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Thevenin KR, Tieche IS, Di Benedetto CE, Schrager M, Dye KN. The small tumor antigen of Merkel cell polyomavirus accomplishes cellular transformation by uniquely localizing to the nucleus despite the absence of a known nuclear localization signal. Virol J 2024; 21:125. [PMID: 38831469 PMCID: PMC11149282 DOI: 10.1186/s12985-024-02395-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
BACKGROUND Merkel Cell Carcinoma (MCC) is an aggressive skin cancer that is three times deadlier than melanoma. In 2008, it was found that 80% of MCC cases are caused by the genomic integration of a novel polyomavirus, Merkel Cell Polyomavirus (MCPyV), and the expression of its small and truncated large tumor antigens (ST and LT-t, respectively). MCPyV belongs to a family of human polyomaviruses; however, it is the only one with a clear association to cancer. METHODS To investigate the role and mechanisms of various polyomavirus tumor antigens in cellular transformation, Rat-2 and 293A cells were transduced with pLENTI MCPyV LT-t, MCPyV ST, TSPyV ST, HPyV7 ST, or empty pLENTI and assessed through multiple transformation assays, and subcellular fractionations. One-way ANOVA tests were used to assess statistical significance. RESULTS Soft agar, proliferation, doubling time, glucose uptake, and serum dependence assays confirmed ST to be the dominant transforming protein of MCPyV. Furthermore, it was found that MCPyV ST is uniquely transforming, as the ST antigens of other non-oncogenic human polyomaviruses such as Trichodysplasia Spinulosa-Associated Polyomavirus (TSPyV) and Human Polyomavirus 7 (HPyV7) were not transforming when similarly assessed. Identification of structural dissimilarities between transforming and non-transforming tumor antigens revealed that the uniquely transforming domain(s) of MCPyV ST are likely located within the structurally dissimilar loops of the MCPyV ST unique region. Of all known MCPyV ST cellular interactors, 62% are exclusively or transiently nuclear, suggesting that MCPyV ST localizes to the nucleus despite the absence of a canonical nuclear localization signal. Indeed, subcellular fractionations confirmed that MCPyV ST could achieve nuclear localization through a currently unknown, regulated mechanism independent of its small size, as HPyV7 and TSPyV ST proteins were incapable of nuclear translocation. Although nuclear localization was found to be important for several transforming properties of MCPyV ST, some properties were also performed by a cytoplasmic sequestered MCPyV ST, suggesting that MCPyV ST may perform different transforming functions in individual subcellular compartments. CONCLUSIONS Together, these data further elucidate the unique differences between MCPyV ST and other polyomavirus ST proteins necessary to understand MCPyV as the only known human oncogenic polyomavirus.
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Affiliation(s)
- Kaira R Thevenin
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Isabella S Tieche
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Cody E Di Benedetto
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Matt Schrager
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA
| | - Kristine N Dye
- Department of Health Sciences, Stetson University, 421 N Woodland Blvd, DeLand, FL, 32723, USA.
- Department of Biology, Stetson University, DeLand, FL, 32723, USA.
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Salisbury NJH, Amonkar S, Vinueza JL, Carter JJ, Roman A, Galloway DA. Polyomavirus ALTOs, but not MTs, downregulate viral early gene expression by activating the NF-κB pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595774. [PMID: 38826197 PMCID: PMC11142227 DOI: 10.1101/2024.05.24.595774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Polyomaviruses are small, circular dsDNA viruses that can cause cancer. Alternative splicing of polyomavirus early transcripts generates large and small tumor antigens (LT, ST) that play essential roles in viral replication and tumorigenesis. Some polyomaviruses also express middle tumor antigens (MTs) or Alternate LT ORFs (ALTOs), which are evolutionarily related but have distinct gene structures. MTs are a splice variant of the early transcript whereas ALTOs are overprinted on the second exon of the LT transcript in an alternate reading frame and are translated via an alternative start codon. Merkel cell polyomavirus (MCPyV), the only human polyomavirus that causes cancer, encodes an ALTO but its role in the viral lifecycle and tumorigenesis has remained elusive. Here, we show MCPyV ALTO acts as a tumor suppressor and is silenced in Merkel cell carcinoma (MCC). Rescuing ALTO in MCC cells induces growth arrest and activates NF-κB signaling. ALTO activates NF-κB by binding SQSTM1 and TRAF2&3 via two N-Terminal Activating Regions (NTAR1+2), resembling Epstein-Barr virus (EBV) Latent Membrane Protein 1 (LMP1).. Following activation, NF-κB dimers bind the MCPyV non-coding control region (NCCR) and downregulate early transcription. Beyond MCPyV, NTAR motifs are conserved in other polyomavirus ALTOs, which activate NF-κB signaling, but are lacking in MTs that do not. Furthermore, polyomavirus ALTOs downregulate their respective viral early transcription in an NF-κB and NTAR dependent manner. Our findings suggest that ALTOs evolved to suppress viral replication and promote viral latency and that MCPyV ALTO must be silenced for MCC to develop.
