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James CD, Lewis RL, Fakunmoju AL, Witt AJ, Youssef AH, Wang X, Rais NM, Tadimari Prabhakar A, Machado JM, Otoa R, Bristol ML. Fibroblast Stromal Support Model for Predicting Human Papillomavirus-Associated Cancer Drug Responses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.09.588680. [PMID: 38644998 PMCID: PMC11030318 DOI: 10.1101/2024.04.09.588680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Currently, there are no specific antiviral therapeutic approaches targeting Human papillomaviruses (HPVs), which cause around 5% of all human cancers. Specific antiviral reagents are particularly needed for HPV-related oropharyngeal cancers (HPV+OPCs) whose incidence is increasing and for which there are no early diagnostic tools available. We and others have demonstrated that the estrogen receptor alpha (ERα) is overexpressed in HPV+OPCs, compared to HPV-negative cancers in this region, and that these elevated levels are associated with an improved disease outcome. Utilizing this HPV+ specific overexpression profile, we previously demonstrated that estrogen attenuates the growth and cell viability of HPV+ keratinocytes and HPV+ cancer cells in vitro. Expansion of this work in vivo failed to replicate this sensitization. The role of stromal support from the tumor microenvironment (TME) has previously been tied to both the HPV lifecycle and in vivo therapeutic responses. Our investigations revealed that in vitro co-culture with fibroblasts attenuated HPV+ specific estrogen growth responses. Continuing to monopolize on the HPV+ specific overexpression of ERα, our co-culture models then assessed the suitability of the selective estrogen receptor modulators (SERMs), raloxifene and tamoxifen, and showed growth attenuation in a variety of our models to one or both of these drugs in vitro. Utilization of these SERMs in vivo closely resembled the sensitization predicted by our co-culture models. Therefore, the in vitro fibroblast co-culture model better predicts in vivo responses. We propose that utilization of our co-culture in vitro model can accelerate cancer therapeutic drug discovery.
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Affiliation(s)
- Claire D. James
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Rachel L. Lewis
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Alexis L. Fakunmoju
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Austin J. Witt
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Aya H. Youssef
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Xu Wang
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Nabiha M. Rais
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Apurva Tadimari Prabhakar
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - J. Mathew Machado
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Raymonde Otoa
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Molly L. Bristol
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
- VCU Massey Comprehensive Cancer Center, Richmond, Virginia, USA
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2
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Prabhakar AT, James CD, Fontan CT, Otoa R, Wang X, Bristol ML, Yeager C, Hill RD, Dubey A, Wu SY, Chiang CM, Morgan IM. Direct interaction with the BRD4 carboxyl-terminal motif (CTM) and TopBP1 is required for human papillomavirus 16 E2 association with mitotic chromatin and plasmid segregation function. J Virol 2023; 97:e0078223. [PMID: 37712702 PMCID: PMC10617519 DOI: 10.1128/jvi.00782-23] [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: 05/24/2023] [Accepted: 07/25/2023] [Indexed: 09/16/2023] Open
Abstract
IMPORTANCE Human papillomavirus 16 (HPV16) is a causative agent in around 3%-4% of all human cancers, and currently, there are no anti-viral therapeutics available for combating this disease burden. In order to identify new therapeutic targets, we must increase our understanding of the HPV16 life cycle. Previously, we demonstrated that an interaction between E2 and the cellular protein TopBP1 mediates the plasmid segregation function of E2, allowing distribution of viral genomes into daughter nuclei following cell division. Here, we demonstrate that E2 interaction with an additional host protein, BRD4, is also essential for E2 segregation function, and that BRD4 exists in a complex with TopBP1. Overall, these results enhance our understanding of a critical part of the HPV16 life cycle and presents several therapeutic targets for disruption of the viral life cycle.
