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Lacunza E, Ahuja A, Coso OA, Abba M, Ramos JC, Cesarman E, Mesri EA, Naipauer J. Unveiling the role of KSHV-infected human mesenchymal stem cells in Kaposi's sarcoma initiation. J Med Virol 2024; 96:e29684. [PMID: 38773828 DOI: 10.1002/jmv.29684] [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: 01/04/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/24/2024]
Abstract
Kaposi's sarcoma (KS) may derive from Kaposi's sarcoma herpesvirus (KSHV)-infected human mesenchymal stem cells (hMSCs) that migrate to sites characterized by inflammation and angiogenesis, promoting the initiation of KS. By analyzing the RNA sequences of KSHV-infected primary hMSCs, we have identified specific cell subpopulations, mechanisms, and conditions involved in the initial stages of KSHV-induced transformation and reprogramming of hMSCs into KS progenitor cells. Under proangiogenic environmental conditions, KSHV can reprogram hMSCs to exhibit gene expression profiles more similar to KS tumors, activating cell cycle progression, cytokine signaling pathways, endothelial differentiation, and upregulating KSHV oncogenes indicating the involvement of KSHV infection in inducing the mesenchymal-to-endothelial (MEndT) transition of hMSCs. This finding underscores the significance of this condition in facilitating KSHV-induced proliferation and reprogramming of hMSCs towards MEndT and closer to KS gene expression profiles, providing further evidence of these cell subpopulations as precursors of KS cells that thrive in a proangiogenic environment.
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Affiliation(s)
- Ezequiel Lacunza
- Centro de Investigaciones Inmunologicas Basicas y Aplicadas, Facultad de Ciencias Medicas, Universidad Nacional de La Plata, La Plata, Argentina
- University of Miami-Centre for AIDS Research/Sylvester Cancer Comprehensive Center Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Anuj Ahuja
- Tumor Biology Program, Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research, Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Omar A Coso
- University of Miami-Centre for AIDS Research/Sylvester Cancer Comprehensive Center Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, Florida, USA
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martin Abba
- Centro de Investigaciones Inmunologicas Basicas y Aplicadas, Facultad de Ciencias Medicas, Universidad Nacional de La Plata, La Plata, Argentina
- University of Miami-Centre for AIDS Research/Sylvester Cancer Comprehensive Center Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Juan Carlos Ramos
- University of Miami-Centre for AIDS Research/Sylvester Cancer Comprehensive Center Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, Florida, USA
- Department of Medicine, Division of Hematology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida, USA
- Center for AIDS Research, University of Miami Miller School of Medicine, Miami, Florida, USA
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Enrique A Mesri
- University of Miami-Centre for AIDS Research/Sylvester Cancer Comprehensive Center Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, Florida, USA
- Tumor Biology Program, Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research, Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Julian Naipauer
- University of Miami-Centre for AIDS Research/Sylvester Cancer Comprehensive Center Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, Florida, USA
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
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Naipauer J, Mesri EA. The Kaposi's sarcoma progenitor enigma: KSHV-induced MEndT-EndMT axis. Trends Mol Med 2023; 29:188-200. [PMID: 36635149 PMCID: PMC9957928 DOI: 10.1016/j.molmed.2022.12.003] [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: 09/29/2022] [Revised: 12/02/2022] [Accepted: 12/13/2022] [Indexed: 01/11/2023]
Abstract
Endothelial-to-mesenchymal transition has been described in tumors as a source of mesenchymal stroma, while the reverse process has been proposed in tumor vasculogenesis and angiogenesis. A human oncogenic virus, Kaposi's sarcoma herpes virus (KSHV), can regulate both processes in order to transit through this transition 'boulevard' when infecting KS oncogenic progenitor cells. Endothelial or mesenchymal circulating progenitor cells can serve as KS oncogenic progenitors recruited by inflammatory cytokines because KSHV can reprogram one into the other through endothelial-to-mesenchymal and mesenchymal-to-endothelial transitions. Through these novel insights, the identity of the potential oncogenic progenitor of KS is revealed while gaining knowledge of the biology of the mesenchymal-endothelial differentiation axis and pointing to this axis as a therapeutic target in KS.