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Affiliation(s)
- Nicholas J. H. Salisbury
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
| | - Supriya Amonkar
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
| | - Joselyn Landazuri Vinueza
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
- University of Washington, Department of Microbiology, Seattle, WA, 98109, USA
| | - Joseph J. Carter
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
| | - Ann Roman
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
- University of Washington, Department of Microbiology, Seattle, WA, 98109, USA
| | - Denise A. Galloway
- Fred Hutchinson Cancer Center, Pathogen-Associated Malignancies Integrated Research Center, Seattle, WA, 98109 USA
- University of Washington, Department of Microbiology, Seattle, WA, 98109, USA
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Torre-Castro J, Rodríguez M, Alonso-Alonso R, Mendoza Cembranos MD, Díaz-Alejo JF, Rebollo-González M, Borregón J, Nájera Botello L, Mahillo-Fernández I, Samimi M, Kervarrec T, Requena L, Piris MÁ. LT and SOX9 expression are associated with gene sets that distinguish Merkel cell polyomavirus (MCPyV)-positive and MCPyV-negative Merkel cell carcinoma. Br J Dermatol 2024; 190:876-884. [PMID: 38261397 DOI: 10.1093/bjd/ljae033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024]
Abstract
BACKGROUND Merkel cell carcinoma (MCC) is an aggressive malignant neuroendocrine tumour. There are two subsets of MCC, one related to Merkel cell polyomavirus (MCPyV) and the other to ultraviolet radiation (UVR). MCPyV-positive and MCPyV-negative MCCs have been considered to be different tumours, as the former harbour few DNA mutations and are not related to UVR, and the latter usually arise in sun-exposed areas and may be found in conjunction with other keratinocytic tumours, mostly squamous cell carcinomas. Two viral oncoproteins, large T antigen (LT; coded by MCPyV_gp3) and small T antigen (sT; coded by MCPyV_gp4), promote different carcinogenic pathways. OBJECTIVES To determine which genes are differentially expressed in MCPyV-positive and MCPyV-negative MCC; to describe the mutational burden and the most frequently mutated genes in both MCC subtypes; and to identify the clinical and molecular factors that may be related to patient survival. METHODS Ninety-two patients with a diagnosis of MCC were identified from the medical databases of participating centres. To study gene expression, a customized panel of 172 genes was developed. Gene expression profiling was performed with nCounter technology. For mutational studies, a customized panel of 26 genes was designed. Somatic single nucleotide variants (SNVs) were identified following the GATK Best Practices workflow for somatic mutations. RESULTS The expression of LT enabled the series to be divided into two groups (LT positive, n = 55; LT negative, n = 37). Genes differentially expressed in LT-negative patients were related to epithelial differentiation, especially SOX9, or proliferation and the cell cycle (MYC, CDK6), among others. Congruently, LT displayed lower expression in SOX9-positive patients, and differentially expressed genes in SOX9-positive patients were related to epithelial/squamous differentiation. In LT-positive patients, the mean SNV frequency was 4.3; in LT-negative patients it was 10 (P = 0.03). On multivariate survival analysis, the expression of SNAI1 [hazard ratio (HR) 1.046, 95% confidence interval (CI) 1.007-1.086; P = 0.02] and CDK6 (HR 1.049, 95% CI 1.020-1.080; P = 0.001) were identified as risk factors. CONCLUSIONS Tumours with weak LT expression tend to co-express genes related to squamous differentiation and the cell cycle, and to have a higher mutational burden. These findings are congruent with those of earlier studies.
