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Lo Cigno I, Calati F, Girone C, Catozzo M, Gariglio M. High-risk HPV oncoproteins E6 and E7 and their interplay with the innate immune response: Uncovering mechanisms of immune evasion and therapeutic prospects. J Med Virol 2024; 96:e29685. [PMID: 38783790 DOI: 10.1002/jmv.29685] [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: 02/20/2024] [Revised: 04/22/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
Human papillomaviruses (HPVs) are double-stranded DNA (dsDNA) tumor viruses causally associated with 5% of human cancers, comprising both anogenital and upper aerodigestive tract carcinomas. Despite the availability of prophylactic vaccines, HPVs continue to pose a significant global health challenge, primarily due to inadequate vaccine access and coverage. These viruses can establish persistent infections by evading both the intrinsic defenses of infected tissues and the extrinsic defenses provided by professional innate immune cells. Crucial for their evasion strategies is their unique intraepithelial life cycle, which effectively shields them from host detection. Thus, strategies aimed at reactivating the innate immune response within infected or transformed epithelial cells, particularly through the production of type I interferons (IFNs) and lymphocyte-recruiting chemokines, are considered viable solutions to counteract the adverse effects of persistent infections by these oncogenic viruses. This review focuses on the complex interplay between the high-risk HPV oncoproteins E6 and E7 and the innate immune response in epithelial cells and HPV-associated cancers. In particular, it details the molecular mechanisms by which E6 and E7 modulate the innate immune response, highlighting significant progress in our comprehension of these processes. It also examines forward-looking strategies that exploit the innate immune system to ameliorate existing anticancer therapies, thereby providing crucial insights into future therapeutic developments.
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Affiliation(s)
- Irene Lo Cigno
- Virology Unit, Department of Translational Medicine, Eastern Piedmont University, Novara, Italy
| | - Federica Calati
- Virology Unit, Department of Translational Medicine, Eastern Piedmont University, Novara, Italy
| | - Carlo Girone
- Virology Unit, Department of Translational Medicine, Eastern Piedmont University, Novara, Italy
| | - Marta Catozzo
- Virology Unit, Department of Translational Medicine, Eastern Piedmont University, Novara, Italy
| | - Marisa Gariglio
- Virology Unit, Department of Translational Medicine, Eastern Piedmont University, Novara, Italy
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2
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Cabibi D, Giannone AG, Quattrocchi A, Lo Coco R, Formisano E, Porcasi R, Benfante V, Comelli A, Capra G. High-Risk HPV CISH Detection in Cervical Biopsies with Weak and/or Focal p16 Immunohistochemical Positivity. Int J Mol Sci 2024; 25:5354. [PMID: 38791395 PMCID: PMC11121605 DOI: 10.3390/ijms25105354] [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: 03/17/2024] [Revised: 04/19/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
In cervical biopsies, for diagnosis of Human Papilloma Virus (HPV) related conditions, the immunohistochemical staining for p16 has a diagnostic value only if diffusely and strongly positive, pattern named "block-like". "Weak and/or focal (w/f) p16 expression" is commonly considered nonspecific. In our previous study, we demonstrated the presence of high-risk HPV (hrHPV) DNA by LiPa method in biopsies showing w/f p16 positivity. The aim of the present study was to investigate the presence of hrHPV-DNA by CISH in the areas showing w/f p16 expression. We assessed the presence of hrHPV16, 18, 31, 33, 51 by CISH in a group of 20 cervical biopsies showing w/f p16 expression, some with increased Ki67, and in 10 cases of block-like expression, employed as control. The immunohistochemical p16 expression was also assessed by digital pathology. hrHPV-CISH nuclear positivity was encountered in 12/20 cases of w/f p16 expression (60%). Different patterns of nuclear positivity were identified, classified as punctate, diffuse and mixed, with different epithelial distributions. Our results, albeit in a limited casuistry, show the presence of HPV in an integrated status highlighted by CISH in w/f p16 positive cases. This could suggest the necessity of a careful follow-up of the patients with "weak" and/or "focal" immunohistochemical patterns of p16, mainly in cases of increased Ki67 cell proliferation index, supplemented with molecular biology examinations.
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Affiliation(s)
- Daniela Cabibi
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
| | - Antonino Giulio Giannone
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
| | - Alberto Quattrocchi
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
| | - Roberta Lo Coco
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
| | - Eleonora Formisano
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
| | - Rossana Porcasi
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
| | - Viviana Benfante
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
- Ri.MED Foundation, Via Bandiera 11, 90133 Palermo, Italy
| | - Albert Comelli
- Ri.MED Foundation, Via Bandiera 11, 90133 Palermo, Italy
| | - Giuseppina Capra
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy
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Wang Z, Liu C, Liu W, Lv X, Hu T, Yang F, Yang W, He L, Huang X. Long-read sequencing reveals the structural complexity of genomic integration of HPV DNA in cervical cancer cell lines. BMC Genomics 2024; 25:198. [PMID: 38378450 PMCID: PMC10877919 DOI: 10.1186/s12864-024-10101-y] [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: 06/16/2023] [Accepted: 02/08/2024] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND Cervical cancer (CC) causes more than 311,000 deaths annually worldwide. The integration of human papillomavirus (HPV) is a crucial genetic event that contributes to cervical carcinogenesis. Despite HPV DNA integration is known to disrupt the genomic architecture of both the host and viral genomes in CC, the complexity of this process remains largely unexplored. RESULTS In this study, we conducted whole-genome sequencing (WGS) at 55-65X coverage utilizing the PacBio long-read sequencing platform in SiHa and HeLa cells, followed by comprehensive analyses of the sequence data to elucidate the complexity of HPV integration. Firstly, our results demonstrated that PacBio long-read sequencing effectively identifies HPV integration breakpoints with comparable accuracy to targeted-capture Next-generation sequencing (NGS) methods. Secondly, we constructed detailed models of complex integrated genome structures that included both the HPV genome and nearby regions of the human genome by utilizing PacBio long-read WGS. Thirdly, our sequencing results revealed the occurrence of a wide variety of genome-wide structural variations (SVs) in SiHa and HeLa cells. Additionally, our analysis further revealed a potential correlation between changes in gene expression levels and SVs on chromosome 13 in the genome of SiHa cells. CONCLUSIONS Using PacBio long-read sequencing, we have successfully constructed complex models illustrating HPV integrated genome structures in SiHa and HeLa cells. This accomplishment serves as a compelling demonstration of the valuable capabilities of long-read sequencing in detecting and characterizing HPV genomic integration structures within human cells. Furthermore, these findings offer critical insights into the complex process of HPV16 and HPV18 integration and their potential contribution to the development of cervical cancer.
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Affiliation(s)
- Zhijie Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Chen Liu
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Wanxin Liu
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Xinyi Lv
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Ting Hu
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Fan Yang
- Wuhan Kandwise Biotechnology, Inc. Wuhan, Hubei, China
| | - Wenhui Yang
- Wuhan Kandwise Biotechnology, Inc. Wuhan, Hubei, China
| | - Liang He
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
| | - Xiaoyuan Huang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
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Jönsson J, Wang L, Kajitani N, Schwartz S. A novel HPV16 splicing enhancer critical for viral oncogene expression and cell immortalization. Nucleic Acids Res 2024; 52:316-336. [PMID: 37994701 PMCID: PMC10783526 DOI: 10.1093/nar/gkad1099] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 10/18/2023] [Accepted: 11/03/2023] [Indexed: 11/24/2023] Open
Abstract
High-risk carcinogenic human papillomaviruses (HPVs), e.g. HPV16, express the E6 and E7 oncogenes from two mRNAs that are generated in a mutually exclusive manner by splicing. The HPV16 E7 mRNA, also known as the E6*I/E7 mRNA, is produced by splicing between splice sites SD226 and SA409, while E6 mRNAs retain the intron between these splice sites. We show that splicing between HPV16 splice sites SD226 and SA409 is controlled by a splicing enhancer consisting of a perfect repeat of an adenosine-rich, 11 nucleotide sequence: AAAAGCAAAGA. Two nucleotide substitutions in both 11 nucleotide sequences specifically inhibited production of the spliced E6*I/E7 mRNA. As a result, production of E7 protein was reduced and the ability of HPV16 to immortalize human primary keratinocytes was abolished. The splicing-enhancing effect was mediated by the cellular TRAP150/THRAP3 protein that also enhanced splicing of other high-risk HPV E6*I/E7 mRNAs, but had no effect on low-risk HPV mRNAs. In summary, we have identified a novel splicing enhancer in the E6 coding region that is specific for high-risk HPVs and that is critically linked to HPV16 carcinogenic properties.
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Affiliation(s)
- Johanna Jönsson
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC-B9, 751 23 Uppsala, Sweden
| | - Lianqing Wang
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC-B9, 751 23 Uppsala, Sweden
- Center of Translational Medicine, Zibo Central Hospital, 255036 Zibo, China
| | - Naoko Kajitani
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC-B9, 751 23 Uppsala, Sweden
| | - Stefan Schwartz
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC-B9, 751 23 Uppsala, Sweden
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5
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Sausen DG, Shechter O, Gallo ES, Dahari H, Borenstein R. Herpes Simplex Virus, Human Papillomavirus, and Cervical Cancer: Overview, Relationship, and Treatment Implications. Cancers (Basel) 2023; 15:3692. [PMID: 37509353 PMCID: PMC10378257 DOI: 10.3390/cancers15143692] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
There is a significant body of research examining the role of human papillomavirus (HPV) in the pathogenesis of cervical cancer, with a particular emphasis on the oncogenic proteins E5, E6, and E7. What is less well explored, however, is the relationship between cervical cancer and herpes simplex virus (HSV). To date, studies examining the role of HSV in cervical cancer pathogenesis have yielded mixed results. While several experiments have determined that HPV/HSV-2 coinfection results in a higher risk of developing cervical cancer, others have questioned the validity of this association. However, clarifying the potential role of HSV in the pathogenesis of cervical cancer may have significant implications for both the prevention and treatment of this disease. Should this relationship be clarified, treating and preventing HSV could open another avenue with which to prevent cervical cancer. The importance of this is highlighted by the fact that, despite the creation of an effective vaccine against HPV, cervical cancer still impacts 604,000 women and is responsible for 342,000 deaths annually. This review provides an overview of HSV and HPV infections and then delves into the possible links between HPV, HSV, and cervical cancer. It concludes with a summary of preventive measures against and recent treatment advances in cervical cancer.
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Affiliation(s)
- Daniel G. Sausen
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, USA; (D.G.S.); (O.S.)
| | - Oren Shechter
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, USA; (D.G.S.); (O.S.)
| | - Elisa S. Gallo
- Division of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv 64239, Israel
| | - Harel Dahari
- The Program for Experimental and Theoretical Modeling, Division of Hepatology, Department of Medicine, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA;
| | - Ronen Borenstein
- The Program for Experimental and Theoretical Modeling, Division of Hepatology, Department of Medicine, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA;
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Shimazaki Y, Yoneya S, Fujita S, Nakashima T, Nabeshima K, Sudoh S, Matsubara K, Okumura N, Kondo H, Nishifuji K, Koba R, Tohya Y. Identification and characterization of the genome of a papillomavirus from skin lesions of four-toed hedgehogs (Atelerix albiventris). Virus Genes 2023; 59:234-239. [PMID: 36626061 DOI: 10.1007/s11262-022-01965-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 12/20/2022] [Indexed: 01/11/2023]
Abstract
The present study describes the clinical and pathological characteristics of skin lesions in two four-toed hedgehogs (Atelerix albiventris). We performed inverse PCR to identify the genome of papillomavirus (PV) in the skin lesions and subsequently sequenced the full genome of the virus, which was tentatively named Atelerix albiventris papillomavirus 1 (AalbPV1). The overall sequences of the viral genomes of both four-toed hedgehogs were identical. This study first identified the presence of a novel PV in Japanese four-toed hedgehogs and provided genetic information about this virus.
