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Gupta P, Venuti A, Savoldy M, Harold A, Zito FA, Taverniti V, Romero-Medina MC, Galati L, Sirand C, Shahzad N, Shuda M, Gheit T, Accardi R, Tommasino M. Merkel Cell Polyomavirus targets SET/PP2A complex to promote cellular proliferation and migration. Virology 2024; 597:110143. [PMID: 38917692 DOI: 10.1016/j.virol.2024.110143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 05/28/2024] [Accepted: 06/14/2024] [Indexed: 06/27/2024]
Abstract
Merkel Cell Carcinoma (MCC) is a rare neuroendocrine skin cancer. In our previous work, we decoded genes specifically deregulated by MCPyV early genes as opposed to other polyomaviruses and established functional importance of NDRG1 in inhibiting cellular proliferation and migration in MCC. In the present work, we found the SET protein, (I2PP2A, intrinsic inhibitor of PP2A) upstream of NDRG1 which was modulated by MCPyV early genes, both in hTERT-HK-MCPyV and MCPyV-positive (+) MCC cell lines. Additionally, MCC dermal tumour nodule tissues showed strong SET expression. Inhibition of the SET-PP2A interaction in hTERT-HK-MCPyV using the small molecule inhibitor, FTY720, increased NDRG1 expression and inhibited cell cycle regulators, cyclinD1 and CDK2. SET inhibition by shRNA and FTY720 also decreased cell proliferation and colony formation in MCPyV(+) MCC cells. Overall, these results pave a path for use of drugs targeting SET protein for the treatment of MCC.
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Affiliation(s)
- Purnima Gupta
- International Agency for Research on Cancer, Lyon, France.
| | - Assunta Venuti
- International Agency for Research on Cancer, Lyon, France
| | - Michelle Savoldy
- Cancer Virology Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alexis Harold
- Cancer Virology Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Francesco A Zito
- Bari Dipartimento dei Servizi, U.O.C. di Anatomia Patologica, Istituto Tumori IRCCS "Giovanni Paolo II", Italy
| | | | | | - Luisa Galati
- International Agency for Research on Cancer, Lyon, France
| | - Cecilia Sirand
- International Agency for Research on Cancer, Lyon, France
| | - Naveed Shahzad
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Masahiro Shuda
- Cancer Virology Program, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Tarik Gheit
- International Agency for Research on Cancer, Lyon, France.
| | - Rosita Accardi
- International Agency for Research on Cancer, Lyon, France
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Thevenin KR, Tieche IS, Di Benedetto CE, Schrager M, Dye KN. The small tumor antigen of Merkel cell polyomavirus accomplishes cellular transformation by uniquely localizing to the nucleus despite the absence of a known nuclear localization signal. Virol J 2024; 21:125. [PMID: 38831469 PMCID: PMC11149282 DOI: 10.1186/s12985-024-02395-x] [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: 01/19/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
BACKGROUND Merkel Cell Carcinoma (MCC) is an aggressive skin cancer that is three times deadlier than melanoma. In 2008, it was found that 80% of MCC cases are caused by the genomic integration of a novel polyomavirus, Merkel Cell Polyomavirus (MCPyV), and the expression of its small and truncated large tumor antigens (ST and LT-t, respectively). MCPyV belongs to a family of human polyomaviruses; however, it is the only one with a clear association to cancer. METHODS To investigate the role and mechanisms of various polyomavirus tumor antigens in cellular transformation, Rat-2 and 293A cells were transduced with pLENTI MCPyV LT-t, MCPyV ST, TSPyV ST, HPyV7 ST, or empty pLENTI and assessed through multiple transformation assays, and subcellular fractionations. One-way ANOVA tests were used to assess statistical significance. RESULTS Soft agar, proliferation, doubling time, glucose uptake, and serum dependence assays confirmed ST to be the dominant transforming protein of MCPyV. Furthermore, it was found that MCPyV ST is uniquely transforming, as the ST antigens of other non-oncogenic human polyomaviruses such as Trichodysplasia Spinulosa-Associated Polyomavirus (TSPyV) and Human Polyomavirus 7 (HPyV7) were not transforming when similarly assessed. Identification of structural dissimilarities between transforming and non-transforming tumor antigens revealed that the uniquely transforming domain(s) of MCPyV ST are likely located within the structurally dissimilar loops of the MCPyV ST unique region. Of all known MCPyV ST cellular interactors, 62% are exclusively or transiently nuclear, suggesting that MCPyV ST localizes to the nucleus despite the absence of a canonical nuclear localization signal. Indeed, subcellular fractionations confirmed that MCPyV ST could achieve nuclear localization through a currently unknown, regulated mechanism independent of its small size, as HPyV7 and TSPyV ST proteins were incapable of nuclear translocation. Although nuclear localization was found to be important for several transforming properties of MCPyV ST, some properties were also performed by a cytoplasmic sequestered MCPyV ST, suggesting that MCPyV ST may perform different transforming functions in individual subcellular compartments. CONCLUSIONS Together, these data further elucidate the unique differences between MCPyV ST and other polyomavirus ST proteins necessary to understand MCPyV as the only known human oncogenic polyomavirus.
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Affiliation(s)
- Kaira R Thevenin
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Isabella S Tieche
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Cody E Di Benedetto
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Matt Schrager
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Kristine N Dye
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA.
- Department of Biology, Stetson University, DeLand, FL, 32723, USA.
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Salisbury NJH, Amonkar S, Vinueza JL, Carter JJ, Roman A, Galloway DA. Polyomavirus ALTOs, but not MTs, downregulate viral early gene expression by activating the NF-κB pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595774. [PMID: 38826197 PMCID: PMC11142227 DOI: 10.1101/2024.05.24.595774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Polyomaviruses are small, circular dsDNA viruses that can cause cancer. Alternative splicing of polyomavirus early transcripts generates large and small tumor antigens (LT, ST) that play essential roles in viral replication and tumorigenesis. Some polyomaviruses also express middle tumor antigens (MTs) or Alternate LT ORFs (ALTOs), which are evolutionarily related but have distinct gene structures. MTs are a splice variant of the early transcript whereas ALTOs are overprinted on the second exon of the LT transcript in an alternate reading frame and are translated via an alternative start codon. Merkel cell polyomavirus (MCPyV), the only human polyomavirus that causes cancer, encodes an ALTO but its role in the viral lifecycle and tumorigenesis has remained elusive. Here, we show MCPyV ALTO acts as a tumor suppressor and is silenced in Merkel cell carcinoma (MCC). Rescuing ALTO in MCC cells induces growth arrest and activates NF-κB signaling. ALTO activates NF-κB by binding SQSTM1 and TRAF2&3 via two N-Terminal Activating Regions (NTAR1+2), resembling Epstein-Barr virus (EBV) Latent Membrane Protein 1 (LMP1).. Following activation, NF-κB dimers bind the MCPyV non-coding control region (NCCR) and downregulate early transcription. Beyond MCPyV, NTAR motifs are conserved in other polyomavirus ALTOs, which activate NF-κB signaling, but are lacking in MTs that do not. Furthermore, polyomavirus ALTOs downregulate their respective viral early transcription in an NF-κB and NTAR dependent manner. Our findings suggest that ALTOs evolved to suppress viral replication and promote viral latency and that MCPyV ALTO must be silenced for MCC to develop.
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Affiliation(s)
- Nicholas J. H. Salisbury
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
| | - Supriya Amonkar
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
| | - Joselyn Landazuri Vinueza
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
- University of Washington, Department of Microbiology, Seattle, WA, 98109, USA
| | - Joseph J. Carter
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
| | - Ann Roman
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
- University of Washington, Department of Microbiology, Seattle, WA, 98109, USA
| | - Denise A. Galloway
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
- University of Washington, Department of Microbiology, Seattle, WA, 98109, USA
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Torre-Castro J, Rodríguez M, Alonso-Alonso R, Mendoza Cembranos MD, Díaz-Alejo JF, Rebollo-González M, Borregón J, Nájera Botello L, Mahillo-Fernández I, Samimi M, Kervarrec T, Requena L, Piris MÁ. LT and SOX9 expression are associated with gene sets that distinguish Merkel cell polyomavirus (MCPyV)-positive and MCPyV-negative Merkel cell carcinoma. Br J Dermatol 2024; 190:876-884. [PMID: 38261397 DOI: 10.1093/bjd/ljae033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024]
Abstract
BACKGROUND Merkel cell carcinoma (MCC) is an aggressive malignant neuroendocrine tumour. There are two subsets of MCC, one related to Merkel cell polyomavirus (MCPyV) and the other to ultraviolet radiation (UVR). MCPyV-positive and MCPyV-negative MCCs have been considered to be different tumours, as the former harbour few DNA mutations and are not related to UVR, and the latter usually arise in sun-exposed areas and may be found in conjunction with other keratinocytic tumours, mostly squamous cell carcinomas. Two viral oncoproteins, large T antigen (LT; coded by MCPyV_gp3) and small T antigen (sT; coded by MCPyV_gp4), promote different carcinogenic pathways. OBJECTIVES To determine which genes are differentially expressed in MCPyV-positive and MCPyV-negative MCC; to describe the mutational burden and the most frequently mutated genes in both MCC subtypes; and to identify the clinical and molecular factors that may be related to patient survival. METHODS Ninety-two patients with a diagnosis of MCC were identified from the medical databases of participating centres. To study gene expression, a customized panel of 172 genes was developed. Gene expression profiling was performed with nCounter technology. For mutational studies, a customized panel of 26 genes was designed. Somatic single nucleotide variants (SNVs) were identified following the GATK Best Practices workflow for somatic mutations. RESULTS The expression of LT enabled the series to be divided into two groups (LT positive, n = 55; LT negative, n = 37). Genes differentially expressed in LT-negative patients were related to epithelial differentiation, especially SOX9, or proliferation and the cell cycle (MYC, CDK6), among others. Congruently, LT displayed lower expression in SOX9-positive patients, and differentially expressed genes in SOX9-positive patients were related to epithelial/squamous differentiation. In LT-positive patients, the mean SNV frequency was 4.3; in LT-negative patients it was 10 (P = 0.03). On multivariate survival analysis, the expression of SNAI1 [hazard ratio (HR) 1.046, 95% confidence interval (CI) 1.007-1.086; P = 0.02] and CDK6 (HR 1.049, 95% CI 1.020-1.080; P = 0.001) were identified as risk factors. CONCLUSIONS Tumours with weak LT expression tend to co-express genes related to squamous differentiation and the cell cycle, and to have a higher mutational burden. These findings are congruent with those of earlier studies.
