular phenotype by KSHV following de novo infection is an important pathogenic component mediating tumor progression. The metastasis suppressor gene known as Nm23-H1 regulates tumor cell invasiveness, but whether KSHV itself regulates Nm23-H1 expression or subcellular localization, and whether this impacts cell invasiveness, has not been established. We found that KSHV increases expression and nuclear translocation of Nm23-H1 and that nuclear translocation of Nm23-H1 is regulated by the KSHV-encoded latency-associated nuclear antigen (LANA). Moreover, activation of the Ras-BRaf-MAPK (mitogen-activated protein kinase) signal transduction pathway, secretion of promigratory factors associated with this pathway, and cell invasiveness are dependent on KSHV regulation of Nm23-H1. Finally, induction of cytoplasmic overexpression of Nm23-H1 using a pharmacologic inhibitor of DNA methylation reduced KSHV-associated Ras-BRaf-MAPK pathway activation and suppressed KSHV-induced invasiveness. These data provide the first evidence for KSHV regulation of Nm23-H1 as a mechanism for KSHV induction of an invasive cellular phenotype and support the potential utility of targeting Nm23-H1 as a therapeutic approach for the treatment of KS.
Collapse
|
39
|
Lee HR, Lee S, Chaudhary PM, Gill P, Jung JU. Immune evasion by Kaposi's sarcoma-associated herpesvirus. Future Microbiol 2011; 5:1349-65. [PMID: 20860481 DOI: 10.2217/fmb.10.105] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Persistent viral infections are often associated with serious diseases, primarily by altering functions of the host immune system. The hallmark of Kaposi's sarcoma-associated herpesvirus (KSHV) infection is the establishment of a life-long persistent infection, which leads to several clinical, epidemiological and infectious diseases, such as Kaposi's sarcoma, a plasmablastic variant of multicentric Castleman's disease, and primary effusion lymphoma. To sustain an efficient life-long persistency, KSHV dedicates a large portion of its genome to encoding immunomodulatory proteins that antagonize the immune system of its host. In this article, we highlight the strategies KSHV uses to evade, escape and survive its battle against the host's immune system.
Collapse
Affiliation(s)
- Hye-Ra Lee
- Department of Molecular Microbiology & Immunology, University of Southern California, Los Angeles, CA 90033, USA.
| | | | | | | | | |
Collapse
|
40
|
Ahmad A, Groshong JS, Matta H, Schamus S, Punj V, Robinson LJ, Gill PS, Chaudhary PM. Kaposi sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 cooperates with Myc to promote lymphoma in mice. Cancer Biol Ther 2010; 10:1033-40. [PMID: 20818173 DOI: 10.4161/cbt.10.10.13291] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Primary effusion lymphoma (PEL) is an aggressive form of lymphoma that is associated with infection by Kaposi's sarcoma-associated herpesvirus (KSHV). One of the KSHV genes expressed in PEL cells is K13, a potent activator of the NF-κB pathway. K13 transgenic mice develop lymphomas, but after a long period of latency. A possible candidate that could cooperate with K13 in the development of PEL is c-Myc, whose expression is frequently dysregulated in PEL cells. To study the cooperative interaction between K13 and c-Myc in the pathogenesis of PEL, we crossed the K13 transgenic mice to iMyc(Eμ) transgenic mice that overexpress Myc. We report that lymphomas in the K13/iMyc(Eμ) double transgenic mice developed with shorter latency and were histologically distinct from those observed in the iMyc(Eμ) mice. Lymphomas in the K13/iMyc(Eμ) mice also lacked the expression of B- and T-cell markers, thus resembling the immunophenotype of PEL. The accelerated development of lymphoma in the K13/iMyc(Eμ) mice was associated with increased expression of K13, elevated NF-κB activity and decrease in apoptosis. Taken collectively, our results demonstrate a cooperative interaction between the NF-κB and Myc pathways in lymphomagenesis.