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Affiliation(s)
- Yotaro Shimazaki
- Faculty of Agriculture, Animal Medical Center, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan
| | - Shion Yoneya
- Laboratory of Veterinary Microbiology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
| | - Shigeru Fujita
- Laboratory of Veterinary Microbiology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
- Division of Systems Virology, Department of Infectious Disease Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Tomomi Nakashima
- IDEXX Laboratories, K.K., 5-8-18 Kajinocho, Koganei-shi, Tokyo, 184-8515, Japan
| | - Kei Nabeshima
- Ecological Risk Assessment and Control Section Center for Environmental Biology and Ecosystem, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba-shi, Ibaraki, 305-8506, Japan
| | - Sumire Sudoh
- Banquet Animal Hospital, 1-3-23 Mishuku, Setagaya-ku, Tokyo, 154-0005, Japan
| | - Katsuki Matsubara
- Banquet Animal Hospital, 1-3-23 Mishuku, Setagaya-ku, Tokyo, 154-0005, Japan
| | - Naka Okumura
- Laboratory of Veterinary Pathology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
| | - Hirotaka Kondo
- Laboratory of Veterinary Pathology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
| | - Koji Nishifuji
- Division of Animal Life Science, Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan
| | - Ryota Koba
- Laboratory of Veterinary Microbiology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan.
| | - Yukinobu Tohya
- Laboratory of Veterinary Microbiology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
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Kajitani N, Schwartz S. The role of RNA-binding proteins in the processing of mRNAs produced by carcinogenic papillomaviruses. Semin Cancer Biol 2022; 86:482-496. [PMID: 35181475 DOI: 10.1016/j.semcancer.2022.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 02/08/2023]
Abstract
Human papillomaviruses (HPV) are epitheliotropic DNA tumor viruses that are prevalent in the human population. A subset of the HPVs termed high-risk HPVs (HR-HPVs) are causative agents of anogenital cancers and head-and-neck cancers. Cancer is the result of persistent high-risk HPV infections that have not been cleared by the immune system of the host. These infections are characterized by dysregulated HPV gene expression, in particular constitutive high expression of the HPV E6 and E7 oncogenes and absence of the highly immunogenic viral L1 and L2 capsid proteins. HPVs make extensive use of alternative mRNA splicing to express its genes and are therefore highly dependent on cellular RNA-binding proteins for proper gene expression. Levels of RNA-binding proteins are altered in HPV-containing premalignant cervical lesions and in cervical cancer. Here we review our current knowledge of RNA-binding proteins that control HPV gene expression. We focus on RNA-binding proteins that control expression of the E6 and E7 oncogenes since they initiate and drive development of cancer and on the immunogenic L1 and L2 proteins as there silencing may contribute to immune evasion during carcinogenesis. Furthermore, cellular RNA-binding proteins are essential for HPV gene expression and as such may be targets for therapy to HPV infections and HPV-driven cancers.
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Affiliation(s)
- Naoko Kajitani
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23, Uppsala, Sweden; Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden
| | - Stefan Schwartz
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23, Uppsala, Sweden; Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden.
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8
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Zhou ZW, Long HZ, Xu SG, Li FJ, Cheng Y, Luo HY, Gao LC. Therapeutic Effects of Natural Products on Cervical Cancer: Based on Inflammatory Pathways. Front Pharmacol 2022; 13:899208. [PMID: 35645817 PMCID: PMC9136176 DOI: 10.3389/fphar.2022.899208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/26/2022] [Indexed: 12/09/2022] Open
Abstract
Inflammation is a protective response of the body to an irritant. When an inflammatory response occurs, immune cells are recruited to the injury, eliminating the irritation. The excessive inflammatory response can cause harm to the organism. Inflammation has been found to contribute to cervical cancer if there is a problem with the regulation of inflammatory response. Cervical cancer is one of the most common malignant tumors globally, and the incidence tends to be younger. The harm of cervical cancer cannot be ignored. The standard treatments for cervical cancer include surgery, radiotherapy and chemotherapy. However, the prognosis for this treatment is poor, so it is urgent to find a safer and more effective treatment. Natural products are considered excellent candidates for the treatment of cervical cancer. In this review, we first describe the mechanisms by which inflammation induces cervical cancer. Subsequently, we highlight natural products that can treat cervical cancer through inflammatory pathways. We also introduce natural products for the treatment of cervical cancer in clinical trials. Finally, methods to improve the anticancer properties of natural products were added, and the development status of natural products was discussed.
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Affiliation(s)
- Zi-Wei Zhou
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
| | - Hui-Zhi Long
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
| | - Shuo-Guo Xu
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
| | - Feng-Jiao Li
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
| | - Yan Cheng
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
| | - Hong-Yu Luo
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
| | - Li-Chen Gao
- School of Pharmacy, University of South China, Phase I Clinical Trial Centre, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Changsha, China
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9
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Hao C, Zheng Y, Jönsson J, Cui X, Yu H, Wu C, Kajitani N, Schwartz S. hnRNP G/RBMX enhances HPV16 E2 mRNA splicing through a novel splicing enhancer and inhibits production of spliced E7 oncogene mRNAs. Nucleic Acids Res 2022; 50:3867-3891. [PMID: 35357488 PMCID: PMC9023273 DOI: 10.1093/nar/gkac213] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/11/2022] [Accepted: 03/18/2022] [Indexed: 12/27/2022] Open
Abstract
Human papillomavirus type 16 (HPV16) E2 is an essential HPV16 protein. We have investigated how HPV16 E2 expression is regulated and have identifed a splicing enhancer that is required for production of HPV16 E2 mRNAs. This uridine-less splicing enhancer sequence (ACGAGGACGAGGACAAGGA) contains 84% adenosine and guanosine and 16% cytosine and consists of three ‘AC(A/G)AGG’-repeats. Mutational inactivation of the splicing enhancer reduced splicing to E2-mRNA specific splice site SA2709 and resulted in increased levels of unspliced E1-encoding mRNAs. The splicing enhancer sequence interacted with cellular RNA binding protein hnRNP G that promoted splicing to SA2709 and enhanced E2 mRNA production. The splicing-enhancing function of hnRNP G mapped to amino acids 236–286 of hnRNP G that were also shown to interact with splicing factor U2AF65. The interactions between hnRNP G and HPV16 E2 mRNAs and U2AF65 increased in response to keratinocyte differentiation as well as by the induction of the DNA damage response (DDR). The DDR reduced sumoylation of hnRNP G and pharmacological inhibition of sumoylation enhanced HPV16 E2 mRNA splicing and interactions between hnRNP G and E2 mRNAs and U2AF65. Intriguingly, hnRNP G also promoted intron retention of the HPV16 E6 coding region thereby inhibiting production of spliced E7 oncogene mRNAs.
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Affiliation(s)
- Chengyu Hao
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Yunji Zheng
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden.,School of Pharmacy, Binzhou Medical University, 264003 Yantai, China
| | - Johanna Jönsson
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23 Uppsala, Sweden.,Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Xiaoxu Cui
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Chengjun Wu
- School of Biomedical Engineering, Dalian University of Technology, Liaoning IC Technology Key Lab, 116024 Dalian, China
| | - Naoko Kajitani
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23 Uppsala, Sweden.,Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Stefan Schwartz
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23 Uppsala, Sweden.,Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
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10
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Hu C, Bugbee T, Dacus D, Palinski R, Wallace N. Beta human papillomavirus 8 E6 allows colocalization of non-homologous end joining and homologous recombination repair factors. PLoS Pathog 2022; 18:e1010275. [PMID: 35148356 PMCID: PMC8836322 DOI: 10.1371/journal.ppat.1010275] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022] Open
Abstract
Beta human papillomavirus (β-HPV) are hypothesized to make DNA damage more mutagenic and potentially more carcinogenic. Double strand breaks (DSBs) are the most deleterious DNA lesion. They are typically repaired by homologous recombination (HR) or non-homologous end joining (NHEJ). HR occurs after DNA replication while NHEJ can occur at any point in the cell cycle. HR and NHEJ are not thought to occur in the same cell at the same time. HR is restricted to cells in phases of the cell cycle where homologous templates are available, while NHEJ occurs primarily during G1. β-HPV type 8 protein E6 (8E6) attenuates both repair pathways. We use a series of immunofluorescence microscopy and flow cytometry experiments to better define the impact of this attenuation. We found that 8E6 causes colocalization of HR factors (RPA70 and RAD51) with an NHEJ factor (activated DNA-PKcs or pDNA-PKcs) at persistent DSBs. 8E6 also causes RAD51 foci to form during G1. The initiation of NHEJ and HR at the same lesion could lead to antagonistic DNA end processing. Further, HR cannot be readily completed in an error-free manner during G1. Both aberrant repair events would cause deletions. To determine if these mutations were occurring, we used next generation sequencing of the 200kb surrounding a CAS9-induced DSB. 8E6 caused a 21-fold increase in deletions. Chemical and genetic inhibition of p300 as well as an 8E6 mutant that is incapable of destabilizing p300 demonstrates that 8E6 is acting via p300 destabilization. More specific chemical inhibitors of DNA repair provided mechanistic insight by mimicking 8E6-induced dysregulation of DNA repair in a virus-free system. Specifically, inhibition of NHEJ causes RAD51 foci to form in G1 and colocalization of RAD51 with pDNA-PKcs. Our previous work shows that a master transcription regulator, p300, facilitates two major DNA double strand break (DSB) repair pathways: non-homologous end joining (NHEJ) and homologous recombination (HR). By degrading p300, beta genus human papillomavirus 8 protein E6 (8E6) hinders pDNA-PKcs resolution, an essential step during NHEJ. NHEJ and HR are known to compete, with only one pathway initiating repair of a DSB. NHEJ tends to be used in G1 and HR occurs in S/G2. Here, we show that 8E6 allows NHEJ and HR to initiate at the same break site. We show that 8E6 allows HR to initiate in G1, suggesting that NHEJ starts but fails before HR is initiated at the same DSB. Next generation sequencing of the region surrounding a CAS9-induced DSB supports our hypothesis that this dysregulation of DSB repair is mutagenic as 8E6 caused a 15- to 20-fold increase in mutations associated with a CAS9-induced DSB. These studies support the putative role of HPV8 infections in non-melanoma skin cancer development.
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Affiliation(s)
- Changkun Hu
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Taylor Bugbee
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Dalton Dacus
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Rachel Palinski
- Kansas State Veterinary Diagnostic Laboratory, Kansas State University, Manhattan, Kansas, United States of America
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, Kansas, United States of America
| | - Nicholas Wallace
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
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11
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Fu X, Tao L, Zhang X. A chimeric virus-based probe unambiguously detects live circulating tumor cells with high specificity and sensitivity. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 23:78-86. [PMID: 34631928 PMCID: PMC8476710 DOI: 10.1016/j.omtm.2021.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/24/2021] [Indexed: 02/06/2023]
Abstract
The current methods for detecting circulating tumor cells (CTCs) suffer from several drawbacks. We report a novel method that is based on a chimeric virus probe and can detect CTCs with extremely high specificity and sensitivity. Moreover, it exclusively detects live CTCs, and its detection efficacy is not impacted by the variation of epithelial cell adhesion molecule (EpCAM) expression. The chimeric virus probe is composed of a capsid from human papillomavirus that provides the detection with high specificity and an SV40-based genome that can amplify extensively inside CTCs and, hence, endows the detection with high sensitivity. Furthermore, different marker genes can be incorporated into the probe to provide detection with versatility. These unique capabilities will likely improve the validity and utility of this CTC detection in several clinical applications, which is one of the drawbacks suffered by many of the current CTC detection methods.