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Affiliation(s)
| | - Marta Rodríguez
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
- Center for Biomedical Network on Cancer (CIBERONC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Ruth Alonso-Alonso
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
- Center for Biomedical Network on Cancer (CIBERONC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | | | - Jesús Frutos Díaz-Alejo
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
| | - Marcos Rebollo-González
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
| | - Jennifer Borregón
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
| | - Laura Nájera Botello
- Pathology Department, Hospital Universitario Puerta de Hierro, Universidad Autónoma, Madrid, Spain
| | - Ignacio Mahillo-Fernández
- Biostatistics and Epidemiology Unit, Hospital Universitario Fundación Jiménez Díaz, Fundación Instituto de Investigación Sanitaria, Madrid, Spain
| | | | | | | | - Miguel Ángel Piris
- Pathology, Hospital Universitario Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
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Zhao J, Cato LD, Arora UP, Bao EL, Bryant SC, Williams N, Jia Y, Goldman SR, Nangalia J, Erb MA, Vos SM, Armstrong SA, Sankaran VG. Inherited blood cancer predisposition through altered transcription elongation. Cell 2024; 187:642-658.e19. [PMID: 38218188 PMCID: PMC10872907 DOI: 10.1016/j.cell.2023.12.016] [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: 06/06/2023] [Revised: 11/26/2023] [Accepted: 12/08/2023] [Indexed: 01/15/2024]
Abstract
Despite advances in defining diverse somatic mutations that cause myeloid malignancies, a significant heritable component for these cancers remains largely unexplained. Here, we perform rare variant association studies in a large population cohort to identify inherited predisposition genes for these blood cancers. CTR9, which encodes a key component of the PAF1 transcription elongation complex, is among the significant genes identified. The risk variants found in the cases cause loss of function and result in a ∼10-fold increased odds of acquiring a myeloid malignancy. Partial CTR9 loss of function expands human hematopoietic stem cells (HSCs) by increased super elongation complex-mediated transcriptional activity, which thereby increases the expression of key regulators of HSC self-renewal. By following up on insights from a human genetic study examining inherited predisposition to the myeloid malignancies, we define a previously unknown antagonistic interaction between the PAF1 and super elongation complexes. These insights could enable targeted approaches for blood cancer prevention.
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Affiliation(s)
- Jiawei Zhao
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Center for Cancer Immunology, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen, China.
| | - Liam D Cato
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Uma P Arora
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Erik L Bao
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Nicholas Williams
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK; UK and MRC-Wellcome Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Yuemeng Jia
- Harvard Stem Cell Institute, Cambridge, MA, USA; Stem Cell Program, Boston Children's Hospital, Boston, MA, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Seth R Goldman
- Nascent Transcriptomics Core, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Jyoti Nangalia
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK; UK and MRC-Wellcome Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Michael A Erb
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Seychelle M Vos
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Scott A Armstrong
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Vijay G Sankaran
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, USA.