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Affiliation(s)
- Julian Naipauer
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina; Tumor Biology Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA; University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, USA; Miami Center for AIDS Research, Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, USA.
| | - Enrique A Mesri
- Tumor Biology Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA; University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, USA; Miami Center for AIDS Research, Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, USA
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3
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Li D, Baloch Z, Zhao Y, Bai L, Wang X, Wang G, Zhang AM, Lan K, Xia X. Establishment of Tree Shrew Animal Model for Kaposi's Sarcoma-Associated Herpesvirus (HHV-8) Infection. Front Microbiol 2021; 12:710067. [PMID: 34603235 PMCID: PMC8481836 DOI: 10.3389/fmicb.2021.710067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 07/01/2021] [Indexed: 01/22/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is the most common cause of Kaposi’s sarcoma (KS) and other malignant growths in humans. However, the lack of a KSHV-infected small animal model has hampered understanding of the mechanisms of KSHV infection, virus replication, pathogenesis, and persistence. This study was designed to explore the susceptibility of tree shrews as a possible KSHV-infected small animal model. A recombinant GFP (latent)/RFP (lytic)-positive rKSHV.219 strain was used to infect primary cells cultured from different tissues of tree shrews as an in vitro model and adult tree shrews as an in vivo model. KSHV latent nuclear antigen (LANA) and DNA were successfully detected in primary cells of tree shrews. Among them, tree shrew kidney epithelial cells (TSKEC) were the most susceptible cells to KSHV infection compared to other cells. KSHV genomic DNA, mRNA, and KSHV-specific proteins were readily detected in the TSKEC cultured up to 32 dpi. Moreover, KSHV DNA and mRNA transcription were also readily detected in the peripheral blood mononuclear cells (PBMCs) and various tissues of tree shrews infected with KSHV. Haematoxylin and eosin (HE) staining showed lymphocyte infiltration, lymphoid tissue focal aggregation, alveolar wall thickening, hepatocyte edema, hepatic necrosis in the spleen, lung, and liver of KSHV-infected animals. Additionally, immune-histochemical (IHC) staining showed that LANA or ORF62-positive cells were present in the spleen, lung, liver, and kidney of KSHV-infected tree shrews. Here, we have successfully established in vitro and in vivo KSHV latent infection in tree shrews. This small animal model is not only useful for studying the pathogenesis of KSHV in vivo but can also be a useful model to study transmission routes of viral infection and a useful platform to characterize the novel therapeutics against KSHV.
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Affiliation(s)
- Daoqun Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China.,Institute of Basic Medicine, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Zulqarnain Baloch
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Yang Zhao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Lei Bai
- State Key Laboratory of Virology, College of Life Sciences, Medical Research Institute, Wuhan University, Wuhan, China
| | - Xing Wang
- State Key Laboratory of Virology, College of Life Sciences, Medical Research Institute, Wuhan University, Wuhan, China
| | - Gang Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - A-Mei Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Medical Research Institute, Wuhan University, Wuhan, China
| | - Xueshan Xia
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
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KSHV G-protein coupled receptor vGPCR oncogenic signaling upregulation of Cyclooxygenase-2 expression mediates angiogenesis and tumorigenesis in Kaposi's sarcoma. PLoS Pathog 2020; 16:e1009006. [PMID: 33057440 PMCID: PMC7591070 DOI: 10.1371/journal.ppat.1009006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 10/27/2020] [Accepted: 09/27/2020] [Indexed: 11/19/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) vGPCR is a constitutively active G protein-coupled receptor that subverts proliferative and inflammatory signaling pathways to induce cell transformation in Kaposi's sarcoma. Cyclooxygenase-2 (COX-2) is an inflammatory mediator that plays a key regulatory role in the activation of tumor angiogenesis. Using two different transformed mouse models and tumorigenic full KSHV genome-bearing cells, including KSHV-Bac16 based mutant system with a vGPCR deletion, we demostrate that vGPCR upregulates COX-2 expression and activity, signaling through selective MAPK cascades. We show that vGPCR expression triggers signaling pathways that upregulate COX-2 levels due to a dual effect upon both its gene promoter region and, in mature mRNA, the 3'UTR region that control mRNA stability. Both events are mediated by signaling through ERK1/2 MAPK pathway. Inhibition of COX-2 in vGPCR-transformed cells impairs vGPCR-driven angiogenesis and treatment with the COX-2-selective inhibitory drug Celecoxib produces a significant decrease in tumor growth, pointing to COX-2 activity as critical for vGPCR oncogenicity in vivo and indicating that COX-2-mediated angiogenesis could play a role in KS tumorigenesis. These results, along with the overexpression of COX-2 in KS lesions, define COX-2 as a potential target for the prevention and treatment of KSHV-oncogenesis.