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Affiliation(s)
- Xinping Fu
- Department of Biology and Biochemistry and Center for Nuclear Receptor and Cell Signaling, University of Houston, Houston, TX 77204, USA
| | - Lihua Tao
- Department of Biology and Biochemistry and Center for Nuclear Receptor and Cell Signaling, University of Houston, Houston, TX 77204, USA
| | - Xiaoliu Zhang
- Department of Biology and Biochemistry and Center for Nuclear Receptor and Cell Signaling, University of Houston, Houston, TX 77204, USA
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12
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BRD4S interacts with viral E2 protein to limit human papillomavirus late transcription. J Virol 2021; 95:JVI.02032-20. [PMID: 33731454 PMCID: PMC8139696 DOI: 10.1128/jvi.02032-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The E2 protein encoded by human papillomaviruses (HPV) is a sequence-specific DNA-binding protein that recruits viral and cellular proteins. Bromodomain-containing protein 4 (BRD4) is a highly conserved interactor for E2 proteins that has been linked to E2's functions as transcription modulator, activator of viral replication and segregation factor for viral genomes. In addition to BRD4, a short form of BRD4 (BRD4S) is expressed from the BRD4 gene which lacks the C-terminal domain of BRD4. E2 proteins interact with the C-terminal motif (CTM) of BRD4, but a recent study suggested that the phospho-dependent interaction domain (PDID) and the basic interaction domain (BID) in BRD4 also bind to E2. These domains are also present in BRD4S. We now find that HPV31 E2 interacts with the isolated PDID domain in living cells and also with BRD4S which is present in detectable amounts in HPV-positive cell lines and is recruited into HPV31 E1 and E2 induced replication foci. Overexpression and knockdown experiments surprisingly indicate that BRD4S inhibits activities of E2. In line with that, the specific knockdown of BRD4S in the HPV31-positive CIN612-9E cell line induces mainly late viral transcripts. This occurs only in undifferentiated but not differentiated cells in which the productive viral replication cycle is induced. These data suggest that the BRD4S-E2 interaction is important to prevent HPV late gene expression in undifferentiated keratinocytes which may contribute to immune evasion and HPV persistence.ImportanceHuman papillomaviruses (HPV) have coevolved with their host by using cellular factors like bromodomain-containing protein 4 (BRD4) to control viral processes such as genome maintenance, gene expression and replication. We here show that, in addition to the C-terminal motif in BRD4, the phospho-dependent interaction domain in BRD4 interacts with E2 proteins which enable the recruitment of BRD4S, the short isoform of BRD4, to E2. Knock-down and overexpression of BRD4S reveals that BRD4S is a negative regulator of E2 activities. Importantly, the knockdown of BRD4S induces mainly L1 transcripts in undifferentiated CIN612-9E cells, which maintain replicating HPV31 genomes. Our study reveals an inhibitory role of BRD4S on HPV transcription, which may serve as an immune escape mechanism by the suppression of L1 transcripts and thus contribute to the establishment of persistent HPV infections.
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13
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Kajitani N, Schwartz S. Role of Viral Ribonucleoproteins in Human Papillomavirus Type 16 Gene Expression. Viruses 2020; 12:E1110. [PMID: 33007936 PMCID: PMC7600041 DOI: 10.3390/v12101110] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 09/25/2020] [Accepted: 09/26/2020] [Indexed: 02/06/2023] Open
Abstract
Human papillomaviruses (HPVs) depend on the cellular RNA-processing machineries including alternative RNA splicing and polyadenylation to coordinate HPV gene expression. HPV RNA processing is controlled by cis-regulatory RNA elements and trans-regulatory factors since the HPV splice sites are suboptimal. The definition of HPV exons and introns may differ between individual HPV mRNA species and is complicated by the fact that many HPV protein-coding sequences overlap. The formation of HPV ribonucleoproteins consisting of HPV pre-mRNAs and multiple cellular RNA-binding proteins may result in the different outcomes of HPV gene expression, which contributes to the HPV life cycle progression and HPV-associated cancer development. In this review, we summarize the regulation of HPV16 gene expression at the level of RNA processing with focus on the interactions between HPV16 pre-mRNAs and cellular RNA-binding factors.
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Affiliation(s)
- Naoko Kajitani
- Department of Laboratory Medicine, Lund University, 22184 Lund, Sweden;
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14
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Eyvazi S, Hejazi MS, Kahroba H, Abasi M, Zamiri RE, Tarhriz V. CDK9 as an Appealing Target for Therapeutic Interventions. Curr Drug Targets 2020; 20:453-464. [PMID: 30362418 DOI: 10.2174/1389450119666181026152221] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 02/05/2023]
Abstract
Cyclin Dependent Kinase 9 (CDK9) as a serine/threonine kinase belongs to a great number of CDKs. CDK9 is the main core of PTEF-b complex and phosphorylates RNA polymerase (RNAP) II besides other transcription factors which regulate gene transcription elongation in numerous physiological processes. Multi-functional nature of CDK9 in diverse cellular pathways proposes that it is as an appealing target. In this review, we summarized the recent findings on the molecular interaction of CDK9 with critical participant molecules to modulate their activity in various diseases. Furthermore, the presented review provides a rationale supporting the use of CDK9 as a therapeutic target in clinical developments for crucial diseases; particularly cancers will be reviewed.
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Affiliation(s)
- Shirin Eyvazi
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Saeid Hejazi
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Homan Kahroba
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mozghan Abasi
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran.,Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Eghdam Zamiri
- Faculty of medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vahideh Tarhriz
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
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15
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Zheng Y, Cui X, Nilsson K, Yu H, Gong L, Wu C, Schwartz S. Efficient production of HPV16 E2 protein from HPV16 late mRNAs spliced from SD880 to SA2709. Virus Res 2020; 285:198004. [PMID: 32380211 DOI: 10.1016/j.virusres.2020.198004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 12/31/2022]
Abstract
Human papillomaviruses (HPVs) produce a large number of alternatively spliced mRNAs, including a number of differently spliced mRNAs with the potential to produce E2 protein. To identify the alternatively spliced HPV16 mRNA with the highest ability to produce E2 protein, we have generated E2 cDNA expression plasmids representing the most common, alternatively spliced E2 mRNAs, and assessed their translational potential. Our results revealed that an mRNA initiated at the HPV16 late promoter p670 and spliced from the HPV16 5'-splice site SD880 to the HPV16 3'-splice site SA2709, located immediately upstream of the E2 ATG, produced higher levels of E2 than any of the other alternatively spliced, E2-encoding mRNAs. Utilization of a known, alternative 3'-splice site located upstream of the E2 ATG named SA2582, generated mRNAs with lower ability to produce E2 than mRNAs spliced to SA2709. Finally, analysis of HPV16 mRNA splicing demonstrated that SA2709 was more efficiently spliced to the upstream 5'-splice site SD880 than to the upstream 5'-splice site SD226. In conclusion, the HPV16 mRNA with the greatest ability to produce E2 protein is generated from the HPV16 late promoter and is spliced between HPV16 5'-splice site SD880 and HPV16 3'-splice site SA2709.
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Affiliation(s)
- Yunji Zheng
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden
| | - Xiaoxu Cui
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden
| | - Kersti Nilsson
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden
| | - Lijing Gong
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden; China Institute of Sport and Health Sciences, Beijing Sport University, Xinxi Road 48, Haidian District, 100084, Beijing, China
| | - Chengjun Wu
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden; The First Affiliated Hospital of Shandong First Medical University, No.16766 Jingshi Road, Jinan, Shandong Province, 250014, China; Institute of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, No.18877 Jingshi Road, Jinan, Shandong Province, 250062, China.
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84, Lund, Sweden.
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16
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Subversion of Host Innate Immunity by Human Papillomavirus Oncoproteins. Pathogens 2020; 9:pathogens9040292. [PMID: 32316236 PMCID: PMC7238203 DOI: 10.3390/pathogens9040292] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/19/2022] Open
Abstract
The growth of human papillomavirus (HPV)-transformed cells depends on the ability of the viral oncoproteins E6 and E7, especially those from high-risk HPV16/18, to manipulate the signaling pathways involved in cell proliferation, cell death, and innate immunity. Emerging evidence indicates that E6/E7 inhibition reactivates the host innate immune response, reversing what until then was an unresponsive cellular state suitable for viral persistence and tumorigenesis. Given that the disruption of distinct mechanisms of immune evasion is an attractive strategy for cancer therapy, the race is on to gain a better understanding of E6/E7-induced immune escape and cancer progression. Here, we review recent literature on the interplay between E6/E7 and the innate immune signaling pathways cGAS/STING/TBK1, RIG-I/MAVS/TBK1, and Toll-like receptors (TLRs). The overall emerging picture is that E6 and E7 have evolved broad-spectrum mechanisms allowing for the simultaneous depletion of multiple rather than single innate immunity effectors. The cGAS/STING/TBK1 pathway appears to be the most heavily impacted, whereas the RIG-I/MAVS/TBK1, still partially functional in HPV-transformed cells, can be activated by the powerful RIG-I agonist M8, triggering the massive production of type I and III interferons (IFNs), which potentiates chemotherapy-mediated cell killing. Overall, the identification of novel therapeutic targets to restore the innate immune response in HPV-transformed cells could transform the way HPV-associated cancers are treated.
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17
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Ferreira AR, Ramalho AC, Marques M, Ribeiro D. The Interplay between Antiviral Signalling and Carcinogenesis in Human Papillomavirus Infections. Cancers (Basel) 2020; 12:cancers12030646. [PMID: 32164347 PMCID: PMC7139948 DOI: 10.3390/cancers12030646] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/20/2022] Open
Abstract
Human papillomaviruses (HPV) are the causative agents of the most common sexually transmitted infection worldwide. While infection is generally asymptomatic and can be cleared by the host immune system, when persistence occurs, HPV can become a risk factor for malignant transformation. Progression to cancer is actually an unintended consequence of the complex HPV life cycle. Different antiviral defence mechanisms recognize HPV early in infection, leading to the activation of the innate immune response. However, the virus has evolved several specific strategies to efficiently evade the antiviral immune signalling. Here, we review and discuss the interplay between HPV and the host cell innate immunity. We further highlight the evasion strategies developed by different HPV to escape this cellular response and focus on the correlation with HPV-induced persistence and tumorigenesis.
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Affiliation(s)
| | | | | | - Daniela Ribeiro
- Correspondence: ; Tel.: +351-234-247 014; Fax: +351-234-372-587
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18
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Impact of HPV E5 on viral life cycle via EGFR signaling. Microb Pathog 2020; 139:103923. [DOI: 10.1016/j.micpath.2019.103923] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 12/28/2022]
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19
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Piirsoo A, Pink A, Kasak L, Kala M, Kasvandik S, Ustav M, Piirsoo M. Differential phosphorylation determines the repressor and activator potencies of GLI1 proteins and their efficiency in modulating the HPV life cycle. PLoS One 2019; 14:e0225775. [PMID: 31770404 PMCID: PMC6879148 DOI: 10.1371/journal.pone.0225775] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 11/19/2022] Open
Abstract
The Sonic Hedgehog (Shh) signalling pathway plays multiple roles during embryonic development and under pathological conditions. Although the core components of the Shh pathway are conserved, the regulation of signal transduction varies significantly among species and cell types. Protein kinases Ulk3 and Pka are involved in the Shh pathway as modulators of the activities of Gli transcription factors, which are the nuclear mediators of the signal. Here, we investigate the regulation and activities of two GLI1 isoforms, full-length GLI1 (GLI1FL) and GLI1ΔN. The latter protein lacks the first 128 amino acids including the conserved phosphorylation cluster and the binding motif for SUFU, the key regulator of GLI activity. Both GLI1 isoforms are co-expressed in all human cell lines analysed and possess similar DNA binding activity. ULK3 potentiates the transcriptional activity of both GLI1 proteins, whereas PKA inhibits the activity of GLI1ΔN, but not GLI1FL. In addition to its well-established role as a transcriptional activator, GLI1FL acts as a repressor by inhibiting transcription from the early promoters of human papillomavirus type 18 (HPV18). Additionally, compared to GLI1ΔN, GLI1FL is a more potent suppressor of replication of several HPV types. Altogether, our data show that the N-terminal part of GLI1FL is crucial for the realization of its full potential as a transcriptional regulator.