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5
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Thevenin KR, Tieche IS, Di Benedetto CE, Schrager M, Dye KN. The Small Tumor Antigen of Merkel Cell Polyomavirus Accomplishes Cellular Transformation by Uniquely Localizing to the Nucleus Despite the Absence of a Known Nuclear Localization Signal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.28.569067. [PMID: 38293082 PMCID: PMC10827104 DOI: 10.1101/2023.11.28.569067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Background Merkel Cell Carcinoma (MCC) is an aggressive skin cancer that is three times deadlier than melanoma. In 2008, it was found that 80% of MCC cases are caused by the genomic integration of a novel polyomavirus, Merkel Cell Polyomavirus (MCPyV), and the expression of its small and truncated large tumor antigens (ST and LT-t, respectively). MCPyV belongs to a family of human polyomaviruses; however, it is the only one with a clear association to cancer. Methods To investigate the role and mechanisms of various polyomavirus tumor antigens in cellular transformation, Rat-2, 293A, and human foreskin fibroblasts were transduced with pLENTI MCPyV LT-t, MCPyV ST, TSPyV ST, HPyV7 ST, or empty pLENTI and assessed through multiple transformation assays, and subcellular fractionations. One-way ANOVA tests were used to assess statistical significance. Results Soft agar, proliferation, doubling time, glucose uptake, and serum dependence assays confirmed ST to be the dominant transforming protein of MCPyV. Furthermore, it was found that MCPyV ST is uniquely transforming, as the ST antigens of other non-oncogenic human polyomaviruses such as Trichodysplasia Spinulosa Polyomavirus (TSPyV) and Human Polyomavirus 7 (HPyV7) were not transforming when similarly assessed. Identification of structural dissimilarities between transforming and non-transforming tumor antigens revealed that the uniquely transforming domain(s) of MCPyV ST are likely located within the structurally dissimilar loops of the MCPyV ST unique region. Of all known MCPyV ST cellular interactors, 62% are exclusively or transiently nuclear, suggesting that MCPyV ST localizes to the nucleus despite the absence of a canonical nuclear localization signal. Indeed, subcellular fractionations confirmed that MCPyV ST could achieve nuclear localization through a currently unknown, regulated mechanism independent of its small size, as HPyV7 and TSPyV ST proteins were incapable of nuclear translocation. Although nuclear localization was found to be important for several transforming properties of MCPyV ST, some properties were also performed by a cytoplasmic sequestered MCPyV ST, suggesting that MCPyV ST may perform different transforming functions in individual subcellular compartments. Conclusions Together, these data further elucidate the unique differences between MCPyV ST and other polyomavirus ST proteins necessary to understand MCPyV as the only known human oncogenic polyomavirus.
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6
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Houben R, Alimova P, Sarma B, Hesbacher S, Schulte C, Sarosi EM, Adam C, Kervarrec T, Schrama D. 4-[(5-Methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone Inhibits MCPyV T Antigen Expression in Merkel Cell Carcinoma Independent of Aurora Kinase A. Cancers (Basel) 2023; 15:cancers15092542. [PMID: 37174007 PMCID: PMC10177447 DOI: 10.3390/cancers15092542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Merkel cell carcinoma (MCC) is frequently caused by the Merkel cell polyomavirus (MCPyV), and MCPyV-positive tumor cells depend on expression of the virus-encoded T antigens (TA). Here, we identify 4-[(5-methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone (PHT)-a reported inhibitor of Aurora kinase A-as a compound inhibiting growth of MCC cells by repressing noncoding control region (NCCR)-controlled TA transcription. Surprisingly, we find that TA repression is not caused by inhibition of Aurora kinase A. However, we demonstrate that β-catenin-a transcription factor repressed by active glycogen synthase kinase 3 (GSK3)-is activated by PHT, suggesting that PHT bears a hitherto unreported inhibitory activity against GSK3, a kinase known to function in promoting TA transcription. Indeed, applying an in vitro kinase assay, we demonstrate that PHT directly targets GSK3. Finally, we demonstrate that PHT exhibits in vivo antitumor activity in an MCC xenograft mouse model, suggesting a potential use in future therapeutic settings for MCC.
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Affiliation(s)
- Roland Houben
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Pamela Alimova
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Bhavishya Sarma
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Sonja Hesbacher
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Carolin Schulte
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Eva-Maria Sarosi
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Christian Adam
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Thibault Kervarrec
- Department of Pathology, Centre Hospitalier Universitaire de Tours, INRA UMR 1282 BIP, 37200 Tours, France
| | - David Schrama
- Department of Dermatology, Venereology und Allergology, University Hospital Würzburg, 97080 Würzburg, Germany
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Gambichler T, Brüggestrat LG, Skrygan M, Scheel CH, Susok L, Becker JC. The Antineoplastic Effect of Dimethyl Fumarate on Virus-Negative Merkel Cell Carcinoma Cell Lines: Preliminary Results. Cancers (Basel) 2023; 15:cancers15020547. [PMID: 36672496 PMCID: PMC9857057 DOI: 10.3390/cancers15020547] [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: 12/07/2022] [Revised: 01/07/2023] [Accepted: 01/10/2023] [Indexed: 01/19/2023] Open
Abstract
Merkel cell carcinoma (MCC) is a rare, difficult-to-treat skin cancer once immunotherapy has failed. MCC is associated either with the clonal integration of the Merkel cell polyomavirus (MCPyV) or mutagenic UV-radiation. Fumaric acid esters, including dimethyl fumarate (DMF), have been shown to inhibit cell growth in cutaneous melanoma and lymphoma. We aimed to explore the effects of DMF on MCPyV-negative MCC cell lines. Three MCC cell lines (MCC13, MCC14.2, and MCC26) were treated with different doses of DMF. The cytotoxic effects and cell proliferation were assessed by the MTT cytotoxicity assay and BrdU proliferation assay at different time points. A significant reduction in cell viability and proliferation were demonstrated for all the cell lines used, with DMF proving to be effective.