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Affiliation(s)
| | - Marta Rodríguez
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
- Center for Biomedical Network on Cancer (CIBERONC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Ruth Alonso-Alonso
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
- Center for Biomedical Network on Cancer (CIBERONC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | | | - Jesús Frutos Díaz-Alejo
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
| | - Marcos Rebollo-González
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
| | - Jennifer Borregón
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
| | - Laura Nájera Botello
- Pathology Department, Hospital Universitario Puerta de Hierro, Universidad Autónoma, Madrid, Spain
| | - Ignacio Mahillo-Fernández
- Biostatistics and Epidemiology Unit, Hospital Universitario Fundación Jiménez Díaz, Fundación Instituto de Investigación Sanitaria, Madrid, Spain
| | | | | | | | - Miguel Ángel Piris
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
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Thevenin KR, Tieche IS, Di Benedetto CE, Schrager M, Dye KN. The Small Tumor Antigen of Merkel Cell Polyomavirus Accomplishes Cellular Transformation by Uniquely Localizing to the Nucleus Despite the Absence of a Known Nuclear Localization Signal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.28.569067. [PMID: 38293082 PMCID: PMC10827104 DOI: 10.1101/2023.11.28.569067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Background Merkel Cell Carcinoma (MCC) is an aggressive skin cancer that is three times deadlier than melanoma. In 2008, it was found that 80% of MCC cases are caused by the genomic integration of a novel polyomavirus, Merkel Cell Polyomavirus (MCPyV), and the expression of its small and truncated large tumor antigens (ST and LT-t, respectively). MCPyV belongs to a family of human polyomaviruses; however, it is the only one with a clear association to cancer. Methods To investigate the role and mechanisms of various polyomavirus tumor antigens in cellular transformation, Rat-2, 293A, and human foreskin fibroblasts were transduced with pLENTI MCPyV LT-t, MCPyV ST, TSPyV ST, HPyV7 ST, or empty pLENTI and assessed through multiple transformation assays, and subcellular fractionations. One-way ANOVA tests were used to assess statistical significance. Results Soft agar, proliferation, doubling time, glucose uptake, and serum dependence assays confirmed ST to be the dominant transforming protein of MCPyV. Furthermore, it was found that MCPyV ST is uniquely transforming, as the ST antigens of other non-oncogenic human polyomaviruses such as Trichodysplasia Spinulosa Polyomavirus (TSPyV) and Human Polyomavirus 7 (HPyV7) were not transforming when similarly assessed. Identification of structural dissimilarities between transforming and non-transforming tumor antigens revealed that the uniquely transforming domain(s) of MCPyV ST are likely located within the structurally dissimilar loops of the MCPyV ST unique region. Of all known MCPyV ST cellular interactors, 62% are exclusively or transiently nuclear, suggesting that MCPyV ST localizes to the nucleus despite the absence of a canonical nuclear localization signal. Indeed, subcellular fractionations confirmed that MCPyV ST could achieve nuclear localization through a currently unknown, regulated mechanism independent of its small size, as HPyV7 and TSPyV ST proteins were incapable of nuclear translocation. Although nuclear localization was found to be important for several transforming properties of MCPyV ST, some properties were also performed by a cytoplasmic sequestered MCPyV ST, suggesting that MCPyV ST may perform different transforming functions in individual subcellular compartments. Conclusions Together, these data further elucidate the unique differences between MCPyV ST and other polyomavirus ST proteins necessary to understand MCPyV as the only known human oncogenic polyomavirus.
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Shadbash P, Hosseini SM, Shoraka S, Ghaemi A, Haghazali M, Mohebbi SR. Possible association between polyomaviruses and gastrointestinal complications: a narrative review. GASTROENTEROLOGY AND HEPATOLOGY FROM BED TO BENCH 2024; 17:121-131. [PMID: 38994506 PMCID: PMC11234488 DOI: 10.22037/ghfbb.v17i2.2796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 02/03/2024] [Indexed: 07/13/2024]
Abstract
Polyomaviruses are a group of small, double-stranded DNA viruses that are known to be associated with the development of certain human diseases, but there is evidence that these viruses might be associated with gastrointestinal (GI) cancers. Several polyomaviruses have been identified, such as JC polyomavirus (JCPyV), BK polyomavirus (BKPyV) and recently Merkel cell polyomavirus (MCPyV). Although the direct effects of polyomaviruses on transformation of human cells and cancer development are not clearly recognized, their association with certain human diseases including GI cancers has been proposed through several molecular and epidemiological studies. For example, JCPyV and BKPyV have been linked to colorectal cancer, as there is growing evidence of finding viral genomes in cancerous tissues. Nevertheless, the major role of JCPyV, BKPyV and MCPyV in colorectal cancer progression is still under extensive investigation, and further surveys is required to establish a conclusive cause-and-effect relationship. Understanding the role of these viruses in cancer development has significant implications for diagnosis, treatment, and prevention strategies. It seems that proving a causal link between polyomaviruses and GI cancers might provide a novel path for targeted therapies or design and development of specific therapeutic vaccines. In addition, performing research on the possible link can provide insights into the underlying molecular mechanisms of carcinogenesis, potentially leading to the identification of novel biomarkers. This review focuses on polyomaviruses, in particular a recently discovered polyomavirus, MCPyV, and their possible link with human gastrointestinal disorders.
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Affiliation(s)
- Piruz Shadbash
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Seyed Masoud Hosseini
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Shahrzad Shoraka
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Ghaemi
- Department of Virology, Pasteur Institute of Iran, Tehran, Iran
| | - Mehrdad Haghazali
- Behbood Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Reza Mohebbi
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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DeCoste RC, Carter MD, Ly TY, Gruchy JR, Nicolela AP, Pasternak S. Merkel cell carcinoma: an update. Hum Pathol 2023; 140:39-52. [PMID: 36898590 DOI: 10.1016/j.humpath.2023.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/06/2023] [Indexed: 03/11/2023]
Abstract
Merkel cell carcinoma (MCC) is an uncommon primary cutaneous neuroendocrine carcinoma associated with an adverse prognosis. In recent years, our understanding of MCC biology has markedly progressed. Since the discovery of the Merkel cell polyomavirus, it has become clear that MCC represents an ontogenetically dichotomous group of neoplasms with overlapping histopathology. Specifically, most MCCs arise secondary to viral oncogenesis, while a smaller subset is the direct result of UV-associated mutations. The distinction of these groups bears relevance in their immunohistochemical and molecular characterization, as well as in disease prognosis. Further recent developments relate to the landmark utilization of immunotherapeutics in MCC, providing optimistic options for the management of this aggressive disease. In this review, we discuss both fundamental and emerging concepts in MCC, with a particular focus on topics of practical relevance to the surgical or dermatopathologist.
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Affiliation(s)
- Ryan C DeCoste
- Department of Pathology and Laboratory Medicine, QEII Health Science Centre, Nova Scotia Health, Halifax, Nova Scotia, B3H 1V8, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 1V8, Canada.
| | - Michael D Carter
- Department of Pathology and Laboratory Medicine, QEII Health Science Centre, Nova Scotia Health, Halifax, Nova Scotia, B3H 1V8, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 1V8, Canada
| | - Thai Yen Ly
- Department of Pathology and Laboratory Medicine, QEII Health Science Centre, Nova Scotia Health, Halifax, Nova Scotia, B3H 1V8, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 1V8, Canada
| | - Jennette R Gruchy
- Department of Pathology and Laboratory Medicine, QEII Health Science Centre, Nova Scotia Health, Halifax, Nova Scotia, B3H 1V8, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 1V8, Canada
| | - Anna P Nicolela
- Department of Biomedical and Molecular Sciences, Queens University, Kingston, Ontario, K7L 3N6, Canada
| | - Sylvia Pasternak
- Department of Pathology and Laboratory Medicine, QEII Health Science Centre, Nova Scotia Health, Halifax, Nova Scotia, B3H 1V8, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 1V8, Canada
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Yang JF, Liu W, You J. Characterization of molecular mechanisms driving Merkel cell polyomavirus oncogene transcription and tumorigenic potential. PLoS Pathog 2023; 19:e1011598. [PMID: 37647312 PMCID: PMC10468096 DOI: 10.1371/journal.ppat.1011598] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/03/2023] [Indexed: 09/01/2023] Open
Abstract
Merkel cell polyomavirus (MCPyV) is associated with approximately 80% of cases of Merkel cell carcinoma (MCC), an aggressive type of skin cancer. The incidence of MCC has tripled over the past twenty years, but there are currently very few effective targeted treatments. A better understanding of the MCPyV life cycle and its oncogenic mechanisms is needed to unveil novel strategies for the prevention and treatment of MCC. MCPyV infection and oncogenesis are reliant on the expression of the early viral oncoproteins, which drive the viral life cycle and MCPyV+ MCC tumor cell growth. To date, the molecular mechanisms regulating the transcription of the MCPyV oncogenes remain largely uncharacterized. In this study, we investigated how MCPyV early transcription is regulated to support viral infection and MCC tumorigenesis. Our studies established the roles of multiple cellular factors in the control of MCPyV gene expression. Inhibitor screening experiments revealed that the histone acetyltransferases p300 and CBP positively regulate MCPyV transcription. Their regulation of viral gene expression occurs through coactivation of the transcription factor NF-κB, which binds to the viral genome to drive MCPyV oncogene expression in a manner that is tightly controlled through a negative feedback loop. Furthermore, we discovered that small molecule inhibitors specifically targeting p300/CBP histone acetyltransferase activity are effective at blocking MCPyV tumor antigen expression and MCPyV+ MCC cell proliferation. Together, our work establishes key cellular factors regulating MCPyV transcription, providing the basis for understanding the largely unknown mechanisms governing MCPyV transcription that defines its infectious host cell tropism, viral life cycle, and oncogenic potential. Our studies also identify a novel therapeutic strategy against MCPyV+ MCC through specific blockage of MCPyV oncogene expression and MCC tumor growth.
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Affiliation(s)
- June F. Yang
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Wei Liu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Celikdemir B, Houben R, Kervarrec T, Samimi M, Schrama D. Current and preclinical treatment options for Merkel cell carcinoma. Expert Opin Biol Ther 2023; 23:1015-1034. [PMID: 37691397 DOI: 10.1080/14712598.2023.2257603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/12/2023]
Abstract
INTRODUCTION Merkel cell carcinoma (MCC) is a rare, highly aggressive form of skin cancer with neuroendocrine features. The origin of this cancer is still unclear, but research in the last 15 years has demonstrated that MCC arises via two distinct etiologic pathways, i.e. virus and UV-induced. Considering the high mortality rate and the limited therapeutic options available, this review aims to highlight the significance of MCC research and the need for advancement in MCC treatment. AREAS COVERED With the advent of the immune checkpoint inhibitor therapies, we now have treatment options providing a survival benefit for patients with advanced MCC. However, the issue of primary and acquired resistance to these therapies remains a significant concern. Therefore, ongoing efforts seeking additional therapeutic targets and approaches for MCC therapy are a necessity. Through a comprehensive literature search, we provide an overview on recent preclinical and clinical studies with respect to MCC therapy. EXPERT OPINION Currently, the only evidence-based therapy for MCC is immune checkpoint blockade with anti-PD-1/PD-L1 for advanced patients. Neoadjuvant, adjuvant and combined immune checkpoint blockade are promising treatment options.
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Affiliation(s)
- Büke Celikdemir
- Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, Würzburg, Germany
| | - Roland Houben
- Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, Würzburg, Germany
| | - Thibault Kervarrec
- Department of Pathology, Centre Hospitalier Universitaire De Tours, Tours, France
| | - Mahtab Samimi
- Department of Dermatology, University Hospital of Tours, Tours, France
| | - David Schrama
- Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, Würzburg, Germany
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Imon RR, Samad A, Alam R, Alsaiari AA, Talukder MEK, Almehmadi M, Ahammad F, Mohammad F. Computational formulation of a multiepitope vaccine unveils an exceptional prophylactic candidate against Merkel cell polyomavirus. Front Immunol 2023; 14:1160260. [PMID: 37441076 PMCID: PMC10333698 DOI: 10.3389/fimmu.2023.1160260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/30/2023] [Indexed: 07/15/2023] Open
Abstract
Merkel cell carcinoma (MCC) is a rare neuroendocrine skin malignancy caused by human Merkel cell polyomavirus (MCV), leading to the most aggressive skin cancer in humans. MCV has been identified in approximately 43%-100% of MCC cases, contributing to the highly aggressive nature of primary cutaneous carcinoma and leading to a notable mortality rate. Currently, no existing vaccines or drug candidates have shown efficacy in addressing the ailment caused by this specific pathogen. Therefore, this study aimed to design a novel multiepitope vaccine candidate against the virus using integrated immunoinformatics and vaccinomics approaches. Initially, the highest antigenic, immunogenic, and non-allergenic epitopes of cytotoxic T lymphocytes, helper T lymphocytes, and linear B lymphocytes corresponding to the virus whole protein sequences were identified and retrieved for vaccine construction. Subsequently, the selected epitopes were linked with appropriate linkers and added an adjuvant in front of the construct to enhance the immunogenicity of the vaccine candidates. Additionally, molecular docking and dynamics simulations identified strong and stable binding interactions between vaccine candidates and human Toll-like receptor 4. Furthermore, computer-aided immune simulation found the real-life-like immune response of vaccine candidates upon administration to the human body. Finally, codon optimization was conducted on the vaccine candidates to facilitate the in silico cloning of the vaccine into the pET28+(a) cloning vector. In conclusion, the vaccine candidate developed in this study is anticipated to augment the immune response in humans and effectively combat the virus. Nevertheless, it is imperative to conduct in vitro and in vivo assays to evaluate the efficacy of these vaccine candidates thoroughly. These evaluations will provide critical insights into the vaccine's effectiveness and potential for further development.