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Affiliation(s)
- Alla Piirsoo
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Anne Pink
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Lagle Kasak
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Martin Kala
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Sergo Kasvandik
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Mart Ustav
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Marko Piirsoo
- Institute of Technology, University of Tartu, Tartu, Estonia
- * E-mail:
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20
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Acetylation of E2 by P300 Mediates Topoisomerase Entry at the Papillomavirus Replicon. J Virol 2019; 93:JVI.02224-18. [PMID: 30651357 DOI: 10.1128/jvi.02224-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/08/2019] [Indexed: 12/29/2022] Open
Abstract
Human papillomavirus (HPV) E2 proteins are integral for the transcription of viral genes and the replication and maintenance of viral genomes in host cells. E2 recruits the viral DNA helicase E1 to the origin. A lysine (K111), highly conserved among almost all papillomavirus (PV) E2 proteins, is a target for P300 (EP300) acetylation and is critical for viral DNA replication (E. J. Quinlan, S. P. Culleton, S. Y. Wu, C. M. Chiang, et al., J Virol 87:1497-1507, 2013, https://doi.org/10.1128/JVI.02771-12; Y. Thomas and E. J. Androphy, J Virol 92:e01912-17, 2018, https://doi.org/10.1128/JVI.01912-17). Since the viral genome exists as a covalently closed circle of double-stranded DNA, topoisomerase 1 (Topo1) is thought to be required for progression of the replication forks. Due to the specific effect of K111 mutations on DNA unwinding (Y. Thomas and E. J. Androphy, J Virol 92:e01912-17, 2018, https://doi.org/10.1128/JVI.01912-17), we demonstrate that the E2 protein targets Topo1 to the viral origin, and this depends on acetylation of K111. The effect was corroborated by functional replication assays, in which higher levels of P300, but not its homolog CBP, caused enhanced replication with wild-type E2 but not the acetylation-defective K111 arginine mutant. These data reveal a novel role for lysine acetylation during viral DNA replication by regulating topoisomerase recruitment to the replication origin.IMPORTANCE Human papillomaviruses affect an estimated 75% of the sexually active adult population in the United States, with 5.5 million new cases emerging every year. More than 200 HPV genotypes have been identified; a subset of them are linked to the development of cancers from these epithelial infections. Specific antiviral medical treatments for infected individuals are not available. This project examines the mechanisms that control viral genome replication and may allow the development of novel therapeutics.
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21
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Luff J, Mader M, Rowland P, Britton M, Fass J, Yuan H. Viral genome integration of canine papillomavirus 16. PAPILLOMAVIRUS RESEARCH 2019; 7:88-96. [PMID: 30771493 PMCID: PMC6402295 DOI: 10.1016/j.pvr.2019.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/30/2019] [Accepted: 02/12/2019] [Indexed: 01/03/2023]
Abstract
Papillomaviruses infect humans and animals, most often causing benign proliferations on skin or mucosal surfaces. Rarely, these infections persist and progress to cancer. In humans, this transformation most often occurs with high-risk papillomaviruses, where viral integration is a critical event in carcinogenesis. The first aim of this study was to sequence the viral genome of canine papillomavirus (CPV) 16 from a pigmented viral plaque that progressed to metastatic squamous cell carcinoma in a dog. The second aim was to characterize multiple viral genomic deletions and translocations as well as host integration sites. The full viral genome was identified using a combination of PCR and high throughput sequencing. CPV16 is most closely related to chipapillomaviruses CPV4, CPV9, and CPV12 and we propose CPV16 be classified as a chipapillomavirus. Assembly of the full viral genome enabled identification of deletion of portions of the E1 and E2/E4 genes and two viral translocations within the squamous cell carcinoma. Genome walking was performed which identified four sites of viral integration into the host genome. This is the first description of integration of a canine papillomavirus into the host genome, raising the possibility that CPV16 may be a potential canine high-risk papillomavirus type.
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Affiliation(s)
- Jennifer Luff
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA.
| | - Michelle Mader
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA
| | | | - Monica Britton
- UC Davis Genome Center-Bioinformatics Core, University of California, Davis, CA, USA
| | - Joseph Fass
- UC Davis Genome Center-Bioinformatics Core, University of California, Davis, CA, USA
| | - Hang Yuan
- Department of Pathology, Georgetown University Medical Center, Washington, DC, USA
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22
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Wu C, Nilsson K, Zheng Y, Ekenstierna C, Sugiyama N, Forslund O, Kajitani N, Yu H, Wennerberg J, Ekblad L, Schwartz S. Short half-life of HPV16 E6 and E7 mRNAs sensitizes HPV16-positive tonsillar cancer cell line HN26 to DNA-damaging drugs. Int J Cancer 2019; 144:297-310. [PMID: 30303514 PMCID: PMC6587446 DOI: 10.1002/ijc.31918] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/10/2018] [Accepted: 09/17/2018] [Indexed: 12/12/2022]
Abstract
Here we show that treatment of the HPV16-positive tonsillar cancer cell line HN26 with DNA alkylating cancer drug melphalan-induced p53 and activated apoptosis. Melphalan reduced the levels of RNA polymerase II and cellular transcription factor Sp1 that were associated with HPV16 DNA. The resulting inhibition of transcription caused a rapid loss of the HPV16 early mRNAs encoding E6 and E7 as a result of their inherent instability. As a consequence of HPV16 E6 and E7 down-regulation, the DNA damage inflicted on the cells by melphalan caused induction of p53 and activation of apoptosis in the HN26 cells. The BARD1-negative phenotype of the HN26 cells may have contributed to the failure to repair DNA damage caused by melphalan, as well as to the efficient apoptosis induction. Finally, nude mice carrying the HPV16 positive tonsillar cancer cells responded better to melphalan than to cisplatin, the chemotherapeutic drug of choice for tonsillar cancer. We concluded that the short half-life of the HPV16 E6 and E7 mRNAs renders HPV16-driven tonsillar cancer cells particularly sensitive to DNA damaging agents such as melphalan since melphalan both inhibits transcription and causes DNA damage.
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Affiliation(s)
- Chengjun Wu
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Kersti Nilsson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Yunji Zheng
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Camilla Ekenstierna
- Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Skane University Hospital, Lund, Sweden
| | - Natsuki Sugiyama
- Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Skane University Hospital, Lund, Sweden
| | - Ola Forslund
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Naoko Kajitani
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Johan Wennerberg
- Department of Clinical Sciences Lund, Oto-rhino-laryngology, Head and Neck Surgery, Lund University, Skane University Hospital, Lund, Sweden
| | - Lars Ekblad
- Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Skane University Hospital, Lund, Sweden
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund University, Lund, Sweden
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Squarzanti DF, Sorrentino R, Landini MM, Chiesa A, Pinato S, Rocchio F, Mattii M, Penengo L, Azzimonti B. Human papillomavirus type 16 E6 and E7 oncoproteins interact with the nuclear p53-binding protein 1 in an in vitro reconstructed 3D epithelium: new insights for the virus-induced DNA damage response. Virol J 2018; 15:176. [PMID: 30445982 PMCID: PMC6240266 DOI: 10.1186/s12985-018-1086-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/22/2018] [Indexed: 12/28/2022] Open
Abstract
Background Despite vaccination and screening measures, anogenital cancer, mainly promoted by HPV16 oncoproteins, still represents the fourth tumor and the second cause of death among women. Cell replication fidelity is the result of the host DNA damage response (DDR). Unlike many DNA viruses that promote their life cycle through the DDR inactivation, HR-HPVs encourage cells proliferation despite the DDR turned on. Why and how it occurs has been only partially elucidated. During HPV16 infection, E6 links and degrades p53 via the binding to the E6AP LXXLL sequence; unfortunately, E6 direct role in the DDR response has not clearly identified yet. Similarly, E7 increases DDR by competing with E2F1-pRb interaction, thus leading to the inactivation of pRb, and promotion, E2F1 mediated, of DDR genes translation, by binding to the pRb-like proteins CBP/p300 and p107, that also harbour LXXLL sequence, and via the interaction and activation of several DDR proteins. Methods To gain information regarding E6 and E7 contribution in DDR activation, we produced an in vitro 3D HPV16-E6E7 infected epithelium, already consolidated study model for HPVs, and validated it by assessing H&E staining and BrdU, HPV16 DNA, E6E7 proteins and γH2A.X/53BP1 double-strand break (DSBs) sensors expression; then we made an immuno-colocalization of E6 and E7 with cyclin E2 and B1. Since 53BP1, like E6 and E7, also binds p53 and pRb, we supposed their possible direct binding. To explore this hypothesis, we performed a double immunofluorescence of E6 and E7 with 53BP1, a sequence analysis of 53BP1 within its BRCT2 domain and then an in situ PLA within CaSki, E6E7HPV16 NHEKs and the 3D model. Results The in vitro epithelium resembled the histology and the events typical of in vivo infected tissues. E6E7HPV16 were both expressed in basal and differentiated strata and induced H2A.X phosphorylation and 53BP1 increment into nuclear foci. After highlighting E6 and E7 co-expression with 53BP1 and a LKVLL sequence within the 53BP1 BRCT2 domain, we demonstrated the bindings via the PLA technique. Conclusions Our results reinforce E6 and E7 role in cellular function control providing potentially new insights into the activity of this tumor virus.
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Affiliation(s)
- Diletta Francesca Squarzanti
- Laboratory of applied Microbiology, Department of Health Sciences, University of Piemonte Orientale (UPO), Via Solaroli 17, 28100, Novara, Italy
| | - Rita Sorrentino
- Laboratory of Biomedical Materials, Department of Health Sciences, University of Piemonte Orientale (UPO), Novara, Italy
| | - Manuela Miriam Landini
- Laboratory of applied Microbiology, Department of Health Sciences, University of Piemonte Orientale (UPO), Via Solaroli 17, 28100, Novara, Italy
| | - Andrea Chiesa
- Laboratory of applied Microbiology, Department of Health Sciences, University of Piemonte Orientale (UPO), Via Solaroli 17, 28100, Novara, Italy
| | - Sabrina Pinato
- Laboratory of Molecular Biology, Department of Pharmaceutical Sciences, University of Piemonte Orientale (UPO), Novara, Italy
| | - Francesca Rocchio
- Laboratory of Molecular Biology, Department of Pharmaceutical Sciences, University of Piemonte Orientale (UPO), Novara, Italy
| | - Martina Mattii
- Laboratory of applied Microbiology, Department of Health Sciences, University of Piemonte Orientale (UPO), Via Solaroli 17, 28100, Novara, Italy
| | - Lorenza Penengo
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Barbara Azzimonti
- Laboratory of applied Microbiology, Department of Health Sciences, University of Piemonte Orientale (UPO), Via Solaroli 17, 28100, Novara, Italy. .,Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM, Firenze, Italy- Local Unit of Piemonte Orientale, UPO, Novara, Italy.