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Affiliation(s)
- Apurva T. Prabhakar
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Claire D. James
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Christian T. Fontan
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Raymonde Otoa
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Xu Wang
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Molly L. Bristol
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
| | - Calvin Yeager
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Ronald D. Hill
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Aanchal Dubey
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Shwu-Yuan Wu
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Cheng-Ming Chiang
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Iain M. Morgan
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
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3
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Rao A, Ni Z, Suresh D, Mohanty C, Wang AR, Lee DL, Nickel KP, Varambally SRJ, Lambert PF, Kendziorski C, Iyer G. Targeted inhibition of BET proteins in HPV-16 associated head and neck squamous cell carcinoma reveals heterogeneous transcription response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560587. [PMID: 37873389 PMCID: PMC10592929 DOI: 10.1101/2023.10.02.560587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Integrated human papillomavirus (HPV-16) associated head and neck squamous cell carcinoma (HNSCC) tumors have worse survival outcomes compared to episomal HPV-16 HNSCC tumors. Therefore, there is a need to differentiate treatment for HPV-16 integrated HNSCC from other viral forms. We analyzed TCGA data and found that HPV+ HNSCC expressed higher transcript levels of the bromodomain and extra terminal domain (BET) family of transcriptional coregulators. However, the mechanism of BET protein-mediated transcription of viral-cellular genes in the integrated viral-HNSCC genomes needs to be better understood. We show that BET inhibition downregulates E6 significantly independent of the viral transcription factor, E2, and there was overall heterogeneity in the downregulation of viral transcription in response to the effects of BET inhibition across HPV-associated cell lines. Chemical BET inhibition was phenocopied with the knockdown of BRD4 and mirrored downregulation of viral E6 and E7 expression. Strikingly, there was heterogeneity in the reactivation of p53 levels despite E6 downregulation, while E7 downregulation did not alter Rb levels significantly. We identified that BET inhibition directly downregulated c-Myc and E2F expression and induced CDKN1A expression. Overall, our studies show that BET inhibition provokes a G1-cell cycle arrest with apoptotic activity and suggests that BET inhibition regulates both viral and cellular gene expression in HPV-associated HNSCC.
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Affiliation(s)
- Aakarsha Rao
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
| | - Zijian Ni
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Dhruthi Suresh
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
| | - Chitrasen Mohanty
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Albert R. Wang
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Denis L Lee
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- University of Wisconsin Carbone Cancer Center, Madison, 53705, WI, USA
| | - Kwangok P. Nickel
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Sooryanarayana Randall J. Varambally
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, 35233, 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
- University of Wisconsin Carbone Cancer Center, Madison, 53705, WI, USA
| | - Christina Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Gopal Iyer
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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4
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Prabhakar AT, James CD, Fontan CT, Otoa R, Wang X, Bristol ML, Hill RD, Dubey A, Wu SY, Chiang CM, Morgan IM. Direct interaction with the BRD4 carboxyl-terminal motif (CTM) and TopBP1 is required for human papillomavirus 16 E2 association with mitotic chromatin and plasmid segregation function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.25.542291. [PMID: 37292798 PMCID: PMC10245903 DOI: 10.1101/2023.05.25.542291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
During the human papillomavirus 16 life cycle, the E2 protein binds simultaneously to the viral genome and host chromatin throughout mitosis, ensuring viral genomes reside in daughter cell nuclei following cell division. Previously, we demonstrated that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1, and that this interaction is required for optimum E2 mitotic chromatin association and plasmid segregation function. Others have implicated BRD4 in mediating the plasmid segregation function of E2 and we have demonstrated that there is a TopBP1-BRD4 complex in the cell. We therefore further investigated the role of the E2-BRD4 interaction in mediating E2 association with mitotic chromatin and plasmid segregation function. Using a combination of immunofluorescence and our novel plasmid segregation assay in U2OS and N/Tert-1 cells stably expressing a variety of E2 mutants, we report that direct interaction with the BRD4 carboxyl-terminal motif (CTM) and TopBP1 is required for E2 association with mitotic chromatin and plasmid segregation. We also identify a novel TopBP1 mediated interaction between E2 and the BRD4 extra-terminal (ET) domain in vivo . Overall, the results demonstrate that direct interaction with TopBP1 and the BRD4 CTM are required for E2 mitotic chromatin association and plasmid segregation function. Disruption of this complex offers therapeutic options for targeting segregation of viral genomes into daughter cells, potentially combatting HPV16 infections, and cancers that retain episomal genomes. Importance HPV16 is a causative agent in around 3-4% of all human cancers and currently there are no anti-viral therapeutics available for combating this disease burden. In order to identify new therapeutic targets, we must increase our understanding of the HPV16 life cycle. Previously, we demonstrated that an interaction between E2 and the cellular protein TopBP1 mediates the plasmid segregation function of E2, allowing distribution of viral genomes into daughter nuclei following cell division. Here, we demonstrate that E2 interaction with an additional host protein, BRD4, is also essential for E2 segregation function, and that BRD4 exists in a complex with TopBP1. Overall, these results enhance our understanding of a critical part of the HPV16 life cycle and presents several therapeutic targets for disruption of the viral life cycle.