Collapse
Affiliation(s)
- Anwaar Ahmad
- Department of Medicine, University of Pittsburgh Cancer Institute, PA, USA
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Abstract
Kaposi's sarcoma (KS) is the most common cancer in HIV-infected untreated individuals. Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 (HHV8)) is the infectious cause of this neoplasm. In this Review we describe the epidemiology of KS and KSHV, and the insights into the remarkable mechanisms through which KSHV can induce KS that have been gained in the past 16 years. KSHV latent transcripts, such as latency-associated nuclear antigen (LANA), viral cyclin, viral FLIP and viral-encoded microRNAs, drive cell proliferation and prevent apoptosis, whereas KSHV lytic proteins, such as viral G protein-coupled receptor, K1 and virally encoded cytokines (viral interleukin-6 and viral chemokines) further contribute to the unique angioproliferative and inflammatory KS lesions through a mechanism called paracrine neoplasia.
Collapse
Affiliation(s)
- Enrique A Mesri
- Viral Oncology Program, Developmental Center for AIDS Research, and Department of Microbiology & Immunology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1,550 NW 10th Avenue, 109 Papanicolau Building, Miami, Florida 33136, USA.
| | | | | |
Collapse
|
42
|
Regulation of tumor necrosis factor-like weak inducer of apoptosis receptor protein (TWEAKR) expression by Kaposi's sarcoma-associated herpesvirus microRNA prevents TWEAK-induced apoptosis and inflammatory cytokine expression. J Virol 2010; 84:12139-51. [PMID: 20844036 DOI: 10.1128/jvi.00884-10] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is the causative agent of KS, the second most common AIDS-associated malignancy. KSHV expresses at least 18 different mature microRNAs (miRNAs) during latency. To identify cellular targets of KSHV miRNAs, we have analyzed a previously reported series of microarrays examining changes in cellular gene expression in the presence of KSHV miRNAs. Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) receptor (TWEAKR) was among the most consistently and robustly downregulated genes in the presence of KSHV miR-K12-10a (miR-K10a). Results from luciferase assays with reporter plasmids containing the 3' untranslated region (UTR) of TWEAKR suggest a targeting of TWEAKR by miR-K10a. The mutation of two predicted miR-K10a recognition sites within the 3' UTR of TWEAKR completely disrupts inhibition by miR-K10a. The expression of TWEAKR was downregulated in cells transfected with miR-K10a as well as during de novo KSHV infection. In a KS tumor-derived endothelial cell line, the downregulation of TWEAKR by miR-K10a resulted in reduced levels of TWEAK-induced caspase activation. In addition, cells transfected with miR-K10a showed less induction of apoptosis by annexin V staining and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assays. Finally, the downregulation of TWEAKR by miR-K10a in primary human endothelial cells resulted in a decrease in levels of expression of the proinflammatory cytokines interleukin-8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) in response to TWEAK. These results identify and validate an important cellular target of KSHV miRNAs. Furthermore, we demonstrate that a viral miRNA protects cells from apoptosis and suppresses a proinflammatory response, which may have significant implications in the complex context of KS lesions.
Collapse
|
43
|
Lee JY, Song JJ, Wooming A, Li X, Zhou H, Bottje WG, Kong BW. Transcriptional profiling of host gene expression in chicken embryo lung cells infected with laryngotracheitis virus. BMC Genomics 2010; 11:445. [PMID: 20663125 PMCID: PMC3091642 DOI: 10.1186/1471-2164-11-445] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Accepted: 07/21/2010] [Indexed: 01/04/2023] Open
Abstract
Background Infection by infectious laryngotracheitis virus (ILTV; gallid herpesvirus 1) causes acute respiratory diseases in chickens often with high mortality. To better understand host-ILTV interactions at the host transcriptional level, a microarray analysis was performed using 4 × 44 K Agilent chicken custom oligo microarrays. Results Microarrays were hybridized using the two color hybridization method with total RNA extracted from ILTV infected chicken embryo lung cells at 0, 1, 3, 5, and 7 days post infection (dpi). Results showed that 789 genes were differentially expressed in response to ILTV infection that include genes involved in the immune system (cytokines, chemokines, MHC, and NF-κB), cell cycle regulation (cyclin B2, CDK1, and CKI3), matrix metalloproteinases (MMPs) and cellular metabolism. Differential expression for 20 out of 789 genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of 789 differentially expressed genes revealed that 21 possible gene networks with intermolecular connections among 275 functionally identified genes. These 275 genes were classified into a number of functional groups that included cancer, genetic disorder, cellular growth and proliferation, and cell death. Conclusion The results of this study provide comprehensive knowledge on global gene expression, and biological functionalities of differentially expressed genes in chicken embryo lung cells in response to ILTV infections.
