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Chen L, Ding L, Wang X, Huang Y, Gao SJ. Activation of glucocorticoid receptor signaling inhibits KSHV-induced inflammation and tumorigenesis. mBio 2024; 15:e0301123. [PMID: 38117084 PMCID: PMC10790708 DOI: 10.1128/mbio.03011-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Kaposi's sarcoma (KS) is the most common cancer in HIV-infected patients caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Hyperinflammation is the hallmark of KS. In this study, we have shown that KSHV mediates hyperinflammation by inducing IL-1α and suppressing IL-1Ra. Mechanistically, KSHV miRNAs and vFLIP induce hyperinflammation by activating the NF-κB pathway. A common anti-inflammatory agent dexamethasone blocks KSHV-induced hyperinflammation and tumorigenesis by activating glucocorticoid receptor signaling to suppress IL-1α and induce IL-1Ra. This work has identified IL-1-mediated inflammation as a potential therapeutic target and dexamethasone as a potential therapeutic agent for KSHV-induced malignancies.
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Affiliation(s)
- Luping Chen
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Ling Ding
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Xian Wang
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Yufei Huang
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shou-Jiang Gao
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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2
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Chen L, Ding L, Wang X, Huang Y, Gao SJ. Activation of glucocorticoid receptor signaling inhibits KSHV-induced inflammation and tumorigenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.10.566578. [PMID: 38014281 PMCID: PMC10680621 DOI: 10.1101/2023.11.10.566578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Hyperinflammation is the hallmark of Kaposi's sarcoma (KS), the most common cancer in AIDS patients caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection. However, the role and mechanism of induction of inflammation in KS remain unclear. In a screening for inhibitors of KSHV-induced oncogenesis, over half of the identified candidates were anti-inflammatory agents including dexamethasone functions by activating glucocorticoid receptor (GR) signaling. Here, we examined the mechanism mediating KSHV-induced inflammation. We found that numerous inflammatory pathways were activated in KSHV-transformed cells. Particularly, interleukin-1 alpha (IL-1α) and IL-1 receptor antagonist (IL-1Ra) from the IL-1 family were the most induced and suppressed cytokines, respectively. We found that KSHV miRNAs mediated IL-1α induction while both miRNAs and vFLIP mediated IL-1Ra suppression. Furthermore, GR signaling was inhibited in KSHV-transformed cells, which was mediated by vFLIP and vCyclin. Dexamethasone treatment activated GR signaling, and inhibited cell proliferation and colony formation in soft agar of KSHV-transformed cells but had a minimal effect on matched primary cells. Consequently, dexamethasone suppressed the initiation and growth of KSHV-induced tumors in mice. Mechanistically, dexamethasone suppressed IL-1α but induced IL-1Ra expression. Treatment with recombinant IL-1α protein rescued the inhibitory effect of dexamethasone while overexpression of IL-1Ra caused a weak growth inhibition of KSHV-transformed cells. Furthermore, dexamethasone induced IκBα expression resulting in inhibition of NF-κB pathway and IL-1α expression. These results reveal an important role of IL-1 pathway in KSHV-induced inflammation and oncogenesis, which can be inhibited by dexamethasone-activated GR signaling, and identify IL-1-mediated inflammation as a potential therapeutic target for KSHV-induced malignancies.