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5
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Deregulation of host gene expression by HPV16 E8^E2 knock-out genomes is due to increased productive replication. Virology 2023; 581:39-47. [PMID: 36870121 DOI: 10.1016/j.virol.2023.02.007] [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: 12/20/2022] [Revised: 02/06/2023] [Accepted: 02/13/2023] [Indexed: 02/24/2023]
Abstract
Productive replication of human papillomaviruses (HPV) only takes place in differentiating keratinocytes. The HPV16 E8^E2 protein acts as a repressor of viral gene expression and genome replication and HPV16 E8^E2 knock-out (E8-) genomes display enhanced viral late protein expression in differentiated cells. Global transcriptome analysis of differentiated HPV16 wild-type and E8-cell lines revealed a small number of differentially expressed genes which are not related to cell cycle, DNA metabolism or keratinocyte differentiation. The analysis of selected genes suggested that deregulation requires cell differentiation and positively correlated with the expression of viral late, not early transcripts. Consistent with this, the additional knock-out of the viral E4 and E5 genes, which are known to enhance productive replication, attenuated the deregulation of these host cell genes. In summary, these data reveal that productive HPV16 replication modulates host cell transcription.
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6
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Nantajit D, Presta L, Sauter T, Tavassoli M. EGFR-induced suppression of HPV E6/E7 is mediated by microRNA-9-5p silencing of BRD4 protein in HPV-positive head and neck squamous cell carcinoma. Cell Death Dis 2022; 13:921. [PMID: 36333293 PMCID: PMC9636399 DOI: 10.1038/s41419-022-05269-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022]
Abstract
EGFR upregulation is an established biomarker of treatment resistance and aggressiveness in head and neck cancers (HNSCC). EGFR-targeted therapies have shown benefits for HPV-negative HNSCC; surprisingly, inhibiting EGFR in HPV-associated HNSCC led to inferior therapeutic outcomes suggesting opposing roles for EGFR in the two HNSCC subtypes. The current study aimed to understand the link between EGFR and HPV-infected HNSCC particularly the regulation of HPV oncoproteins E6 and E7. We demonstrate that EGFR overexpression suppresses cellular proliferation and increases radiosensitivity of HPV-positive HNSCC cell lines. EGFR overexpression inhibited protein expression of BRD4, a known cellular transcriptional regulator of HPV E6/E7 expression and DNA damage repair facilitator. Inhibition of EGFR by cetuximab restored the expression of BRD4 leading to increased HPV E6 and E7 transcription. Concordantly, pharmacological inhibition of BRD4 led to suppression of HPV E6 and E7 transcription, delayed cellular proliferation and sensitised HPV-positive HNSCC cells to ionising radiation. This effect was shown to be mediated through EGFR-induced upregulation of microRNA-9-5p and consequent silencing of its target BRD4 at protein translational level, repressing HPV E6 and E7 transcription and restoring p53 tumour suppressor functions. These results suggest a novel mechanism for EGFR inhibition of HPV E6/E7 oncoprotein expression through an epigenetic pathway, independent of MAPK, but mediated through microRNA-9-5p/BRD4 regulation. Therefore, targeting EGFR may not be the best course of therapy for certain cancer types including HPV-positive HNSCC, while targeting specific signalling pathways such as BRD4 could provide a better and potentially new treatment to improve HNSCC therapeutic outcome.
