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Zebardast A, Latifi T, shirzad M, Goodarzi G, Ebrahimi Fana S, Samavarchi Tehrani S, Yahyapour Y. Critical involvement of circular RNAs in virus-associated cancers. Genes Dis 2023; 10:2296-2305. [PMID: 37554189 PMCID: PMC10404876 DOI: 10.1016/j.gendis.2022.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 03/25/2022] [Accepted: 04/06/2022] [Indexed: 12/09/2022] Open
Abstract
Virus-related cancer is cancer where viral infection leads to the malignant transformation of the host's infected cells. Seven viruses (e.g., human papillomavirus (HPV), Epstein-Barr virus (EBV), Kaposi's sarcoma herpesvirus (KSHV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human T-lymphotropic virus (HTLV), and Merkel cell polyomavirus (MCV)) that infect humans have been identified as an oncogene and have been associated with several human malignancies. Recently, growing attention has been attracted to exploring the pathogenesis of virus-related cancers. One of the most mysterious molecules involved in carcinogenesis and progression of virus-related cancers is circular RNAs (circRNA). These emerging non-coding RNAs (ncRNAs), due to the absence of 5' and 3' ends, have high stability than linear RNAs and are found in some species across the eukaryotic organisms. Compelling evidence has revealed that viruses also encode a repertoire of circRNAs, as well as dysregulation of these viral circRNAs play a critical role in the pathogenesis and progression of different types of virus-related cancers. Therefore, understanding the exact role and function of the virally encoded circRNAs with virus-associated cancers will open a new road for increasing our knowledge about the RNA world. Hence, in this review, we will focus on emerging roles of virus-encoded circRNAs in multiple cancers, including cervical cancer, gastric cancer, Merkel cell carcinoma, nasopharyngeal carcinoma, Kaposi cancer, and liver cancer.
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Affiliation(s)
- Arghavan Zebardast
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran 1417613151, Iran
| | - Tayebeh Latifi
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran 1417613151, Iran
| | - Moein shirzad
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol 47176, Iran
| | - Golnaz Goodarzi
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran 1417613151, Iran
- Student Scientific Research Center, Tehran University of Medical Sciences, Tehran 1417613151, Iran
| | - Saeed Ebrahimi Fana
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran 1417613151, Iran
- Student Scientific Research Center, Tehran University of Medical Sciences, Tehran 1417613151, Iran
| | - Sadra Samavarchi Tehrani
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran 1417613151, Iran
- Student Scientific Research Center, Tehran University of Medical Sciences, Tehran 1417613151, Iran
| | - Yousef Yahyapour
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol 47176, Iran
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Loke ASW, Lambert PF, Spurgeon ME. Current In Vitro and In Vivo Models to Study MCPyV-Associated MCC. Viruses 2022; 14:2204. [PMID: 36298759 PMCID: PMC9607385 DOI: 10.3390/v14102204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/01/2022] [Accepted: 10/02/2022] [Indexed: 11/06/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) is the only human polyomavirus currently known to cause human cancer. MCPyV is believed to be an etiological factor in at least 80% of cases of the rare but aggressive skin malignancy Merkel cell carcinoma (MCC). In these MCPyV+ MCC tumors, clonal integration of the viral genome results in the continued expression of two viral proteins: the viral small T antigen (ST) and a truncated form of the viral large T antigen. The oncogenic potential of MCPyV and the functional properties of the viral T antigens that contribute to neoplasia are becoming increasingly well-characterized with the recent development of model systems that recapitulate the biology of MCPyV+ MCC. In this review, we summarize our understanding of MCPyV and its role in MCC, followed by the current state of both in vitro and in vivo model systems used to study MCPyV and its contribution to carcinogenesis. We also highlight the remaining challenges within the field and the major considerations related to the ongoing development of in vitro and in vivo models of MCPyV+ MCC.
