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Ohnezeit D, Huang J, Westerkamp U, Brinschwitz V, Schmidt C, Günther T, Czech-Sioli M, Weißelberg S, Schlemeyer T, Nakel J, Mai J, Schreiner S, Schneider C, Friedel CC, Schwanke H, Brinkmann MM, Grundhoff A, Fischer N. Merkel cell polyomavirus small tumor antigen contributes to immune evasion by interfering with type I interferon signaling. PLoS Pathog 2024; 20:e1012426. [PMID: 39110744 PMCID: PMC11333005 DOI: 10.1371/journal.ppat.1012426] [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: 08/09/2023] [Revised: 08/19/2024] [Accepted: 07/15/2024] [Indexed: 08/21/2024] Open
Abstract
Merkel cell polyomavirus (MCPyV) is the causative agent of the majority of Merkel cell carcinomas (MCC). The virus has limited coding capacity, with its early viral proteins, large T (LT) and small T (sT), being multifunctional and contributing to infection and transformation. A fundamental difference in early viral gene expression between infection and MCPyV-driven tumorigenesis is the expression of a truncated LT (LTtr) in the tumor. In contrast, sT is expressed in both conditions and contributes significantly to oncogenesis. Here, we identified novel functions of early viral proteins by performing genome-wide transcriptome and chromatin studies in primary human fibroblasts. Due to current limitations in infection and tumorigenesis models, we mimic these conditions by ectopically expressing sT, LT or LTtr, individually or in combination, at different time points. In addition to its known function in cell cycle and inflammation modulation, we reveal a fundamentally new function of sT. We show that sT regulates the type I interferon (IFN) response downstream of the type I interferon receptor (IFNAR) by interfering with the interferon-stimulated gene factor 3 (ISGF3)-induced interferon-stimulated gene (ISG) response. Expression of sT leads to a reduction in the expression of interferon regulatory factor 9 (IRF9) which is a central component of the ISGF3 complex. We further show that this function of sT is conserved in BKPyV. We provide a first mechanistic understanding of which early viral proteins trigger and control the type I IFN response, which may influence MCPyV infection, persistence and, during MCC progression, regulation of the tumor microenvironment.
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Affiliation(s)
- Denise Ohnezeit
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jiabin Huang
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ute Westerkamp
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Veronika Brinschwitz
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Claudia Schmidt
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Manja Czech-Sioli
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Samira Weißelberg
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tabea Schlemeyer
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Julia Mai
- Institute of Virology, Hannover Medical School, Hannover, Germany
- Institute of Virology, Freiburg, Germany
| | - Sabrina Schreiner
- Institute of Virology, Hannover Medical School, Hannover, Germany
- Institute of Virology, Freiburg, Germany
| | | | - Caroline C. Friedel
- Institute of Informatics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Hella Schwanke
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Melanie M. Brinkmann
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Nicole Fischer
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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2
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Li Z, Ji W, Hu Q, Zhu P, Jin Y, Duan G. Current status of Merkel cell carcinoma: Epidemiology, pathogenesis and prognostic factors. Virology 2024; 599:110186. [PMID: 39098121 DOI: 10.1016/j.virol.2024.110186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 07/09/2024] [Accepted: 07/20/2024] [Indexed: 08/06/2024]
Abstract
Merkel cell carcinoma (MCC) is an extremely rare cutaneous neuroendocrine cancer, with an incidence approximately 40 times lower than that of malignant melanoma; however, its significantly inferior survival rate compared to melanoma establishes MCC as the most lethal form of skin cancer. In recent years, a substantial body of literature has demonstrated a gradual increase in the incidence of MCC. Although the two factors that contribute to MCC, ultraviolet radiation and Merkel cell polyomavirus infection, have been well established, the specific pathogenesis of this disease remains unclear. Additionally, considering the high lethality and recurrence rates of MCC, as well as the absence of specific antitumor drugs, it is crucial to elucidate the factors that can accurately predict patients' outcomes. In this review, we summarized the significant advancements in the epidemiological characteristics, pathogenesis, and the factors that influence patient prognosis of MCC to enhance clinical practices and public health efforts.
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Affiliation(s)
- Zijie Li
- Department of Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Wangquan Ji
- Department of Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Quanman Hu
- Department of Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Peiyu Zhu
- Department of Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Yuefei Jin
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Zhengzhou, 450018, China.
| | - Guangcai Duan
- Department of Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, 450001, China.
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3
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Pedersen EA, Verhaegen ME, Joseph MK, Harms KL, Harms PW. Merkel cell carcinoma: updates in tumor biology, emerging therapies, and preclinical models. Front Oncol 2024; 14:1413793. [PMID: 39136002 PMCID: PMC11317257 DOI: 10.3389/fonc.2024.1413793] [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: 04/07/2024] [Accepted: 07/08/2024] [Indexed: 08/15/2024] Open
Abstract
Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma thought to arise via either viral (Merkel cell polyomavirus) or ultraviolet-associated pathways. Surgery and radiotherapy have historically been mainstays of management, and immunotherapy has improved outcomes for advanced disease. However, there remains a lack of effective therapy for those patients who fail to respond to these established approaches, underscoring a critical need to better understand MCC biology for more effective prognosis and treatment. Here, we review the fundamental aspects of MCC biology and the recent advances which have had profound impact on management. The first genetically-engineered mouse models for MCC tumorigenesis provide opportunities to understand the potential MCC cell of origin and may prove useful for preclinical investigation of novel therapeutics. The MCC cell of origin debate has also been advanced by recent observations of MCC arising in association with a clonally related hair follicle tumor or squamous cell carcinoma in situ. These studies also suggested a role for epigenetics in the origin of MCC, highlighting a potential utility for this therapeutic avenue in MCC. These and other therapeutic targets form the basis for a wealth of ongoing clinical trials to improve MCC management. Here, we review these recent advances in the context of the existing literature and implications for future investigations.
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Affiliation(s)
| | | | - Mallory K. Joseph
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
| | - Kelly L. Harms
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
| | - Paul W. Harms
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
- Department of Pathology, University of Michigan, Ann Arbor, MI, United States
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4
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Maio N, Heffner AL, Rouault TA. Iron‑sulfur clusters in viral proteins: Exploring their elusive nature, roles and new avenues for targeting infections. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119723. [PMID: 38599324 PMCID: PMC11139609 DOI: 10.1016/j.bbamcr.2024.119723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/13/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
Viruses have evolved complex mechanisms to exploit host factors for replication and assembly. In response, host cells have developed strategies to block viruses, engaging in a continuous co-evolutionary battle. This dynamic interaction often revolves around the competition for essential resources necessary for both host cell and virus replication. Notably, iron, required for the biosynthesis of several cofactors, including iron‑sulfur (FeS) clusters, represents a critical element in the ongoing competition for resources between infectious agents and host. Although several recent studies have identified FeS cofactors at the core of virus replication machineries, our understanding of their specific roles and the cellular processes responsible for their incorporation into viral proteins remains limited. This review aims to consolidate our current knowledge of viral components that have been characterized as FeS proteins and elucidate how viruses harness these versatile cofactors to their benefit. Its objective is also to propose that viruses may depend on incorporation of FeS cofactors more extensively than is currently known. This has the potential to revolutionize our understanding of viral replication, thereby carrying significant implications for the development of strategies to target infections.