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Affiliation(s)
- Luping Chen
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Ling Ding
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Xian Wang
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Yufei Huang
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shou-Jiang Gao
- Cancer Virology Program, University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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3
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Gao R, Li T, Tan B, Ramos da Silva S, Jung JU, Feng P, Gao SJ. FoxO1 Suppresses Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication and Controls Viral Latency. J Virol 2019; 93:JVI.01681-18. [PMID: 30404794 PMCID: PMC6340022 DOI: 10.1128/jvi.01681-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 10/31/2018] [Indexed: 02/05/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has latent and lytic replication phases, both of which contribute to the development of KSHV-induced malignancies. Among the numerous factors identified to regulate the KSHV life cycle, oxidative stress, caused by imbalanced clearing and production of reactive oxygen species (ROS), has been shown to robustly disrupt KSHV latency and induce viral lytic replication. In this study, we identified an important role of the antioxidant defense factor forkhead box protein O1 (FoxO1) in the KSHV life cycle. Either chemical inhibition of the FoxO1 function or knockdown of FoxO1 expression led to an increase in the intracellular ROS level that was subsequently sufficient to disrupt KSHV latency and induce viral lytic reactivation. On the other hand, treatment with N-acetyl-l-cysteine (NAC), an oxygen free radical scavenger, led to a reduction in the FoxO1 inhibition-induced ROS level and, ultimately, the attenuation of KSHV lytic reactivation. These findings reveal that FoxO1 plays a critical role in keeping KSHV latency in check by maintaining the intracellular redox balance.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with several cancers, including Kaposi's sarcoma (KS). Both the KSHV latent and lytic replication phases are important for the development of KS. Identification of factors regulating the KSHV latent phase-to-lytic phase switch can provide insights into the pathogenesis of KSHV-induced malignancies. In this study, we show that the antioxidant defense factor forkhead box protein O1 (FoxO1) maintains KSHV latency by suppressing viral lytic replication. Inhibition of FoxO1 disrupts KSHV latency and induces viral lytic replication by increasing the intracellular ROS level. Significantly, treatment with an oxygen free radical scavenger, N-acetyl-l-cysteine (NAC), attenuated the FoxO1 inhibition-induced intracellular ROS level and KSHV lytic replication. Our works reveal a critical role of FoxO1 in suppressing KSHV lytic replication, which could be targeted for antiviral therapy.
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Affiliation(s)
- Ruoyun Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Tingting Li
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Brandon Tan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Suzane Ramos da Silva
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Pinghui Feng
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, Guangdong, China
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4
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Bergson S, Itzhak I, Wasserman T, Gelgor A, Kalt I, Sarid R. The Kaposi's-sarcoma-associated herpesvirus orf35 gene product is required for efficient lytic virus reactivation. Virology 2016; 499:91-98. [PMID: 27639575 DOI: 10.1016/j.virol.2016.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/07/2016] [Accepted: 09/08/2016] [Indexed: 11/30/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is implicated in the etiology of several human malignancies. KSHV open reading frame (orf) 35 encodes a conserved gammaherpesvirus protein with an, as yet, unknown function. Employing the bacterial artificial chromosome (BAC) system, we generated a recombinant viral clone that fails to express ORF35 (BAC16-ORF35-stop) but preserves intact adjacent and overlapping reading frames. Using this construct, we studied the role of this previously uncharacterized gene product during lytic reactivation of KSHV. Upon lytic reactivation, the ORF35-stop recombinant virus displayed significantly reduced lytic viral gene expression, viral DNA replication, and progeny virus production as compared to control wild-type virus. Exogenous expression of ORF35-Flag reversed the effects of ORF35 deficiency. These results demonstrate that ORF35 is important for efficient lytic virus reactivation.
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Affiliation(s)
- Shir Bergson
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Inbal Itzhak
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Talya Wasserman
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Anastasia Gelgor
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Inna Kalt
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Ronit Sarid
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan 5290002, Israel.
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5
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Viral Bcl-2 Encoded by the Kaposi's Sarcoma-Associated Herpesvirus Is Vital for Virus Reactivation. J Virol 2015; 89:5298-307. [PMID: 25740992 DOI: 10.1128/jvi.00098-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 02/26/2015] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED The Kaposi's sarcoma-associated herpesvirus (KSHV) open reading frame 16 (orf16) encodes a viral Bcl-2 (vBcl-2) protein which shares sequence and functional homology with the Bcl-2 family. Like its cellular homologs, vBcl-2 protects various cell types from apoptosis and can also negatively regulate autophagy. vBcl-2 is transcribed during lytic infection; however, its exact function has not been determined to date. By using bacterial artificial chromosome 16 (BAC16) clone carrying the full-length KSHV genome, we have generated recombinant KSHV mutants that fail to express vBcl-2 or express mCherry-tagged vBcl-2. We show that the vBcl-2 protein is expressed at relatively low levels during lytic induction and that a lack of vBcl-2 largely reduces the efficiency of KSHV reactivation in terms of lytic gene expression, viral DNA replication, and production of infectious particles. In contrast, the establishment of latency was not affected by the absence of vBcl-2. Our findings suggest an important role for vBcl-2 during initial phases of lytic reactivation and/or during subsequent viral propagation. Given the known functions of vBcl-2 in regulating apoptosis and autophagy, which involve its direct interaction with cellular proteins and thus require high levels of protein expression, it appears that vBcl-2 may have additional regulatory functions that do not depend on high levels of protein expression. IMPORTANCE The present study shows for the first time the expression of endogenous vBcl-2 protein in KSHV-infected cell lines and demonstrates the importance of vBcl-2 during the initial phases of lytic reactivation and/or during its subsequent propagation. It is suggested that vBcl-2 has additional regulatory functions beyond apoptosis and autophagy repression that do not depend on high levels of protein expression.