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Affiliation(s)
| | | | - Megan E. Spurgeon
- McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine & Public Health, University of Wisconsin, Madison, WI 53705, USA
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Osipov EM, Munawar AH, Beelen S, Fearon D, Douangamath A, Wild C, Weeks SD, Van Aerschot A, von Delft F, Strelkov SV. Discovery of novel druggable pockets on polyomavirus VP1 through crystallographic fragment-based screening to develop capsid assembly inhibitors. RSC Chem Biol 2022; 3:1013-1027. [PMID: 35974998 PMCID: PMC9347357 DOI: 10.1039/d2cb00052k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/24/2022] [Indexed: 11/21/2022] Open
Abstract
Polyomaviruses are a family of ubiquitous double-stranded DNA viruses many of which are human pathogens. These include BK polyomavirus which causes severe urinary tract infection in immunocompromised patients and Merkel cell polyomavirus associated with aggressive cancers. The small genome of polyomaviruses lacks conventional drug targets, and no specific drugs are available at present. Here we focus on the main structural protein VP1 of BK polyomavirus which is responsible for icosahedral capsid formation. To provide a foundation towards rational drug design, we crystallized truncated VP1 pentamers and subjected them to a high-throughput screening for binding drug-like fragments through a direct X-ray analysis. To enable a highly performant screening, rigorous optimization of the crystallographic pipeline and processing with the latest generation PanDDA2 software were necessary. As a result, a total of 144 binding hits were established. Importantly, the hits are well clustered in six surface pockets. Three pockets are located on the outside of the pentamer and map on the regions where the 'invading' C-terminal arm of another pentamer is attached upon capsid assembly. Another set of three pockets is situated within the wide pore along the five-fold axis of the VP1 pentamer. These pockets are situated at the interaction interface with the minor capsid protein VP2 which is indispensable for normal functioning of the virus. Here we systematically analyse the three outside pockets which are highly conserved across various polyomaviruses, while point mutations in these pockets are detrimental for viral replication. We show that one of the pockets can accommodate antipsychotic drug trifluoperazine. For each pocket, we derive pharmacophore features which enable the design of small molecules preventing the interaction between VP1 pentamers and therefore inhibiting capsid assembly. Our data lay a foundation towards a rational development of first-in-class drugs targeting polyomavirus capsid.
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Affiliation(s)
| | - Ali H Munawar
- Biocrystallography, KU Leuven Herestraat 49 Leuven Belgium
- Orthogon Therapeutics LLC 45 Dan Road Suite 126 Canton MA 02021 USA
- Pledge Tx B.V. Gaston Geenslaan 1 Leuven Belgium
| | - Steven Beelen
- Biocrystallography, KU Leuven Herestraat 49 Leuven Belgium
| | - Daren Fearon
- Diamond Light Source Ltd., Harwell Science and Innovation Campus Didcot UK
- Research Complex at Harwell, Harwell Science and Innovation Campus Didcot OX11 0FA UK
| | - Alice Douangamath
- Diamond Light Source Ltd., Harwell Science and Innovation Campus Didcot UK
- Research Complex at Harwell, Harwell Science and Innovation Campus Didcot OX11 0FA UK
| | - Conor Wild
- Centre for Medicines Discovery, University of Oxford South Parks Road Headington OX3 7DQ UK
- Department of Statistics, University of Oxford 29 St Giles' Oxford OX1 3LB UK
| | - Stephen D Weeks
- Biocrystallography, KU Leuven Herestraat 49 Leuven Belgium
- Pledge Tx B.V. Gaston Geenslaan 1 Leuven Belgium
| | - Arthur Van Aerschot
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven Herestraat 49 Leuven Belgium
| | - Frank von Delft
- Diamond Light Source Ltd., Harwell Science and Innovation Campus Didcot UK
- Research Complex at Harwell, Harwell Science and Innovation Campus Didcot OX11 0FA UK
- Centre for Medicines Discovery, University of Oxford South Parks Road Headington OX3 7DQ UK
- Structural Genomics Consortium, University of Oxford Old Road Campus Roosevelt Drive Headington OX3 7DQ UK
- Department of Biochemistry, University of Johannesburg Auckland Park 2006 South Africa
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Kines RC, Schiller JT. Harnessing Human Papillomavirus’ Natural Tropism to Target Tumors. Viruses 2022; 14:v14081656. [PMID: 36016277 PMCID: PMC9413966 DOI: 10.3390/v14081656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 02/06/2023] Open
Abstract
Human papillomaviruses (HPV) are small non-enveloped DNA tumor viruses established as the primary etiological agent for the development of cervical cancer. Decades of research have elucidated HPV’s primary attachment factor to be heparan sulfate proteoglycans (HSPG). Importantly, wounding and exposure of the epithelial basement membrane was found to be pivotal for efficient attachment and infection of HPV in vivo. Sulfation patterns on HSPG’s become modified at the site of wounds as they serve an important role promoting tissue healing, cell proliferation and neovascularization and it is these modifications recognized by HPV. Analogous HSPG modification patterns can be found on tumor cells as they too require the aforementioned processes to grow and metastasize. Although targeting tumor associated HSPG is not a novel concept, the use of HPV to target and treat tumors has only been realized in recent years. The work herein describes how decades of basic HPV research has culminated in the rational design of an HPV-based virus-like infrared light activated dye conjugate for the treatment of choroidal melanoma.