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Affiliation(s)
- Raihan Rahman Imon
- Laboratory of Computational Biology, Biological Solution Centre (BioSol Centre), Jashore, Bangladesh
- Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Abdus Samad
- Laboratory of Computational Biology, Biological Solution Centre (BioSol Centre), Jashore, Bangladesh
- Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Rahat Alam
- Laboratory of Computational Biology, Biological Solution Centre (BioSol Centre), Jashore, Bangladesh
- Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Ahad Amer Alsaiari
- Clinical Laboratories Science Department, College of Applied Medical Science, Taif University, Taif, Saudi Arabia
| | - Md. Enamul Kabir Talukder
- Laboratory of Computational Biology, Biological Solution Centre (BioSol Centre), Jashore, Bangladesh
- Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Mazen Almehmadi
- Clinical Laboratories Science Department, College of Applied Medical Science, Taif University, Taif, Saudi Arabia
| | - Foysal Ahammad
- Laboratory of Computational Biology, Biological Solution Centre (BioSol Centre), Jashore, Bangladesh
- Division of Biological and Biomedical Sciences (BBS), College of Health and Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Farhan Mohammad
- Division of Biological and Biomedical Sciences (BBS), College of Health and Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
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11
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Sun R, Guo S, Shuda Y, Chakka AB, Rigatti LH, Zhao G, Ali MAE, Park CY, Chandran U, Yu J, Bakkenist CJ, Shuda M, Moore PS, Chang Y. Mitotic CDK1 and 4E-BP1 I: Loss of 4E-BP1 serine 82 phosphorylation promotes proliferative polycystic disease and lymphoma in aged or sublethally irradiated mice. PLoS One 2023; 18:e0282722. [PMID: 37145994 PMCID: PMC10162543 DOI: 10.1371/journal.pone.0282722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/21/2023] [Indexed: 05/07/2023] Open
Abstract
4E-BP1 is a tumor suppressor regulating cap-dependent translation that is in turn controlled by mechanistic target of rapamycin (mTOR) or cyclin-dependent kinase 1 (CDK1) phosphorylation. 4E-BP1 serine 82 (S82) is phosphorylated by CDK1, but not mTOR, and the consequences of this mitosis-specific phosphorylation are unknown. Knock-in mice were generated with a single 4E-BP1 S82 alanine (S82A) substitution leaving other phosphorylation sites intact. S82A mice were fertile and exhibited no gross developmental or behavioral abnormalities, but the homozygotes developed diffuse and severe polycystic liver and kidney disease with aging, and lymphoid malignancies after irradiation. Sublethal irradiation caused immature T-cell lymphoma only in S82A mice while S82A homozygous mice have normal T-cell hematopoiesis before irradiation. Whole genome sequencing identified PTEN mutations in S82A lymphoma and impaired PTEN expression was verified in S82A lymphomas derived cell lines. Our study suggests that the absence of 4E-BP1S82 phosphorylation, a subtle change in 4E-BP1 phosphorylation, might predispose to polycystic proliferative disease and lymphoma under certain stressful circumstances, such as aging and irradiation.
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Affiliation(s)
- Rui Sun
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Siying Guo
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Yoko Shuda
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Anish B. Chakka
- Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Lora H. Rigatti
- Division of Laboratory Animal Resources, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America
| | - Guangyi Zhao
- Department of Pathology, University of Pittsburgh School of Medicine, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Mohammed A. E. Ali
- Department of Pathology, NYU Grossman School of Medicine, Perlmutter Cancer Center, New York, New York, United States of America
| | - Christopher Y. Park
- Department of Pathology, NYU Grossman School of Medicine, Perlmutter Cancer Center, New York, New York, United States of America
| | - Uma Chandran
- Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jian Yu
- Department of Pathology, University of Pittsburgh School of Medicine, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Christopher J. Bakkenist
- Radiation Oncology, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Masahiro Shuda
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Patrick S. Moore
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Yuan Chang
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
- Department of Pathology, University of Pittsburgh School of Medicine, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
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12
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Houben R, Alimova P, Sarma B, Hesbacher S, Schulte C, Sarosi EM, Adam C, Kervarrec T, Schrama D. 4-[(5-Methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone Inhibits MCPyV T Antigen Expression in Merkel Cell Carcinoma Independent of Aurora Kinase A. Cancers (Basel) 2023; 15:cancers15092542. [PMID: 37174007 PMCID: PMC10177447 DOI: 10.3390/cancers15092542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Merkel cell carcinoma (MCC) is frequently caused by the Merkel cell polyomavirus (MCPyV), and MCPyV-positive tumor cells depend on expression of the virus-encoded T antigens (TA). Here, we identify 4-[(5-methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone (PHT)-a reported inhibitor of Aurora kinase A-as a compound inhibiting growth of MCC cells by repressing noncoding control region (NCCR)-controlled TA transcription. Surprisingly, we find that TA repression is not caused by inhibition of Aurora kinase A. However, we demonstrate that β-catenin-a transcription factor repressed by active glycogen synthase kinase 3 (GSK3)-is activated by PHT, suggesting that PHT bears a hitherto unreported inhibitory activity against GSK3, a kinase known to function in promoting TA transcription. Indeed, applying an in vitro kinase assay, we demonstrate that PHT directly targets GSK3. Finally, we demonstrate that PHT exhibits in vivo antitumor activity in an MCC xenograft mouse model, suggesting a potential use in future therapeutic settings for MCC.
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Affiliation(s)
- Roland Houben
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Pamela Alimova
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Bhavishya Sarma
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Sonja Hesbacher
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Carolin Schulte
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Eva-Maria Sarosi
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Christian Adam
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Thibault Kervarrec
- Department of Pathology, Centre Hospitalier Universitaire de Tours, INRA UMR 1282 BIP, 37200 Tours, France
| | - David Schrama
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
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13
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Wang R, Yang JF, Senay TE, Liu W, You J. Characterization of the Impact of Merkel Cell Polyomavirus-Induced Interferon Signaling on Viral Infection. J Virol 2023; 97:e0190722. [PMID: 36946735 PMCID: PMC10134799 DOI: 10.1128/jvi.01907-22] [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: 12/09/2022] [Accepted: 03/05/2023] [Indexed: 03/23/2023] Open
Abstract
Merkel cell polyomavirus (MCPyV) has been associated with approximately 80% of Merkel cell carcinoma (MCC), an aggressive and increasingly incident skin cancer. The link between host innate immunity, viral load control, and carcinogenesis has been established but poorly characterized. We previously established the importance of the STING and NF-κB pathways in the host innate immune response to viral infection. In this study, we further discovered that MCPyV infection of human dermal fibroblasts (HDFs) induces the expression of type I and III interferons (IFNs), which in turn stimulate robust expression of IFN-stimulated genes (ISGs). Blocking type I IFN downstream signaling using an IFN-β antibody, JAK inhibitors, and CRISPR knockout of the receptor dramatically repressed MCPyV infection-induced ISG expression but did not significantly restore viral replication activities. These findings suggest that IFN-mediated induction of ISGs in response to MCPyV infection is not crucial to viral control. Instead, we found that type I IFN exerts a more direct effect on MCPyV infection postentry by repressing early viral transcription. We further demonstrated that growth factors normally upregulated in wounded or UV-irradiated human skin can significantly stimulate MCPyV gene expression and replication. Together, these data suggest that in healthy individuals, host antiviral responses, such as IFN production induced by viral activity, may restrict viral propagation to reduce MCPyV burden. Meanwhile, growth factors induced by skin abrasion or UV irradiation may stimulate infected dermal fibroblasts to promote MCPyV propagation. A delicate balance of these mutually antagonizing factors provides a mechanism to support persistent MCPyV infection. IMPORTANCE Merkel cell carcinoma is an aggressive skin cancer that is particularly lethal to immunocompromised individuals. Though rare, MCC incidence has increased significantly in recent years. There are no lasting and effective treatments for metastatic disease, highlighting the need for additional treatment and prevention strategies. By investigating how the host innate immune system interfaces with Merkel cell polyomavirus, the etiological agent of most of these cancers, our studies identified key factors necessary for viral control, as well as conditions that support viral propagation. These studies provide new insights for understanding how the virus balances the effects of the host immune defenses and of growth factor stimulation to achieve persistent infection. Since virus-positive MCC requires the expression of viral oncogenes to survive, our observation that type I IFN can repress viral oncogene transcription indicates that these cytokines could be explored as a viable therapeutic option for treating patients with virus-positive MCC.
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Affiliation(s)
- Ranran Wang
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - June F. Yang
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Taylor E. Senay
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wei Liu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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14
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Zou W, Imperiale MJ. Regulation of Virus Replication by BK Polyomavirus Small T Antigen. J Virol 2023; 97:e0007723. [PMID: 36916919 PMCID: PMC10062181 DOI: 10.1128/jvi.00077-23] [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: 01/13/2023] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
Polyomavirus small T antigen (tAg) plays important roles in regulating viral replication, the innate immune response, apoptosis, and transformation for SV40, Merkel cell polyomavirus (MCPyV), murine polyomavirus (MuPyV), and JC polyomavirus (JCPyV). However, the function of BK polyomavirus (BKPyV) tAg has been much less studied. Here, we constructed mutant viruses that do not express tAg, and we showed that, in contrast with other polyomaviruses, BKPyV tAg inhibits large T antigen (TAg) gene expression and viral DNA replication. However, this occurs only in an archetype viral background. We also observed that the transduction of cells with a lentivirus-expressing BKPyV tAg kills the cells. We further discovered that BKPyV tAg interacts not only with PP2A A and C subunits, as has been demonstrated for other polyomavirus tAg proteins, but also with PP2A B''' subunit members. Knocking down either of two B''' subunits, namely STRN or STRN3, mimics the phenotype of the tAg mutant virus. However, a virus containing a point mutation in the PP2A binding domain of tAg only partially affected virus TAg expression and DNA replication. These results indicate that BKPyV tAg downregulates viral gene expression and DNA replication and that this occurs in part through interactions with PP2A. IMPORTANCE BK polyomavirus is a virus that establishes a lifelong infection of the majority of people. The infection usually does not cause any clinical symptoms, but, in transplant recipients whose immune systems have been suppressed, unchecked virus replication can cause severe disease. In this study, we show that a viral protein called small T antigen is one of the ways that the virus can persist without high levels of replication. Understanding which factors control viral replication enhances our knowledge of the virus life cycle and could lead to potential interventions for these patients.
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Affiliation(s)
- Wei Zou
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael J. Imperiale
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
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15
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Merkel Cell Polyomavirus Large T Antigen Induces Cellular Senescence for Host Growth Arrest and Viral Genome Persistence through Its Unique Domain. Cells 2023; 12:cells12030380. [PMID: 36766726 PMCID: PMC9913222 DOI: 10.3390/cells12030380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Senescent cells accumulate in the host during the aging process and are associated with age-related pathogeneses, including cancer. Although persistent senescence seems to contribute to many aspects of cellular pathways and homeostasis, the role of senescence in virus-induced human cancer is not well understood. Merkel cell carcinoma (MCC) is an aggressive skin cancer induced by a life-long human infection of Merkel cell polyomavirus (MCPyV). Here, we show that MCPyV large T (LT) antigen expression in human skin fibroblasts causes a novel nucleolar stress response, followed by p21-dependent senescence and senescence-associated secretory phenotypes (SASPs), which are required for MCPyV genome maintenance. Senolytic and navitoclax treatments result in decreased senescence and MCPyV genome levels, suggesting a potential therapeutic for MCC prevention. Our results uncover the mechanism of a host stress response regulating human polyomavirus genome maintenance in viral persistency, which may lead to targeted intervention for MCC.