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Affiliation(s)
- Nunziata Maio
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
| | - Audrey L Heffner
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA; Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Tracey A Rouault
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, 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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Passerini S, Babini G, Merenda E, Carletti R, Scribano D, Rosa L, Conte AL, Moens U, Ottolenghi L, Romeo U, Conte MP, Di Gioia CRT, Pietropaolo V. Merkel Cell Polyomavirus in the Context of Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders. Biomedicines 2024; 12:709. [PMID: 38672065 PMCID: PMC11047982 DOI: 10.3390/biomedicines12040709] [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: 02/27/2024] [Revised: 03/15/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024] Open
Abstract
Despite recent advances in prevention, detection and treatment, oral squamous cell carcinoma (OSCC) remains a global health concern, strongly associated with environmental and lifestyle risk factors and infection with oncogenic viruses. Merkel Cell Polyomavirus (MCPyV), well known to be the causative agent of Merkel Cell Carcinoma (MCC) has been found in OSCC, suggesting its potential role as a co-factor in the development of oral cavity cancers. To improve our understanding about MCPyV in oral cavities, the detection and analysis of MCPyV DNA, transcripts and miRNA were performed on OSCCs and oral potentially malignant disorders (OPMDs). In addition, the cellular miR-375, known to be deregulated in tumors, was examined. MCPyV DNA was found in 3 out of 11 OSCC and 4 out of 12 OPMD samples, with a viral mean value of 1.49 × 102 copies/mL. Viral integration was not observed and LTAg and VP1 transcripts were detected. Viral miRNAs were not detected whereas the cellular miR-375 was found over expressed in all MCPyV positive oral specimens. Our results reported evidence of MCPyV replication in both OSCC and OPMD suggesting the oral cavity as a site of replicative MCPyV infection, therefore underscoring an active role of this virus in the occurrence of oral lesions.
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Affiliation(s)
- Sara Passerini
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy; (G.B.); (D.S.); (A.L.C.); (M.P.C.)
| | - Giulia Babini
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy; (G.B.); (D.S.); (A.L.C.); (M.P.C.)
| | - Elisabetta Merenda
- Department of Radiological, Oncological and Pathological Science, “Sapienza” University of Rome, 00161 Rome, Italy; (E.M.); (R.C.); (C.R.T.D.G.)
| | - Raffaella Carletti
- Department of Radiological, Oncological and Pathological Science, “Sapienza” University of Rome, 00161 Rome, Italy; (E.M.); (R.C.); (C.R.T.D.G.)
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy; (G.B.); (D.S.); (A.L.C.); (M.P.C.)
| | - Luigi Rosa
- Laboratory of Virology, National Institute for Infectious Diseases “Spallanzani”, 00149 Rome, Italy;
| | - Antonietta Lucia Conte
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy; (G.B.); (D.S.); (A.L.C.); (M.P.C.)
| | - Ugo Moens
- Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, UiT-The Arctic University of Norway, 9037 Tromsø, Norway;
| | - Livia Ottolenghi
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, Via Caserta 6, 00161 Rome, Italy; (L.O.); (U.R.)
| | - Umberto Romeo
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, Via Caserta 6, 00161 Rome, Italy; (L.O.); (U.R.)
| | - Maria Pia Conte
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy; (G.B.); (D.S.); (A.L.C.); (M.P.C.)
| | - Cira Rosaria Tiziana Di Gioia
- Department of Radiological, Oncological and Pathological Science, “Sapienza” University of Rome, 00161 Rome, Italy; (E.M.); (R.C.); (C.R.T.D.G.)
| | - Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy; (G.B.); (D.S.); (A.L.C.); (M.P.C.)
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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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8
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Weber M, Nguyen MB, Li MY, Flora P, Shuda M, Ezhkova E. Merkel Cell Polyomavirus T Antigen-Mediated Reprogramming in Adult Merkel Cell Progenitors. J Invest Dermatol 2023; 143:2163-2176.e6. [PMID: 37257637 PMCID: PMC10592583 DOI: 10.1016/j.jid.2023.04.031] [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: 06/24/2022] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 06/02/2023]
Abstract
Whether Merkel cells regenerate in adult skin and from which progenitor cells they regenerate are a subject of debate. Understanding Merkel cell regeneration is of interest to the study of Merkel cell carcinoma, a rare neuroendocrine skin cancer hypothesized to originate in a Merkel cell progenitor transformed by Merkel cell polyomavirus small and large T antigens. We sought to understand what the adult Merkel cell progenitors are and whether they can give rise to Merkel cell carcinoma. We used lineage tracing to identify SOX9-expressing cells (SOX9+ cells) as Merkel cell progenitors in postnatal murine skin. Merkel cell regeneration from SOX9+ progenitors occurs rarely in mature skin unless in response to minor mechanical injury. Merkel cell polyomavirus small T antigen and functional imitation of large T antigen in SOX9+ cells enforced neuroendocrine and Merkel cell lineage reprogramming in a subset of cells. These results identify SOX9+ cells as postnatal Merkel cell progenitors that can be reprogrammed by Merkel cell polyomavirus T antigens to express neuroendocrine markers.
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Affiliation(s)
- Madison Weber
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Minh Binh Nguyen
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Meng Yen Li
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Pooja Flora
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Masahiro Shuda
- Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Elena Ezhkova
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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9
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Durand MA, Drouin A, Mouchard A, Durand L, Esnault C, Berthon P, Tallet A, Le Corre Y, Hainaut-Wierzbicka E, Blom A, Saiag P, Beneton N, Bens G, Nardin C, Aubin F, Dinulescu M, Collin C, Fromont-Hankard G, Cribier B, Laurent-Roussel S, Cokelaere K, Houben R, Schrama D, Peixoto P, Hervouet E, Bachiri K, Kantar D, Coyaud E, Guyétant S, Samimi M, Touzé A, Kervarrec T. Distinct Regulation of EZH2 and its Repressive H3K27me3 Mark in Polyomavirus-Positive and -Negative Merkel Cell Carcinoma. J Invest Dermatol 2023; 143:1937-1946.e7. [PMID: 37037414 DOI: 10.1016/j.jid.2023.02.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 04/12/2023]
Abstract
Merkel cell carcinoma (MCC) is an aggressive skin cancer for which Merkel cell polyomavirus integration and expression of viral oncogenes small T and Large T have been identified as major oncogenic determinants. Recently, a component of the PRC2 complex, the histone methyltransferase enhancer of zeste homolog 2 (EZH2) that induces H3K27 trimethylation as a repressive mark has been proposed as a potential therapeutic target in MCC. Because divergent results have been reported for the levels of EZH2 and trimethylation of lysine 27 on histone 3, we analyzed these factors in a large MCC cohort to identify the molecular determinants of EZH2 activity in MCC and to establish MCC cell lines' sensitivity to EZH2 inhibitors. Immunohistochemical expression of EZH2 was observed in 92% of MCC tumors (156 of 170), with higher expression levels in virus-positive than virus-negative tumors (P = 0.026). For the latter, we showed overexpression of EZHIP, a negative regulator of the PRC2 complex. In vitro, ectopic expression of the large T antigen in fibroblasts led to the induction of EZH2 expression, whereas the knockdown of T antigens in MCC cell lines resulted in decreased EZH2 expression. EZH2 inhibition led to selective cytotoxicity on virus-positive MCC cell lines. This study highlights the distinct mechanisms of EZH2 induction between virus-negative and -positive MCC.