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Affiliation(s)
| | - John T. Schiller
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA;
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Replication Kinetics for a Reporter Merkel Cell Polyomavirus. Viruses 2022; 14:v14030473. [PMID: 35336880 PMCID: PMC8950423 DOI: 10.3390/v14030473] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/18/2022] [Accepted: 02/20/2022] [Indexed: 01/27/2023] Open
Abstract
Merkel cell polyomavirus (MCV) causes one of the most aggressive human skin cancers, but laboratory studies on MCV replication have proven technically difficult. We report the first recombinase-mediated MCV minicircle (MCVmc) system that generates high levels of circularized virus, allowing facile MCV genetic manipulation and characterization of viral gene expression kinetics during replication. Mutations to Fbw7, Skp2, β-TrCP and hVam6p interaction sites, or to the stem loop sequence for the MCV-encoded miRNA precursor, markedly increase viral replication, whereas point mutation to an origin-binding site eliminates active virus replication. To further increase the utility of this system, an mScarlet fusion protein was inserted into the VP1 c-terminus to generate a non-infectious reporter virus for studies on virus kinetics. When this reporter virus genome is heterologously expressed together with MCV VP1 and VP2, virus-like particles are generated. The reporter virus genome is encapsidated and can be used at lower biosafety levels for one-round infection studies. Our findings reveal that MCV has multiple, self-encoded viral restriction mechanisms to promote viral latency over lytic replication, and these mechanisms are now amenable to examination using a recombinase technology.
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Epigenetic Dysregulations in Merkel Cell Polyomavirus-Driven Merkel Cell Carcinoma. Int J Mol Sci 2021; 22:ijms222111464. [PMID: 34768895 PMCID: PMC8584046 DOI: 10.3390/ijms222111464] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 12/14/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) is a small DNA virus with oncogenic potential. MCPyV is the causative agent of Merkel Cell Carcinoma (MCC), a rare but aggressive tumor of the skin. The role of epigenetic mechanisms, such as histone posttranslational modifications (HPTMs), DNA methylation, and microRNA (miRNA) regulation on MCPyV-driven MCC has recently been highlighted. In this review, we aim to describe and discuss the latest insights into HPTMs, DNA methylation, and miRNA regulation, as well as their regulative factors in the context of MCPyV-driven MCC, to provide an overview of current findings on how MCPyV is involved in the dysregulation of these epigenetic processes. The current state of the art is also described as far as potentially using epigenetic dysregulations and related factors as diagnostic and prognostic tools is concerned, in addition to targets for MCPyV-driven MCC therapy. Growing evidence suggests that the dysregulation of HPTMs, DNA methylation, and miRNA pathways plays a role in MCPyV-driven MCC etiopathogenesis, which, therefore, may potentially be clinically significant for this deadly tumor. A deeper understanding of these mechanisms and related factors may improve diagnosis, prognosis, and therapy for MCPyV-driven MCC.
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Krump NA, You J. From Merkel Cell Polyomavirus Infection to Merkel Cell Carcinoma Oncogenesis. Front Microbiol 2021; 12:739695. [PMID: 34566942 PMCID: PMC8457551 DOI: 10.3389/fmicb.2021.739695] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) infection causes near-ubiquitous, asymptomatic infection in the skin, but occasionally leads to an aggressive skin cancer called Merkel cell carcinoma (MCC). Epidemiological evidence suggests that poorly controlled MCPyV infection may be a precursor to MCPyV-associated MCC. Clearer understanding of host responses that normally control MCPyV infection could inform prophylactic measures in at-risk groups. Similarly, the presence of MCPyV in most MCCs could imbue them with vulnerabilities that-if better characterized-could yield targeted intervention solutions for metastatic MCC cases. In this review, we discuss recent developments in elucidating the interplay between host cells and MCPyV within the context of viral infection and MCC oncogenesis. We also propose a model in which insufficient restriction of MCPyV infection in aging and chronically UV-damaged skin causes unbridled viral replication that licenses MCC tumorigenesis.