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16
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Merkel Cell Polyomavirus: Infection, Genome, Transcripts and Its Role in Development of Merkel Cell Carcinoma. Cancers (Basel) 2023; 15:cancers15020444. [PMID: 36672392 PMCID: PMC9857234 DOI: 10.3390/cancers15020444] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/23/2022] [Accepted: 12/27/2022] [Indexed: 01/13/2023] Open
Abstract
The best characterized polyomavirus family member, i.e., simian virus 40 (SV40), can cause different tumors in hamsters and can transform murine and human cells in vitro. Hence, the SV40 contamination of millions of polio vaccine doses administered from 1955-1963 raised fears that this may cause increased tumor incidence in the vaccinated population. This is, however, not the case. Indeed, up to now, the only polyomavirus family member known to be the most important cause of a specific human tumor entity is Merkel cell polyomavirus (MCPyV) in Merkel cell carcinoma (MCC). MCC is a highly deadly form of skin cancer for which the cellular origin is still uncertain, and which appears as two clinically very similar but molecularly highly different variants. While approximately 80% of cases are found to be associated with MCPyV the remaining MCCs carry a high mutational load. Here, we present an overview of the multitude of molecular functions described for the MCPyV encoded oncoproteins and non-coding RNAs, present the available MCC mouse models and discuss the increasing evidence that both, virus-negative and -positive MCC constitute epithelial tumors.
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17
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Rapchak K, Yagobian SD, Moore J, Khattri M, Shuda M. Merkel cell polyomavirus small T antigen is a viral transcription activator that is essential for viral genome maintenance. PLoS Pathog 2022; 18:e1011039. [PMID: 36574443 PMCID: PMC9829177 DOI: 10.1371/journal.ppat.1011039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/09/2023] [Accepted: 12/01/2022] [Indexed: 12/29/2022] Open
Abstract
Merkel cell polyomavirus (MCV) is a small DNA tumor virus that persists in human skin and causes Merkel cell carcinoma (MCC) in immunocompromised individuals. The multi-functional protein MCV small T (sT) activates viral DNA replication by stabilizing large T (LT) and promotes cell transformation through the LT stabilization domain (LTSD). Using MCVΔsT, a mutant MCV clone that ablates sT, we investigated the role of sT in MCV genome maintenance. sT was dispensable for initiation of viral DNA replication, but essential for maintenance of the MCV genome and activation of viral early and late gene expression for progression of the viral lifecycle. Furthermore, in phenotype rescue studies, exogenous sT activated viral DNA replication and mRNA expression in MCVΔsT through the LTSD. While exogenous LT expression, which mimics LT stabilization, increased viral DNA replication, it did not activate viral mRNA expression. After cataloging transcriptional regulator proteins by proximity-based MCV sT-host protein interaction analysis, we validated LTSD-dependent sT interaction with four transcriptional regulators: Cux1, c-Jun, BRD9, and CBP. Functional studies revealed Cux1 and c-Jun as negative regulators, and CBP and BRD9 as positive regulators of MCV transcription. CBP inhibitor A-485 suppressed sT-induced viral gene activation in replicating MCVΔsT and inhibited early gene expression in MCV-integrated MCC cells. These results suggest that sT promotes viral lifecycle progression by activating mRNA expression and capsid protein production through interaction with the transcriptional regulators. This activity is essential for MCV genome maintenance, suggesting a critical role of sT in MCV persistence and MCC carcinogenesis.
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Affiliation(s)
- Kyle Rapchak
- Cancer Virology Program, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Shiva D. Yagobian
- Cancer Virology Program, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Jackson Moore
- Cancer Virology Program, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Michelle Khattri
- Cancer Virology Program, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Masahiro Shuda
- Cancer Virology Program, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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18
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Zaggana E, Konstantinou MP, Krasagakis GH, de Bree E, Kalpakis K, Mavroudis D, Krasagakis K. Merkel Cell Carcinoma-Update on Diagnosis, Management and Future Perspectives. Cancers (Basel) 2022; 15:cancers15010103. [PMID: 36612102 PMCID: PMC9817518 DOI: 10.3390/cancers15010103] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/11/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
MCC is a rare but highly aggressive skin cancer. The identification of the driving role of Merkel cell polyomavirus (MCPyV) and ultraviolet-induced DNA damage in the oncogenesis of MCC allowed a better understanding of its biological behavior. The presence of MCPyV-specific T cells and lymphocytes exhibiting an 'exhausted' phenotype in the tumor microenvironment along with the high prevalence of immunosuppression among affected patients are strong indicators of the immunogenic properties of MCC. The use of immunotherapy has revolutionized the management of patients with advanced MCC with anti-PD-1/PD L1 blockade, providing objective responses in as much as 50-70% of cases when used in first-line treatment. However, acquired resistance or contraindication to immune checkpoint inhibitors can be an issue for a non-negligible number of patients and novel therapeutic strategies are warranted. This review will focus on current management guidelines for MCC and future therapeutic perspectives for advanced disease with an emphasis on molecular pathways, targeted therapies, and immune-based strategies. These new therapies alone or in combination with anti-PD-1/PD-L1 inhibitors could enhance immune responses against tumor cells and overcome acquired resistance to immunotherapy.
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Affiliation(s)
- Eleni Zaggana
- Department of Dermatology, University General Hospital of Heraklion, 71500 Crete, Greece
| | - Maria Polina Konstantinou
- Department of Dermatology, University General Hospital of Heraklion, 71500 Crete, Greece
- Correspondence: ; Tel.: +30-2810-3925-82; Fax: +30-2810-5420-85
| | | | - Eelco de Bree
- Medical School, University of Crete, 71500 Crete, Greece
- Department of Surgical Oncology, University General Hospital of Heraklion, 71500 Crete, Greece
| | - Konstantinos Kalpakis
- Medical School, University of Crete, 71500 Crete, Greece
- Department of Medical Oncology, University General Hospital of Heraklion, 71500 Crete, Greece
| | - Dimitrios Mavroudis
- Medical School, University of Crete, 71500 Crete, Greece
- Department of Medical Oncology, University General Hospital of Heraklion, 71500 Crete, Greece
| | - Konstantinos Krasagakis
- Department of Dermatology, University General Hospital of Heraklion, 71500 Crete, Greece
- Medical School, University of Crete, 71500 Crete, Greece
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19
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An Update on the Metabolic Landscape of Oncogenic Viruses. Cancers (Basel) 2022; 14:cancers14235742. [PMID: 36497226 PMCID: PMC9738352 DOI: 10.3390/cancers14235742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/10/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Viruses play an important role in cancer development as about 12% of cancer types are linked to viral infections. Viruses that induce cellular transformation are known as oncoviruses. Although the mechanisms of viral oncogenesis differ between viruses, all oncogenic viruses share the ability to establish persistent chronic infections with no obvious symptoms for years. During these prolonged infections, oncogenic viruses manipulate cell signaling pathways that control cell cycle progression, apoptosis, inflammation, and metabolism. Importantly, it seems that most oncoviruses depend on these changes for their persistence and amplification. Metabolic changes induced by oncoviruses share many common features with cancer metabolism. Indeed, viruses, like proliferating cancer cells, require increased biosynthetic precursors for virion production, need to balance cellular redox homeostasis, and need to ensure host cell survival in a given tissue microenvironment. Thus, like for cancer cells, viral replication and persistence of infected cells frequently depend on metabolic changes. Here, we draw parallels between metabolic changes observed in cancers or induced by oncoviruses, with a focus on pathways involved in the regulation of glucose, lipid, and amino acids. We describe whether and how oncoviruses depend on metabolic changes, with the perspective of targeting them for antiviral and onco-therapeutic approaches in the context of viral infections.
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20
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Soikkeli AI, Kyläniemi MK, Sihto H, Alinikula J. Oncogenic Merkel Cell Polyomavirus T Antigen Truncating Mutations are Mediated by APOBEC3 Activity in Merkel Cell Carcinoma. CANCER RESEARCH COMMUNICATIONS 2022; 2:1344-1354. [PMID: 36970060 PMCID: PMC10035372 DOI: 10.1158/2767-9764.crc-22-0211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/17/2022] [Accepted: 09/28/2022] [Indexed: 11/06/2022]
Abstract
Merkel cell carcinoma (MCC) is an aggressive skin cancer, which is frequently caused by Merkel cell polyomavirus (MCPyV). Mutations of MCPyV tumor (T) antigens are major pathologic events of virus-positive (MCPyV+) MCCs, but their source is unclear. Activation-induced cytidine deaminase (AID)/APOBEC family cytidine deaminases contribute to antiviral immunity by mutating viral genomes and are potential carcinogenic mutators. We studied the contribution of AID/APOBEC cytidine deaminases to MCPyV large T (LT) truncation events. The MCPyV LT area in MCCs was enriched with cytosine-targeting mutations, and a strong APOBEC3 mutation signature was observed in MCC sequences. AICDA and APOBEC3 expression were detected in the Finnish MCC sample cohort, and LT expression correlated with APOBEC3H and APOBEC3G. Marginal but statistically significant somatic hypermutation targeting activity was detected in the MCPyV regulatory region. Our results suggest that APOBEC3 cytidine deaminases are a plausible cause of the LT truncating mutations in MCPyV+ MCC, while the role of AID in MCC carcinogenesis is unlikely.
Significance:
We uncover APOBEC3 mutation signature in MCPyV LT that reveals the likely cause of mutations underlying MCPyV+ MCC. We further reveal an expression pattern of APOBECs in a large Finnish MCC sample cohort. Thus, the findings presented here suggest a molecular mechanism underlying an aggressive carcinoma with poor prognosis.
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Affiliation(s)
- Anni I. Soikkeli
- 1Unit of Infection and Immunity, Institute of Biomedicine, University of Turku, Turku, Finland
- 2Turku Doctoral Programme of Molecular Medicine, University of Turku, Turku, Finland
| | - Minna K. Kyläniemi
- 3Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Harri Sihto
- 4Department of Pathology, University of Helsinki, Helsinki, Finland
| | - Jukka Alinikula
- 1Unit of Infection and Immunity, Institute of Biomedicine, University of Turku, Turku, Finland
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21
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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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22
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Therapeutic Potential of 5'-Methylschweinfurthin G in Merkel Cell Polyomavirus-Positive Merkel Cell Carcinoma. Viruses 2022; 14:v14091848. [PMID: 36146655 PMCID: PMC9506461 DOI: 10.3390/v14091848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/13/2022] [Accepted: 08/19/2022] [Indexed: 02/08/2023] Open
Abstract
Merkel cell carcinoma (MCC) is a rare but aggressive form of skin cancer predominantly caused by the human Merkel cell polyomavirus (MCPyV). Treatment for MCC includes excision and radiotherapy of local disease, and chemotherapy or immunotherapy for metastatic disease. The schweinfurthin family of natural compounds previously displayed potent and selective growth inhibitory activity against the NCI-60 panel of human-derived cancer cell lines. Here, we investigated the impact of schweinfurthin on human MCC cell lines. Treatment with the schweinfurthin analog, 5'-methylschweinfurth G (MeSG also known as TTI-3114), impaired metabolic activity through induction of an apoptotic pathway. MeSG also selectively inhibited PI3K/AKT and MAPK/ERK pathways in the MCPyV-positive MCC cell line, MS-1. Interestingly, expression of the MCPyV small T (sT) oncogene selectively sensitizes mouse embryonic fibroblasts to MeSG. These results suggest that the schweinfurthin family of compounds display promising potential as a novel therapeutic option for virus-induced MCCs.