Collapse
Affiliation(s)
- Jeong Yoon Lee
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
West JA, Damania B. Kaposi's sarcoma-associated herpesvirus and innate immunity. Future Virol 2010; 5:185-196. [PMID: 20414330 DOI: 10.2217/fvl.10.5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the most recently discovered human herpesvirus, first isolated and identified from a Kaposi's sarcoma lesion in 1994. It is the etiological agent of Kaposi's sarcoma, a vascular lesion that is the predominant cancer among AIDS patients. KSHV is also the primary etiological agent of two B-cell lymphomas, primary effusion lymphoma and multicentric Castleman's disease. KSHV can exist in either a lytic phase, in which the viral DNA is actively replicated and virions are assembled, or in a latent phase, in which the viral genome is tethered to the host chromosome via protein-protein interactions. The lytic cycle generally occurs following primary infection, and within 72-96 h in most cell types, the virus enters the latent state. Reactivation from latency also leads to the intiation of the lytic cycle, which is necessary for virus propagation and survival in the host. Several KSHV proteins have been implicated in modulation of the host immune response to viral infection. This article summarizes recent discoveries involving the innate immune response to KSHV infection.
Collapse
Affiliation(s)
- John A West
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA and Department of Microbiology & Immunology, University of North Carolina, Chapel Hill Chapel Hill, NC 27599, USA
| | | |
Collapse
|
45
|
Cai Q, Verma SC, Lu J, Robertson ES. Molecular biology of Kaposi's sarcoma-associated herpesvirus and related oncogenesis. Adv Virus Res 2010; 78:87-142. [PMID: 21040832 PMCID: PMC3142360 DOI: 10.1016/b978-0-12-385032-4.00003-3] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Kaposi's Sarcoma-associated Herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is the most recently identified human tumor virus,and is associated with the pathogenesis of Kaposi's sarcoma and two lymphoproliferative disorders known to occur frequently in AIDS patients-primary effusion lymphoma and multicentric Castleman disease. In the 15 years since its discovery, intense studies have demonstrated an etiologic role for KSHV in the development of these malignancies. Here, we review the recent advances linked to understanding KSHV latent and lytic life cycle and the molecular mechanisms of KSHV-mediated oncogenesis in terms of transformation, cell signaling, cell growth and survival, angiogenesis, immune invasion and response to microenvironmental stress, and highlight the potential therapeutic targets for blocking KSHV tumorigenesis.
Collapse
Affiliation(s)
- Qiliang Cai
- Department of Microbiology, Abramson, Comprehensive Cancer Center, University of Pennsylvania Medical School, Philadelphia, Pennsylvania, USA
| | | | | | | |
Collapse
|
46
|
Punj V, Matta H, Schamus S, Tamewitz A, Anyang B, Chaudhary PM. Kaposi's sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 suppresses CXCR4 expression by upregulating miR-146a. Oncogene 2009; 29:1835-44. [PMID: 20023696 PMCID: PMC2845732 DOI: 10.1038/onc.2009.460] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV)-encoded viral FLICE inhibitory protein (vFLIP) K13 is a potent activator of the nuclear factor-kappaB (NF-kappaB) pathway. In this study, we show that infection with KHSV and ectopic expression of K13, but not its NF-kappaB-defective mutant, suppressed the expression of CXCR4. Suppression of CXCR4 by KSHV and K13 was associated with upregulated expression of miR-146a, a microRNA that is known to bind to the 3'-untranslated region of CXCR4 mRNA. Reporter studies identified two NF-kappaB sites in the promoter of miR-146a that were essential for its activation by K13. Accordingly, ectopic expression of K13, but not its NF-kappaB-defective mutant or other vFLIPs, strongly stimulated the miR-146a promoter activity, which could be blocked by specific genetic and pharmacological inhibitors of the NF-kappaB pathway. Finally, expression of CXCR4 was downregulated in clinical samples of KS and this was accompanied by an increased expression of miR-146a. Our results show that K13-induced NF-kappaB activity suppresses CXCR4 through upregulation of miR-146a. Downregulation of CXCR4 expression by K13 may contribute to KS development by promoting premature release of KSHV-infected endothelial progenitors into the circulation.