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Affiliation(s)
- Thilo Gambichler
- Skin Cancer Center, Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, 44791 Bochum, Germany
- Correspondence:
| | - Lyn G. Brüggestrat
- Skin Cancer Center, Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, 44791 Bochum, Germany
| | - Marina Skrygan
- Skin Cancer Center, Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, 44791 Bochum, Germany
| | - Christina H. Scheel
- Skin Cancer Center, Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, 44791 Bochum, Germany
| | - Laura Susok
- Skin Cancer Center, Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, 44791 Bochum, Germany
| | - Jürgen C. Becker
- Translational Skin Cancer Research, German Cancer Consortium (DKTK) Partner Site Essen, Düsseldorf, Department of Dermatology, University Duisburg-Essen, 45117 Essen, Germany
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg, Germany
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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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9
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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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10
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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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11
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Role of Peritoneal Mesothelial Cells in the Progression of Peritoneal Metastases. Cancers (Basel) 2022; 14:cancers14122856. [PMID: 35740521 PMCID: PMC9221366 DOI: 10.3390/cancers14122856] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/19/2022] [Accepted: 06/06/2022] [Indexed: 11/17/2022] Open
Abstract
Peritoneal metastatic cancer comprises a heterogeneous group of primary tumors that originate in the peritoneal cavity or metastasize into the peritoneal cavity from a different origin. Metastasis is a characteristic of end-stage disease, often indicative of a poor prognosis with limited treatment options. Peritoneal mesothelial cells (PMCs) are a thin layer of cells present on the surface of the peritoneum. They display differentiated characteristics in embryonic development and adults, representing the first cell layer encountering peritoneal tumors to affect their progression. PMCs have been traditionally considered a barrier to the intraperitoneal implantation and metastasis of tumors; however, recent studies indicate that PMCs can either inhibit or actively promote tumor progression through distinct mechanisms. This article presents a review of the role of PMCs in the progression of peritoneum implanted tumors, offering new ideas for therapeutic targets and related research.
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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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Ursu RG, Damian C, Porumb-Andrese E, Ghetu N, Cobzaru RG, Lunca C, Ripa C, Costin D, Jelihovschi I, Petrariu FD, Iancu LS. Merkel Cell Polyoma Virus and Cutaneous Human Papillomavirus Types in Skin Cancers: Optimal Detection Assays, Pathogenic Mechanisms, and Therapeutic Vaccination. Pathogens 2022; 11:pathogens11040479. [PMID: 35456154 PMCID: PMC9032856 DOI: 10.3390/pathogens11040479] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 02/06/2023] Open
Abstract
Oncogenic viruses are recognized to be involved in some cancers, based on very well-established criteria of carcinogenicity. For cervical cancer and liver cancer, the responsible viruses are well-known (e.g., HPV, HBV); in the case of skin cancer, there are still many studies which are trying to identify the possible viral etiologic agents as principal co-factors in the oncogenic process. We analysed scientific literature published in the last 5 years regarding mechanisms of carcinogenicity, methods of detection, available targeted therapy, and vaccination for Merkel cell polyomavirus, and beta human papillomavirus types, in relation to skin cancer. This review is targeted at presenting the recent findings which support the involvement of these viruses in the development of some types of skin cancers. In order to optimize the management of skin cancer, a health condition of very high importance, it would be ideal that the screening of skin cancer for these two analysed viruses (MCPyV and beta HPV types) to be implemented in each region's/country's cancer centres' molecular detection diagnostic platforms, with multiplex viral capability, optimal sensitivity, and specificity; clinically validated, and if possible, at acceptable costs. For confirmatory diagnosis of skin cancer, another method should be used, with a different principle, such as immunohistochemistry, with specific antibodies for each virus.