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Small DNA tumor viruses and human cancer: Preclinical models of virus infection and disease. Tumour Virus Res 2022; 14:200239. [PMID: 35636683 PMCID: PMC9194455 DOI: 10.1016/j.tvr.2022.200239] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/05/2022] [Accepted: 05/25/2022] [Indexed: 01/13/2023] Open
Abstract
Human tumor viruses cause various human cancers that account for at least 15% of the global cancer burden. Among the currently identified human tumor viruses, two are small DNA tumor viruses: human papillomaviruses (HPVs) and Merkel cell polyomavirus (MCPyV). The study of small DNA tumor viruses (adenoviruses, polyomaviruses, and papillomaviruses) has facilitated several significant biological discoveries and established some of the first animal models of virus-associated cancers. The development and use of preclinical in vivo models to study HPVs and MCPyV and their role in human cancer is the focus of this review. Important considerations in the design of animal models of small DNA tumor virus infection and disease, including host range, cell tropism, choice of virus isolates, and the ability to recapitulate human disease, are presented. The types of infection-based and transgenic model strategies that are used to study HPVs and MCPyV, including their strengths and limitations, are also discussed. An overview of the current models that exist to study HPV and MCPyV infection and neoplastic disease are highlighted. These comparative models provide valuable platforms to study various aspects of virus-associated human disease and will continue to expand knowledge of human tumor viruses and their relationship with their hosts.
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Liu N, Shi F, Yang L, Liao W, Cao Y. Oncogenic viral infection and amino acid metabolism in cancer progression: Molecular insights and clinical implications. Biochim Biophys Acta Rev Cancer 2022; 1877:188724. [DOI: 10.1016/j.bbcan.2022.188724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/15/2022] [Accepted: 03/15/2022] [Indexed: 02/08/2023]
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25
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Genomic evidence suggests that cutaneous neuroendocrine carcinomas can arise from squamous dysplastic precursors. Mod Pathol 2022; 35:506-514. [PMID: 34593967 PMCID: PMC8964828 DOI: 10.1038/s41379-021-00928-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/24/2021] [Accepted: 09/07/2021] [Indexed: 02/06/2023]
Abstract
Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma without a known dysplastic precursor. In some cases, MCC is associated with SCCIS in the overlying epidermis; however, the MCC and SCCIS populations display strikingly different morphologies, and thus far a relationship between these components has not been demonstrated. To better understand the relationship between these distinct tumor cell populations, we evaluated 7 pairs of MCC-SCCIS for overlapping genomic alterations by cancer profiling panel. A subset was further characterized by transcriptional profiling and immunohistochemistry. In 6 of 7 MCC-SCCIS pairs there was highly significant mutational overlap including shared TP53 and/or RB1 mutations. In some cases, oncogenic events previously implicated in MCC (MYCL gain, MDM4 gain, HRAS mutation) were detected in both components. Although FBXW7 mutations were enriched in MCC, no gene mutation was unique to the MCC component across all cases. Transcriptome analysis identified 2736 differentially expressed genes between MCC and SCCIS. Genes upregulated in the MCC component included Polycomb repressive complex targets; downregulated transcripts included epidermal markers, and immune genes such as HLA-A. Immunohistochemical studies revealed increased expression of SOX2 in the MCC component, with diminished H3K27Me3, Rb, and HLA-A expression. In summary, MCC-SCCIS pairs demonstrate clonal relatedness. The shift to neuroendocrine phenotype is associated with loss of Rb protein expression, decrease in global H3K27Me3, and increased expression of Merkel cell genes such as SOX2. Our findings suggest an epidermal origin of MCC in this setting, and to our knowledge provide the first molecular evidence that intraepithelial squamous dysplasia may represent a direct precursor for small cell carcinoma.
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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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27
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Moens U, Prezioso C, Pietropaolo V. Functional Domains of the Early Proteins and Experimental and Epidemiological Studies Suggest a Role for the Novel Human Polyomaviruses in Cancer. Front Microbiol 2022; 13:834368. [PMID: 35250950 PMCID: PMC8894888 DOI: 10.3389/fmicb.2022.834368] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
As their name indicates, polyomaviruses (PyVs) can induce tumors. Mouse PyV, hamster PyV and raccoon PyV have been shown to cause tumors in their natural host. During the last 30 years, 15 PyVs have been isolated from humans. From these, Merkel cell PyV is classified as a Group 2A carcinogenic pathogen (probably carcinogenic to humans), whereas BKPyV and JCPyV are class 2B (possibly carcinogenic to humans) by the International Agency for Research on Cancer. Although the other PyVs recently detected in humans (referred to here as novel HPyV; nHPyV) share many common features with PyVs, including the viral oncoproteins large tumor antigen and small tumor antigen, as their role in cancer is questioned. This review discusses whether the nHPyVs may play a role in cancer based on predicted and experimentally proven functions of their early proteins in oncogenic processes. The functional domains that mediate the oncogenic properties of early proteins of known PyVs, that can cause cancer in their natural host or animal models, have been well characterized and we examined whether these functional domains are conserved in the early proteins of the nHPyVs and presented experimental evidence that these conserved domains are functional. Furthermore, we reviewed the literature describing the detection of nHPyV in human tumors.
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Affiliation(s)
- Ugo Moens
- Faculty of Health Sciences, Department of Medical Biology, University of Tromsø – The Arctic University of Norway, Tromsø, Norway
- *Correspondence: Ugo Moens,
| | - Carla Prezioso
- Microbiology of Chronic Neuro-Degenerative Pathologies, IRCSS San Raffaele Roma, Rome, Italy
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
- Valeria Pietropaolo,
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Ahmed MM, Cushman CH, DeCaprio JA. Merkel Cell Polyomavirus: Oncogenesis in a Stable Genome. Viruses 2021; 14:v14010058. [PMID: 35062263 PMCID: PMC8781562 DOI: 10.3390/v14010058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 12/14/2022] Open
Abstract
Merkel cell polyomavirus (MCV) is the causative agent for the majority of Merkel cell carcinoma (MCC) cases. Polyomavirus-associated MCC (MCCP) is characterized by the integration of MCV DNA into the tumor genome and a low tumor mutational burden. In contrast, nonviral MCC (MCCN) is characterized by a high tumor mutational burden induced by UV damage. Since the discovery of MCV, much work in the field has focused on understanding the molecular mechanisms of oncogenesis driven by the MCV tumor (T) antigens. Here, we review our current understanding of how the activities of large T (LT) and small T (ST) promote MCC oncogenesis in the absence of genomic instability. We highlight how both LT and ST inhibit tumor suppressors to evade growth suppression, an important cancer hallmark. We discuss ST interactions with cellular proteins, with an emphasis on those that contribute to sustaining proliferative signaling. Finally, we examine active areas of research into open questions in the field, including the origin of MCC and mechanisms of viral integration.
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Affiliation(s)
- Mona M. Ahmed
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA; (M.M.A.); (C.H.C.)
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Camille H. Cushman
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA; (M.M.A.); (C.H.C.)
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - James A. DeCaprio
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA; (M.M.A.); (C.H.C.)
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Correspondence:
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29
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Hernandez LE, Mohsin N, Yaghi M, Frech F, Dreyfuss I, Nouri K. Merkel Cell Carcinoma: An updated review of pathogenesis, diagnosis, and treatment options. Dermatol Ther 2021; 35:e15292. [PMID: 34967084 DOI: 10.1111/dth.15292] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 12/26/2021] [Indexed: 11/28/2022]
Abstract
Merkel cell carcinoma is a rare neuroendocrine carcinoma that typically appears in sun-exposed areas of the elderly. It has a poor prognosis and with its incidence projected to increase, it is vital for dermatologists to remain up to date with recent updates in this malignancy's pathogenesis and treatment. In the past few decades Merkel cell carcinoma's pathogenesis, more specifically its relation to the Merkel cell polyomavirus, has sparked further interest in the study of this carcinoma. Most cases are attributed to malignant transformation secondary to the Merkel cell polyomavirus, with a minority derived from DNA damage resulting from ultraviolet radiation. Investigators have also determined that there are immunologic influences in the development and prognosis of Merkel cell carcinoma, as individuals with HIV, solid organ transplants, and lymphoproliferative malignancies are at a greater risk of developing this carcinoma. Also, this immunologic link carries treatment value, as immunologic therapies are currently being investigated. This article provides a comprehensive review of the epidemiology and pathogenesis of Merkel cell carcinoma as well as the current treatments available and clinical trials underway. We also touch upon the updated National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology in respect to its diagnosis and recommended treatment modalities.
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Affiliation(s)
- Loren E Hernandez
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Noreen Mohsin
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Marita Yaghi
- Department of Hematology-Oncology, Maroone Cancer Center, Cleveland Clinic Florida, USA
| | - Fabio Frech
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Isabella Dreyfuss
- Nova Southeastern University, Dr. Kiran C. Patel College of Osteopathic Medicine, Fort Lauderdale, Florida, USA
| | - Keyvan Nouri
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
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Tanda ET, d'Amato AL, Rossi G, Croce E, Boutros A, Cecchi F, Spagnolo F, Queirolo P. Merkel Cell Carcinoma: An Immunotherapy Fairy-Tale? Front Oncol 2021; 11:739006. [PMID: 34631574 PMCID: PMC8495203 DOI: 10.3389/fonc.2021.739006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/02/2021] [Indexed: 12/12/2022] Open
Abstract
Merkel cell carcinoma (MCC) is a rare, highly aggressive, neuroendocrine cutaneous tumor. The incidence of MCC is growing worldwide, and the disease-related mortality is about three-fold higher than melanoma. Since a few years ago, very little has been known about this disease, and chemotherapy has been the standard of care. Nowadays, new discoveries about the pathophysiology of this neoplasm and the introduction of immunotherapy allowed to completely rewrite the history of these patients. In this review, we provide a summary of the most important changes in the management of Merkel cell carcinoma, with a focus on immunotherapy and a landscape of future treatment strategies.
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Affiliation(s)
- Enrica Teresa Tanda
- Genetics of Rare Cancers, Department of Internal Medicine and Medical Specialties, University of Genoa, Genova, Italy.,Medical Oncology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genova, Italy
| | - Agostina Lagodin d'Amato
- Medical Oncology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genova, Italy.,Department of Internal Medicine and Medical Specialties (DiMI), School of Medicine, University of Genova, Genova, Italy
| | - Giovanni Rossi
- Medical Oncology, Ospedale Padre Antero Micone, Genova, Italy.,Department on Medical, Surgical and Experimental Sciences, University of Sassari, Sassari, Italy
| | - Elena Croce
- Medical Oncology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genova, Italy.,Department of Internal Medicine and Medical Specialties (DiMI), School of Medicine, University of Genova, Genova, Italy
| | - Andrea Boutros
- Medical Oncology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genova, Italy.,Department of Internal Medicine and Medical Specialties (DiMI), School of Medicine, University of Genova, Genova, Italy
| | - Federica Cecchi
- Medical Oncology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genova, Italy
| | - Francesco Spagnolo
- Medical Oncology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genova, Italy
| | - Paola Queirolo
- Division of Medical Oncology for Melanoma, Sarcoma, and Rare Tumors, Istituto Europeo di Oncologia (IEO), European Institute of Oncology IRCCS, Milano, Italy
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31
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Dubey AR, Jagtap YA, Kumar P, Patwa SM, Kinger S, Kumar A, Singh S, Prasad A, Jana NR, Mishra A. Biochemical strategies of E3 ubiquitin ligases target viruses in critical diseases. J Cell Biochem 2021; 123:161-182. [PMID: 34520596 DOI: 10.1002/jcb.30143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/23/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022]
Abstract
Viruses are known to cause various diseases in human and also infect other species such as animal plants, fungi, and bacteria. Replication of viruses depends upon their interaction with hosts. Human cells are prone to such unwanted viral infections. Disintegration and reconstitution require host machinery and various macromolecules like DNA, RNA, and proteins are invaded by viral particles. E3 ubiquitin ligases are known for their specific function, that is, recognition of their respective substrates for intracellular degradation. Still, we do not understand how ubiquitin proteasome system-based enzymes E3 ubiquitin ligases do their functional interaction with different viruses. Whether E3 ubiquitin ligases help in the elimination of viral components or viruses utilize their molecular capabilities in their intracellular propagation is not clear. The first time our current article comprehends fundamental concepts and new insights on the different viruses and their interaction with various E3 Ubiquitin Ligases. In this review, we highlight the molecular pathomechanism of viruses linked with E3 Ubiquitin Ligases dependent mechanisms. An enhanced understanding of E3 Ubiquitin Ligase-mediated removal of viral proteins may open new therapeutic strategies against viral infections.