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Affiliation(s)
- Danupon Nantajit
- grid.13097.3c0000 0001 2322 6764Centre for Host-Microbiome Interactions, King’s College London, London, United Kingdom ,grid.512982.50000 0004 7598 2416Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Luana Presta
- grid.16008.3f0000 0001 2295 9843Department of Life Sciences and Medicine, University of Luxembourg, Belvaux, Luxembourg
| | - Thomas Sauter
- grid.16008.3f0000 0001 2295 9843Department of Life Sciences and Medicine, University of Luxembourg, Belvaux, Luxembourg
| | - Mahvash Tavassoli
- grid.13097.3c0000 0001 2322 6764Centre for Host-Microbiome Interactions, King’s College London, London, United Kingdom
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7
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Zandian M, Chen IP, Byrareddy SN, Fujimori DG, Ott M, Kutateladze TG. Catching BETs by viruses. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194859. [PMID: 35985635 PMCID: PMC9381978 DOI: 10.1016/j.bbagrm.2022.194859] [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] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/22/2022]
Abstract
Viruses use diverse tactics to hijack host cellular machineries to evade innate immune responses and maintain their life cycles. Being critical transcriptional regulators, human BET proteins are prominent targets of a growing number of viruses. The BET proteins associate with chromatin through the interaction of their bromodomains with acetylated histones, whereas the carboxy-terminal domains of these proteins contain docking sites for various human co-transcriptional regulators. The same docking sites however can be occupied by viral proteins that exploit the BET proteins to anchor their genome components to chromatin in the infected host cell. In this review we highlight the pathological functions of the BET proteins upon viral infection, focusing on the mechanisms underlying their direct interactions with viral proteins, such as the envelope protein from SARS-CoV-2.
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Affiliation(s)
- Mohamad Zandian
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Irene P Chen
- Gladstone Institutes, and Department of Medicine, University of California San Francisco, San Francisco, CA 94158, USA
| | - Siddappa N Byrareddy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68131, USA
| | - Danica Galonić Fujimori
- Quantitative Biosciences Institute, and Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Melanie Ott
- Gladstone Institutes, and Department of Medicine, University of California San Francisco, San Francisco, CA 94158, USA
| | - Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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Interaction with TopBP1 Is Required for Human Papillomavirus 16 E2 Plasmid Segregation/Retention Function during Mitosis. J Virol 2022; 96:e0083022. [PMID: 35880889 PMCID: PMC9400484 DOI: 10.1128/jvi.00830-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human papillomavirus 16 (HPV16) E2 is a DNA-binding protein that regulates transcription, replication and potentially, segregation of the HPV16 genome during the viral life cycle. In the segregation model, E2 simultaneously binds to viral and host chromatin, acting as a bridge to ensure that viral genomes reside in daughter nuclei following cell division. The host chromatin receptor for E2 mediating this function is unknown. Recently, we demonstrated that CK2 phosphorylation of E2 on serine 23 (S23) is required for interaction with TopBP1, and that this interaction promotes E2 and TopBP1 recruitment to mitotic chromatin. Here, we demonstrate that in U2OS cells expressing wild-type E2 and a non-TopBP1-binding mutant (S23A, serine 23 mutated to alanine), interaction with TopBP1 is essential for E2 recruitment of plasmids to mitotic chromatin. Using novel quantitative segregation assays, we demonstrate that interaction with TopBP1 is required for E2 plasmid segregation function in U2OS and N/Tert-1 cells. Small interfering RNA (siRNA) knockdown of TopBP1 or CK2 enzyme components disrupts E2 segregation/retention function. The interaction of E2 with TopBP1 promotes increased levels of E2 protein during mitosis in U2OS and N/Tert-1 cells, as well as in human foreskin keratinocytes (HFK) immortalized by the HPV16 genome. Overall, our results demonstrate that E2 has plasmid segregation activity, and that the E2-TopBP1 interaction is essential for this E2 function. IMPORTANCE HPV16 causes 3% to 4% of all human cancers. It is proposed that during the viral life cycle, the viral genome is actively segregated into daughter nuclei, ensuring viral replication in the subsequent S phase. The E2 protein potentially bridges the viral and host genomes during mitosis to mediate segregation of the circular viral plasmid. Here, we demonstrate that E2 has the ability to mediate plasmid segregation, and that this function is dependent upon interaction with the host protein TopBP1. Additionally, we demonstrate that the E2-TopBP1 interaction promotes enhanced E2 expression during mitosis, which likely promotes the plasmid segregation function of E2. Overall, our results present a mechanism of how HPV16 can segregate its viral genome during an active infection, a critical aspect of the viral life cycle.