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Affiliation(s)
- Marie-Alice Durand
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Aurélie Drouin
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Alice Mouchard
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France; Department of Dermatology, CHRU of Tours, University of Tours, Chambray-lès-Tours, France
| | - Laurine Durand
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Clara Esnault
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Patricia Berthon
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Anne Tallet
- Platform of Somatic Tumor Molecular Genetics, CHU of Tours, University of Tours, Tours, France
| | - Yannick Le Corre
- Dermatology Department, CHU of Angers, LUNAM University, Angers, France
| | | | - Astrid Blom
- Department of General and Oncologic Dermatology, Ambroise-Paré Hospital, CARADERM Network, Boulogne-Billancourt, France; Research unit EA 4340, University of Versailles-Saint-Quentin-en-Yvelines, Paris-Saclay University, Boulogne-Billancourt, France
| | - Philippe Saiag
- Department of General and Oncologic Dermatology, Ambroise-Paré Hospital, CARADERM Network, Boulogne-Billancourt, France; Research unit EA 4340, University of Versailles-Saint-Quentin-en-Yvelines, Paris-Saclay University, Boulogne-Billancourt, France
| | - Nathalie Beneton
- Dermatology Department, CHU of Le Mans, University of Le Mans, Le Mans, France
| | - Guido Bens
- Dermatology department, CHR Orleans, Orleans, France
| | - Charlee Nardin
- Dermatology, CHU Besançon, Besançon, France; INSERM 1098, Université Bourgogne Franche-Comté, Besançon, France
| | - François Aubin
- Dermatology, CHU Besançon, Besançon, France; INSERM 1098, Université Bourgogne Franche-Comté, Besançon, France
| | - Monica Dinulescu
- Dermatology department, CHU Rennes, Institut Dermatologique du Grand Ouest (IDGO), Rennes, France
| | - Christine Collin
- Platform of Somatic Tumor Molecular Genetics, CHU of Tours, University of Tours, Tours, France
| | | | - Bernard Cribier
- Dermatology Department, CHU of Strasbourg, University of Strasbourg, Strasbourg, France
| | | | | | - Roland Houben
- Department of Dermatology, Venerology and Allergology, University Hospital of Würzburg, Würzburg, Germany
| | - David Schrama
- Department of Dermatology, Venerology and Allergology, University Hospital of Würzburg, Würzburg, Germany
| | - Paul Peixoto
- INSERM, EFS-BFC, UMR 1098 RIGHT, University Bourgogne-Franche-Comté, Besançon, France; EPIgenetics and GENe Expression Technical Platform (EPIGENExp), University Bourgogne Franche-Comté, Besançon, France
| | - Eric Hervouet
- INSERM, EFS-BFC, UMR 1098 RIGHT, University Bourgogne-Franche-Comté, Besançon, France; EPIgenetics and GENe Expression Technical Platform (EPIGENExp), University Bourgogne Franche-Comté, Besançon, France
| | - Kamel Bachiri
- Department of Biology, Inserm U1192, Protéomique Réponse Inflammatoire Spectrométrie de Masse-PRISM, CHU Lille, Université de Lille, Lille, France
| | - Diala Kantar
- Department of Biology, Inserm U1192, Protéomique Réponse Inflammatoire Spectrométrie de Masse-PRISM, CHU Lille, Université de Lille, Lille, France
| | - Etienne Coyaud
- Department of Biology, Inserm U1192, Protéomique Réponse Inflammatoire Spectrométrie de Masse-PRISM, CHU Lille, Université de Lille, Lille, France
| | - Serge Guyétant
- Pathology Department, CHU of Tours, University of Tours, Tours, France; Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Mahtab Samimi
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France; Department of Dermatology, CHRU of Tours, University of Tours, Chambray-lès-Tours, France
| | - Antoine Touzé
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France
| | - Thibault Kervarrec
- Team "Biologie des Infections à Polyomavirus", ISP UMR 1282, INRAE, University of Tours, Tours, France; Pathology Department, CHU of Tours, University of Tours, Tours, France.
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10
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Quan T, Xia W, He T, Calderone K, Bou-Gharios G, Voorhees JJ, Dlugosz AA, Fisher GJ. Matrix Metalloproteinase-1 Expression in Fibroblasts Accelerates Dermal Aging and Promotes Papilloma Development in Mouse Skin. J Invest Dermatol 2023; 143:1700-1707.e1. [PMID: 36914001 DOI: 10.1016/j.jid.2023.02.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 03/13/2023]
Abstract
Fragmentation, disorganization, and depletion of the collagen-rich dermal extracellular matrix are hallmarks of aged human skin. These deleterious alterations are thought to critically mediate many of the prominent clinical attributes of aged skin, including thinning, fragility, impaired wound healing, and a propensity for carcinoma. Matrix metalloproteinase-1 (MMP1) initiates the cleavage of collagen fibrils and is significantly increased in dermal fibroblasts in aged human skin. To investigate the role of elevated MMP1 in skin aging, we generated a conditional bitransgenic mouse (type I collagen alpha chain 2; human MMP1 [Col1a2;hMMP1]) that expresses full-length, catalytically active hMMP1 in dermal fibroblasts. hMMP1 expression is activated by a tamoxifen-inducible Cre recombinase that is driven by the Col1a2 promoter and upstream enhancer. Tamoxifen induced hMMP1 expression and activity throughout the dermis Col1a2:hMMP1 mice. At 6 months of age, Col1a2;hMMP1 mice displayed loss and fragmentation of dermal collagen fibrils, which was accompanied by many of the features of aged human skin, such as contracted fibroblast morphology, reduced collagen production, increased expression of multiple endogenous MMPs, and proinflammatory mediators. Interestingly, Col1a2;hMMP1 mice displayed substantially increased susceptibility to skin papilloma development. These data demonstrate that fibroblast expression of hMMP1 is a critical mediator of dermal aging and creates a dermal microenvironment that promotes keratinocyte tumor development.
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Affiliation(s)
- Taihao Quan
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Wei Xia
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Tianyuan He
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kenneth Calderone
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - George Bou-Gharios
- Institute of Ageing and Chronic Diseases, University of Liverpool, Liverpool United Kingdom
| | - John J Voorhees
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Andrzej A Dlugosz
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Gary J Fisher
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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11
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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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12
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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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13
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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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14
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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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15
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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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16
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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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17
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Venuti A, Romero-Medina MC, Melita G, Ceraolo MG, Brancaccio RN, Sirand C, Taverniti V, Steenbergen R, Gheit T, Tommasino M. Lyon IARC Polyomavirus Displays Transforming Activities in Primary Human Cells. J Virol 2022; 96:e0206121. [PMID: 35770990 PMCID: PMC9327700 DOI: 10.1128/jvi.02061-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/13/2022] [Indexed: 01/01/2023] Open
Abstract
Several studies reported the presence of a recently discovered polyomavirus (PyV), Lyon IARC PyV (LIPyV), in human and domestic animal specimens. LIPyV has some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV (MCPyV), respectively. In this study, we demonstrate that LIPyV early proteins immortalize human foreskin keratinocytes. LIPyV LT binds pRb, accordingly cell cycle checkpoints are altered in primary human fibroblasts and keratinocytes expressing LIPyV early genes. Mutation of the pRb binding site in LT strongly affected the ability of LIPyV ER to induced HFK immortalization. LIPyV LT also binds p53 and alters p53 functions activated by cellular stresses. Finally, LIPyV early proteins activate telomerase reverse transcriptase (hTERT) gene expression, via accumulation of the Sp1 transcription factor. Sp1 recruitment to the hTERT promoter is controlled by its phosphorylation, which is mediated by ERK1 and CDK2. Together, these data highlight the transforming properties of LIPyV in in vitro experimental models, supporting its possible oncogenic nature. IMPORTANCE Lyon IARC PyV is a recently discovered polyomavirus that shows some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV, respectively. Here, we show the capability of LIPyV to efficiently promote cellular transformation of primary human cells, suggesting a possible oncogenic role of this virus in domestic animals and/or humans. Our study identified a novel virus-mediated mechanism of activation of telomerase reverse transcriptase gene expression, via accumulation of the Sp1 transcription factor. In addition, because the persistence of infection is a key event in virus-mediated carcinogenesis, it will be important to determine whether LIPyV can deregulate immune-related pathways, similarly to the well-established oncogenic viruses.