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Affiliation(s)
- Ankur R Dubey
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Yuvraj A Jagtap
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Prashant Kumar
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Som M Patwa
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Sumit Kinger
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, India
| | - Sarika Singh
- Department of Neuroscience and Ageing Biology, Division of Toxicology and Experimental Medicine, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Amit Prasad
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
| | - Nihar R Jana
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Amit Mishra
- Department of Bioscience and Bioengineering, Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
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Innate Immune Evasion of Porcine Epidemic Diarrhea Virus through Degradation of F-box and WD repeat domain-containing 7 protein via Ubiquitin-proteasome Pathway. J Virol 2021; 96:e0088921. [PMID: 34495699 DOI: 10.1128/jvi.00889-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) causes a porcine disease associated with swine epidemic diarrhea. Different antagonistic strategies have been identified, and the mechanism by which PEDV infection impairs the production of interferon (IFN) and delays the activation of the IFN response to escape host innate immunity has been determined, but the pathogenic mechanisms of PEDV infection remain enigmatic. Our preliminary results revealed that endogenous F-box and WD repeat domain-containing 7 (FBXW7), the substrate recognition component of the SCF-type E3 ubiquitin ligase, is downregulated in PEDV-infected Vero E6 cells, according to the results from an isobaric tags for relative and absolute quantification (iTRAQ) analysis. Overexpression of FBXW7 in target cells makes them more resistant to PEDV infection, whereas ablation of FBXW7 expression by small interfering RNA (siRNA) significantly promotes PEDV infection. In addition, FBXW7 was verified as an innate antiviral factor capable of enhancing the expression of RIG-I and TBK1, and it was found to induce interferon-stimulated genes (ISGs), which led to an elevated antiviral state of the host cells. Moreover, we revealed that PEDV nonstructural protein 2 (nsp2) interacts with FBXW7 and targets FBXW7 for degradation through the K48-linked ubiquitin-proteasome pathway. Consistent with the results proven in vitro, FBXW7 reduction was also confirmed in different intestinal tissues from PEDV-infected specific-pathogen-free (SPF) pigs. Taken together, the data indicated that PEDV has evolved with a distinct antagonistic strategy to circumvent the host antiviral response by targeting the ubiquitin-proteasome-mediated degradation of FBXW7. Our findings provide novel insights into PEDV infection and pathogenesis. IMPORTANCE To counteract the host antiviral defenses, most viruses, including coronaviruses, have evolved with diverse strategies to dampen host IFN-mediated antiviral response, wither by interfering with or evading specific host regulators at multiple steps of this response. In this study, a novel antagonistic strategy was revealed showing that PEDV infection could circumvent the host innate response by targeted degradation of endogenous FBXW7 in target cells, a process that was verified to be a positive modulator for the host innate immune system. Degradation of FBXW7 hampers host innate antiviral activation and facilitates PEDV replication. Our findings reveal a new mechanism exploited by PEDV to suppress the host antiviral response.
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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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34
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Rasheed K, Sveinbjørnsson B, Moens U. Reciprocal transactivation of Merkel cell polyomavirus and high-risk human papillomavirus promoter activities and increased expression of their oncoproteins. Virol J 2021; 18:139. [PMID: 34217322 PMCID: PMC8254899 DOI: 10.1186/s12985-021-01613-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/29/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Approximately 15% of human cancers are attributed to viruses. Numerous studies have shown that high-risk human polyomaviruses (HR-HPV) and Merkel cell polyomavirus (MCPyV) are two human tumor viruses associated with anogenetal and oropharyngeal cancers, and with Merkel cell carcinoma, respectively. MCPyV has been found in HR-HPV positive anogenetal and oropharyngeal tumors, suggesting that MCPyV can act as a co-factor in HR-HPV induced oncogenesis. This prompted us to investigate whether the oncoproteins large T-antigen (LT) and small antigen (sT) of MCPyV could affect the transcriptional activity HPV16 and HPV18 and vice versa whether HPV16 and HPV18 E6 and E7 oncoproteins affected the expression of MCPyV LT and sT. Reciprocal stimulation of these viral oncoproteinscould enhance the oncogenic processes triggered by these tumor viruses. METHODS Transient co-transfection studies using a luciferase reporter plasmid with the long control region of HPV16 or HPV18, or the early or late promoter of MCPyV and expression plasmids for LT and sT, or E6 and E7, respectively were performed in the HPV-negative cervical cancer cell line C33A, in the keratinocyte cell line HaCaT, and in the oral squamous cell carcinoma cell line HSC-3. Transfections were also performed with deletion mutants of all these promoters and with mutants of all four oncoproteins. Finally, the effect of E6 and E7 on LT and sT expression in the MCPyV-positive Merkel cell carcinoma cell line WaGa and the effect of LT and sT on the expression of E6 and E7 was monitored by Western blotting. RESULTS LT and sT stimulated the transcriptional activity of the HPV16 and HPV18 LCR and v.v. E6 and E7 potentiated the MCPyV early and late promoter in all cell lines. Induction by E6 and E7 was p53- and pRb-independent, and transactivation by LT did not require DNA binding, nuclear localization and HSC70/pRb interaction, whereas sT stimulated the HPV16/18 LCR activity in a PP2A- and DnaJ-independent manner. CONCLUSIONS These results indicate that the co-infection of MCPyV may act as a co-factor in the initiation and/or progression of HPV-induced cancers.
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Affiliation(s)
- Kashif Rasheed
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, 9037, Tromsø, Norway.,Institute for Clinical and Molecular Medicine, Norwegian University of Science and Technology, NTNU Trondheim, Trondheim, Norway
| | - Baldur Sveinbjørnsson
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, 9037, Tromsø, Norway.,Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, 1176, Stockholm, Sweden
| | - Ugo Moens
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, 9037, Tromsø, Norway.
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35
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Stachyra K, Dudzisz-Śledź M, Bylina E, Szumera-Ciećkiewicz A, Spałek MJ, Bartnik E, Rutkowski P, Czarnecka AM. Merkel Cell Carcinoma from Molecular Pathology to Novel Therapies. Int J Mol Sci 2021; 22:6305. [PMID: 34208339 PMCID: PMC8231245 DOI: 10.3390/ijms22126305] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/24/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
Merkel cell carcinoma (MCC) is an uncommon and highly aggressive skin cancer. It develops mostly within chronically sun-exposed areas of the skin. MCPyV is detected in 60-80% of MCC cases as integrated within the genome and is considered a major risk factor for MCC. Viral negative MCCs have a high mutation burden with a UV damage signature. Aberrations occur in RB1, TP53, and NOTCH genes as well as in the PI3K-AKT-mTOR pathway. MCC is highly immunogenic, but MCC cells are known to evade the host's immune response. Despite the characteristic immunohistological profile of MCC, the diagnosis is challenging, and it should be confirmed by an experienced pathologist. Sentinel lymph node biopsy is considered the most reliable staging tool to identify subclinical nodal disease. Subclinical node metastases are present in about 30-50% of patients with primary MCC. The basis of MCC treatment is surgical excision. MCC is highly radiosensitive. It becomes chemoresistant within a few months. MCC is prone to recurrence. The outcomes in patients with metastatic disease are poor, with a historical 5-year survival of 13.5%. The median progression-free survival is 3-5 months, and the median overall survival is ten months. Currently, immunotherapy has become a standard of care first-line therapy for advanced MCC.
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Affiliation(s)
- Karolina Stachyra
- Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland; (K.S.); (M.D.-Ś.); (E.B.); (M.J.S.); (P.R.)
- Faculty of Medicine, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Monika Dudzisz-Śledź
- Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland; (K.S.); (M.D.-Ś.); (E.B.); (M.J.S.); (P.R.)
| | - Elżbieta Bylina
- Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland; (K.S.); (M.D.-Ś.); (E.B.); (M.J.S.); (P.R.)
- Department of Clinical Trials, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Anna Szumera-Ciećkiewicz
- Department of Pathology and Laboratory Diagnostics, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland;
- Department of Diagnostic Hematology, Institute of Hematology and Transfusion Medicine, 00-791 Warsaw, Poland
| | - Mateusz J. Spałek
- Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland; (K.S.); (M.D.-Ś.); (E.B.); (M.J.S.); (P.R.)
| | - Ewa Bartnik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland;
| | - Piotr Rutkowski
- Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland; (K.S.); (M.D.-Ś.); (E.B.); (M.J.S.); (P.R.)
| | - Anna M. Czarnecka
- Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland; (K.S.); (M.D.-Ś.); (E.B.); (M.J.S.); (P.R.)
- Department of Experimental Pharmacology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland
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Abstract
Polyomaviruses are a family of non-enveloped DNA viruses with wide host ranges. Human polyomaviruses typically cause asymptomatic infection and establish persistence but can be reactivated under certain conditions and cause severe diseases. Most well studied polyomaviruses encode a viral miRNA that regulates viral replication and pathogenesis by targeting both viral early genes and host genes. In this review, we summarize the current knowledge of polyomavirus miRNAs involved in virus infection. We review in detail the regulation of polyomavirus miRNA expression, as well as the role polyomavirus miRNAs play in viral pathogenesis by controlling both host and viral gene expression. An overview of the potential application of polyomavirus miRNA as a marker for the progression of polyomaviruses associated diseases and polyomaviruses reactivation is also included.
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Affiliation(s)
- Wei Zou
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
| | - Michael J Imperiale
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
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Distinct Signatures of Genomic Copy Number Variants Define Subgroups of Merkel Cell Carcinoma Tumors. Cancers (Basel) 2021; 13:cancers13051134. [PMID: 33800889 PMCID: PMC7961454 DOI: 10.3390/cancers13051134] [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: 01/25/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Cancer results from genetic changes in cells. These changes are often mutations that alter the DNA sequence of critical genes. However, duplications and deletions in cancer-related genes can also contribute to malignant transformation. In this study we use Nanostring technology to assess DNA copy number changes in samples of Merkel cell carcinoma (MCC), a rare and aggressive neuroendocrine skin tumor. We were able to identify recurrent amplifications and deletions in cancer-related genes. We also found that MCC tumors grouped into three distinct copy number variant profiles. The first group consisted of tumors with multiple deletions. The second group contained tumors with low levels of genomic structural alterations. The last group comprised tumors containing multiple amplifications. Our study suggests that most MCC tumors are associated with deletions in cancer-related genes or are lacking in copy number changes, whereas a small percentage of tumors are associated with genomic amplifications. Abstract Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer. Most MCC tumors contain integrated Merkel cell polyomavirus DNA (virus-positive MCC, VP-MCC) and carry a low somatic mutation burden whereas virus-negative MCC (VN-MCC) possess numerous ultraviolet-signature mutations. In contrast to viral oncogenes and sequence mutations, little is known about genomic structural variants in MCC. To identify copy number variants in commonly altered genes, we analyzed genomic DNA from 31 tumor samples using the Nanostring nCounter copy number cancer panel. Unsupervised clustering revealed three tumor groups with distinct genomic structural variant signatures. The first cluster was characterized by multiple recurrent deletions in genes such as RB1 and WT1. The second cluster contained eight VP-MCC and displayed very few structural variations. The final cluster contained one VP-MCC and four VN-MCC with predominantly genomic amplifications in genes like MDM4, SKP2, and KIT and deletions in TP53. Overall, VN-MCC contained more structure variation than VP-MCC but did not cluster separately from VP-MCC. The observation that most MCC tumors demonstrate a deletion-dominated structural group signature, independent of virus status, suggests a shared pathophysiology among most VP-MCC and VN-MCC tumors.