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The SMC5/6 Complex Interacts with the Papillomavirus E2 Protein and Influences Maintenance of Viral Episomal DNA. J Virol 2018; 92:JVI.00356-18. [PMID: 29848583 DOI: 10.1128/jvi.00356-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/21/2018] [Indexed: 12/31/2022] Open
Abstract
The papillomavirus E2 protein executes numerous essential functions related to viral transcription, replication of viral DNA, and viral genome maintenance. Because E2 lacks enzymatic activity, many of these functions are mediated by interactions with host cellular proteins. Unbiased proteomics approaches have successfully identified a number of E2-host protein interactions. We have extended such studies and have identified and validated the cellular proteins structural maintenance of chromosome 5 (SMC5) and SMC6 as interactors of the viral E2 protein. These two proteins make up the core components of the SMC5/6 complex. The SMC5/6 complex is a member of the conserved structural maintenance of chromosomes (SMC) family of proteins, which are essential for genome maintenance. We have examined the role of SMC5/6 in various E2 functions. Our data suggest that SMC6 is not required for E2-mediated transcriptional activation, E1/E2-mediated transient replication, or differentiation-dependent amplification of viral DNA. Our data, however, suggest a role for SMC5/6 in viral genome maintenance.IMPORTANCE The high-risk human papillomaviruses (HPVs) are the etiological cause of cervical cancer and the most common sexually transmitted infection. While the majority of infections may be asymptomatic or cause only benign lesions, persistent infection with the oncogenic high-risk HPV types may lead to serious diseases, such as cervical cancer, anogenital carcinoma, or head and neck oropharyngeal squamous cell carcinoma. The identification of virus-host protein interactions provides insights into the mechanisms of viral DNA persistence, viral genome replication, and cellular transformation. Elucidating the mechanism of early events in the virus replication cycle as well as of integration of viral DNA into host chromatin may present novel antiviral strategies and targets for counteracting persistent infection. The E2 protein is an important viral regulatory protein whose functions are mediated through interactions with host cell proteins. Here we explore the interaction of E2 with SMC5/6 and the functional consequences.
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Nilsson K, Wu C, Schwartz S. Role of the DNA Damage Response in Human Papillomavirus RNA Splicing and Polyadenylation. Int J Mol Sci 2018; 19:E1735. [PMID: 29895741 PMCID: PMC6032147 DOI: 10.3390/ijms19061735] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 05/29/2018] [Accepted: 06/08/2018] [Indexed: 12/16/2022] Open
Abstract
Human papillomaviruses (HPVs) have evolved to use the DNA repair machinery to replicate its DNA genome in differentiated cells. HPV activates the DNA damage response (DDR) in infected cells. Cellular DDR factors are recruited to the HPV DNA genome and position the cellular DNA polymerase on the HPV DNA and progeny genomes are synthesized. Following HPV DNA replication, HPV late gene expression is activated. Recent research has shown that the DDR factors also interact with RNA binding proteins and affects RNA processing. DDR factors activated by DNA damage and that associate with HPV DNA can recruit splicing factors and RNA binding proteins to the HPV DNA and induce HPV late gene expression. This induction is the result of altered alternative polyadenylation and splicing of HPV messenger RNA (mRNA). HPV uses the DDR machinery to replicate its DNA genome and to activate HPV late gene expression at the level of RNA processing.
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Affiliation(s)
- Kersti Nilsson
- Department of Laboratory Medicine, Lund University, 221 84 Lund, Sweden.
| | - Chengjun Wu
- Department of Laboratory Medicine, Lund University, 221 84 Lund, Sweden.
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund University, 221 84 Lund, Sweden.
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DeSmet M, Kanginakudru S, Jose L, Xie F, Gilson T, Androphy EJ. Papillomavirus E2 protein is regulated by specific fibroblast growth factor receptors. Virology 2018; 521:62-68. [PMID: 29885490 DOI: 10.1016/j.virol.2018.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 02/01/2023]
Abstract
The papillomavirus (PV) E2 protein activates transcription and replication by recruiting cellular proteins and the E1 DNA helicase to their binding sites in the viral genome. We recently demonstrated that phosphorylation of tyrosine 102 in the bovine papillomavirus (BPV-1) E2 protein restricts these activities and that fibroblast growth factor receptor-3 (FGFR3) tyrosine kinase binds PV E2. Expression of FGFR3 decreased viral replication with both wild-type and the phenylalanine substitution at position 102, inferring that another kinase targets Y102. Here we tested FGFR- 1, -2 and -4 for association with PV E2 proteins. FGFR2 but not FGFR1 or FGFR4 co-immunoprecipitated with BPV-1 E2. We found that FGFR2 suppressed replication but did not depend on phosphorylation of BPV-1 Y102. HPV-16 and -31 E2 interacted with FGFR1, -2, and -4. These results imply that the expression and activity of FGF receptors in epithelial cells can regulate the function of E2 in viral replication.
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Affiliation(s)
- Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Leny Jose
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Fang Xie
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Dermatology, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Timra Gilson
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Nilsson K, Wu C, Kajitani N, Yu H, Tsimtsirakis E, Gong L, Winquist EB, Glahder J, Ekblad L, Wennerberg J, Schwartz S. The DNA damage response activates HPV16 late gene expression at the level of RNA processing. Nucleic Acids Res 2018; 46:5029-5049. [PMID: 29596642 PMCID: PMC6007495 DOI: 10.1093/nar/gky227] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/15/2018] [Accepted: 03/19/2018] [Indexed: 12/13/2022] Open
Abstract
We show that the alkylating cancer drug melphalan activated the DNA damage response and induced human papillomavirus type 16 (HPV16) late gene expression in an ATM- and Chk1/2-dependent manner. Activation of HPV16 late gene expression included inhibition of the HPV16 early polyadenylation signal that resulted in read-through into the late region of HPV16. This was followed by activation of the exclusively late, HPV16 splice sites SD3632 and SA5639 and production of spliced late L1 mRNAs. Altered HPV16 mRNA processing was paralleled by increased association of phosphorylated BRCA1, BARD1, BCLAF1 and TRAP150 with HPV16 DNA, and increased association of RNA processing factors U2AF65 and hnRNP C with HPV16 mRNAs. These RNA processing factors inhibited HPV16 early polyadenylation and enhanced HPV16 late mRNA splicing, thereby activating HPV16 late gene expression.
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Affiliation(s)
- Kersti Nilsson
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Chengjun Wu
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Naoko Kajitani
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | | | - Lijing Gong
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
- China Academy of Sport and Health Sciences, Beijing Sport University, Xinxi Road 48, Haidian District, 100084 Beijing, China
| | - Ellenor B Winquist
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Jacob Glahder
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Lars Ekblad
- Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Skane University Hospital, 221 85 Lund, Sweden
| | - Johan Wennerberg
- Department of Clinical Sciences Lund, Oto-rhino-laryngology, Head and Neck Surgery, Lund University, Skane University Hospital, 221 85 Lund, Sweden
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
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Nulton TJ, Kim NK, DiNardo LJ, Morgan IM, Windle B. Patients with integrated HPV16 in head and neck cancer show poor survival. Oral Oncol 2018; 80:52-55. [PMID: 29706188 PMCID: PMC5930384 DOI: 10.1016/j.oraloncology.2018.03.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/15/2018] [Accepted: 03/23/2018] [Indexed: 01/20/2023]
Abstract
OBJECTIVES We previously reported identifying three categories of HPV16-positive head and neck tumors based on The Cancer Genome Atlas (TCGA) RNA and DNA sequence data. Category 1 had truly integrated HPV16 genomes, category 2 had simple episomal genomes, and category 3 had novel episomes that were a hybrid between viral and human DNA. Using our categorization, we investigated in this study survival of patients with integrated HPV16 tumors versus patients with episomal HPV16 tumors. MATERIALS AND METHODS The TCGA RNA-Seq sequence reads were used to quantify HPV E2 and E7 gene expression, which was used as a marker for HPV integration. RESULTS The results demonstrate that integration is associated with poor survival; those patients with integrated HPV tumors fared no better than non-HPV tumors in their five-year survival. Integrated HPV in tumors was found strikingly to be prevalent in patients born earlier while episomal HPV was prevalent in patients born later. We also observed a fairly constant incidence of all HPV forms among head and neck cancer patients over the last eight years of this study (2006-2013). CONCLUSION We propose our characterization of HPV integrated and episomal state is more accurate than previous studies that may have mischaracterized the hybrid HPV-human DNA episomes as integrated. The state of integrated HPV is associated with a poor clinical outcome. Results suggest that the incidence of integrated HPV among all HPV forms peaked and is decreasing. We discuss the importance of our findings for the management of HPV positive head and neck cancer.
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Affiliation(s)
- Tara J Nulton
- Philips Institute for Oral Health Research, Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Box 980566, Richmond, VA 23298, USA.
| | - Nak-Kyeong Kim
- VCU Massey Cancer Center, Box 980037, Richmond, VA 23298, USA; Department of Biostatistics, School of Medicine, Virginia Commonwealth University, Box 980032, Richmond, VA, USA.
| | - Laurence J DiNardo
- VCU Massey Cancer Center, Box 980037, Richmond, VA 23298, USA; Department of Otolaryngology - Head and Neck Surgery, School of Medicine, Virginia Commonwealth University, Box 980146, Richmond, VA 23298, USA.
| | - Iain M Morgan
- Philips Institute for Oral Health Research, Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Box 980566, Richmond, VA 23298, USA; VCU Massey Cancer Center, Box 980037, Richmond, VA 23298, USA.
| | - Brad Windle
- Philips Institute for Oral Health Research, Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Box 980566, Richmond, VA 23298, USA; VCU Massey Cancer Center, Box 980037, Richmond, VA 23298, USA.
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Ajiro M, Sakai H, Onogi H, Yamamoto M, Sumi E, Sawada T, Nomura T, Kabashima K, Hosoya T, Hagiwara M. CDK9 Inhibitor FIT-039 Suppresses Viral Oncogenes E6 and E7 and Has a Therapeutic Effect on HPV-Induced Neoplasia. Clin Cancer Res 2018; 24:4518-4528. [DOI: 10.1158/1078-0432.ccr-17-3119] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 03/14/2018] [Accepted: 04/25/2018] [Indexed: 11/16/2022]
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Human Papillomavirus Replication Regulation by Acetylation of a Conserved Lysine in the E2 Protein. J Virol 2018; 92:JVI.01912-17. [PMID: 29142126 DOI: 10.1128/jvi.01912-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/05/2017] [Indexed: 12/25/2022] Open
Abstract
The papillomavirus (PV) E2 protein is a sequence-specific DNA binding protein that recruits cellular factors to its genome in infected epithelial cells. E2 also binds to and loads the viral E1 DNA helicase at the origin of replication. Posttranslational modifications (PTMs) of PV E2 have been identified as potential regulators of E2 functions. We recently reported lysine 111 (K111) as a target of p300 acetylation in bovine PV (BPV). The di-lysines at 111 and 112 are conserved in almost all papillomaviruses. We pursued a mutational approach to query the functional significance of lysine in human PV (HPV) E2. Amino acid substitutions that prevent acetylation, including arginine, were unable to stimulate transcription and E1-mediated DNA replication. The arginine K111 mutant retained E2 transcriptional repression, nuclear localization, DNA and chromatin binding, and association with E2 binding partners involved in PV transcription and replication. While the replication-defective E2-K111R mutant recruited E1 to the viral replication origin, surprisingly, unwinding of the duplex DNA did not occur. In contrast, the K111 glutamine (K111Q) mutant increased origin melting and stimulated replication compared to wild-type E2. These experiments reveal a novel activity of E2 necessary for denaturing the viral origin that likely depends on acetylation of highly conserved lysine 111.IMPORTANCE HPV is one of the most common sexually transmitted infections in the United States. Over 200 HPVs have been described, and they manifest in a variety of ways; they can be asymptomatic or can result in benign lesions (papillomas) or progress to malignancy. Although 90% of infections are asymptomatic and resolve easily, HPV16 and -18 alone are responsible for 70% of all cervical cancers, which are almost entirely caused by HPV infection. Interestingly, 60 to 90% of other cancers have been linked to HPV. The goal of this research is to further elucidate the mechanisms that regulate and mediate viral replication.