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Affiliation(s)
- Assunta Venuti
- International Agency for Research on Cancer (IARC), World Health Organization, Lyon Cedex, France
| | | | - Giusi Melita
- International Agency for Research on Cancer (IARC), World Health Organization, Lyon Cedex, France
| | - Maria Grazia Ceraolo
- International Agency for Research on Cancer (IARC), World Health Organization, Lyon Cedex, France
| | | | - Cecilia Sirand
- International Agency for Research on Cancer (IARC), World Health Organization, Lyon Cedex, France
| | - Valerio Taverniti
- International Agency for Research on Cancer (IARC), World Health Organization, Lyon Cedex, France
| | - Renske Steenbergen
- VU University Medical Center Amsterdam, Department of Pathology, Amsterdam, The Netherlands
| | - Tarik Gheit
- International Agency for Research on Cancer (IARC), World Health Organization, Lyon Cedex, France
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18
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Diagnosis and treatment of Merkel cell carcinoma: European consensus-based interdisciplinary guideline - Update 2022. Eur J Cancer 2022; 171:203-231. [PMID: 35732101 DOI: 10.1016/j.ejca.2022.03.043] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 03/17/2022] [Indexed: 11/22/2022]
Abstract
Merkel cell carcinoma (MCC) is a rare skin cancer, accounting for less than 1% of all cutaneous malignancies. It is found predominantly in white populations and risk factors include advanced age, ultraviolet exposure, male sex, immunosuppression, such as AIDS/HIV infection, haematological malignancies or solid organ transplantation, and Merkel cell polyomavirus infection. MCC is an aggressive tumour with 26% of cases presenting lymph node involvement at diagnosis and 8% with distant metastases. Five-year overall survival rates range between 48% and 63%. Two subsets of MCC have been characterised with distinct molecular pathogenetic pathways: ultraviolet-induced MCC versus virus-positive MCC, which carries a better prognosis. In both subtypes, there are alterations in the retinoblastoma protein and p53 gene structure and function. MCC typically manifests as a red nodule or plaque with fast growth, most commonly on sun exposed areas. Histopathology (small-cell neuroendocrine appearance) and immunohistochemistry (CK20 positivity and TTF-1 negativity) confirm the diagnosis. The current staging systems are the American Joint Committee on Cancer/Union for international Cancer control 8th edition. Baseline whole body imaging is encouraged to rule out regional and distant metastasis. For localised MCC, first-line treatment is surgical excision with postoperative margin assessment followed by adjuvant radiation therapy (RT). Sentinel lymph node biopsy is recommended in all patients with MCC without clinically detectable lymph nodes or distant metastasis. Adjuvant RT alone, eventually combined with complete lymph nodes dissection is proposed in case of micrometastatic nodal involvement. In case of macroscopic nodal involvement, the standard of care is complete lymph nodes dissection potentially followed by post-operative RT. Immunotherapy with anti-PD-(L)1 antibodies should be offered as first-line systemic treatment in advanced MCC. Chemotherapy can be used when patients fail to respond or are intolerant for anti-PD-(L)1 immunotherapy or clinical trials.
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19
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Yang JF, You J. Merkel cell polyomavirus and associated Merkel cell carcinoma. Tumour Virus Res 2022; 13:200232. [PMID: 34920178 PMCID: PMC8715208 DOI: 10.1016/j.tvr.2021.200232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/08/2021] [Accepted: 12/13/2021] [Indexed: 12/22/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) is a ubiquitous skin infection that can cause Merkel cell carcinoma (MCC), a highly lethal form of skin cancer with a nearly 50% mortality rate. Since the discovery of MCPyV in 2008, great advances have been made to improve our understanding of how the viral encoded oncoproteins contribute to MCC oncogenesis. However, our knowledge of the MCPyV infectious life cycle and its oncogenic mechanisms are still incomplete. The incidence of MCC has tripled over the past two decades, but effective treatments are lacking. Only recently have there been major victories in combatting metastatic MCC with the application of PD-1 immune checkpoint blockade. Still, these immune-based therapies are not ideal for patients with a medical need to maintain systemic immune suppression. As such, a better understanding of MCPyV's oncogenic mechanisms is needed in order to develop more effective and targeted therapies against virus-associated MCC. In this review, we discuss current areas of interest for MCPyV and MCC research and the progress made in elucidating both the natural host of MCPyV infection and the cell of origin for MCC. We also highlight the remaining gaps in our knowledge on the transcriptional regulation of MCPyV, which may be key to understanding and targeting viral oncogenesis for developing future therapies.
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Affiliation(s)
- June F Yang
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6076, USA
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6076, USA.
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20
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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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21
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Spurgeon ME, Cheng J, Ward-Shaw E, Dick FA, DeCaprio JA, Lambert PF. Merkel cell polyomavirus large T antigen binding to pRb promotes skin hyperplasia and tumor development. PLoS Pathog 2022; 18:e1010551. [PMID: 35560034 PMCID: PMC9132321 DOI: 10.1371/journal.ppat.1010551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 05/25/2022] [Accepted: 04/26/2022] [Indexed: 12/14/2022] Open
Abstract
Clear evidence supports a causal link between Merkel cell polyomavirus (MCPyV) and the highly aggressive human skin cancer called Merkel cell carcinoma (MCC). Integration of viral DNA into the human genome facilitates continued expression of the MCPyV small tumor (ST) and large tumor (LT) antigens in virus-positive MCCs. In MCC tumors, MCPyV LT is truncated in a manner that renders the virus unable to replicate yet preserves the LXCXE motif that facilitates its binding to and inactivation of the retinoblastoma tumor suppressor protein (pRb). We previously developed a MCPyV transgenic mouse model in which MCC tumor-derived ST and truncated LT expression were targeted to the stratified epithelium of the skin, causing epithelial hyperplasia, increased proliferation, and spontaneous tumorigenesis. We sought to determine if any of these phenotypes required the association between the truncated MCPyV LT and pRb. Mice were generated in which K14-driven MCPyV ST/LT were expressed in the context of a homozygous RbΔLXCXE knock-in allele that attenuates LT-pRb interactions through LT's LXCXE motif. We found that many of the phenotypes including tumorigenesis that develop in the K14-driven MCPyV transgenic mice were dependent upon LT's LXCXE-dependent interaction with pRb. These findings highlight the importance of the MCPyV LT-pRb interaction in an in vivo model for MCPyV-induced tumorigenesis.
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Affiliation(s)
- Megan E. Spurgeon
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
- * E-mail:
| | - Jingwei Cheng
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, United States of America
| | - Ella Ward-Shaw
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Frederick A. Dick
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children’s Health Research Institute, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
| | - James A. DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Paul F. Lambert
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
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22
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Merkel cell carcinoma and immune evasion: Merkel cell polyomavirus small T-antigen induced surface changes can be reverted by therapeutic intervention. J Invest Dermatol 2022; 142:3071-3081.e13. [DOI: 10.1016/j.jid.2022.04.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 04/21/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022]
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23
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Thibault K. Evidence of an epithelial origin of Merkel cell carcinoma. Mod Pathol 2022; 35:446-448. [PMID: 34732840 DOI: 10.1038/s41379-021-00964-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Kervarrec Thibault
- Department of Pathology, University Hospital Center of Tours, Tours, France. .,"Biologie des infections à Polyomavirus" team, UMR INRA ISP1282, University of Tours, Tours, France.