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Regulation of KSHV Latency and Lytic Reactivation. Viruses 2020; 12:v12091034. [PMID: 32957532 PMCID: PMC7551196 DOI: 10.3390/v12091034] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/10/2020] [Accepted: 09/12/2020] [Indexed: 02/06/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is associated with three malignancies— Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman’s disease (MCD). Central to the pathogenesis of these diseases is the KSHV viral life cycle, which is composed of a quiescent latent phase and a replicative lytic phase. While the establishment of latency enables persistent KSHV infection and evasion of the host immune system, lytic replication is essential for the dissemination of the virus between hosts and within the host itself. The transition between these phases, known as lytic reactivation, is controlled by a complex set of environmental, host, and viral factors. The effects of these various factors converge on the regulation of two KSHV proteins whose functions facilitate each phase of the viral life cycle—latency-associated nuclear antigen (LANA) and the master switch of KSHV reactivation, replication and transcription activator (RTA). This review presents the current understanding of how the transition between the phases of the KSHV life cycle is regulated, how the various phases contribute to KSHV pathogenesis, and how the viral life cycle can be exploited as a therapeutic target.
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PDGFRA defines the mesenchymal stem cell Kaposi's sarcoma progenitors by enabling KSHV oncogenesis in an angiogenic environment. PLoS Pathog 2019; 15:e1008221. [PMID: 31881074 PMCID: PMC6980685 DOI: 10.1371/journal.ppat.1008221] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 01/24/2020] [Accepted: 11/15/2019] [Indexed: 11/19/2022] Open
Abstract
Kaposi's sarcoma (KS) is an AIDS-defining cancer caused by the KS-associated herpesvirus (KSHV). Unanswered questions regarding KS are its cellular ontology and the conditions conducive to viral oncogenesis. We identify PDGFRA(+)/SCA-1(+) bone marrow-derived mesenchymal stem cells (Pα(+)S MSCs) as KS spindle-cell progenitors and found that pro-angiogenic environmental conditions typical of KS are critical for KSHV sarcomagenesis. This is because growth in KS-like conditions generates a de-repressed KSHV epigenome allowing oncogenic KSHV gene expression in infected Pα(+)S MSCs. Furthermore, these growth conditions allow KSHV-infected Pα(+)S MSCs to overcome KSHV-driven oncogene-induced senescence and cell cycle arrest via a PDGFRA-signaling mechanism; thus identifying PDGFRA not only as a phenotypic determinant for KS-progenitors but also as a critical enabler for viral oncogenesis.
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Rhesus Macaque Rhadinovirus Encodes a Viral Interferon Regulatory Factor To Disrupt Promyelocytic Leukemia Nuclear Bodies and Antagonize Type I Interferon Signaling. J Virol 2019; 93:JVI.02147-18. [PMID: 30626678 DOI: 10.1128/jvi.02147-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 01/03/2019] [Indexed: 12/17/2022] Open
Abstract
Interferon (IFN) production and the subsequent induction of IFN-stimulated genes (ISGs) are highly effective innate strategies utilized by cells to protect against invading pathogens, including viruses. Critical components involved in this innate process are promyelocytic leukemia nuclear bodies (PML-NBs), which are subnuclear structures required for the development of a robust IFN response. As such, PML-NBs serve as an important hurdle for viruses to overcome to successfully establish an infection. Both Kaposi's sarcoma-associated herpesvirus (KSHV) and the closely related rhesus macaque rhadinovirus (RRV) are unique for encoding viral homologs of IFN regulatory factors (termed vIRFs) that can manipulate the host immune response by multiple mechanisms. All four KSHV vIRFs inhibit the induction of IFN, while vIRF1 and vIRF2 can inhibit ISG induction downstream of the IFN receptor. Less is known about the RRV vIRFs. RRV vIRF R6 can inhibit the induction of IFN by IRF3; however, it is not known whether any RRV vIRFs inhibit ISG induction following IFN receptor signaling. In our present study, we demonstrate that the RRV vIRF R12 aids viral replication in the presence of the type I IFN response. This is achieved in part through the disruption of PML-NBs and the inhibition of robust ISG transcription.IMPORTANCE KSHV and RRV encode a unique set of homologs of cellular IFN regulatory factors, termed vIRFs, which are hypothesized to help these viruses evade the innate immune response and establish infections in their respective hosts. Our work elucidates the role of one RRV vIRF, R12, and demonstrates that RRV can dampen the type I IFN response downstream of IFN signaling, which would be important for establishing a successful infection in vivo.