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Affiliation(s)
- Ramona Gabriela Ursu
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Costin Damian
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Elena Porumb-Andrese
- Department of Medical Specialties (III)—Dermatology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Nicolae Ghetu
- Department of Plastic Surgery, Regional Oncology Institute, 700483 Iasi, Romania
- Correspondence:
| | - Roxana Gabriela Cobzaru
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Catalina Lunca
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Carmen Ripa
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Diana Costin
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Igor Jelihovschi
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Florin Dumitru Petrariu
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
| | - Luminita Smaranda Iancu
- Department of Preventive Medicine and Interdisciplinarity (IX)—Microbiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (R.G.U.); (C.D.); (R.G.C.); (C.L.); (C.R.); (D.C.); (I.J.); (F.D.P.); (L.S.I.)
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14
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
As their name indicates, polyomaviruses (PyVs) can induce tumors. Mouse PyV, hamster PyV and raccoon PyV have been shown to cause tumors in their natural host. During the last 30 years, 15 PyVs have been isolated from humans. From these, Merkel cell PyV is classified as a Group 2A carcinogenic pathogen (probably carcinogenic to humans), whereas BKPyV and JCPyV are class 2B (possibly carcinogenic to humans) by the International Agency for Research on Cancer. Although the other PyVs recently detected in humans (referred to here as novel HPyV; nHPyV) share many common features with PyVs, including the viral oncoproteins large tumor antigen and small tumor antigen, as their role in cancer is questioned. This review discusses whether the nHPyVs may play a role in cancer based on predicted and experimentally proven functions of their early proteins in oncogenic processes. The functional domains that mediate the oncogenic properties of early proteins of known PyVs, that can cause cancer in their natural host or animal models, have been well characterized and we examined whether these functional domains are conserved in the early proteins of the nHPyVs and presented experimental evidence that these conserved domains are functional. Furthermore, we reviewed the literature describing the detection of nHPyV in human tumors.
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Affiliation(s)
- Ugo Moens
- Faculty of Health Sciences, Department of Medical Biology, University of Tromsø – The Arctic University of Norway, Tromsø, Norway
- *Correspondence: Ugo Moens,
| | - Carla Prezioso
- Microbiology of Chronic Neuro-Degenerative Pathologies, IRCSS San Raffaele Roma, Rome, Italy
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
- Valeria Pietropaolo,
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Ahmed MM, Cushman CH, DeCaprio JA. Merkel Cell Polyomavirus: Oncogenesis in a Stable Genome. Viruses 2021; 14:v14010058. [PMID: 35062263 PMCID: PMC8781562 DOI: 10.3390/v14010058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 12/14/2022] Open
Abstract
Merkel cell polyomavirus (MCV) is the causative agent for the majority of Merkel cell carcinoma (MCC) cases. Polyomavirus-associated MCC (MCCP) is characterized by the integration of MCV DNA into the tumor genome and a low tumor mutational burden. In contrast, nonviral MCC (MCCN) is characterized by a high tumor mutational burden induced by UV damage. Since the discovery of MCV, much work in the field has focused on understanding the molecular mechanisms of oncogenesis driven by the MCV tumor (T) antigens. Here, we review our current understanding of how the activities of large T (LT) and small T (ST) promote MCC oncogenesis in the absence of genomic instability. We highlight how both LT and ST inhibit tumor suppressors to evade growth suppression, an important cancer hallmark. We discuss ST interactions with cellular proteins, with an emphasis on those that contribute to sustaining proliferative signaling. Finally, we examine active areas of research into open questions in the field, including the origin of MCC and mechanisms of viral integration.
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Affiliation(s)
- Mona M. Ahmed
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA; (M.M.A.); (C.H.C.)
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Camille H. Cushman
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA; (M.M.A.); (C.H.C.)
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - James A. DeCaprio
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA; (M.M.A.); (C.H.C.)