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24
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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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25
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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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26
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Verhaegen ME, Harms PW, Van Goor JJ, Arche J, Patrick MT, Wilbert D, Zabawa H, Grachtchouk M, Liu CJ, Hu K, Kelly MC, Chen P, Saunders TL, Weidinger S, Syu LJ, Runge JS, Gudjonsson JE, Wong SY, Brownell I, Cieslik M, Udager AM, Chinnaiyan AM, Tsoi LC, Dlugosz AA. Direct cellular reprogramming enables development of viral T antigen-driven Merkel cell carcinoma in mice. J Clin Invest 2022; 132:152069. [PMID: 35143422 PMCID: PMC8970662 DOI: 10.1172/jci152069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Abstract
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer that frequently carries an integrated Merkel cell polyomavirus (MCPyV) genome and expresses viral transforming antigens (TAgs). MCC tumor cells also express signature genes detected in skin-resident, postmitotic Merkel cells, including atonal bHLH transcription factor 1 (ATOH1), which is required for Merkel cell development from epidermal progenitors. We now report the use of in vivo cellular reprogramming, using ATOH1, to drive MCC development from murine epidermis. We generated mice that conditionally expressed MCPyV TAgs and ATOH1 in epidermal cells, yielding microscopic collections of proliferating MCC-like cells arising from hair follicles. Immunostaining of these nascent tumors revealed p53 accumulation and apoptosis, and targeted deletion of transformation related protein 53 (Trp53) led to development of gross skin tumors with classic MCC histology and marker expression. Global transcriptome analysis confirmed the close similarity of mouse and human MCCs, and hierarchical clustering showed conserved upregulation of signature genes. Our data establish that expression of MCPyV TAgs in ATOH1-reprogrammed epidermal cells and their neuroendocrine progeny initiates hair follicle–derived MCC tumorigenesis in adult mice. Moreover, progression to full-blown MCC in this model requires loss of p53, mimicking the functional inhibition of p53 reported in human MCPyV-positive MCCs.
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Affiliation(s)
- Monique E Verhaegen
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Paul W Harms
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Julia J Van Goor
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Jacob Arche
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Matthew T Patrick
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Dawn Wilbert
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Haley Zabawa
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Marina Grachtchouk
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Chia-Jen Liu
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Kevin Hu
- Department of Computational Medicine & Bioinformatics, University of Michigan, Ann Arbor, United States of America
| | - Michael C Kelly
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States of America
| | - Ping Chen
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States of America
| | - Thomas L Saunders
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States of America
| | - Stephan Weidinger
- Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Li-Jyun Syu
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - John S Runge
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Johann E Gudjonsson
- Department of Dermatology, University of Michigan, Ann Arbor, United States of America
| | - Sunny Y Wong
- Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, United States of America
| | - Isaac Brownell
- Dermatology Branch, National Cancer Institute, Bethesda, United States of America
| | - Marcin Cieslik
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Aaron M Udager
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Arul M Chinnaiyan
- Department of Pathology, University of Michigan, Ann Arbor, United States of America
| | - Lam C Tsoi
- Department of Biostatistics, University of Michigan, Ann Arbor, United States of America
| | - Andrzej A Dlugosz
- Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, United States of America
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27
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Inhibition of T-antigen expression promoting glycogen synthase kinase 3 impairs merkel cell carcinoma cell growth. Cancer Lett 2022; 524:259-267. [PMID: 34715251 DOI: 10.1016/j.canlet.2021.10.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/08/2021] [Accepted: 10/18/2021] [Indexed: 12/12/2022]
Abstract
Merkel cell carcinoma is an aggressive skin cancer frequently caused by the Merkel cell polyomavirus (MCPyV). Since proliferation of MCPyV-positive MCC tumor cells strictly depends on expression of the virus-encoded T antigens (TA), these proteins theoretically represent ideal targets for different kinds of therapeutic approaches. Here we developed a cell-based assay to identify compounds which specifically inhibit growth of MCC cells by repressing TA expression. Applying this technique we screened a kinase inhibitor library and identified six compounds targeting glycogen synthase kinase 3 (GSK3) such as CHIR99021 as suppressors of TA transcription in MCC cells. Involvement of GSK3α and -β in the regulation of TA-expression was confirmed by combining GSK3A knockout with inducible GSK3B shRNA knockdown since double knockouts could not be generated. Finally, we demonstrate that CHIR99021 exhibits in vivo antitumor activity in an MCC xenograft mouse model suggesting GSK3 inhibitors as potential therapeutics for the treatment of MCC in the future.
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28
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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: 19] [Impact Index Per Article: 6.3] [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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29
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Kitsou K, Iliopoulou M, Spoulou V, Lagiou P, Magiorkinis G. Viral Causality of Human Cancer and Potential Roles of Human Endogenous Retroviruses in the Multi-Omics Era: An Evolutionary Epidemiology Review. Front Oncol 2021; 11:687631. [PMID: 34778024 PMCID: PMC8586426 DOI: 10.3389/fonc.2021.687631] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 10/12/2021] [Indexed: 12/20/2022] Open
Abstract
Being responsible for almost 12% of cancers worldwide, viruses are among the oldest known and most prevalent oncogenic agents. The quality of the evidence for the in vivo tumorigenic potential of microorganisms varies, thus accordingly, viruses were classified in 4 evidence-based categories by the International Agency for Research on Cancer in 2009. Since then, our understanding of the role of viruses in cancer has significantly improved, firstly due to the emergence of high throughput sequencing technologies that allowed the “brute-force” recovery of unknown viral genomes. At the same time, multi-omics approaches unravelled novel virus-host interactions in stem-cell biology. We now know that viral elements, either exogenous or endogenous, have multiple sometimes conflicting roles in human pathophysiology and the development of cancer. Here we integrate emerging evidence on viral causality in human cancer from basic mechanisms to clinical studies. We analyze viral tumorigenesis under the scope of deep-in-time human-virus evolutionary relationships and critically comment on the evidence through the eyes of clinical epidemiology, firstly by reviewing recognized oncoviruses and their mechanisms of inducing tumorigenesis, and then by examining the potential role of integrated viruses in our genome in the process of carcinogenesis.
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Affiliation(s)
- Konstantina Kitsou
- Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.,Immunobiology and Vaccinology Research Laboratory, First Department of Peadiatrics, "Aghia Sophia" Children's Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Iliopoulou
- Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Vana Spoulou
- Immunobiology and Vaccinology Research Laboratory, First Department of Peadiatrics, "Aghia Sophia" Children's Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Pagona Lagiou
- Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Gkikas Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
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30
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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: 28] [Impact Index Per Article: 9.3] [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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31
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Merkel Cell Carcinoma of the Head and Neck: Epidemiology, Pathogenesis, Current State of Treatment and Future Directions. Cancers (Basel) 2021; 13:cancers13143506. [PMID: 34298720 PMCID: PMC8305628 DOI: 10.3390/cancers13143506] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/07/2021] [Accepted: 07/07/2021] [Indexed: 12/12/2022] Open
Abstract
Merkel cell carcinoma (MCC) is a rare, cutaneous neuroendocrine malignancy with increasing incidence. The skin of the head and neck is a common subsite for MCC with distinctions in management from other anatomic areas. Given the rapid pace of developments regarding MCC pathogenesis (Merkel cell polyoma virus (MCPyV)-positive or virus-negative, cell of origin), diagnosis, staging and treatment, and up to date recommendations are critical for optimizing outcomes. This review aims to summarize currently available literature for MCC of the head and neck. The authors reviewed current literature, including international guidelines regarding MCC pathogenesis, epidemiology, diagnosis, staging, and treatment. Subsequently recommendations were derived including the importance of baseline imaging, MCPyV serology testing, primary site surgery, nodal evaluation, radiotherapy, and the increasing role of immune modulating agents in MCC. MCPyV serology testing is increasingly important with potential distinctions in treatment response and surveillance between virus-positive and virus-negative MCC. Surgical management continues to balance optimizing local control with minimal morbidity. Similarly, radiotherapy continues to have importance in the adjuvant, definitive, and palliative setting for MCC of the head and neck. Immunotherapy has changed the paradigm for advanced MCC, with increasing work focusing on optimizing outcomes for non-responders and high-risk patients, including those with immunosuppression.