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6
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Fluorescent tagging and cellular distribution of the Kaposi's sarcoma-associated herpesvirus ORF45 tegument protein. J Virol 2014; 88:12839-52. [PMID: 25165104 DOI: 10.1128/jvi.01091-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is a cancer-related human virus, classified as a member of the Gammaherpesvirinae subfamily. We report here the construction of a dual fluorescent-tagged KSHV genome (BAC16-mCherry-ORF45), which constitutively expresses green fluorescent protein (GFP) and contains the tegument multifunctional ORF45 protein as a fusion protein with monomeric Cherry fluorescent protein (mCherry). We confirmed that this virus is properly expressed and correctly replicates and that the mCherry-ORF45 protein is incorporated into the virions. Using this labeled virus, we describe the dynamics of mCherry-ORF45 expression and localization in newly infected cells as well as in latently infected cells undergoing lytic induction and show that mCherry can be used to monitor cells undergoing the lytic viral cycle. This virus is likely to enable future studies monitoring the dynamics of viral trafficking and tegumentation during viral ingress and egress. IMPORTANCE The present study describes the construction and characterization of a new recombinant KSHV genome BAC16 clone which expresses mCherry-tagged ORF45. This virus enables the tracking of cells undergoing lytic infection and can be used to address issues related to the trafficking and maturation pathways of KSHV virions.
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7
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Matteoli B, Broccolo F, Scaccino A, Cottoni F, Angeloni A, Faggioni A, Ceccherini-Nelli L. In vivo and in vitro evidence for an association between the route-specific transmission of HHV-8 and the virus genotype. J Med Virol 2012; 84:786-91. [PMID: 22431027 DOI: 10.1002/jmv.23246] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The study was performed to determine if there is an association between the genotype and transmission of HHV-8 types A and C. These HHV-8 subtypes are prevalent in the area of North of Sardinia, which is an island off west Italy's mainland that has a high HHV-8 seroprevalence (35%). Blood and saliva samples from 30 patients with classic Kaposi's sarcoma who were lifetime residents of North Sardinia were analyzed to identify the HHV-8 genotype and quantitate the viral load. Genotype A, especially A1 subtype, was found more frequently (9/30 patients) and had a significantly higher viral load in saliva compared to blood (P = 0.029), where type C was found more frequently but with a viral load lower than 10(3) copies/ml. To determine if there is a correlation between the viral genotype and cellular tropism, type A1 and C3 HHV-8 viral particles were obtained from cell lines BCBL1 and BC3 infected chronically with HHV-8 A1 and C3 genotypes respectively and used to infect HEK293 epithelial origin cells and PBMCs in vitro. The data indicate that the A1 HHV-8 genotype is tropic and replicates at higher levels in the epithelial cell lines.