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9
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Fontan CT, James CD, Prabhakar AT, Bristol ML, Otoa R, Wang X, Karimi E, Rajagopalan P, Basu D, Morgan IM. A Critical Role for p53 during the HPV16 Life Cycle. Microbiol Spectr 2022; 10:e0068122. [PMID: 35608342 PMCID: PMC9241828 DOI: 10.1128/spectrum.00681-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/22/2022] [Indexed: 12/15/2022] Open
Abstract
Human papillomaviruses (HPV) are causative agents in ano-genital and oral cancers; HPV16 is the most prevalent type detected in human cancers. The HPV16 E6 protein targets p53 for proteasomal degradation to facilitate proliferation of the HPV16 infected cell. However, in HPV16 immortalized cells E6 is predominantly spliced (E6*) and unable to degrade p53. Here, we demonstrate that human foreskin keratinocytes immortalized by HPV16 (HFK+HPV16), and HPV16 positive oropharyngeal cancers, retain significant expression of p53. In addition, p53 levels increase in HPV16+ head and neck cancer cell lines following treatment with cisplatin. Introduction of full-length E6 into HFK+HPV16 resulted in attenuation of cellular growth (in hTERT immortalized HFK, E6 expression promoted enhanced proliferation). An understudied interaction is that between E2 and p53 and we investigated whether this was important for the viral life cycle. We generated mutant genomes with E2 unable to interact with p53 resulting in profound phenotypes in primary HFK. The mutant induced hyper-proliferation, but an ultimate arrest of cell growth; β-galactosidase staining demonstrated increased senescence, and COMET assays showed increased DNA damage compared with HFK+HPV16 wild-type cells. There was failure of the viral life cycle in organotypic rafts with the mutant HFK resulting in premature differentiation and reduced proliferation. The results demonstrate that p53 expression is critical during the HPV16 life cycle, and that this may be due to a functional interaction between E2 and p53. Disruption of this interaction has antiviral potential. IMPORTANCE Human papillomaviruses are causative agents in around 5% of all cancers. There are currently no antivirals available to combat these infections and cancers, therefore it remains a priority to enhance our understanding of the HPV life cycle. Here, we demonstrate that an interaction between the viral replication/transcription/segregation factor E2 and the tumor suppressor p53 is critical for the HPV16 life cycle. HPV16 immortalized cells retain significant expression of p53, and the critical role for the E2-p53 interaction demonstrates why this is the case. If the E2-p53 interaction is disrupted then HPV16 immortalized cells fail to proliferate, have enhanced DNA damage and senescence, and there is premature differentiation during the viral life cycle. Results suggest that targeting the E2-p53 interaction would have therapeutic benefits, potentially attenuating the spread of HPV16.
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Affiliation(s)
- Christian T. Fontan
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Claire D. James
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Apurva T. Prabhakar
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Molly L. Bristol
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
| | - Raymonde Otoa
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Xu Wang
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Elmira Karimi
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
| | - Pavithra Rajagopalan
- Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Devraj Basu
- Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- The Wistar Institute Cancer Center, Philadelphia, Pennsylvania, USA
| | - Iain M. Morgan
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University (VCU), Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
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10
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Regulation of HPV18 Genome Replication, Establishment and Persistence by Sequences in the Viral Upstream Regulatory Region. J Virol 2021; 95:e0068621. [PMID: 34232709 DOI: 10.1128/jvi.00686-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During persistent human papillomavirus infection, the viral genome replicates as an extrachromosomal plasmid that is efficiently partitioned to daughter cells during cell division. We have previously shown that an element which overlaps the HPV18 transcriptional enhancer promotes stable DNA replication of replicons containing the viral replication origin. Here we perform comprehensive analyses to elucidate the function of this maintenance element. We conclude that no unique element or binding site in this region is absolutely required for persistent replication and partitioning, and instead propose that the overall chromatin architecture of this region is important to promote efficient use of the replication origin. These results have important implications on the genome partitioning mechanism of papillomaviruses. Importance Persistent infection with oncogenic HPVs is responsible for ∼5% human cancers. The viral DNA replicates as an extrachromosomal plasmid and is partitioned to daughter cells in dividing keratinocytes. Using a complementation assay that allows us to separate viral transcription and replication, we provide insight into viral sequences that are required for long term replication and persistence in keratinocytes. Understanding how viral genomes replicate persistently for such long periods of time will guide the development of anti-viral therapies.