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Correspondence:
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Abstract
Viral infection is an indisputable causal factor for nearly 17% of all human cancers. However, the diversity and complexity of oncogenic mechanisms raises new questions as to the mechanistic role of viruses in cancer. Classical viral oncogenes have been identified for all tumor-associated viruses. These oncogenes can have multiple oncogenic activities that may or may not be utilized in a particular tumor cell. In addition, stochastic events, like viral mutation and integration, as well as heritable host susceptibilities and immune deficiencies are also implicated in tumorigenesis. A more contemporary view of tumor biology highlights the importance of evolutionary forces that select for phenotypes better adapted to a complex and changing environment. Given the challenges of prioritizing singular mechanistic causes, it may be necessary to integrate concepts from evolutionary theory and systems biology to better understand viral cancer-driving forces. Here, we propose that viral infection provides a biological “entropy” that increases genetic variation and phenotypic plasticity, accelerating the main driving forces of cancer cell evolution. Viruses can also influence the evolutionary selection criteria by altering the tumor microenvironment and immune signaling. Utilizing concepts from cancer cell evolution, population genetics, thermodynamics, and systems biology may provide new perspectives on viral oncogenesis and identify novel therapeutic strategies for treating viruses and cancer.
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Affiliation(s)
- Italo Tempera
- Program in Gene Expression and Regulation, The Wistar Institute, Philadelphia, PA, United States
| | - Paul M Lieberman
- Program in Gene Expression and Regulation, The Wistar Institute, Philadelphia, PA, United States
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17
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Krump NA, You J. From Merkel Cell Polyomavirus Infection to Merkel Cell Carcinoma Oncogenesis. Front Microbiol 2021; 12:739695. [PMID: 34566942 PMCID: PMC8457551 DOI: 10.3389/fmicb.2021.739695] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) infection causes near-ubiquitous, asymptomatic infection in the skin, but occasionally leads to an aggressive skin cancer called Merkel cell carcinoma (MCC). Epidemiological evidence suggests that poorly controlled MCPyV infection may be a precursor to MCPyV-associated MCC. Clearer understanding of host responses that normally control MCPyV infection could inform prophylactic measures in at-risk groups. Similarly, the presence of MCPyV in most MCCs could imbue them with vulnerabilities that-if better characterized-could yield targeted intervention solutions for metastatic MCC cases. In this review, we discuss recent developments in elucidating the interplay between host cells and MCPyV within the context of viral infection and MCC oncogenesis. We also propose a model in which insufficient restriction of MCPyV infection in aging and chronically UV-damaged skin causes unbridled viral replication that licenses MCC tumorigenesis.
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Affiliation(s)
| | - Jianxin You
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Smith EA, Hill NT, Gelb T, Garman KA, Goncharova EI, Bokesch HR, Kim CK, Wendt KL, Cichewicz RH, Gustafson KR, Brownell I, Henrich CJ. Identification of natural product modulators of Merkel cell carcinoma cell growth and survival. Sci Rep 2021; 11:13597. [PMID: 34193920 PMCID: PMC8245553 DOI: 10.1038/s41598-021-93097-9] [Citation(s) in RCA: 3] [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: 05/11/2021] [Accepted: 06/21/2021] [Indexed: 12/04/2022] Open
Abstract
Merkel cell carcinoma (MCC) is a rare, but aggressive skin cancer the incidence of which has increased significantly in recent years. The majority of MCCs have incorporated Merkel cell polyomavirus (VP-MCC) while the remainder are virus-negative (VN-MCC). Although a variety of therapeutic options have shown promise in treating MCC, there remains a need for additional therapeutics as well as probes for better understanding MCC. A high-throughput screening campaign was used to assess the ability of > 25,000 synthetic and natural product compounds as well as > 20,000 natural product extracts to affect growth and survival of VN-MCC and VP-MCC cell lines. Sixteen active compounds were identified that have mechanisms of action reported in the literature along with a number of compounds with unknown mechanisms. Screening results with pure compounds suggest a range of potential targets for MCC including DNA damage, inhibition of DNA or protein synthesis, reactive oxygen species, and proteasome inhibition as well as NFκB inhibition while also suggesting the importance of zinc and/or copper binding. Many of the active compounds, particularly some of the natural products, have multiple reported targets suggesting that this strategy might be a particularly fruitful approach. Processing of several active natural product extracts resulted in the identification of additional MCC-active compounds. Based on these results, further investigations focused on natural products sources, particularly of fungal origin, are expected to yield further potentially useful modulators of MCC.