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Tilborghs S, Corthouts J, Verhoeven Y, Arias D, Rolfo C, Trinh XB, van Dam PA. The role of Nuclear Factor-kappa B signaling in human cervical cancer. Crit Rev Oncol Hematol 2017; 120:141-150. [PMID: 29198328 DOI: 10.1016/j.critrevonc.2017.11.001] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/01/2017] [Indexed: 12/27/2022] Open
Abstract
Background The Nuclear Factor kappaB (NF-kB) family consists of transcription factors that play a complex and essential role in the regulation of immune responses and inflammation. NF-kB has recently generated considerable interest as it has been implicated in human cancer initiation, progression and resistance to treatment. In the present comprehensive review the different aspects of NF-kB signaling in the carcinogenesis of cancer of the uterine cervix are discussed. NF-kB functions as part of a network, which determines the pattern of its effects on the expression of several other genes (such as crosstalks with reactive oxygen species, p53, STAT3 and miRNAS) and thus its function. Activation of NF-kB triggered by a HPV infection is playing an important role in the innate and adaptive immune response of the host. The virus induces down regulation of NF-kB to liquidate the inhibitory activity for its replication triggered by the immune system leading a status of persistant HPV infection. During the progression to high grade intraepithelial neoplasia and cervical cancer NF-KB becomes constitutionally activated again. Mutations in NF-kB genes are rare in solid tumors but mutations of upstream signaling molecules such as RAS, EGFR, PGF, HER2 have been implicated in elevated NF-kB signaling. NF-kB can stimulate transcription of proliferation regulating genes (eg. cyclin D1 and c-myc), genes involved in metastasis, VEGF dependent angiogenesis and cell immortality by telomerase. NF-kB activation can also induce the expression of activation-induced cytodine deaminase (AID) and the APOBEC proteins, providing a mechanistic link between the NF-kB pathway and mutagenic characteristic of cervical cancer. Inhibition of NF-kB has the potential to be used to reverse resistance to radiotherapy and systemic anti-cancer medication, but currently no clinicaly active NF-kB targeting strategies are available.
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Affiliation(s)
- Sam Tilborghs
- Multidisciplinary Oncologic Centre Antwerp (MOCA) Antwerp University Hospital, Edegem, Belgium
| | - Jerome Corthouts
- Multidisciplinary Oncologic Centre Antwerp (MOCA) Antwerp University Hospital, Edegem, Belgium
| | - Yannick Verhoeven
- Multidisciplinary Oncologic Centre Antwerp (MOCA) Antwerp University Hospital, Edegem, Belgium
| | - David Arias
- Phase I - Early Clinical Trials Unit & Center for Oncological Research (CORE), Antwerp University, Belgium
| | - Christian Rolfo
- Multidisciplinary Oncologic Centre Antwerp (MOCA) Antwerp University Hospital, Edegem, Belgium; Phase I - Early Clinical Trials Unit & Center for Oncological Research (CORE), Antwerp University, Belgium
| | - Xuan Bich Trinh
- Multidisciplinary Oncologic Centre Antwerp (MOCA) Antwerp University Hospital, Edegem, Belgium; Gynecologic Oncology Unit, Antwerp University Hospital & Centre of Oncologic Research (CORE), Antwerp University, Belgium
| | - Peter A van Dam
- Multidisciplinary Oncologic Centre Antwerp (MOCA) Antwerp University Hospital, Edegem, Belgium; Gynecologic Oncology Unit, Antwerp University Hospital & Centre of Oncologic Research (CORE), Antwerp University, Belgium.
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Kajitani N, Glahder J, Wu C, Yu H, Nilsson K, Schwartz S. hnRNP L controls HPV16 RNA polyadenylation and splicing in an Akt kinase-dependent manner. Nucleic Acids Res 2017; 45:9654-9678. [PMID: 28934469 PMCID: PMC5766200 DOI: 10.1093/nar/gkx606] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 07/04/2017] [Indexed: 11/14/2022] Open
Abstract
Inhibition of the Akt kinase activates HPV16 late gene expression by reducing HPV16 early polyadenylation and by activating HPV16 late L1 mRNA splicing. We identified ‘hot spots’ for RNA binding proteins at the early polyA signal and at splice sites on HPV16 late mRNAs. We observed that hnRNP L was associated with sequences at all HPV16 late splice sites and at the early polyA signal. Akt kinase inhibition resulted in hnRNP L dephosphorylation and reduced association of hnRNP L with HPV16 mRNAs. This was accompanied by an increased binding of U2AF65 and Sam68 to HPV16 mRNAs. Furthermore, siRNA knock-down of hnRNP L or Akt induced HPV16 gene expression. Treatment of HPV16 immortalized keratinocytes with Akt kinase inhibitor reduced hnRNP L binding to HPV16 mRNAs and induced HPV16 L1 mRNA production. Finally, deletion of the hnRNP L binding sites in HPV16 subgenomic expression plasmids resulted in activation of HPV16 late gene expression. In conclusion, the Akt kinase inhibits HPV16 late gene expression at the level of RNA processing by controlling the RNA-binding protein hnRNP L. We speculate that Akt kinase activity upholds an intracellular milieu that favours HPV16 early gene expression and suppresses HPV16 late gene expression.
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Affiliation(s)
- Naoko Kajitani
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Jacob Glahder
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Chengjun Wu
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Kersti Nilsson
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
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Abstract
Individuals with inherited immunodeficiencies, autoimmune disorders, organ or bone marrow transplantation, or infection with human immunodeficiency virus (HIV) are at increased risk of infection with both low-risk and high-risk human papillomavirus (HPV) types. Chronic immunosuppression provides an environment for persistent HPV infection which carries a higher risk of malignant transformation. Screening guidelines have been developed or advocated for processes that have detectable premalignant lesions, such as anal cancer or cervical cancer. For other anatomic locations, such as cutaneous, penile, and oropharyngeal, a biopsy of suspicious lesions is necessary for diagnosis. HPV cannot be cultured from clinical specimens in the laboratory, and diagnosis relies on cytologic, histologic, or molecular methods.
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The ins and outs of eukaryotic viruses: Knowledge base and ontology of a viral infection. PLoS One 2017; 12:e0171746. [PMID: 28207819 PMCID: PMC5313201 DOI: 10.1371/journal.pone.0171746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/25/2017] [Indexed: 12/19/2022] Open
Abstract
Viruses are genetically diverse, infect a wide range of tissues and host cells and follow unique processes for replicating themselves. All these processes were investigated and indexed in ViralZone knowledge base. To facilitate standardizing data, a simple ontology of viral life-cycle terms was developed to provide a common vocabulary for annotating data sets. New terminology was developed to address unique viral replication cycle processes, and existing terminology was modified and adapted. The virus life-cycle is classically described by schematic pictures. Using this ontology, it can be represented by a combination of successive terms: “entry”, “latency”, “transcription”, “replication” and “exit”. Each of these parts is broken down into discrete steps. For example Zika virus “entry” is broken down in successive steps: “Attachment”, “Apoptotic mimicry”, “Viral endocytosis/ macropinocytosis”, “Fusion with host endosomal membrane”, “Viral factory”. To demonstrate the utility of a standard ontology for virus biology, this work was completed by annotating virus data in the ViralZone, UniProtKB and Gene Ontology databases.
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Association of Human Papillomavirus 16 E2 with Rad50-Interacting Protein 1 Enhances Viral DNA Replication. J Virol 2017; 91:JVI.02305-16. [PMID: 28031358 PMCID: PMC5309968 DOI: 10.1128/jvi.02305-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 12/15/2016] [Indexed: 12/19/2022] Open
Abstract
Rad50-interacting protein 1 (Rint1) associates with the DNA damage response protein Rad50 during the transition from the S phase to the G2/M phase and functions in radiation-induced G2 checkpoint control. It has also been demonstrated that Rint1 is essential in vesicle trafficking from the Golgi apparatus to the endoplasmic reticulum (ER) through an interaction with Zeste-White 10 (ZW10). We have isolated a novel interaction between Rint1 and the human papillomavirus 16 (HPV16) transcription and replication factor E2. E2 binds to Rint1 within its ZW10 interaction domain, and we show that in the absence of E2, Rint1 is localized to the ER and associates with ZW10. E2 expression results in a disruption of the Rint1-ZW10 interaction and an accumulation of nuclear Rint1, coincident with a significant reduction in vesicle movement from the ER to the Golgi apparatus. Interestingly, nuclear Rint1 and members of the Mre11/Rad50/Nbs1 (MRN) complex were found in distinct E2 nuclear foci, which peaked during mid-S phase, indicating that the recruitment of Rint1 to E2 foci within the nucleus may also result in the recruitment of this DNA damage-sensing protein complex. We show that exogenous Rint1 expression enhances E2-dependent virus replication. Conversely, the overexpression of a truncated Rint1 protein that retains the E2 binding domain but not the Rad50 binding domain acts as a dominant negative inhibitor of E2-dependent HPV replication. Put together, these experiments demonstrate that the interaction between Rint1 and E2 has an important function in HPV replication. IMPORTANCE HPV infections are an important driver of many epithelial cancers, including those within the anogenital and oropharyngeal tracts. The HPV life cycle is tightly regulated and intimately linked to the differentiation of the epithelial cells that it infects. HPV replication factories formed in the nucleus are locations where viral DNA is copied to support virus persistence and amplification of infection. The recruitment of specific cellular protein complexes to these factories aids efficient and controlled viral replication. We have identified a novel HPV-host interaction that functions in the cellular response to DNA damage and cell cycle control. We show that the HPV E2 protein targets Rad50-interacting protein 1 (Rint1) to facilitate virus genome replication. These findings add to our understanding of how HPV replicates and the host cell pathways that are targeted by HPV to support virus replication. Understanding these pathways will allow further research into novel inhibitors of HPV genome replication.
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Splicing and Polyadenylation of Human Papillomavirus Type 16 mRNAs. Int J Mol Sci 2017; 18:ijms18020366. [PMID: 28208770 PMCID: PMC5343901 DOI: 10.3390/ijms18020366] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/29/2017] [Accepted: 02/03/2017] [Indexed: 12/24/2022] Open
Abstract
The human papillomavirus type 16 (HPV16) life cycle can be divided into an early stage in which the HPV16 genomic DNA is replicated, and a late stage in which the HPV16 structural proteins are synthesized and virions are produced. A strong coupling between the viral life cycle and the differentiation state of the infected cell is highly characteristic of all HPVs. The switch from the HPV16 early gene expression program to the late requires a promoter switch, a polyadenylation signal switch and a shift in alternative splicing. A number of cis-acting RNA elements on the HPV16 mRNAs and cellular and viral factors interacting with these elements are involved in the control of HPV16 gene expression. This review summarizes our knowledge of HPV16 cis-acting RNA elements and cellular and viral trans-acting factors that regulate HPV16 gene expression at the level of splicing and polyadenylation.