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Purushothaman P, Uppal T, Sarkar R, Verma SC. KSHV-Mediated Angiogenesis in Tumor Progression. Viruses 2016; 8:E198. [PMID: 27447661 PMCID: PMC4974533 DOI: 10.3390/v8070198] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/18/2016] [Accepted: 07/07/2016] [Indexed: 12/14/2022] Open
Abstract
Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is a malignant human oncovirus belonging to the gamma herpesvirus family. HHV-8 is closely linked to the pathogenesis of Kaposi's sarcoma (KS) and two other B-cell lymphoproliferative diseases: primary effusion lymphoma (PEL) and a plasmablastic variant of multicentric Castleman's disease (MCD). KS is an invasive tumor of endothelial cells most commonly found in untreated HIV-AIDS or immuno-compromised individuals. KS tumors are highly vascularized and have abnormal, excessive neo-angiogenesis, inflammation, and proliferation of infected endothelial cells. KSHV directly induces angiogenesis in an autocrine and paracrine fashion through a complex interplay of various viral and cellular pro-angiogenic and inflammatory factors. KS is believed to originate due to a combination of KSHV's efficient strategies for evading host immune systems and several pro-angiogenic and pro-inflammatory stimuli. In addition, KSHV infection of endothelial cells produces a wide array of viral oncoproteins with transforming capabilities that regulate multiple host-signaling pathways involved in the activation of angiogenesis. It is likely that the cellular-signaling pathways of angiogenesis and lymph-angiogenesis modulate the rate of tumorigenesis induction by KSHV. This review summarizes the current knowledge on regulating KSHV-mediated angiogenesis by integrating the findings reported thus far on the roles of host and viral genes in oncogenesis, recent developments in cell-culture/animal-model systems, and various anti-angiogenic therapies for treating KSHV-related lymphoproliferative disorders.
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Affiliation(s)
- Pravinkumar Purushothaman
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Timsy Uppal
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Roni Sarkar
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Subhash C Verma
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
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Udayakumar TS, Stoyanova R, Shareef MM, Mu Z, Philip S, Burnstein KL, Pollack A. Edelfosine Promotes Apoptosis in Androgen-Deprived Prostate Tumors by Increasing ATF3 and Inhibiting Androgen Receptor Activity. Mol Cancer Ther 2016; 15:1353-63. [PMID: 26944919 DOI: 10.1158/1535-7163.mct-15-0332] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 02/15/2016] [Indexed: 12/31/2022]
Abstract
Edelfosine is a synthetic alkyl-lysophospholipid that possesses significant antitumor activity in several human tumor models. Here, we investigated the effects of edelfosine combined with androgen deprivation (AD) in LNCaP and VCaP human prostate cancer cells. This treatment regimen greatly decreased cell proliferation compared with single agent or AD alone, resulting in higher levels of apoptosis in LNCaP compared with VCaP cells. Edelfosine caused a dose-dependent decrease in AKT activity, but did not affect the expression of total AKT in either cell line. Furthermore, edelfosine treatment inhibited the expression of androgen receptor (AR) and was associated with an increase in activating transcription factor 3 (ATF3) expression levels, a stress response gene and a negative regulator of AR transactivation. ATF3 binds to AR after edelfosine + AD and represses the transcriptional activation of AR as demonstrated by PSA promoter studies. Knockdown of ATF3 using siRNA-ATF3 reversed the inhibition of PSA promoter activity, suggesting that the growth inhibition effect of edelfosine was ATF3 dependent. Moreover, expression of AR variant 7 (ARv7) and TMPRSS2-ERG fusion gene were greatly inhibited after combined treatment with AD and edelfosine in VCaP cells. In vivo experiments using an orthotopic LNCaP model confirmed the antitumor effects of edelfosine + AD over the individual treatments. A significant decrease in tumor volume and PSA levels was observed when edelfosine and AD were combined, compared with edelfosine alone. Edelfosine shows promise in combination with AD for the treatment of prostate cancer patients. Mol Cancer Ther; 15(6); 1353-63. ©2016 AACR.
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Affiliation(s)
- Thirupandiyur S Udayakumar
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida
| | - Radka Stoyanova
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida
| | - Mohammed M Shareef
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida
| | - Zhaomei Mu
- Department of Medical Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sakhi Philip
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida
| | - Kerry L Burnstein
- Department of Molecular and Cellular Pharmacology, University of Miami, Miami, Florida
| | - Alan Pollack
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida.
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Avey D, Brewers B, Zhu F. Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis. Virol Sin 2015; 30:130-45. [PMID: 25924994 PMCID: PMC8200917 DOI: 10.1007/s12250-015-3595-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 04/16/2015] [Indexed: 02/07/2023] Open
Abstract
It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 (HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.