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32
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Dellambra E, Carbone ML, Ricci F, Ricci F, Di Pietro FR, Moretta G, Verkoskaia S, Feudi E, Failla CM, Abeni D, Fania L. Merkel Cell Carcinoma. Biomedicines 2021; 9:718. [PMID: 34201709 PMCID: PMC8301416 DOI: 10.3390/biomedicines9070718] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/10/2021] [Accepted: 06/21/2021] [Indexed: 12/20/2022] Open
Abstract
Merkel cell carcinoma (MCC) is a rare and extremely aggressive neuroendocrine carcinoma of the skin, with increasing incidence worldwide. This review intends to propose a comprehensive evaluation of MCC epidemiology, clinical features, pathogenetic mechanisms, diagnosis, and therapies. A section is dedicated to immunological aspects and another to the involvement of angiogenesis and angiogenic growth factors in MCC progression, proposing novel diagnostic and therapeutic approaches. Advanced MCC tumors have been treated with immune checkpoint inhibitors with effective results. Therefore, the state of art of this immunotherapy is also examined, reporting on the most recent clinical trials in the field. We conclude by underlining the achievements in the understanding of MCC pathology and indicating the present needs for effective diagnosis and therapeutic management of the disease.
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Affiliation(s)
- Elena Dellambra
- Molecular and Cell Biology Laboratory, IDI-IRCCS, 00167 Rome, Italy;
| | - Maria Luigia Carbone
- Experimental Immunology Laboratory, IDI-IRCCS, 00167 Rome, Italy; (E.F.); (C.M.F.)
| | | | - Francesco Ricci
- Dermatology Department, IDI-IRCCS, 00167 Rome, Italy; (F.R.); (G.M.); (L.F.)
| | | | - Gaia Moretta
- Dermatology Department, IDI-IRCCS, 00167 Rome, Italy; (F.R.); (G.M.); (L.F.)
| | - Sofia Verkoskaia
- Oncology Department, IDI-IRCCS, 00167 Rome, Italy; (F.R.D.P.); (S.V.)
| | - Elisa Feudi
- Experimental Immunology Laboratory, IDI-IRCCS, 00167 Rome, Italy; (E.F.); (C.M.F.)
| | - Cristina M. Failla
- Experimental Immunology Laboratory, IDI-IRCCS, 00167 Rome, Italy; (E.F.); (C.M.F.)
| | - Damiano Abeni
- Clinical Epidemiology Unit, IDI-IRCCS, 00167 Rome, Italy;
| | - Luca Fania
- Dermatology Department, IDI-IRCCS, 00167 Rome, Italy; (F.R.); (G.M.); (L.F.)
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33
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Viral Manipulation of the Host Epigenome as a Driver of Virus-Induced Oncogenesis. Microorganisms 2021; 9:microorganisms9061179. [PMID: 34070716 PMCID: PMC8227491 DOI: 10.3390/microorganisms9061179] [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: 04/28/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/13/2022] Open
Abstract
Tumorigenesis due to viral infection accounts for a high fraction of the total global cancer burden (15–20%) of all human cancers. A comprehensive understanding of the mechanisms by which viral infection leads to tumor development is extremely important. One of the main mechanisms by which viruses induce host cell proliferation programs is through controlling the host’s epigenetic machinery. In this review, we dissect the epigenetic pathways through which oncogenic viruses can integrate their genome into host cell chromosomes and lead to tumor progression. In addition, we highlight the potential use of drugs based on histone modifiers in reducing the global impact of cancer development due to viral infection.
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34
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Suares A, Medina MV, Coso O. Autophagy in Viral Development and Progression of Cancer. Front Oncol 2021; 11:603224. [PMID: 33763351 PMCID: PMC7982729 DOI: 10.3389/fonc.2021.603224] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
Autophagy is a complex degradative process by which eukaryotic cells capture cytoplasmic components for subsequent degradation through lysosomal hydrolases. Although this catabolic process can be triggered by a great variety of stimuli, action in cells varies according to cellular context. Autophagy has been previously linked to disease development modulation, including cancer. Autophagy helps suppress cancer cell advancement in tumor transformation early stages, while promoting proliferation and metastasis in advanced settings. Oncoviruses are a particular type of virus that directly contribute to cell transformation and tumor development. Extensive molecular studies have revealed complex ways in which autophagy can suppress or improve oncovirus fitness while still regulating viral replication and determining host cell fate. This review includes recent advances in autophagic cellular function and emphasizes its antagonistic role in cancer cells.
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Affiliation(s)
- Alejandra Suares
- Departamento de Fisiología y Biología Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET—Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Victoria Medina
- Departamento de Fisiología y Biología Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET—Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Omar Coso
- Departamento de Fisiología y Biología Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET—Universidad de Buenos Aires, Buenos Aires, Argentina
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Suares A, Medina MV, Coso O. Autophagy in Viral Development and Progression of Cancer. Front Oncol 2021. [DOI: 10.3389/fonc.2021.603224
expr 816899697 + 824303767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Autophagy is a complex degradative process by which eukaryotic cells capture cytoplasmic components for subsequent degradation through lysosomal hydrolases. Although this catabolic process can be triggered by a great variety of stimuli, action in cells varies according to cellular context. Autophagy has been previously linked to disease development modulation, including cancer. Autophagy helps suppress cancer cell advancement in tumor transformation early stages, while promoting proliferation and metastasis in advanced settings. Oncoviruses are a particular type of virus that directly contribute to cell transformation and tumor development. Extensive molecular studies have revealed complex ways in which autophagy can suppress or improve oncovirus fitness while still regulating viral replication and determining host cell fate. This review includes recent advances in autophagic cellular function and emphasizes its antagonistic role in cancer cells.