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Iftner T, Haedicke-Jarboui J, Wu SY, Chiang CM. Involvement of Brd4 in different steps of the papillomavirus life cycle. Virus Res 2016; 231:76-82. [PMID: 27965149 DOI: 10.1016/j.virusres.2016.12.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 12/16/2022]
Abstract
Bromodomain-containing protein 4 (Brd4) is a cellular chromatin-binding factor and transcriptional regulator that recruits sequence-specific transcription factors and chromatin modulators to control target gene transcription. Papillomaviruses (PVs) have evolved to hijack Brd4's activity in order to create a facilitating environment for the viral life cycle. Brd4, in association with the major viral regulatory protein E2, is involved in multiple steps of the PV life cycle including replication initiation, viral gene transcription, and viral genome segregation and maintenance. Phosphorylation of Brd4, regulated by casein kinase II (CK2) and protein phosphatase 2A (PP2A), is critical for viral gene transcription as well as E1- and E2-dependent origin replication. Thus, pharmacological agents regulating Brd4 phosphorylation and inhibitors blocking phospho-Brd4 functions are promising candidates for therapeutic intervention in treating human papillomavirus (HPV) infections as well as associated disease.
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Affiliation(s)
- Thomas Iftner
- Division of Experimental Virology, Institute for Medical Virology, University Hospital Tübingen, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany.
| | - Juliane Haedicke-Jarboui
- Division of Experimental Virology, Institute for Medical Virology, University Hospital Tübingen, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Shwu-Yuan Wu
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Cheng-Ming Chiang
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
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Dreer M, Fertey J, van de Poel S, Straub E, Madlung J, Macek B, Iftner T, Stubenrauch F. Interaction of NCOR/SMRT Repressor Complexes with Papillomavirus E8^E2C Proteins Inhibits Viral Replication. PLoS Pathog 2016; 12:e1005556. [PMID: 27064408 PMCID: PMC4827801 DOI: 10.1371/journal.ppat.1005556] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 03/17/2016] [Indexed: 11/19/2022] Open
Abstract
Infections with high-risk human papillomaviruses (HR-HPV) such as HPV16 and 31 can lead to ano-genital and oropharyngeal cancers and HPV types from the beta genus have been implicated in the development of non-melanoma skin cancer. HPV replicate as nuclear extrachromosomal plasmids at low copy numbers in undifferentiated cells. HPV16 and 31 mutants have indicated that these viruses express an E8^E2C protein which negatively regulates genome replication. E8^E2C shares the DNA-binding and dimerization domain (E2C) with the essential viral replication activator E2 and the E8 domain replaces the replication/transcription activation domain of E2. The HR-HPV E8 domain is required for inhibiting viral transcription and the replication of the viral origin mediated by viral E1 and E2 proteins. We show now that E8^E2C also limits replication of HPV1, a mu-PV and HPV8, a beta-PV, in normal human keratinocytes. Proteomic analyses identified all NCoR/SMRT corepressor complex components (HDAC3, GPS2, NCoR, SMRT, TBL1 and TBLR1) as co-precipitating host cell proteins for HPV16 and 31 E8^E2C proteins. Co-immunoprecipitation and co-localization experiments revealed that NCoR/SMRT components interact with HPV1, 8, 16 and 31 E8^E2C proteins in an E8-dependent manner. SiRNA knock-down experiments confirm that NCoR/SMRT components are critical for both the inhibition of transcription and HPV origin replication by E8^E2C proteins. Furthermore, a dominant-negative NCoR fragment activates transcription and replication only from HPV16 and 31 wt but not from mutant genomes encoding NCoR/SMRT-binding deficient E8^E2C proteins. In summary, our data suggest that the repressive function of E8^E2C is highly conserved among HPV and that it is mediated by an E8-dependent interaction with NCoR/SMRT complexes. Our data also indicate for the first time that NCoR/SMRT complexes not only are involved in inhibiting cellular and viral transcription but also in controlling the replication of HPV origins. Human papillomaviruses (HPV) have been shown to cause ano-genital and oropharyngeal cancers and have been also implicated in non-melanoma skin cancer. HPV have a two-stage replication cycle: in undifferentiated keratinocytes only a low level of genome replication without virus production can be observed whereas in differentiated keratinocytes high-level genome replication and virus production takes place. Previous studies have suggested that some HPV encode an E8^E2C protein that limits genome replication in undifferentiated cells. We now demonstrate that E8^E2C proteins from phylogenetically diverse HPV types interact with NCoR/SMRT corepressor complexes to limit viral transcription and genome replication. While NCoR/SMRT complexes are known to mediate the transcription repression functions of a wide variety of host transcription factors, this is the first evidence that NCoR/SMRT proteins also are involved in the repression of the replication of viral origins.
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Affiliation(s)
- Marcel Dreer
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Tuebingen, Germany
| | - Jasmin Fertey
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Tuebingen, Germany
| | - Saskia van de Poel
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Tuebingen, Germany
| | - Elke Straub
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Tuebingen, Germany
| | - Johannes Madlung
- Proteome Center Tuebingen, University of Tuebingen, Tuebingen, Germany
| | - Boris Macek
- Proteome Center Tuebingen, University of Tuebingen, Tuebingen, Germany
| | - Thomas Iftner
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Tuebingen, Germany
| | - Frank Stubenrauch
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Tuebingen, Germany
- * E-mail:
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Requirement for the E1 Helicase C-Terminal Domain in Papillomavirus DNA Replication In Vivo. J Virol 2016; 90:3198-211. [PMID: 26739052 DOI: 10.1128/jvi.03127-15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 12/31/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The papillomavirus (PV) E1 helicase contains a conserved C-terminal domain (CTD), located next to its ATP-binding site, whose function in vivo is still poorly understood. The CTD is comprised of an alpha helix followed by an acidic region (AR) and a C-terminal extension termed the C-tail. Recent biochemical studies on bovine papillomavirus 1 (BPV1) E1 showed that the AR and C-tail regulate the oligomerization of the protein into a double hexamer at the origin. In this study, we assessed the importance of the CTD of human papillomavirus 11 (HPV11) E1 in vivo, using a cell-based DNA replication assay. Our results indicate that combined deletion of the AR and C-tail drastically reduces DNA replication, by 85%, and that further truncation into the alpha-helical region compromises the structural integrity of the E1 helicase domain and its interaction with E2. Surprisingly, removal of the C-tail alone or mutation of highly conserved residues within the domain still allows significant levels of DNA replication (55%). This is in contrast to the absolute requirement for the C-tail reported for BPV1 E1 in vitro and confirmed here in vivo. Characterization of chimeric proteins in which the AR and C-tail from HPV11 E1 were replaced by those of BPV1 indicated that while the function of the AR is transferable, that of the C-tail is not. Collectively, these findings define the contribution of the three CTD subdomains to the DNA replication activity of E1 in vivo and suggest that the function of the C-tail has evolved in a PV type-specific manner. IMPORTANCE While much is known about hexameric DNA helicases from superfamily 3, the papillomavirus E1 helicase contains a unique C-terminal domain (CTD) adjacent to its ATP-binding site. We show here that this CTD is important for the DNA replication activity of HPV11 E1 in vivo and that it can be divided into three functional subdomains that roughly correspond to the three conserved regions of the CTD: an alpha helix, needed for the structural integrity of the helicase domain, followed by an acidic region (AR) and a C-terminal tail (C-tail) that have been shown to regulate the oligomerization of BPV1 E1 in vitro. Characterization of E1 chimeras revealed that, while the function of the AR could be transferred from BPV1 E1 to HPV11 E1, that of the C-tail could not. These results suggest that the E1 CTD performs multiple functions in DNA replication, some of them in a virus type-specific manner.
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Bergner S, Halec G, Schmitt M, Aubin F, Alonso A, Auvinen E. Individual and Complementary Effects of Human Papillomavirus Oncogenes on Epithelial Cell Proliferation and Differentiation. Cells Tissues Organs 2015; 201:97-108. [PMID: 26636751 DOI: 10.1159/000441716] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2015] [Indexed: 11/19/2022] Open
Abstract
Previous studies on human papillomavirus (HPV) type 16 protein functions have established the oncogenic nature of three viral proteins: E5, E6 and E7. Here we have studied the functions of these proteins by functional deletion of the individual E5, E6 or E7, or both E6 and E7 oncogenes in the context of the whole viral genome. These mutants, or the intact wild-type genome, were expressed from the natural viral promoters along with differentiation of epithelial HaCaT cells in three-dimensional collagen raft cultures. High episomal viral copy numbers were obtained using a transfection-based loxp-HPV16-eGFP-N1 vector system. All epithelial equivalents carrying the different HPV type 16 genomes showed pronounced hyperplastic and dysplastic morphology. Particularly the E7 oncogene, with contribution of E6, was shown to enhance cell proliferation. Specifically, the crucial role of E7 in HPV-associated hyperproliferation was clearly manifested. Based on morphological characteristics, immunohistochemical staining for differentiation and proliferation markers, and low expression of E1^E4, we propose that our raft culture models produce cervical intraepithelial neoplasia (CIN)1 and CIN2-like tissue. Our experimental setting provides an alternative tool to study concerted functions of HPV proteins in the development of epithelial dysplasia.
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Affiliation(s)
- Sven Bergner
- Research Program in Infection and Cancer, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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Ekalaksananan T, Jungpol W, Prasitthimay C, Wongjampa W, Kongyingyoes B, Pientong C. Polymorphisms and functional analysis of the intact human papillomavirus16 e2 gene. Asian Pac J Cancer Prev 2015; 15:10255-62. [PMID: 25556457 DOI: 10.7314/apjcp.2014.15.23.10255] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
High risk human papillomavirus (HR-HPV) E2 proteins play roles in transcriptional regulation and are commonly functionally disrupted when the HPV genome integrates into host chromosomes. Some 15-40% of cancer cases, however, contain an intact E2 gene or episomal HPV. In these cases, polymorphism of the E2 gene might be involved. This study aimed to determine polymorphisms of the E2 gene in episomal HPV16 detected in high grade squamous intraepithelial lesions and squamous cell carcinomas and altered functions compared to the E2 prototype. The E2 gene was amplified and sequenced. Two expression vectors containing E2 gene polymorphisms were constructed and transfected in SiHa and C33A cells, then E6 gene as well as Il- 10 and TNF-α expression was determined by quantitative RT-PCR. Expression vectors and reporter vectors containing the HPV16 long control region (LCR) were co-transfected and transcriptional activity was determined. The results showed that a total of 32 nucleotides and 23 amino acids were changed in all 20 cases of study, found in the transactivation (TA) domain, hinge (H) region and DNA binding (DB) domain with 14, 5 and 13 nucleotide positions. They mostly caused amino acid change. The expressing vectors containing different E2 gene polymorphisms showed E6 mRNA suppression, TNF-α mRNA suppression and IL-10 induction but no statistically significant differences when compared to the E2 prototype. Moreover, promoter activity in HPV16 LCR was not affected by E2 protein with different gene polymorphisms, in contrast to nucleotide variations in LCR that showed an effect on transcription activity. These results demonstrated that E2 gene polymorphisms of episomal HPV16 did not affect transcriptional regulation and suggested that nucleotide variation as well as epigenetic modification of the LCR might play a role in inducing malignant transformation of cells containing episomal HPV16.
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Affiliation(s)
- Tipaya Ekalaksananan
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand E-mail :
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Fisher C. Recent Insights into the Control of Human Papillomavirus (HPV) Genome Stability, Loss, and Degradation. J Clin Med 2015; 4:204-30. [PMID: 25798290 PMCID: PMC4366058 DOI: 10.3390/jcm4020204] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Most human papillomavirus (HPV) antiviral strategies have focused upon inhibiting viral DNA replication, but it is increasingly apparent that viral DNA levels can be chemically controlled by approaches that promote its instability. HPVs and other DNA viruses have a tenuous relationship with their hosts. They must replicate and hide from the DNA damage response (DDR) and innate immune systems, which serve to protect cells from foreign or “non-self” DNA, and yet they draft these same systems to support their life cycles. DNA binding antiviral agents promoting massive viral DNA instability and elimination are reviewed. Mechanistic studies of these agents have identified genetic antiviral enhancers and repressors, antiviral sensitizers, and host cell elements that protect and stabilize HPV genomes. Viral DNA degradation appears to be an important means of controlling HPV DNA levels in some cases, but the underlying mechanisms remain poorly understood. These findings may prove useful not only for understanding viral DNA persistence but only in devising future antiviral strategies.