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Affiliation(s)
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Heparan Sulfate Proteoglycans in Viral Infection and Treatment: A Special Focus on SARS-CoV-2. Int J Mol Sci 2021; 22:ijms22126574. [PMID: 34207476 PMCID: PMC8235362 DOI: 10.3390/ijms22126574] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 01/27/2023] Open
Abstract
Heparan sulfate proteoglycans (HSPGs) encompass a group of glycoproteins composed of unbranched negatively charged heparan sulfate (HS) chains covalently attached to a core protein. The complex HSPG biosynthetic machinery generates an extraordinary structural variety of HS chains that enable them to bind a plethora of ligands, including growth factors, morphogens, cytokines, chemokines, enzymes, matrix proteins, and bacterial and viral pathogens. These interactions translate into key regulatory activity of HSPGs on a wide range of cellular processes such as receptor activation and signaling, cytoskeleton assembly, extracellular matrix remodeling, endocytosis, cell-cell crosstalk, and others. Due to their ubiquitous expression within tissues and their large functional repertoire, HSPGs are involved in many physiopathological processes; thus, they have emerged as valuable targets for the therapy of many human diseases. Among their functions, HSPGs assist many viruses in invading host cells at various steps of their life cycle. Viruses utilize HSPGs for the attachment to the host cell, internalization, intracellular trafficking, egress, and spread. Recently, HSPG involvement in the pathogenesis of SARS-CoV-2 infection has been established. Here, we summarize the current knowledge on the molecular mechanisms underlying HSPG/SARS-CoV-2 interaction and downstream effects, and we provide an overview of the HSPG-based therapeutic strategies that could be used to combat such a fearsome virus.
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Structural Insight into Non-Enveloped Virus Binding to Glycosaminoglycan Receptors: A Review. Viruses 2021; 13:v13050800. [PMID: 33946963 PMCID: PMC8146366 DOI: 10.3390/v13050800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 12/26/2022] Open
Abstract
Viruses are infectious agents that hijack the host cell machinery in order to replicate and generate progeny. Viral infection is initiated by attachment to host cell receptors, and typical viral receptors are cell-surface-borne molecules such as proteins or glycan structures. Sialylated glycans (glycans bearing sialic acids) and glycosaminoglycans (GAGs) represent major classes of carbohydrate receptors and have been implicated in facilitating viral entry for many viruses. As interactions between viruses and sialic acids have been extensively reviewed in the past, this review provides an overview of the current state of structural knowledge about interactions between non-enveloped human viruses and GAGs. We focus here on adeno-associated viruses, human papilloma viruses (HPVs), and polyomaviruses, as at least some structural information about the interactions of these viruses with GAGs is available. We also discuss the multivalent potential for GAG binding, highlighting the importance of charged interactions and positively charged amino acids at the binding sites, and point out challenges that remain in the field.
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Structural Analysis of Merkel Cell Polyomavirus (MCPyV) Viral Capsid Protein 1 (VP1) in HIV-1 Infected Individuals. Int J Mol Sci 2020; 21:ijms21217998. [PMID: 33121182 PMCID: PMC7663277 DOI: 10.3390/ijms21217998] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/20/2020] [Accepted: 10/24/2020] [Indexed: 12/12/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) viral protein 1 (VP1) is the capsid protein that mediates virus attachment to host cell receptors and is the major immune target. Given the limited data on MCPyV VP1 mutations, the VP1 genetic variability was examined in 100 plasma and 100 urine samples from 100 HIV+ individuals. Sequencing of VP1 DNA in 17 urine and 17 plasma specimens, simultaneously MCPyV DNA positive, revealed that 27 samples displayed sequences identical to VP1 of MCC350 strain. VP1 from two urine specimens had either Thr47Ser or Ile115Phe substitution, whereas VP1 of one plasma contained Asp69Val and Ser251Phe substitutions plus deletion (∆) of Tyr79. VP1 DNA in the remaining samples had mutations encoding truncated protein. Three-dimensional prediction models revealed that Asp69Val, Ser251Phe, and Ile115Phe caused neutral effects while Thr47Ser and Tyr79∆ produced a deleterious effect reducing VP1 stability. A549 cells infected with urine or plasma samples containing full-length VP1 variants with substitutions, sustained viral DNA replication and VP1 expression. Moreover, medium harvested from these cells was able to infect new A549 cells. In cells infected by samples with truncated VP1, MCPyV replication was hampered. In conclusion, MCPyV strains with unique mutations in the VP1 gene are circulating in HIV+ patients. These strains display altered replication efficiency compared to the MCC350 prototype strain in A549 cells.
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