Collapse
Affiliation(s)
- V Punj
- Division of Hematology-Oncology, Department of Medicine, Hillman Cancer Center, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15213-1863, USA
| | | | | | | | | | | |
Collapse
|
47
|
Punj V, Matta H, Schamus S, Chaudhary PM. Integrated microarray and multiplex cytokine analyses of Kaposi's Sarcoma Associated Herpesvirus viral FLICE Inhibitory Protein K13 affected genes and cytokines in human blood vascular endothelial cells. BMC Med Genomics 2009; 2:50. [PMID: 19660139 PMCID: PMC2732924 DOI: 10.1186/1755-8794-2-50] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Accepted: 08/06/2009] [Indexed: 11/10/2022] Open
Abstract
Background Kaposi's sarcoma (KS) associated herpesvirus (KSHV) is the etiological agent of KS, a neoplasm characterized by proliferating spindle cells, extensive neoangiogenesis and a prominent inflammatory infiltrate. Infection of blood vascular endothelial cells with KSHV in vitro results in their spindle cell transformation, which is accompanied by increased expression of inflammatory chemokines and cytokines, and acquisition of lymphatic endothelial markers. Mimicking the effect of viral infection, ectopic expression of KSHV-encoded latent protein vFLIP K13 is sufficient to induce spindle transformation of vascular endothelial cells. However, the effect of K13 expression on global gene expression and induction of lymphatic endothelial markers in vascular endothelial cells has not been studied. Methods We used gene array analysis to determine change in global gene expression induced by K13 in human vascular endothelial cells (HUVECs). Results of microarray analysis were validated by quantitative RT-PCR, immunoblotting and a multiplex cytokine array. Results K13 affected the expression of several genes whose expression is known to be modulated by KSHV infection, including genes involved in immune and inflammatory responses, anti-apoptosis, stress response, and angiogenesis. The NF-κB pathway was the major signaling pathway affected by K13 expression, and genetic and pharmacological inhibitors of this pathway effectively blocked K13-induced transcriptional activation of the promoter of CXCL10, one of the chemokines whose expression was highly upregulated by K13. However, K13, failed to induce expression of lymphatic markers in blood vascular endothelial cells. Conclusion While K13 may account for change in the expression of a majority of genes observed following KSHV infection, it is not sufficient for inducing lymphatic reprogramming of blood vascular endothelial cells.
Collapse
Affiliation(s)
- Vasu Punj
- Department of Medicine, Division of Hematology-Oncology, Hillman Cancer Center, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA, USA.
| | | | | | | |
Collapse
|
48
|
Induction of CCL20 production by Kaposi sarcoma-associated herpesvirus: role of viral FLICE inhibitory protein K13-induced NF-kappaB activation. Blood 2009; 113:5660-8. [PMID: 19324905 DOI: 10.1182/blood-2008-10-186403] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8, is the etiologic agent of Kaposi sarcoma (KS), an angioproliferative lesion characterized by dramatic angiogenesis and inflammatory infiltration. In this study, we report that expression of chemokine CCL20, a potent chemoattractant of dendritic cells and lymphocytes, is strongly induced in cultured cells either by KSHV infection or on ectopic expression of viral FLICE inhibitory protein K13. This induction is caused by transcriptional activation of CCL20 gene, which is mediated by binding of the p65, p50, and c-Rel subunits of the transcription factor nuclear factor-kappaB (NF-kappaB) to an atypical NF-kappaB-binding site present in the CCL20 gene promoter. The CCL20 gene induction is defective in K13 mutants that lack NF-kappaB activity, and can be blocked by specific genetic and pharmacologic inhibitors of the NF-kappaB pathway. CCR6, the specific receptor for CCL20, is also induced in cultured cells either by KSHV infection or on K13 expression. Finally, expression of CCL20 and CCR6 is increased in clinical samples of KS. These results suggest that KSHV and K13-mediated induction of CCL20 and CCR6 may contribute to the recruitment of dendritic cells and lymphocytes into the KS lesions, and to tumor growth and metastases.