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11
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EXPRESSION OF E8^E2 IS REQUIRED FOR WART FORMATION BY MOUSE PAPILLOMAVIRUS 1 IN VIVO. J Virol 2021; 95:JVI.01930-20. [PMID: 33472931 PMCID: PMC8103706 DOI: 10.1128/jvi.01930-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human papillomavirus (HPV) E1 and E2 proteins activate genome replication. E2 also modulates viral gene expression and is involved in the segregation of viral genomes. In addition to full length E2, almost all PV share the ability to encode an E8^E2 protein, that is a fusion of E8 with the C-terminal half of E2 which mediates specific DNA-binding and dimerization. HPV E8^E2 acts as a repressor of viral gene expression and genome replication. To analyze the function of E8^E2 in vivo, we used the Mus musculus PV1 (MmuPV1)-mouse model system. Characterization of the MmuPV1 E8^E2 protein revealed that it inhibits transcription from viral promoters in the absence and presence of E1 and E2 proteins and that this is partially dependent upon the E8 domain. MmuPV1 genomes, in which the E8 ATG start codon was disrupted (E8-), displayed a 10- to 25-fold increase in viral gene expression compared to wt genomes in cultured normal mouse tail keratinocytes in short-term experiments. This suggests that the function and mechanism of E8^E2 is conserved between MmuPV1 and HPVs. Surprisingly, challenge of athymic nude Foxn1nu/nu mice with MmuPV1 E8- genomes did not induce warts on the tail in contrast to wt MmuPV1. Furthermore, viral gene expression was completely absent at E8- MmuPV1 sites 20 - 22 weeks after DNA challenge on the tail or quasivirus challenge in the vaginal vault. This reveals that expression of E8^E2 is necessary to form tumors in vivo and that this is independent from the presence of T-cells.IMPORTANCE HPV encode an E8^E2 protein which acts as repressors of viral gene expression and genome replication. In cultured normal keratinocytes, E8^E2 is essential for long-term episomal maintenance of HPV31 genomes, but not for HPV16. To understand E8^E2's role in vivo, the Mus musculus PV1 (MmuPV1)-mouse model system was used. This revealed that E8^E2's function as a repressor of viral gene expression is conserved. Surprisingly, MmuPV1 E8^E2 knock out genomes did not induce warts in T-cell deficient mice. This shows for the first time that expression of E8^E2 is necessary for tumor formation in vivo independently of T cell immunity. This indicates that E8^E2 could be an interesting target for anti-viral therapy in vivo.
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Human Papillomavirus 16 (HPV16) E2 Repression of TWIST1 Transcription Is a Potential Mediator of HPV16 Cancer Outcomes. mSphere 2020; 5:5/6/e00981-20. [PMID: 33298572 PMCID: PMC7729257 DOI: 10.1128/msphere.00981-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
HPV16-positive cancers have a better clinical outcome that their non-HPV anatomical counterparts. Furthermore, the presence of HPV16 E2 RNA predicts a better outcome for HPV16-positive tumors; the reasons for this are not known. Human papillomaviruses (HPVs) are causative agents in around 5% of all cancers, including cervical and oropharyngeal. A feature of HPV cancers is their better clinical outcome compared with non-HPV anatomical counterparts. In turn, the presence of E2 predicts a better clinical outcome in HPV-positive cancers; the reason(s) for the better outcome of E2-positive patients is not fully understood. Previously, we demonstrated that HPV16 E2 regulates host gene transcription that is relevant to the HPV16 life cycle in N/Tert-1 cells. One of the genes repressed by E2 and the entire HPV16 genome in N/Tert-1 cells is TWIST1. Here, we demonstrate that TWIST1 RNA levels are reduced in HPV-positive versus HPV-negative head and neck cancer and that E2 and HPV16 downregulate both TWIST1 RNA and protein in our N/Tert-1 model; E6/E7 cannot repress TWIST1. E2 represses the TWIST1 promoter in transient assays and is localized to the TWIST1 promoter; E2 also induces repressive epigenetic changes on the TWIST1 promoter. TWIST1 is a master transcriptional regulator of the epithelial to mesenchymal transition (EMT), and a high level of TWIST1 is a prognostic marker indicative of poor cancer outcomes. We demonstrate that TWIST1 target genes are also downregulated in E2-positive N/Tert-1 cells and that E2 promotes a failure in wound healing, a phenotype of low TWIST1 levels. We propose that the presence of E2 in HPV-positive tumors leads to TWIST1 repression and that this plays a role in the better clinical response of E2-positive HPV tumors. IMPORTANCE HPV16-positive cancers have a better clinical outcome that their non-HPV anatomical counterparts. Furthermore, the presence of HPV16 E2 RNA predicts a better outcome for HPV16-positive tumors; the reasons for this are not known. Here, we demonstrate that E2 represses expression of the TWIST1 gene; an elevated level of this gene is a marker of poor prognosis for a variety of cancers. We demonstrate that E2 directly binds to the TWIST1 promoter and actively represses transcription. TWIST1 is a master regulator promoting EMT, and here, we demonstrate that the presence of E2 reduces the ability of N/Tert-1 cells to wound heal. Overall, we propose that the E2 repression of TWIST1 may contribute to the better clinical outcome of E2-positive HPV16-positive tumors.