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Merkel cell polyomavirus small tumour antigen activates the p38 MAPK pathway to enhance cellular motility. Biochem J 2021; 477:2721-2733. [PMID: 32639530 PMCID: PMC7398664 DOI: 10.1042/bcj20200399] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 12/26/2022]
Abstract
Merkel cell carcinoma (MCC) is an aggressive skin cancer with high rates of recurrence and metastasis. Merkel cell polyomavirus (MCPyV) is associated with the majority of MCC cases. MCPyV-induced tumourigenesis is largely dependent on the expression of the small tumour antigen (ST). Recent findings implicate MCPyV ST expression in the highly metastatic nature of MCC by promoting cell motility and migration, through differential expression of cellular proteins that lead to microtubule destabilisation, filopodium formation and breakdown of cell-cell junctions. However, the molecular mechanisms which dysregulate these cellular processes are yet to be fully elucidated. Here, we demonstrate that MCPyV ST expression activates p38 MAPK signalling to drive cell migration and motility. Notably, MCPyV ST-mediated p38 MAPK signalling occurs through MKK4, as opposed to the canonical MKK3/6 signalling pathway. In addition, our results indicate that an interaction between MCPyV ST and the cellular phospatase subunit PP4C is essential for its effect on p38 MAPK signalling. These results provide novel opportunities for the treatment of metastatic MCC given the intense interest in p38 MAPK inhibitors as therapeutic agents.
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Pearson VR, Bosse JB, Koyuncu OO, Scherer J, Toruno C, Robinson R, Abegglen LM, Schiffman JD, Enquist LW, Rall GF. Identification of African Elephant Polyomavirus in wild elephants and the creation of a vector expressing its viral tumor antigens to transform elephant primary cells. PLoS One 2021; 16:e0244334. [PMID: 33544724 PMCID: PMC7864673 DOI: 10.1371/journal.pone.0244334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/07/2020] [Indexed: 11/29/2022] Open
Abstract
Wild elephant populations are declining rapidly due to rampant killing for ivory and body parts, range fragmentation, and human-elephant conflict. Wild and captive elephants are further impacted by viruses, including highly pathogenic elephant endotheliotropic herpesviruses. Moreover, while the rich genetic diversity of the ancient elephant lineage is disappearing, elephants, with their low incidence of cancer, have emerged as a surprising resource in human cancer research for understanding the intrinsic cellular response to DNA damage. However, studies on cellular resistance to transformation and herpesvirus reproduction have been severely limited, in part due to the lack of established elephant cell lines to enable in vitro experiments. This report describes creation of a recombinant plasmid, pAelPyV-1-Tag, derived from a wild isolate of African Elephant Polyomavirus (AelPyV-1), that can be used to create immortalized lines of elephant cells. This isolate was extracted from a trunk nodule biopsy isolated from a wild African elephant, Loxodonta africana, in Botswana. The AelPyV-1 genome contains open-reading frames encoding the canonical large (LTag) and small (STag) tumor antigens. We cloned the entire early region spanning the LTag and overlapping STag genes from this isolate into a high-copy vector to construct a recombinant plasmid, pAelPyV-1-Tag, which effectively transformed primary elephant endothelial cells. We expect that the potential of this reagent to transform elephant primary cells will, at a minimum, facilitate study of elephant-specific herpesviruses.
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Affiliation(s)
- Virginia R. Pearson
- Fox Chase Cancer Center, Program in Blood Cell Development and Function, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Jens B. Bosse
- RESIST Cluster of Excellence, Institute of Virology at Hannover Medical School, Center for Structural Systems Biology, Hamburg, Germany
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Orkide O. Koyuncu
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States of America
| | - Julian Scherer
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States of America
| | - Cristhian Toruno
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Rosann Robinson
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Lisa M. Abegglen
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Joshua D. Schiffman
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Lynn W. Enquist
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States of America
| | - Glenn F. Rall
- Fox Chase Cancer Center, Program in Blood Cell Development and Function, Philadelphia, Pennsylvania, United States of America
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Mokánszki A, Méhes G, Csoma SL, Kollár S, Chang Chien YC. Molecular Profiling of Merkel Cell Polyomavirus-Associated Merkel Cell Carcinoma and Cutaneous Melanoma. Diagnostics (Basel) 2021; 11:diagnostics11020212. [PMID: 33535453 PMCID: PMC7912722 DOI: 10.3390/diagnostics11020212] [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: 12/22/2020] [Revised: 01/25/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
Merkel cell carcinoma (MCC) is a rare, high-grade, aggressive cutaneous neuroendocrine malignancy most commonly associated with sun-exposed areas of older individuals. A relatively newly identified human virus, the Merkel cell polyomavirus (MCPyV) has been implicated in the pathogenesis of MCC. Our study aimed to examine nine MCC cases and randomly selected 60 melanoma cases to identify MCPyV status and to elucidate genetic differences between virus-positive and -negative cases. Altogether, seven MCPyV-positive MCC samples and four melanoma samples were analyzed. In MCPyV-positive MCC RB1, TP53, FBXW7, CTNNB1, and HNF1A pathogenic variants were identified, while in virus-negative cases only benign variants were found. In MCPyV-positive melanoma cases, besides BRAF mutations the following genes were also affected: PIK3CA, STK11, CDKN2A, SMAD4, and APC. In contrast to studies found in the literature, a higher tumor burden was detected in virus-associated MCC compared to MCPyV-negative cases. No association was identified between virus infection and tumor burden in melanoma samples. We concluded that analyzing the key morphologic and immunohistological features of MCC is critical to avoid confusion with other cutaneous malignancies. Molecular genetic investigations such as next-generation sequencing (NGS) enable molecular stratification, which may have future clinical impact.
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Affiliation(s)
- Attila Mokánszki
- Department of Pathology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (G.M.); (S.L.C.); (Y.-C.C.C.)
- Correspondence: ; Tel.: +36-52-411-600
| | - Gábor Méhes
- Department of Pathology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (G.M.); (S.L.C.); (Y.-C.C.C.)
| | - Szilvia Lilla Csoma
- Department of Pathology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (G.M.); (S.L.C.); (Y.-C.C.C.)
| | - Sándor Kollár
- Department of Pathology, Kenézy Gyula Teaching Hospital, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Yi-Che Chang Chien
- Department of Pathology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (G.M.); (S.L.C.); (Y.-C.C.C.)
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Loke ASW, Longley BJ, Lambert PF, Spurgeon ME. A Novel In Vitro Culture Model System to Study Merkel Cell Polyomavirus-Associated MCC Using Three-Dimensional Organotypic Raft Equivalents of Human Skin. Viruses 2021; 13:138. [PMID: 33478104 PMCID: PMC7835998 DOI: 10.3390/v13010138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 01/14/2021] [Indexed: 12/24/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) is a human polyomavirus causally linked to the development of Merkel cell carcinoma (MCC), an aggressive malignancy that largely arises within the dermis of the skin. In this study, we recapitulate the histopathology of human MCC tumors in vitro using an organotypic (raft) culture system that is traditionally used to recapitulate the dermal and epidermal equivalents of skin in three dimensions (3D). In the optimal culture condition, MCPyV+ MCC cells were embedded in collagen between the epidermal equivalent comprising human keratinocytes and a dermal equivalent containing fibroblasts, resulting in MCC-like lesions arising within the dermal equivalent. The presence and organization of MCC cells within these dermal lesions were characterized through biomarker analyses. Interestingly, co-culture of MCPyV+ MCC together with keratinocytes specifically within the epidermal equivalent of the raft did not reproduce human MCC morphology, nor were any keratinocytes necessary for MCC-like lesions to develop in the dermal equivalent. This 3D tissue culture system provides a novel in vitro platform for studying the role of MCPyV T antigens in MCC oncogenesis, identifying additional factors involved in this process, and for screening potential MCPyV+ MCC therapeutic strategies.
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Affiliation(s)
- Amanda S. W. Loke
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine & Public Health, Madison, WI 53705, USA;
| | - B. Jack Longley
- Department of Dermatology, University of Wisconsin School of Medicine & Public Health, Madison, WI 53705, USA;
| | - Paul F. Lambert
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine & Public Health, Madison, WI 53705, USA;
| | - Megan E. Spurgeon
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine & Public Health, Madison, WI 53705, USA;
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Scott TA, Morris KV. Designer nucleases to treat malignant cancers driven by viral oncogenes. Virol J 2021; 18:18. [PMID: 33441159 PMCID: PMC7805041 DOI: 10.1186/s12985-021-01488-1] [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: 11/11/2020] [Accepted: 01/02/2021] [Indexed: 11/22/2022] Open
Abstract
Viral oncogenic transformation of healthy cells into a malignant state is a well-established phenomenon but took decades from the discovery of tumor-associated viruses to their accepted and established roles in oncogenesis. Viruses cause ~ 15% of know cancers and represents a significant global health burden. Beyond simply causing cellular transformation into a malignant form, a number of these cancers are augmented by a subset of viral factors that significantly enhance the tumor phenotype and, in some cases, are locked in a state of oncogenic addiction, and substantial research has elucidated the mechanisms in these cancers providing a rationale for targeted inactivation of the viral components as a treatment strategy. In many of these virus-associated cancers, the prognosis remains extremely poor, and novel drug approaches are urgently needed. Unlike non-specific small-molecule drug screens or the broad-acting toxic effects of chemo- and radiation therapy, the age of designer nucleases permits a rational approach to inactivating disease-causing targets, allowing for permanent inactivation of viral elements to inhibit tumorigenesis with growing evidence to support their efficacy in this role. Although many challenges remain for the clinical application of designer nucleases towards viral oncogenes; the uniqueness and clear molecular mechanism of these targets, combined with the distinct advantages of specific and permanent inactivation by nucleases, argues for their development as next-generation treatments for this aggressive group of cancers.
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Affiliation(s)
- Tristan A Scott
- Center for Gene Therapy, City of Hope, Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA.
| | - Kevin V Morris
- Center for Gene Therapy, City of Hope, Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA
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Abstract
Merkel cell polyomavirus (MCPyV) is the most recently discovered human oncogenic virus. MCPyV asymptomatically infects most of the human population. In the elderly and immunocompromised, however, it can cause a highly lethal form of human skin cancer called Merkel cell carcinoma (MCC). Distinct from the productive MCPyV infection that replicates the viral genome as episomes, MCC tumors contain replication-incompetent, integrated viral genomes. Mutant MCPyV tumor antigen genes expressed from the integrated viral genomes are essential for driving the oncogenic development of MCPyV-associated MCC. In this chapter, we summarize recent discoveries on MCPyV virology, mechanisms of MCPyV-mediated oncogenesis, and the current therapeutic strategies for MCPyV-associated MCCs.
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Affiliation(s)
- Wei Liu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Merkel Cell Polyomavirus Encodes Circular RNAs (circRNAs) Enabling a Dynamic circRNA/microRNA/mRNA Regulatory Network. mBio 2020; 11:mBio.03059-20. [PMID: 33323517 PMCID: PMC7773998 DOI: 10.1128/mbio.03059-20] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Viral noncoding RNAs have acquired increasing prominence as important regulators of infection and mediators of pathogenesis. Circular RNAs (circRNAs) generated by backsplicing events have been identified in several oncogenic human DNA viruses. Here, we show that Merkel cell polyomavirus (MCV), the etiologic cause of ∼80% of Merkel cell carcinomas (MCCs), also expresses circular RNAs. By RNase R-resistant RNA sequencing, four putative circRNA backsplice junctions (BSJs) were identified from the MCV early region (ER). The most abundantly expressed MCV circRNA, designated circMCV-T, is generated through backsplicing of all of ER exon II to form a 762-nucleotide (nt) circular RNA molecule. Curiously, circMCV-T, as well as two other less abundantly expressed putative MCV circRNAs, overlaps in a complementary fashion with the MCV microRNA (miRNA) locus that encodes MCV-miR-M1. circMCV-T is consistently detected in concert with linear T antigen transcripts throughout infection, suggesting a crucial role for this RNA molecule in the regulatory functions of the early region, known to be vital for viral replication. Knocking out the hairpin structure of MCV-miR-M1 in genomic early region expression constructs and using a new high-efficiency, recombinase-mediated, recircularized MCV molecular clone demonstrates that circMCV-T levels decrease in the presence of MCV-miR-M1, underscoring the interplay between MCV circRNA and miRNA. Furthermore, circMCV-T partially reverses the known inhibitory effect of MCV-miR-M1 on early gene expression. RNase R-resistant RNA sequencing of lytic rat polyomavirus 2 (RatPyV2) identified an analogously located circRNA, stipulating a crucial, conserved regulatory function of this class of RNA molecules in the family of polyomaviruses.IMPORTANCE Covalently closed circular RNAs were recently described in the human DNA tumor viruses Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), and human papillomavirus (HPV). Here, we show that MCV, another DNA tumor virus, generates circRNAs from its early regulatory region in concert with T antigen linear transcripts. MCV circMCV-T interacts with another MCV noncoding RNA, miR-M1, to functionally modulate early region transcript expression important for viral replication and long-term episomal persistence. This work describes a dynamic regulatory network integrating circRNA/miRNA/mRNA biomolecules and underscores the intricate functional modulation between several classes of polyomavirus-encoded RNAs in the control of viral replication.