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Affiliation(s)
- Emily A Smith
- Molecular Targets Program, National Cancer Institute, Frederick, MD, 21702, USA
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Natasha T Hill
- Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD, 20891, USA
| | - Tara Gelb
- Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD, 20891, USA
| | - Khalid A Garman
- Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD, 20891, USA
| | - Ekaterina I Goncharova
- Molecular Targets Program, National Cancer Institute, Frederick, MD, 21702, USA
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Heidi R Bokesch
- Molecular Targets Program, National Cancer Institute, Frederick, MD, 21702, USA
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Chang-Kwon Kim
- Molecular Targets Program, National Cancer Institute, Frederick, MD, 21702, USA
| | - Karen L Wendt
- Natural Products Discovery Group, Department of Chemistry & Biochemistry, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK, 73019, USA
| | - Robert H Cichewicz
- Natural Products Discovery Group, Department of Chemistry & Biochemistry, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK, 73019, USA
| | - Kirk R Gustafson
- Molecular Targets Program, National Cancer Institute, Frederick, MD, 21702, USA
| | - Isaac Brownell
- Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD, 20891, USA
| | - Curtis J Henrich
- Molecular Targets Program, National Cancer Institute, Frederick, MD, 21702, USA.
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
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Yang R, Lee EE, Kim J, Choi JH, Kolitz E, Chen Y, Crewe C, Salisbury NJH, Scherer PE, Cockerell C, Smith TR, Rosen L, Verlinden L, Galloway DA, Buck CB, Feltkamp MC, Sullivan CS, Wang RC. Characterization of ALTO-encoding circular RNAs expressed by Merkel cell polyomavirus and trichodysplasia spinulosa polyomavirus. PLoS Pathog 2021; 17:e1009582. [PMID: 33999949 PMCID: PMC8158866 DOI: 10.1371/journal.ppat.1009582] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/27/2021] [Accepted: 04/24/2021] [Indexed: 12/14/2022] Open
Abstract
Circular RNAs (circRNAs) are a conserved class of RNAs with diverse functions, including serving as messenger RNAs that are translated into peptides. Here we describe circular RNAs generated by human polyomaviruses (HPyVs), some of which encode variants of the previously described alternative large T antigen open reading frame (ALTO) protein. Circular ALTO RNAs (circALTOs) can be detected in virus positive Merkel cell carcinoma (VP-MCC) cell lines and tumor samples. CircALTOs are stable, predominantly located in the cytoplasm, and N6-methyladenosine (m6A) modified. The translation of MCPyV circALTOs into ALTO protein is negatively regulated by MCPyV-generated miRNAs in cultured cells. MCPyV ALTO expression increases transcription from some recombinant promoters in vitro and upregulates the expression of multiple genes previously implicated in MCPyV pathogenesis. MCPyV circALTOs are enriched in exosomes derived from VP-MCC lines and circALTO-transfected 293T cells, and purified exosomes can mediate ALTO expression and transcriptional activation in MCPyV-negative cells. The related trichodysplasia spinulosa polyomavirus (TSPyV) also expresses a circALTO that can be detected in infected tissues and produces ALTO protein in cultured cells. Thus, human polyomavirus circRNAs are expressed in human tumors and infected tissues and express proteins that have the potential to modulate the infectious and tumorigenic properties of these viruses.
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Affiliation(s)
- Rong Yang
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Eunice E. Lee
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jiwoong Kim
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Joon H. Choi
- Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America
| | - Elysha Kolitz
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Yating Chen
- Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America
| | - Clair Crewe
- Touchstone Diabetes Center, Department of Internal Medicine, the UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Nicholas J. H. Salisbury
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Philipp E. Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, the UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Clay Cockerell
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Taylor R. Smith
- Department of Dermatology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Leslie Rosen
- Department of Dermatology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Louisa Verlinden
- Department of Dermatology, Ghent University Hospital, Ghent, Belgium
| | - Denise A. Galloway
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Christopher B. Buck
- Lab of Cellular Oncology, NCI, NIH, Bethesda, Maryland, United States of America
| | - Mariet C. Feltkamp
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Christopher S. Sullivan
- Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America
| | - Richard C. Wang
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas, United States of America
- Harold C. Simmons Cancer Center, UT Southwestern Medical Center, Dallas, Texas, United States of America
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