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Evans MR, James CD, Bristol ML, Nulton TJ, Wang X, Kaur N, White EA, Windle B, Morgan IM. Human Papillomavirus 16 E2 Regulates Keratinocyte Gene Expression Relevant to Cancer and the Viral Life Cycle. J Virol 2019; 93:e01941-18. [PMID: 30518656 PMCID: PMC6364038 DOI: 10.1128/jvi.01941-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/26/2018] [Indexed: 11/20/2022] Open
Abstract
Human papillomaviruses (HPVs) are causative agents in ano-genital and oropharyngeal cancers. The virus must reprogram host gene expression to promote infection, and E6 and E7 contribute to this via the targeting of cellular transcription factors, including p53 and pRb, respectively. The HPV16 E2 protein regulates host gene expression in U2OS cells, and in this study, we extend these observations into telomerase reverse transcriptase (TERT) immortalized oral keratinocytes (NOKs) that are capable of supporting late stages of the HPV16 life cycle. We observed repression of innate immune genes by E2 that are also repressed by the intact HPV16 genome in NOKs. Transcriptome sequencing (RNA-seq) data identified 167 up- and 395 downregulated genes by E2; there was a highly significant overlap of the E2-regulated genes with those regulated by the intact HPV16 genome in the same cell type. Small interfering RNA (siRNA) targeting of E2 reversed the repression of E2-targeted genes. The ability of E2 to repress innate immune genes was confirmed in an ano-genital immortalized keratinocyte cell line, N/Tert-1. We present the analysis of data from The Cancer Genome Atlas (TCGA) for HPV16-positive and -negative head and neck cancers (HNC) suggesting that E2 plays a role in the regulation of the host genome in cancers. Patients with HPV16-positive HNC with a loss of E2 expression exhibited a worse clinical outcome, and we discuss how this could, at least partially, be related to the loss of E2 host gene regulation.IMPORTANCE Human papillomavirus 16 (HPV16)-positive tumors that retain expression of E2 have a better clinical outcome than those that have lost E2 expression. It has been suggested that this is due to a loss of E2 repression of E6 and E7 expression, but this is not supported by data from tumors where there is not more E6 and E7 expression in the absence of E2. Here we report that E2 regulates host gene expression and place this regulation in the context of the HPV16 life cycle and HPV16-positive head and neck cancers (the majority of which retain E2 expression). We propose that this E2 function may play an important part in the increased response of HPV16-positive cancers to radiation therapy. Therefore, host gene regulation by E2 may be important for promotion of the HPV16 life cycle and also for the response of HPV16-positive tumors to radiation therapy.
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Affiliation(s)
- Michael R Evans
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
| | - Claire D James
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
| | - Molly L Bristol
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
| | - Tara J Nulton
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
| | - Xu Wang
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
| | - Namsimar Kaur
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
| | - Elizabeth A White
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Brad Windle
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
| | - Iain M Morgan
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Department of Oral and Craniofacial Molecular Biology, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
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TET1 promotes 5hmC-dependent stemness, and inhibits a 5hmC-independent epithelial-mesenchymal transition, in cervical precancerous lesions. Cancer Lett 2019; 450:53-62. [PMID: 30771438 DOI: 10.1016/j.canlet.2019.01.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/22/2019] [Accepted: 01/28/2019] [Indexed: 12/18/2022]
Abstract
DNA hypermethylation is a driving force in carcinogenesis. However, the role of active DNA hypomethylation in cancer remains largely unknown. This process, facilitated by ten-eleven translocation methylcytosine dioxygenase 1 (TET1), which oxidizes 5-methylcytosine (5 mC) to 5-hydroxymethylcytosine (5hmC), has never been studied in cervical cancer. Here, we found that TET1 and 5hmC correlative increases from normal cervix to Low-grade squamous intraepithelial lesion (LSIL), maximizing in High-grade squamous intraepithelial lesion (HSIL), and decreasing in invasive cancer. Full-length HPV-immortalized HSIL cells demonstrated higher TET1/5hmC levels, and stemness properties, compared to invasive cancer cells. TET1 silencing promoted the epithelial-mesenchymal transition (EMT), to transform precancerous cells in vivo. TET1 increased 5hmC in the ZEB1 and VIM promoters, surprisingly, silencing both genes. TET1 interaction with the histone modifiers, LSD1 and EZH2, on the ZEB1 promoter, resulted in gene silencing, via loss of histone H3K4 trimethylation, and gain of histone H3K27 trimethylation. Taken together, TET1 promotes stemness properties, and inhibits EMT, in HSIL cells, through 5hmC-dependent and -independent mechanisms.