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Affiliation(s)
- Barbara Matteoli
- Virology Unit, Pisa University Hospital (Azienda Ospedaliero-Universitaria Pisana), Pisa, Italy
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8
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Latini A, Bonadies A, Trento E, Bultrini S, Cota C, Solivetti FM, Ferraro C, Ardigò M, Amorosi B, Palamara G, Bucher S, Giuliani M, Cordiali-Fei P, Ensoli F, Di Carlo A. Effective treatment of Kaposi's sarcoma by electrochemotherapy and intravenous bleomycin administration. Dermatol Ther 2012; 25:214-8. [DOI: 10.1111/j.1529-8019.2012.01437.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Latini
- Division of Infective Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - A. Bonadies
- Division of Infective Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - E. Trento
- Clinical Pathology; San Gallicano Dermatology Institute; Rome; Italy
| | - S. Bultrini
- Clinical Pathology; San Gallicano Dermatology Institute; Rome; Italy
| | - C. Cota
- Dermatopathology; San Gallicano Dermatology Institute; Rome; Italy
| | | | - C. Ferraro
- Clinical Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - M. Ardigò
- Clinical Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - B. Amorosi
- Clinical Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - G. Palamara
- Division of Infective Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - S. Bucher
- Dermatologic Surgery; San Gallicano Dermatology Institute; Rome; Italy
| | - M. Giuliani
- Division of Infective Dermatology; San Gallicano Dermatology Institute; Rome; Italy
| | - P. Cordiali-Fei
- Clinical Pathology; San Gallicano Dermatology Institute; Rome; Italy
| | - F. Ensoli
- Clinical Pathology; San Gallicano Dermatology Institute; Rome; Italy
| | - A. Di Carlo
- Division of Infective Dermatology; San Gallicano Dermatology Institute; Rome; Italy
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9
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Dittmer DP, Richards KL, Damania B. Treatment of Kaposi sarcoma-associated herpesvirus-associated cancers. Front Microbiol 2012; 3:141. [PMID: 22529843 PMCID: PMC3328849 DOI: 10.3389/fmicb.2012.00141] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 03/25/2012] [Indexed: 11/13/2022] Open
Abstract
Kaposi sarcoma (KS) is the most frequent AIDS-defining cancer worldwide. KS-associated herpesvirus (KSHV) is the etiological agent of KS, and the virus is also associated with two lymphoproliferative diseases. Both KS and KSHV-associated lymphomas, are cancers of unique molecular composition. They represent a challenge for cancer treatment and an opportunity to identify new mechanisms of transformation. Here, we review the current clinical insights into KSHV-associated cancers and discuss scientific insights into the pathobiology of KS, primary effusion lymphoma, and multicentric Castleman's disease.
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Affiliation(s)
- Dirk P Dittmer
- Program in Global Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill Chapel Hill, NC, USA
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10
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Restricted Kaposi's sarcoma (KS) herpesvirus transcription in KS lesions from patients on successful antiretroviral therapy. mBio 2011; 2:e00138-11. [PMID: 22045987 PMCID: PMC3202757 DOI: 10.1128/mbio.00138-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Kaposi’s sarcoma (KS) is caused by Kaposi’s sarcoma-associated herpesvirus (KSHV; human herpesvirus 8). KS is an AIDS-defining cancer, and it is changing in the post-antiretroviral therapy (post-ART) era. In countries with ready access to ART, approximately one-third of KS cases present in patients with undetectable HIV loads and CD4 counts of ≥200 cells/µl. This is in contrast to pre-ART era KS, which was associated with systemic HIV replication and CD4 counts of ≤200 cells/µl. Using primary patient biopsy specimens, we identified a novel molecular signature that characterizes AIDS KS lesions that develop in HIV-suppressed patients on ART: KSHV transcription is limited in HIV-suppressed patients. With one exception, only the canonical viral latency mRNAs were detectable. In contrast, early AIDS KS lesions expressed many more viral mRNAs, including, for instance, the viral G protein-coupled receptor (vGPCR). This is the first genomewide study of Kaposi’s sarcoma-associated herpesvirus (KSHV) transcription in KS lesions in the post-antiretroviral (post-ART) era. It shows that the gene expression of KSHV is altered in patients on ART, and it provides clinical evidence for active AIDS (as characterized by high HIV load and low CD4 counts) being a potential modulator of KSHV transcription. This implies a novel mode of pathogenesis (tightly latent KS), which may inform KS cancer treatment options in the post-ART era.
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11
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Lu J, Verma SC, Cai Q, Robertson ES. The single RBP-Jkappa site within the LANA promoter is crucial for establishing Kaposi's sarcoma-associated herpesvirus latency during primary infection. J Virol 2011; 85:6148-61. [PMID: 21507979 PMCID: PMC3126528 DOI: 10.1128/jvi.02608-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 04/08/2011] [Indexed: 01/05/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV; or human herpesvirus 8 [HHV8]) is implicated in the pathogenesis of many human malignancies including Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). KSHV infection displays two alternative life cycles, referred to as the latent and lytic or productive cycle. Previously, we have reported that the replication and transcription activator (RTA), a major lytic cycle transactivator, contributes to the development of KSHV latency by inducing latency-associated nuclear antigen (LANA) expression during early stages of infection by targeting RBP-Jκ, the master regulator of the Notch signaling pathway. Here, we generated a bacterial artificial chromosome (BAC) KSHV recombinant virus with a deletion of the RBP-Jκ site within the LANA promoter to evaluate the function of the RBP-Jκ cognate site in establishing primary latent infection. The results showed that genetic disruption of the RBP-Jκ binding site within the KSHV LANA promoter led to enhanced expression of the KSHV-encoded immediate early RTA, resulting in an increase in lytic replication during primary infection of human peripheral blood mononuclear cells (PBMCs). This system provides a powerful tool for use in indentifying additional cellular and viral molecules involved in LANA-mediated latency maintenance during the early stages of KSHV infection.