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A Comprehensive Proteomics Analysis of the JC Virus (JCV) Large and Small Tumor Antigen Interacting Proteins: Large T Primarily Targets the Host Protein Complexes with V-ATPase and Ubiquitin Ligase Activities While Small t Mostly Associates with Those Having Phosphatase and Chromatin-Remodeling Functions. Viruses 2020; 12:v12101192. [PMID: 33092197 PMCID: PMC7594058 DOI: 10.3390/v12101192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 02/06/2023] Open
Abstract
The oncogenic potential of both the polyomavirus large (LT-Ag) and small (Sm t-Ag) tumor antigens has been previously demonstrated in both tissue culture and animal models. Even the contribution of the MCPyV tumor antigens to the development of an aggressive human skin cancer, Merkel cell carcinoma, has been recently established. To date, the known primary targets of these tumor antigens include several tumor suppressors such as pRb, p53, and PP2A. However, a comprehensive list of the host proteins targeted by these proteins remains largely unknown. Here, we report the first interactome of JCV LT-Ag and Sm t-Ag by employing two independent “affinity purification/mass spectroscopy” (AP/MS) assays. The proteomics data identified novel targets for both tumor antigens while confirming some of the previously reported interactions. LT-Ag was found to primarily target the protein complexes with ATPase (v-ATPase and Smc5/6 complex), phosphatase (PP4 and PP1), and ligase (E3-ubiquitin) activities. In contrast, the major targets of Sm t-Ag were identified as Smarca1/6, AIFM1, SdhA/B, PP2A, and p53. The interactions between “LT-Ag and SdhB”, “Sm t-Ag and Smarca5”, and “Sm t-Ag and SDH” were further validated by biochemical assays. Interestingly, perturbations in some of the LT-Ag and Sm t-Ag targets identified in this study were previously shown to be associated with oncogenesis, suggesting new roles for both tumor antigens in novel oncogenic pathways. This comprehensive data establishes new foundations to further unravel the new roles for JCV tumor antigens in oncogenesis and the viral life cycle.
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Lauver MD, Lukacher AE. JCPyV VP1 Mutations in Progressive MultifocalLeukoencephalopathy: Altering Tropismor Mediating Immune Evasion? Viruses 2020; 12:v12101156. [PMID: 33053912 PMCID: PMC7600905 DOI: 10.3390/v12101156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 12/15/2022] Open
Abstract
Polyomaviruses are ubiquitous human pathogens that cause lifelong, asymptomatic infections in healthy individuals. Although these viruses are restrained by an intact immune system, immunocompromised individuals are at risk for developing severe diseases driven by resurgent viral replication. In particular, loss of immune control over JC polyomavirus can lead to the development of the demyelinating brain disease progressive multifocal leukoencephalopathy (PML). Viral isolates from PML patients frequently carry point mutations in the major capsid protein, VP1, which mediates virion binding to cellular glycan receptors. Because polyomaviruses are non-enveloped, VP1 is also the target of the host's neutralizing antibody response. Thus, VP1 mutations could affect tropism and/or recognition by polyomavirus-specific antibodies. How these mutations predispose susceptible individuals to PML and other JCPyV-associated CNS diseases remains to be fully elucidated. Here, we review the current understanding of polyomavirus capsid mutations and their effects on viral tropism, immune evasion, and virulence.
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Abstract
PURPOSE OF REVIEW Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer, which is associated in 80% of cases with the Merkel cell polyomavirus (MCPyV). Advanced stages respond to immune checkpoint inhibitors in 50% of cases. Major issues remain unanswered regarding its oncogenesis and optimal treatment. RECENT FINDINGS MCPyV-negative and MCPyV-positive MCCs have been hypothesized to derive from distinct cells, although the cell of origin remains a matter of debate. The crucial role the MCPyV small T oncoprotein was recently confirmed by its ability to inactivate p53, together with its contribution to the metastatic progression. In advanced cases, tumoral microenvironment may adequately predict responses to immunotherapies, and several mechanisms of primary and secondary resistance have been investigated. SUMMARY Identifying the mechanisms of oncogenesis allow experimentation of new therapeutic targets, which remain mandatory even at the era of immunotherapies. Although new insights in the mechanisms of primary and secondary resistance pave the way for development of further immunotherapy strategies, neoadjuvant strategies may challenge our whole approach of the disease.
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Merkel Cell Polyomavirus Large T Antigen Unique Domain Regulates Its Own Protein Stability and Cell Growth. Viruses 2020; 12:v12091043. [PMID: 32962090 PMCID: PMC7551350 DOI: 10.3390/v12091043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 02/07/2023] Open
Abstract
Merkel cell polyomavirus (MCV) is the only known human oncogenic virus in the polyomaviridae family and the etiological agent of most Merkel cell carcinomas (MCC). MCC is an aggressive and highly metastatic skin cancer with a propensity for recurrence and poor prognosis. Large tumor antigen (LT), is an essential oncoprotein for MCV transcription, viral replication, and cancer cell proliferation. MCV LT is a short-lived protein that encodes a unique domain: MCV LT unique regions (MURs). These domains consist of phosphorylation sites that interact with multiple E3 ligases, thus limiting LT expression and consequently, viral replication. In this study, we show that MURs are necessary for regulating LT stability via multiple E3 ligase interactions, resulting in cell growth arrest. While expression of wild-type MCV LT induced a decrease in cellular proliferation, deletion of the MUR domains resulted in increased LT stability and cell proliferation. Conversely, addition of MURs to SV40 LT propagated E3 ligase interactions, which in turn, reduced SV40 LT stability and decreased cell growth activity. Our results demonstrate that compared to other human polyomaviruses (HPyVs), MCV LT has evolved to acquire the MUR domains that are essential for MCV LT autoregulation, potentially leading to viral latency and MCC.
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Merkel Cell Polyomavirus Small Tumor Antigen Activates Matrix Metallopeptidase-9 Gene Expression for Cell Migration and Invasion. J Virol 2020; 94:JVI.00786-20. [PMID: 32669331 DOI: 10.1128/jvi.00786-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/02/2020] [Indexed: 01/10/2023] Open
Abstract
Merkel cell polyomavirus (MCV) small T antigen (sT) is the main oncoprotein for the development of Merkel cell carcinoma (MCC). MCC is a rare, clinically aggressive neuroendocrine tumor of the skin with a high propensity for local, regional, and distant spread. The dysregulation of matrix metalloproteinase-9 (MMP-9) has been implicated in multiple essential roles in the development of various malignant tumor cell invasion and metastasis. Previously, MCV sT was shown to induce the migratory and invasive phenotype of MCC cells through the transcriptional activation of the sheddase molecule, ADAM 10 (A disintegrin and metalloprotease domain-containing protein 10). In this study, we show that MCV sT protein stimulates differential expression of epithelial-mesenchymal transition (EMT)-associated genes, including MMP-9 and Snail. This effect is dependent on the presence of the large T stabilization domain (LSD), which is known to be responsible for cell transformation through targeting of promiscuous E3 ligases, including FBW7, a known MMP-9 and Snail regulator. Chemical treatments of MMP-9 markedly inhibited MCV sT-induced cell migration and invasion. These results suggest that MCV sT contributes to the activation of MMP-9 as a result of FBW7 targeting and increases the invasive potential of cells, which can be used for targeted therapeutic intervention.IMPORTANCE Merkel cell carcinoma (MCC) is the most aggressive cutaneous tumor without clearly defined treatment. Although MCC has a high propensity for metastasis, little is known about the underlying mechanisms that drive MCC invasion and metastatic progression. MMP-9 has been shown to play a detrimental role in many metastatic human cancers, including melanoma and other nonmelanoma skin cancers. Our study shows that MCV sT-mediated MMP-9 activation is driven through the LSD, a known E3 ligase-targeting domain, in MCC. MMP-9 may serve as the biochemical culprit to target and develop a novel approach for the treatment of metastatic MCC.
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Zhao J, Jia Y, Shen S, Kim J, Wang X, Lee E, Brownell I, Cho-Vega JH, Lewis C, Homsi J, Sharma RR, Wang RC. Merkel Cell Polyomavirus Small T Antigen Activates Noncanonical NF-κB Signaling to Promote Tumorigenesis. Mol Cancer Res 2020; 18:1623-1637. [PMID: 32753470 DOI: 10.1158/1541-7786.mcr-20-0587] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 01/21/2023]
Abstract
Multiple human polyomaviruses (HPyV) can infect the skin, but only Merkel cell polyomavirus (MCPyV) has been implicated in the development of a cancer, Merkel cell carcinoma (MCC). While expression of HPyV6, HPyV7, and MCPyV small T antigens (sT), all induced a senescence-associated secretory phenotype (SASP), MCPyV sT uniquely activated noncanonical NF-κB (ncNF-κB), instead of canonical NF-κB signaling, to evade p53-mediated cellular senescence. Through its large T stabilization domain, MCPyV sT activated ncNF-κB signaling both by inducing H3K4 trimethylation-mediated increases of NFKB2 and RELB transcription and also by promoting NFKB2 stabilization and activation through FBXW7 inhibition. Noncanonical NF-κB signaling was required for SASP cytokine secretion, which promoted the proliferation of MCPyV sT-expressing cells through autocrine signaling. Virus-positive MCC cell lines and tumors showed ncNF-κB pathway activation and SASP gene expression, and the inhibition of ncNF-κB signaling prevented VP-MCC cell growth in vitro and in xenografts. We identify MCPyV sT-induced ncNF-κB signaling as an essential tumorigenic pathway in MCC. IMPLICATIONS: This work is the first to identify the activation of ncNF-κB signaling by any polyomavirus and its critical role in MCC tumorigenesis.
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Affiliation(s)
- Jiawei Zhao
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas.
| | - Yuemeng Jia
- Children's Research Institute, UT Southwestern Medical Center, Dallas, Texas
| | - Shunli Shen
- Department of Hepatic Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jiwoong Kim
- Department of Clinical Science, UT Southwestern Medical Center, Dallas, Texas
| | - Xun Wang
- Children's Research Institute, UT Southwestern Medical Center, Dallas, Texas
| | - Eunice Lee
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas
| | - Isaac Brownell
- Cutaneous Development and Carcinogenesis Section, NIAMS, Bethesda, Maryland
| | - Jeong Hee Cho-Vega
- Department of Pathology and Laboratory Medicine, Sylvester Comprehensive Cancer Center and Miller School of Medicine, University of Miami, Miami, Florida
| | - Cheryl Lewis
- Harold C. Simmons Cancer Center, UT Southwestern Medical Center, Dallas, Texas
| | - Jade Homsi
- Harold C. Simmons Cancer Center, UT Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Rohit R Sharma
- Harold C. Simmons Cancer Center, UT Southwestern Medical Center, Dallas, Texas.,Department of Surgery, UT Southwestern Medical Center, Dallas, Texas
| | - Richard C Wang
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas. .,Harold C. Simmons Cancer Center, UT Southwestern Medical Center, Dallas, Texas
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