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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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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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Spurgeon ME, Liem A, Buehler D, Cheng J, DeCaprio JA, Lambert PF. The Merkel Cell Polyomavirus T Antigens Function as Tumor Promoters in Murine Skin. Cancers (Basel) 2021; 13:cancers13020222. [PMID: 33435392 PMCID: PMC7827793 DOI: 10.3390/cancers13020222] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 02/06/2023] Open
Abstract
Simple Summary Merkel cell polyomavirus, a recently discovered human virus, is linked to the development of a rare form of skin cancer called Merkel cell carcinoma. The virus does not replicate in cancer cells, yet there is continued expression of viral proteins known as T antigens. The T antigens are believed to contribute to Merkel cell carcinoma development, yet how they do so remains an active area of research. In this study, we used transgenic mice expressing the viral T antigens in their skin to determine at which stage of skin cancer development these viral proteins function. We discovered that the Merkel cell polyomavirus T antigens function as tumor promoters, rather than tumor initiators, in the skin. These findings suggest that other tumor-initiating events may cooperate with the tumor-promoting activities of the viral T antigens, thus providing important insight into how Merkel cell polyomavirus can cause cancer in human skin. Abstract Merkel cell polyomavirus (MCPyV) causes the majority of human Merkel cell carcinomas (MCC), a rare but highly aggressive form of skin cancer. We recently reported that constitutive expression of MCC tumor-derived MCPyV tumor (T) antigens in the skin of transgenic mice leads to hyperplasia, increased proliferation, and spontaneous epithelial tumor development. We sought to evaluate how the MCPyV T antigens contribute to tumor formation in vivo using a classical, multi-stage model for squamous cell carcinoma development. In this model, two chemical carcinogens, DMBA and TPA, contribute to two distinct phases of carcinogenesis—initiation and promotion, respectively—that are required for tumors to develop. By treating the MCPyV transgenic mice with each chemical carcinogen, we determined how the viral oncogenes contributed to carcinogenesis. We observed that the MCPyV T antigens synergized with the tumor initiator DMBA, but not with the tumor promoter TPA, cause tumors. Therefore, the MCPyV tumor antigens function primarily as tumor promoters, similar to that seen with human papillomavirus (HPV) oncoproteins. These studies provide insight into the role of MCPyV T antigen expression in tumor formation in vivo and contribute to our understanding of how MCPyV may function as a human DNA tumor virus.
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Affiliation(s)
- Megan E. Spurgeon
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA;
- Correspondence: (M.E.S.); (P.F.L.)
| | - Amy Liem
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA;
| | - Darya Buehler
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA;
| | - Jingwei Cheng
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA;
| | - James A. DeCaprio
- 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 02215, USA
| | - Paul F. Lambert
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA;
- Correspondence: (M.E.S.); (P.F.L.)
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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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DeCaprio JA. Molecular Pathogenesis of Merkel Cell Carcinoma. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2020; 16:69-91. [PMID: 33228463 DOI: 10.1146/annurev-pathmechdis-012419-032817] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma of the skin with two distinct etiologies. Clonal integration of Merkel cell polyomavirus DNA into the tumor genome with persistent expression of viral T antigens causes at least 60% of all MCC. UV damage leading to highly mutated genomes causes a nonviral form of MCC. Despite these distinct etiologies, both forms of MCC are similar in presentation, prognosis, and response to therapy. At least three oncogenic transcriptional programs feature prominently in both forms of MCC driven by the virus or by mutation. Both forms of MCC have a high proliferative growth rate with increased levels of cell cycle-dependent genes due to inactivation of the tumor suppressors RB and p53, a strong MYC signature due to MYCL activation by the virus or gene amplification, and an attenuated neuroendocrine differentiation program driven by the ATOH1 transcription factor.
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Affiliation(s)
- James A DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA; .,Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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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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Merkel Cell Polyomavirus Large T Antigen is Dispensable in G2 and M-Phase to Promote Proliferation of Merkel Cell Carcinoma Cells. Viruses 2020; 12:v12101162. [PMID: 33066686 PMCID: PMC7602435 DOI: 10.3390/v12101162] [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: 08/14/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 11/23/2022] Open
Abstract
Merkel cell carcinoma (MCC) is an aggressive skin cancer frequently caused by the Merkel cell polyomavirus (MCPyV), and proliferation of MCPyV-positive MCC tumor cells depends on the expression of a virus-encoded truncated Large T antigen (LT) oncoprotein. Here, we asked in which phases of the cell cycle LT activity is required for MCC cell proliferation. Hence, we generated fusion-proteins of MCPyV-LT and parts of geminin (GMMN) or chromatin licensing and DNA replication factor1 (CDT1). This allowed us to ectopically express an LT, which is degraded either in the G1 or G2 phase of the cell cycle, respectively, in MCC cells with inducible T antigen knockdown. We demonstrate that LT expressed only in G1 is capable of rescuing LT knockdown-induced growth suppression while LT expressed in S and G2/M phases fails to support proliferation of MCC cells. These results suggest that the crucial function of LT, which has been demonstrated to be inactivation of the cellular Retinoblastoma protein 1 (RB1) is only required to initiate S phase entry.
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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 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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Ahye N, Bellizzi A, May D, Wollebo HS. The Role of the JC Virus in Central Nervous System Tumorigenesis. Int J Mol Sci 2020; 21:ijms21176236. [PMID: 32872288 PMCID: PMC7503523 DOI: 10.3390/ijms21176236] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022] Open
Abstract
Cancer is the second leading cause of mortality worldwide. The study of DNA tumor-inducing viruses and their oncoproteins as a causative agent in cancer initiation and tumor progression has greatly enhanced our understanding of cancer cell biology. The initiation of oncogenesis is a complex process. Specific gene mutations cause functional changes in the cell that ultimately result in the inability to regulate cell differentiation and proliferation effectively. The human neurotropic Polyomavirus JC (JCV) belongs to the family Polyomaviridae and it is the causative agent of progressive multifocal leukoencephalopathy (PML), which is a fatal neurodegenerative disease in an immunosuppressed state. Sero-epidemiological studies have indicated JCV infection is prevalent in the population (85%) and that initial infection usually occurs during childhood. The JC virus has small circular, double-stranded DNA that includes coding sequences for viral early and late proteins. Persistence of the virus in the brain and other tissues, as well as its potential to transform cells, has made it a subject of study for its role in brain tumor development. Earlier observation of malignant astrocytes and oligodendrocytes in PML, as well as glioblastoma formation in non-human primates inoculated with JCV, led to the hypothesis that JCV plays a role in central nervous system (CNS) tumorigenesis. Some studies have reported the presence of both JC viral DNA and its proteins in several primary brain tumor specimens. The discovery of new Polyomaviruses such as the Merkel cell Polyomavirus, which is associated with Merkel cell carcinomas in humans, ignited our interest in the role of the JC virus in CNS tumors. The current evidence known about JCV and its effects, which are sufficient to produce tumors in animal models, suggest it can be a causative factor in central nervous system tumorigenesis. However, there is no clear association between JCV presence in CNS and its ability to initiate CNS cancer and tumor formation in humans. In this review, we will discuss the correlation between JCV and tumorigenesis of CNS in animal models, and we will give an overview of the current evidence for the JC virus’s role in brain tumor formation.
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Czech-Sioli M, Günther T, Therre M, Spohn M, Indenbirken D, Theiss J, Riethdorf S, Qi M, Alawi M, Wülbeck C, Fernandez-Cuesta I, Esmek F, Becker JC, Grundhoff A, Fischer N. High-resolution analysis of Merkel Cell Polyomavirus in Merkel Cell Carcinoma reveals distinct integration patterns and suggests NHEJ and MMBIR as underlying mechanisms. PLoS Pathog 2020; 16:e1008562. [PMID: 32833988 PMCID: PMC7470373 DOI: 10.1371/journal.ppat.1008562] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 09/03/2020] [Accepted: 07/08/2020] [Indexed: 12/17/2022] Open
Abstract
Merkel Cell Polyomavirus (MCPyV) is the etiological agent of the majority of Merkel Cell Carcinomas (MCC). MCPyV positive MCCs harbor integrated, defective viral genomes that constitutively express viral oncogenes. Which molecular mechanisms promote viral integration, if distinct integration patterns exist, and if integration occurs preferentially at loci with specific chromatin states is unknown. We here combined short and long-read (nanopore) next-generation sequencing and present the first high-resolution analysis of integration site structure in MCC cell lines as well as primary tumor material. We find two main types of integration site structure: Linear patterns with chromosomal breakpoints that map closely together, and complex integration loci that exhibit local amplification of genomic sequences flanking the viral DNA. Sequence analysis suggests that linear patterns are produced during viral replication by integration of defective/linear genomes into host DNA double strand breaks via non-homologous end joining, NHEJ. In contrast, our data strongly suggest that complex integration patterns are mediated by microhomology-mediated break-induced replication, MMBIR. Furthermore, we show by ChIP-Seq and RNA-Seq analysis that MCPyV preferably integrates in open chromatin and provide evidence that viral oncogene expression is driven by the viral promoter region, rather than transcription from juxtaposed host promoters. Taken together, our data explain the characteristics of MCPyV integration and may also provide a model for integration of other oncogenic DNA viruses such as papillomaviruses.