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MESH Headings
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/metabolism
- Binding Sites
- Cell Line
- Chromosomes, Artificial, Bacterial
- Gene Expression Regulation, Viral
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/pathogenicity
- Herpesvirus 8, Human/physiology
- Humans
- Immediate-Early Proteins
- Immunoglobulin J Recombination Signal Sequence-Binding Protein/chemistry
- Immunoglobulin J Recombination Signal Sequence-Binding Protein/genetics
- Immunoglobulin J Recombination Signal Sequence-Binding Protein/metabolism
- Leukocytes, Mononuclear/virology
- Nuclear Proteins/chemistry
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Promoter Regions, Genetic/genetics
- Recombination, Genetic
- Trans-Activators
- Virus Activation
- Virus Latency/genetics
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Affiliation(s)
- Jie Lu
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, University of Pennsylvania, School of Medicine, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104
| | - Subhash C. Verma
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno, Nevada 89557
| | - Qiliang Cai
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, University of Pennsylvania, School of Medicine, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104
| | - Erle S. Robertson
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, University of Pennsylvania, School of Medicine, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104
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12
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Abstract
The life cycle of Kaposi's sarcoma-associated herpesvirus (KSHV) consists of latent and lytic replication phases. During latent infection, only a limited number of KSHV genes are expressed. However, this phase of replication is essential for persistent infection, evasion of host immune response, and induction of KSHV-related malignancies. KSHV reactivation from latency produces a wide range of viral products and infectious virions. The resulting de novo infection and viral lytic products modulate diverse cellular pathways and stromal microenvironment, which promote the development of Kaposi's sarcoma (KS). The mechanisms controlling KSHV latency and reactivation are complex, involving both viral and host factors, and are modulated by diverse environmental factors. Here, we review the cellular and molecular basis of KSHV latency and reactivation with a focus on the most recent advancements in the field.
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13
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LANA-1, Bcl-2, Mcl-1 and HIF-1alpha protein expression in HIV-associated Kaposi sarcoma. Virchows Arch 2009; 455:159-70. [PMID: 19484260 DOI: 10.1007/s00428-009-0791-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/02/2009] [Accepted: 05/10/2009] [Indexed: 10/20/2022]
Abstract
Human herpesvirus 8 (HHV8) is necessary for Kaposi sarcoma (KS) to develop, but whether the tissue viral load is a marker of KS progression is still unclear. Little is known about the level of expression of apoptosis-regulating proteins and of hypoxia-inducible factors (HIFs) in KS tumour cells relative to HHV8 expression. We therefore investigated the expression of the latency-associated nuclear antigen (LANA-1) of HHV8, Bcl-2, Mcl-1, Bax, Bcl-xL, caspase 3 and HIF-1alphain KS tissue specimens at different stages of the disease. The expression of these proteins was evaluated immunohistochemically using tissue microarrays (TMAs) in tissue specimens from 245 HIV-positive patients at different stages of the disease. Both LANA-1 and HIF-1alpha were expressed in KS biopsies taken at different stages, but their level increased throughout tumour progression. Additionally, the levels of Bcl-2 and Mcl-1 were higher in visceral KS lesions compared to levels observed in cutaneous and mucosal KS. This study demonstrates that late tumour stages of KS in tissues from HIV-positive patients are associated with high levels of LANA-1, HIF-1alpha and of the anti-apoptotic proteins, Bcl-2 and Mcl-1. Finally, the expression of these proteins can be potentially used as a tissue biomarker in defining patients with a higher risk of disease progression.