Collapse
|
49
|
NF-kappaB serves as a cellular sensor of Kaposi's sarcoma-associated herpesvirus latency and negatively regulates K-Rta by antagonizing the RBP-Jkappa coactivator. J Virol 2009; 83:4435-46. [PMID: 19244329 DOI: 10.1128/jvi.01999-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Successful viral replication is dependent on a conducive cellular environment; thus, viruses must be sensitive to the state of their host cells. We examined the idea that an interplay between viral and cellular regulatory factors determines the switch from Kaposi's sarcoma-associated herpesvirus (KSHV) latency to lytic replication. The immediate-early gene product K-Rta is the first viral protein expressed and an essential factor in reactivation; accordingly, this viral protein is in a key position to serve as a viral sensor of cellular physiology. Our approach aimed to define a host transcription factor, i.e., host sensor, which modulates K-Rta activity on viral promoters. To this end, we developed a panel of reporter plasmids containing all 83 putative viral promoters for a comprehensive survey of the response to both K-Rta and cellular transcription factors. Interestingly, members of the NF-kappaB family were shown to be strong negative regulators of K-Rta transactivation for all but two viral promoters (Ori-RNA and K12). Recruitment of K-Rta to the ORF57 and K-bZIP promoters, but not the K12 promoter, was significantly impaired when NF-kappaB expression was induced. Many K-Rta-responsive promoters modulated by NF-kappaB contain the sequence of the RBP-Jkappa binding site, a major coactivator which anchors K-Rta to target promoters via consensus motifs which overlap with that of NF-kappaB. Gel shift assays demonstrated that NF-kappaB inhibits the binding of RBP-Jkappa and forms a complex with RBP-Jkappa. Our results support a model in which a balance between K-Rta/RBP-Jkappa and NF-kappaB activities determines KSHV reactivation. An important feature of this model is that the interplay between RBP-Jkappa and NF-kappaB on viral promoters controls viral gene expression mediated by K-Rta.
Collapse
|
50
|
A systems biology approach to identify the combination effects of human herpesvirus 8 genes on NF-kappaB activation. J Virol 2009; 83:2563-74. [PMID: 19129458 DOI: 10.1128/jvi.01512-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Human herpesvirus 8 (HHV-8) is the etiologic agent of Kaposi's sarcoma and primary effusion lymphoma. Activation of the cellular transcription factor nuclear factor-kappa B (NF-kappaB) is essential for latent persistence of HHV-8, survival of HHV-8-infected cells, and disease progression. We used reverse-transfected cell microarrays (RTCM) as an unbiased systems biology approach to systematically analyze the effects of HHV-8 genes on the NF-kappaB signaling pathway. All HHV-8 genes individually (n = 86) and, additionally, all K and latent genes in pairwise combinations (n = 231) were investigated. Statistical analyses of more than 14,000 transfections identified ORF75 as a novel and confirmed K13 as a known HHV-8 activator of NF-kappaB. K13 and ORF75 showed cooperative NF-kappaB activation. Small interfering RNA-mediated knockdown of ORF75 expression demonstrated that this gene contributes significantly to NF-kappaB activation in HHV-8-infected cells. Furthermore, our approach confirmed K10.5 as an NF-kappaB inhibitor and newly identified K1 as an inhibitor of both K13- and ORF75-mediated NF-kappaB activation. All results obtained with RTCM were confirmed with classical transfection experiments. Our work describes the first successful application of RTCM for the systematic analysis of pathofunctions of genes of an infectious agent. With this approach, ORF75 and K1 were identified as novel HHV-8 regulatory molecules on the NF-kappaB signal transduction pathway. The genes identified may be involved in fine-tuning of the balance between latency and lytic replication, since this depends critically on the state of NF-kappaB activity.
Collapse
|