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Affiliation(s)
- Manja Czech-Sioli
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Günther
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Marlin Therre
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Spohn
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Daniela Indenbirken
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Juliane Theiss
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sabine Riethdorf
- Institute of Tumorbiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Minyue Qi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Malik Alawi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Corinna Wülbeck
- Translational skin cancer research, German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
| | - Irene Fernandez-Cuesta
- Institute of Nanostructure- and Solid State Physics (INF), Center for Hybrid Nanostructures (CHyN), University of Hamburg, Hamburg, Germany
| | - Franziska Esmek
- Institute of Nanostructure- and Solid State Physics (INF), Center for Hybrid Nanostructures (CHyN), University of Hamburg, Hamburg, Germany
| | - Jürgen C. Becker
- Translational skin cancer research, German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
- Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | - Adam Grundhoff
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- * E-mail: (AG); (NF)
| | - Nicole Fischer
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (AG); (NF)
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Pietropaolo V, Prezioso C, Moens U. Merkel Cell Polyomavirus and Merkel Cell Carcinoma. Cancers (Basel) 2020; 12:E1774. [PMID: 32635198 PMCID: PMC7407210 DOI: 10.3390/cancers12071774] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 12/12/2022] Open
Abstract
Viruses are the cause of approximately 15% of all human cancers. Both RNA and DNA human tumor viruses have been identified, with Merkel cell polyomavirus being the most recent one to be linked to cancer. This virus is associated with about 80% of Merkel cell carcinomas, a rare, but aggressive cutaneous malignancy. Despite its name, the cells of origin of this tumor may not be Merkel cells. This review provides an update on the structure and life cycle, cell tropism and epidemiology of the virus and its oncogenic properties. Putative strategies to prevent viral infection or treat virus-positive Merkel cell carcinoma patients are discussed.
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Affiliation(s)
- Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, “Sapienza” University, 00185 Rome, Italy; (V.P.); (C.P.)
| | - Carla Prezioso
- Department of Public Health and Infectious Diseases, “Sapienza” University, 00185 Rome, Italy; (V.P.); (C.P.)
- IRCSS San Raffaele Pisana, Microbiology of Chronic Neuro-Degenerative Pathologies, 00166 Rome, Italy
| | - 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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Abstract
Viral infection underlies a significant share of the global cancer burden. Merkel cell polyomavirus (MCPyV) is the newest member of the human oncogenic virus family. Its discovery over a decade ago marked the beginning of an exciting era in human tumor virology. Since then, significant evidence has emerged to support the etiologic role of MCPyV in Merkel cell carcinoma (MCC), an extremely lethal form of skin cancer. MCPyV infection is widespread in the general population. MCC diagnoses have tripled over the past 20 years, but effective treatments are currently lacking. In this review, we highlight recent discoveries that have shaped our understanding of MCPyV oncogenic mechanism and host cellular tropism, as well as the molecular events occurring in the viral infectious life cycle. These insights will guide future efforts in developing novel virus-targeted therapeutic strategies for treating the devastating human cancers associated with this new tumorigenic virus.
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Affiliation(s)
- Wei Liu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6076, USA;
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6076, USA;
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Surface charge of Merkel cell polyomavirus small T antigen determines cell transformation through allosteric FBW7 WD40 domain targeting. Oncogenesis 2020; 9:53. [PMID: 32427880 PMCID: PMC7237485 DOI: 10.1038/s41389-020-0235-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
Merkel cell polyomavirus (MCV) small T (sT) is the main oncoprotein in Merkel cell carcinoma (MCC) development. A unique domain of sT, LT stabilization domain (LSD), has been reported to bind and inactivate multiple SCF (Skp1-Cullin-F-box) E3 ligases. These interactions impede the turnover of MCV large T (LT) antigen and cellular oncoproteins such as c-Myc and cyclin E, thereby promoting viral replication and cell transformation. However, it is currently unclear how this LSD region contributes to multiple transforming activities of sT. Structural docking simulation of sT and F-box and WD repeat domain-containing 7 (FBW7) revealed a novel allosteric interaction between sT and FBW7 WD40 domain. This model is supported by experimental evidence confirming that charge engineering in the LSD alters sT-WD40 binding. Specifically, loss of net positive charge in the LSD prevents sT-FBW7 binding by abrogating the electrostatic interaction, thus impeding inhibition of FBW7 by sT. Furthermore, positively charged mutations in the LSD significantly restored the sT function and its ability to transform rodent fibroblast cells. We infer that the surface charge of sT is a major determinant for targeting E3 ligases, which leads to sT-induced cell transformation, an observation that could be used to develop targeted therapeutics for MCC.
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50
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Abdulsalam I, Rasheed K, Sveinbjørnsson B, Ehlers B, Moens U. Promoter activity of Merkel cell Polyomavirus variants in human dermal fibroblasts and a Merkel cell carcinoma cell line. Virol J 2020; 17:54. [PMID: 32306957 PMCID: PMC7168875 DOI: 10.1186/s12985-020-01317-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/10/2020] [Indexed: 12/31/2022] Open
Abstract
Background Merkel cell polyomavirus (MCPyV) is a human polyomavirus that establishes a life-long harmless infection in most individuals, with dermal fibroblasts believed to be the natural host cell. However, this virus is the major cause of Merkel cell carcinoma (MCC), an aggressive skin cancer. Several MCPyV variants with polymorphism in their promoter region have been isolated, but it is not known whether these differences affect the biological properties of the virus. Methods Using transient transfection studies in human dermal fibroblasts and the MCC cell line MCC13, we compared the transcription activity of the early and late promoters of the most commonly described non-coding control region MCPyV variant and six other isolates containing specific mutation patterns. Results Both the early and late promoters were significantly stronger in human dermal fibroblasts compared with MCC13 cells, and a different promoter strength between the MCPyV variants was observed. The expression of full-length large T-antigen, a viral protein that regulates early and late promoter activity, inhibited early and late promoter activities in both cell lines. Nonetheless, a truncated large T-antigen, which is expressed in virus-positive MCCs, stimulated the activity of its cognate promoter. Conclusion The promoter activities of all MCPyV variants tested was stronger in human dermal fibroblasts, a cell line that supports viral replication, than in MCC13 cells, which are not permissive for MCPyV. Truncated large T-antigen, but not full-length large T-antigen stimulated viral promoter activity. Whether, the difference in promoter strength and regulation by large T-antigen may affect the replication and tumorigenic properties of the virus remains to be determined.
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Affiliation(s)
- Ibrahim Abdulsalam
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway.,Present address: Tumor Biology Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
| | - Kashif Rasheed
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
| | - Baldur Sveinbjørnsson
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
| | - Bernhard Ehlers
- Division 12 Measles, Mumps, Rubella and Viruses Affecting Immunocompromised Patients, Robert Koch Institute, Berlin, Germany
| | - Ugo Moens
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway.
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