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14
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Johnston C, Orem J, Okuku F, Kalinaki M, Saracino M, Katongole-Mbidde E, Sande M, Ronald A, McAdam K, Huang ML, Drolette L, Selke S, Wald A, Corey L, Casper C. Impact of HIV infection and Kaposi sarcoma on human herpesvirus-8 mucosal replication and dissemination in Uganda. PLoS One 2009; 4:e4222. [PMID: 19156206 PMCID: PMC2625442 DOI: 10.1371/journal.pone.0004222] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 12/05/2008] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Kaposi sarcoma (KS) is the leading cause of cancer in Uganda and occurs in people with and without HIV. Human herpesvirus-8 (HHV-8) replication is important both in transmission of HHV-8 and progression to KS. We characterized the sites and frequency of HHV-8 detection in Ugandans with and without HIV and KS. METHODS Participants were enrolled into one of four groups on the basis of HIV and KS status (HIV negative/KS negative, HIV positive/KS negative, HIV negative/KS positive, and HIV positive/KS positive). Participants collected oral swabs daily and clinicians collected oral swabs, anogenital swabs, and plasma samples weekly over 4 weeks. HHV-8 DNA at each site was quantified by polymerase chain reaction (PCR). RESULTS 78 participants collected a total of 2063 orals swabs and 358 plasma samples. Of these, 428 (21%) oral swabs and 96 (27%) plasma samples had detectable HHV-8 DNA. HHV-8 was detected more frequently in both the oropharynx of persons with KS (24 (57%) of 42 persons with KS vs. 8 (22%) of 36 persons without, p = 0.002) and the peripheral blood (30 (71%) of 42 persons with KS vs. 8 (22%) of 36 persons without, p<0.001). In a multivariate model, HHV-8 viremia was more frequent among men (IRR = 3.3, 95% CI = 1.7-6.2, p<0.001), persons with KS (IRR = 3.9, 95% CI = 1.7-9.0, p = 0.001) and persons with HIV infection (IRR = 1.7, 95% CI = 1.0-2.7, p = 0.03). Importantly, oral HHV-8 detection predicted the subsequent HHV-8 viremia. HHV-8 viremia was significantly more common when HHV-8 DNA was detected from the oropharynx during the week prior than when oral HHV-8 was not detected (RR = 3.3, 95% CI = 1.8-5.9 p<0.001). Genital HHV-8 detection was rare (9 (3%) of 272 swabs). CONCLUSIONS HHV-8 detection is frequent in the oropharynx and peripheral blood of Ugandans with endemic and epidemic KS. Replication at these sites is highly correlated, and viremia is increased in men and those with HIV. The high incidence of HHV-8 replication at multiple anatomic sites may be an important factor leading to and sustaining the high prevalence of KS in Uganda.
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Affiliation(s)
- Christine Johnston
- Department of Medicine, University of Washington, Seattle, Washington, United States of America.
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Compston LI, Sarkobie F, Li C, Candotti D, Opare-Sem O, Allain JP. Multiplex real-time PCR for the detection and quantification of latent and persistent viral genomes in cellular or plasma blood fractions. J Virol Methods 2008; 151:47-54. [PMID: 18479760 DOI: 10.1016/j.jviromet.2008.03.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/11/2008] [Accepted: 03/17/2008] [Indexed: 01/12/2023]
Abstract
In common with latent viruses such as herpesviruses, parvovirus B19, HBV and GBV-C are contained successfully by the immune response and persist in the host. When immune control breaks down, reactivation of both latent and persistent viruses occurs. Two multiplex assays were developed (B19, HBV, HHV-8), (EBV, CMV, VZV) for blood screening, and tested on blood donor samples from Ghana to determine baseline prevalence of viraemia in immunocompetent persons. Single-virus real-time quantitative PCR (qPCR) assays were optimised for viral load determination of positive initial screening. The qPCR method utilised was absolute quantification with external standards. Multiplex and single-virus qPCR assays had similar sensitivity, except for the B19 assay in which sensitivity was 100-fold lower. Assays were optimised for reproducibility and repeatability, with R(2) of 0.9 being obtained for most assays. With the exception of B19 and CMV, assays had 100% detection limit ranging between 10(1) and 10(2) copies, IU or arbitrary units under single-virus and multiplex assay conditions. The prevalence of viraemia was 1.6% HBV (0.8% DNA+/HBsAg-, 0.8% DNA+/HBsAg+), 0.8% parvovirus B19, and 3.3% GBV-C viraemia in the plasma fraction. The prevalence of four herpesviruses was 1.0% HHV-8, 0.85% CMV, and 8.3% EBV, and no detectable VZV viraemia.
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Affiliation(s)
- Lara Isobel Compston
- Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, UK
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