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Affiliation(s)
- Denis Avey
- Department of Biological Science, Florida State University, Tallahassee, 32306 USA
| | - Brittany Brewers
- Department of Biological Science, Florida State University, Tallahassee, 32306 USA
| | - Fanxiu Zhu
- Department of Biological Science, Florida State University, Tallahassee, 32306 USA
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11
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Ellison TJ, Kedes DH. Variable episomal silencing of a recombinant herpesvirus renders its encoded GFP an unreliable marker of infection in primary cells. PLoS One 2014; 9:e111502. [PMID: 25402328 PMCID: PMC4234296 DOI: 10.1371/journal.pone.0111502] [Citation(s) in RCA: 13] [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: 06/05/2014] [Accepted: 09/30/2014] [Indexed: 12/17/2022] Open
Abstract
The availability of reliable recombinant reporter virus systems has been a great boon to the study of Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8). Unexpectedly, we found that expression of the ostensibly constitutive green fluorescent protein (GFP) marker was progressively lost during unselected passage in primary rat mesenchymal precursor cells (MM), despite efficient maintenance of latent viral gene expression and episomal partitioning. This repression of EF1-α promoter-driven GFP expression appeared to be passage-dependent, however, since functionally immortalized MM cells derived from long serial passage retained stable expression of GFP following rKSHV.219 infection. Chromatin analysis of cultures that we had infected in parallel demonstrated an increase in repressive H3K27 tri-methylation across the viral episome with the exception of the LANA control region in MM cells infected at early rather than late passage post-isolation. The silencing of GFP expression in the MM cells was reversible in a dose-dependent fashion by the histone deacetylase inhibitor valproic acid, further implicating cellular silencing on incoming viral genomes, and underscoring potential differences in viral gene regulation between primary and functionally immortalized cells. Furthermore, using multispectral imaging flow cytometry, we also determined that the extent of GFP expression per cell among those that were positive did not correlate with the number of LANA dots per nucleus nor the extent of overall LANA expression per cell. This suggests a more complex mode of local gene regulation, rather than one that simply reflects the relative intracellular viral copy number. In sum, we have demonstrated the significant potential for false-negative data when using a constitutive marker gene as a sole means of evaluating herpesviral infection, especially in primary cells.
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Affiliation(s)
- Thomas J. Ellison
- Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Dean H. Kedes
- Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Internal Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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12
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Cavallin LE, Goldschmidt-Clermont P, Mesri EA. Molecular and cellular mechanisms of KSHV oncogenesis of Kaposi's sarcoma associated with HIV/AIDS. PLoS Pathog 2014; 10:e1004154. [PMID: 25010730 PMCID: PMC4092131 DOI: 10.1371/journal.ppat.1004154] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Lucas E. Cavallin
- AIDS Malignancies Scientific Working Group, Miami Center for AIDS Research, Department and Graduate Program of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Viral Oncology Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Pascal Goldschmidt-Clermont
- AIDS Malignancies Scientific Working Group, Miami Center for AIDS Research, Department and Graduate Program of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Viral Oncology Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Enrique A. Mesri
- AIDS Malignancies Scientific Working Group, Miami Center for AIDS Research, Department and Graduate Program of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Viral Oncology Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- * E-mail:
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13
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Binding of the Kaposi's sarcoma-associated herpesvirus to the ephrin binding surface of the EphA2 receptor and its inhibition by a small molecule. J Virol 2014; 88:8724-34. [PMID: 24899181 DOI: 10.1128/jvi.01392-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED The ephrin receptor tyrosine kinase A2 (EphA2) is an entry receptor for Kaposi's sarcoma-associated herpesvirus (KSHV) that is engaged by the virus through its gH/gL glycoprotein complex. We describe here that natural ephrin ligands inhibit the gH/gL-EphA2 interaction. The effects of point mutations within EphA2 demonstrated that KSHV gH/gL interacts with EphA2 through a restricted set of the same residues that mediate binding of A-type ephrins. Two previously described inhibitors of the EphA2 interaction with ephrin A5 also inhibited binding of KSHV gH/gL to EphA2. The more potent of the two compounds inhibited KSHV infection of blood vessel and lymphatic endothelial cells in the micromolar concentration range. Our results demonstrate that interaction of KSHV with EphA2 occurs in a fashion similar to that of the natural ephrin ligands. Our data further indicate a new avenue for drug development against KSHV. IMPORTANCE Our study reports two important findings. First, we show that KSHV engages its receptor, the receptor tyrosine kinase EphA2, at a site that overlaps the binding site of the natural ephrin ligands. Second, we demonstrate that KSHV infection of target cells can be blocked by a small-molecule inhibitor of the viral glycoprotein-EphA2 interaction. These findings represent a novel avenue for the development of strategies to treat KSHV-associated diseases.
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