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Araldi RP, Sant’Ana TA, Módolo DG, de Melo TC, Spadacci-Morena DD, de Cassia Stocco R, Cerutti JM, de Souza EB. The human papillomavirus (HPV)-related cancer biology: An overview. Biomed Pharmacother 2018; 106:1537-1556. [DOI: 10.1016/j.biopha.2018.06.149] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/24/2018] [Accepted: 06/27/2018] [Indexed: 02/07/2023] Open
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Shanmugasundaram S, You J. Targeting Persistent Human Papillomavirus Infection. Viruses 2017; 9:v9080229. [PMID: 28820433 PMCID: PMC5580486 DOI: 10.3390/v9080229] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 07/30/2017] [Accepted: 08/15/2017] [Indexed: 12/14/2022] Open
Abstract
While the majority of Human papillomavirus (HPV) infections are transient and cleared within a couple of years following exposure, 10-20% of infections persist latently, leading to disease progression and, ultimately, various forms of invasive cancer. Despite the clinical efficiency of recently developed multivalent prophylactic HPV vaccines, these preventive measures are not effective against pre-existing infection. Additionally, considering that the burden associated with HPV is greatest in regions with limited access to preventative vaccination, the development of effective therapies targeting persistent infection remains imperative. This review discusses not only the mechanisms underlying persistent HPV infection, but also the promise of immunomodulatory therapeutic vaccines and small-molecular inhibitors, which aim to augment the host immune response against the viral infection as well as obstruct critical viral-host interactions.
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Affiliation(s)
- Srinidhi Shanmugasundaram
- 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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Araldi RP, Assaf SMR, Carvalho RFD, Carvalho MACRD, Souza JMD, Magnelli RF, Módolo DG, Roperto FP, Stocco RDC, Beçak W. Papillomaviruses: a systematic review. Genet Mol Biol 2017; 40:1-21. [PMID: 28212457 PMCID: PMC5409773 DOI: 10.1590/1678-4685-gmb-2016-0128] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/28/2016] [Indexed: 12/15/2022] Open
Abstract
In the last decades, a group of viruses has received great attention due to its
relationship with cancer development and its wide distribution throughout the
vertebrates: the papillomaviruses. In this article, we aim to review some of the most
relevant reports concerning the use of bovines as an experimental model for studies
related to papillomaviruses. Moreover, the obtained data contributes to the
development of strategies against the clinical consequences of bovine
papillomaviruses (BPV) that have led to drastic hazards to the herds. To overcome the
problem, the vaccines that we have been developing involve recombinant DNA
technology, aiming at prophylactic and therapeutic procedures. It is important to
point out that these strategies can be used as models for innovative procedures
against HPV, as this virus is the main causal agent of cervical cancer, the second
most fatal cancer in women.
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Affiliation(s)
- Rodrigo Pinheiro Araldi
- Laboratório de Genética, Instituto Butantan, São Paulo, SP, Brazil.,Programa de Pós-graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | | | | | | | - Jacqueline Mazzuchelli de Souza
- Laboratório de Genética, Instituto Butantan, São Paulo, SP, Brazil.,Programa de Pós-graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Roberta Fiusa Magnelli
- Laboratório de Genética, Instituto Butantan, São Paulo, SP, Brazil.,Programa de Pós-graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | | | - Franco Peppino Roperto
- Dipartimento di Medicina Veterinaria e Produzioni Animali, Università degli Studi di Napoli Federico II, Napoli, Campania, Italy
| | | | - Willy Beçak
- Laboratório de Genética, Instituto Butantan, São Paulo, SP, Brazil
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