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Affiliation(s)
- Chris Fisher
- NanoVir, 4717 Campus, Kalamazoo, MI 49008, USA; ; Tel.: +1-269-372-3261
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Murall CL, Bauch CT, Day T. Could the human papillomavirus vaccines drive virulence evolution? Proc Biol Sci 2015; 282:20141069. [PMID: 25429011 DOI: 10.1098/rspb.2014.1069] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The human papillomavirus (HPV) vaccines hold great promise for preventing several cancers caused by HPV infections. Yet little attention has been given to whether HPV could respond evolutionarily to the new selection pressures imposed on it by the novel immunity response created by the vaccine. Here, we present and theoretically validate a mechanism by which the vaccine alters the transmission-recovery trade-off that constrains HPV's virulence such that higher oncogene expression is favoured. With a high oncogene expression strategy, the virus is able to increase its viral load and infected cell population before clearance by the vaccine, thus improving its chances of transmission. This new rapid cell-proliferation strategy is able to circulate between hosts with medium to high turnover rates of sexual partners. We also discuss the importance of better quantifying the duration of challenge infections and the degree to which a vaccinated host can shed virus. The generality of the models presented here suggests a wider applicability of this mechanism, and thus highlights the need to investigate viral oncogenicity from an evolutionary perspective.
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Affiliation(s)
- Carmen Lía Murall
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario, Canada
| | - Chris T Bauch
- Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario, Canada
| | - Troy Day
- Department of Mathematics and Statistics and Department of Biology, Queen's University, Kingston, Ontario, Canada
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Kivipõld P, Võsa L, Ustav M, Kurg R. DAXX modulates human papillomavirus early gene expression and genome replication in U2OS cells. Virol J 2015; 12:104. [PMID: 26148509 PMCID: PMC4492069 DOI: 10.1186/s12985-015-0335-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 06/30/2015] [Indexed: 12/02/2022] Open
Abstract
Background The human papillomavirus (HPV) genomes can replicate, and are maintained as autonomously replicating extrachromosomal plasmids in human U2OS cells. Previous studies have shown that HPV genomes are transcriptionally active in U2OS cells and can express the viral early proteins required for initiation and establishment of HPV replication. In the present work, we have examined the involvement of cellular DAXX protein in HPV replication in U2OS cells. Methods We have used indirect immunofluorescence and FISH analysis in order to study HPV replication compartments in U2OS cells. In addition, we have used siRNA knock-down for examining the effect of the DAXX protein on HPV replication and transcription in U2OS cells. Results We show that a portion of HPV replication foci are partially co-localized with components of ND10, cellular DAXX and PML proteins. In addition, we demonstrate that the knock-down of the cellular DAXX protein modulates the HPV genome replication and transcription in U2OS cells – papillomavirus replication is reduced in the absence of this component of ND10. Conclusions The DAXX protein modulates the early gene expression and the transient replication of HPV genomes in U2OS cells.
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Affiliation(s)
- Piia Kivipõld
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia.
| | - Liisi Võsa
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia.
| | - Mart Ustav
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia.
| | - Reet Kurg
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia.
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Reinson T, Henno L, Toots M, Ustav M, Ustav M. The Cell Cycle Timing of Human Papillomavirus DNA Replication. PLoS One 2015; 10:e0131675. [PMID: 26132923 PMCID: PMC4489393 DOI: 10.1371/journal.pone.0131675] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/04/2015] [Indexed: 11/18/2022] Open
Abstract
Viruses manipulate the cell cycle of the host cell to optimize conditions for more efficient viral genome replication. One strategy utilized by DNA viruses is to replicate their genomes non-concurrently with the host genome; in this case, the viral genome is amplified outside S phase. This phenomenon has also been described for human papillomavirus (HPV) vegetative genome replication, which occurs in G2-arrested cells; however, the precise timing of viral DNA replication during initial and stable replication phases has not been studied. We developed a new method to quantitate newly synthesized DNA levels and used this method in combination with cell cycle synchronization to show that viral DNA replication is initiated during S phase and is extended to G2 during initial amplification but follows the replication pattern of cellular DNA during S phase in the stable maintenance phase. E1 and E2 protein overexpression changes the replication time from S only to both the S and G2 phases in cells that stably maintain viral episomes. These data demonstrate that the active synthesis and replication of the HPV genome are extended into the G2 phase to amplify its copy number and the duration of HPV genome replication is controlled by the level of the viral replication proteins E1 and E2. Using the G2 phase for genome amplification may be an important adaptation that allows exploitation of changing cellular conditions during cell cycle progression. We also describe a new method to quantify newly synthesized viral DNA levels and discuss its benefits for HPV research.
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Affiliation(s)
- Tormi Reinson
- University of Tartu, Institute of Technology Department of Biomedical Technology, Nooruse 1, 50411, Tartu, Estonia
| | - Liisi Henno
- University of Tartu, Institute of Technology Department of Biomedical Technology, Nooruse 1, 50411, Tartu, Estonia
| | - Mart Toots
- University of Tartu, Institute of Technology Department of Biomedical Technology, Nooruse 1, 50411, Tartu, Estonia
| | - Mart Ustav
- University of Tartu, Institute of Technology Department of Biomedical Technology, Nooruse 1, 50411, Tartu, Estonia
| | - Mart Ustav
- University of Tartu, Institute of Technology Department of Biomedical Technology, Nooruse 1, 50411, Tartu, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130, Tallinn, Estonia
- Icosagen Cell Factory OÜ, Nooruse 9, 50411, Tartu, Estonia
- * E-mail:
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Tsakogiannis D, Gortsilas P, Kyriakopoulou Z, Ruether IGA, Dimitriou TG, Orfanoudakis G, Markoulatos P. Sites of disruption within E1 and E2 genes of HPV16 and association with cervical dysplasia. J Med Virol 2015; 87:1973-80. [PMID: 25959607 DOI: 10.1002/jmv.24256] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 04/28/2015] [Indexed: 12/25/2022]
Abstract
Integration of HPV16 DNA into the host chromosome usually disrupts the E1 and/or E2 genes. The present study investigated the disruption of E1, E2 genes in a total of eighty four HPV16-positive precancerous and cervical cancer specimens derived from Greek women (seventeen paraffin-embedded cervical biopsies and sixty seven Thin Prep samples). Complete E2 and E1 genes were amplified using three and nine overlapping primer sets respectively, in order to define the sites of disruption. Extensive mapping analysis revealed that disruption/deletion events within E2 gene occurred in high grade and cervical cancer samples (x(2) test, P < 0.01), while no evidence of E2 gene disruption was documented among low grade cervical intraepithelial neoplasias. In addition, disruptions within the E1 gene occur both in high and low grade cervical intraepithelial neoplasia. This leads to the assumption that in low grade cervical intraepithelial neoplasias only E1 gene disruption was involved (Fisher's exact test, P < 0.05), while in high grade malignancies and cervical cancer cases deletions in both E1 and E2 genes occurred. Furthermore, the most prevalent site of disruption of E1 gene was located between nucleotides 1059 and 1323, while the most prevalent deleted region of the E2 gene was located between nucleotides 3172 and 3649 (E2 hinge region). Therefore, it is proposed that each population has its own profile of frequencies and sites of disruptions and extensive mapping analysis of E1 and E2 genes is mandatory in order to determine suitable markers for HPV16 DNA integration analysis in distinct populations.
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Affiliation(s)
- D Tsakogiannis
- Department of Biochemistry and Biotechnology, Microbiology-Virology Laboratory, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - P Gortsilas
- Department of Biochemistry and Biotechnology, Microbiology-Virology Laboratory, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Z Kyriakopoulou
- Department of Biochemistry and Biotechnology, Microbiology-Virology Laboratory, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - I G A Ruether
- Department of Biochemistry and Biotechnology, Microbiology-Virology Laboratory, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - T G Dimitriou
- Department of Biochemistry and Biotechnology, Microbiology-Virology Laboratory, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - G Orfanoudakis
- University of Strasbourg, Ecole Superieure de Biotechnologie de Strasbourg, CNRS FRE 3211-Oncoprotein Group, Illkirch, France
| | - P Markoulatos
- Department of Biochemistry and Biotechnology, Microbiology-Virology Laboratory, School of Health Sciences, University of Thessaly, Larissa, Greece
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Nakahara T, Tanaka K, Ohno SI, Egawa N, Yugawa T, Kiyono T. Activation of NF-κB by human papillomavirus 16 E1 limits E1-dependent viral replication through degradation of E1. J Virol 2015; 89:5040-59. [PMID: 25717108 PMCID: PMC4403482 DOI: 10.1128/jvi.00389-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 02/14/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED NF-κB is a family of transcription factors that regulate gene expression involved in many processes, such as the inflammatory response and cancer progression. Little is known about associations of NF-κB with the human papillomavirus (HPV) life cycle. We have developed a tissue culture system to conditionally induce E1-dependent replication of the human papillomavirus 16 (HPV16) genome in human cervical keratinocytes and found that expression of HPV16 E1, a viral helicase, results in reduction of IκBα and subsequent activation of NF-κB in a manner dependent on helicase activity. Exogenous expression of a degradation-resistant mutant of IκBα, which inhibits the activation of NF-κB, enhanced E1-dependent replication of the viral genome. Wortmannin, a broad inhibitor of phosphoinositide 3-kinases (PI3Ks), and, to a lesser extent, VE-822, an ATR kinase inhibitor, but not KU55933, an ATM kinase inhibitor, suppressed the activation of NF-κB and augmented E1-dependent replication of the HPV16 genome. Interestingly, the enhancement of E1-dependent replication of the viral genome was associated with increased stability of E1 in the presence of wortmannin as well as the IκBα mutant. Collectively, we propose that expression of E1 induces NF-κB activation at least in part through the ATR-dependent DNA damage response and that NF-κB in turn limits E1-dependent replication of HPV16 through degradation of E1, so that E1 and NF-κB may constitute a negative feedback loop. IMPORTANCE A major risk factor in human papillomavirus (HPV)-associated cancers is persistent infection with high-risk HPVs. To eradicate viruses from infected tissue, it is important to understand molecular mechanisms underlying the establishment and maintenance of persistent infection. In this study, we obtained evidence that human papillomavirus 16 (HPV16) E1, a viral DNA helicase essential for amplification of the viral genomes, induces NF-κB activation and that this limits E1-dependent genome replication of HPV16. These results suggest that NF-κB mediates a negative feedback loop to regulate HPV replication and that this feedback loop could be associated with control of the viral copy numbers. We could thus show for the first time that NF-κB activity is involved in the establishment and maintenance of persistent HPV infection.
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Affiliation(s)
- Tomomi Nakahara
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan
| | - Katsuyuki Tanaka
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan
| | - Shin-ichi Ohno
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan
| | - Nagayasu Egawa
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan
| | - Takashi Yugawa
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan
| | - Tohru Kiyono
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan
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Artificial Recruitment of UAF1-USP Complexes by a PHLPP1-E1 Chimeric Helicase Enhances Human Papillomavirus DNA Replication. J Virol 2015; 89:6227-39. [PMID: 25833051 DOI: 10.1128/jvi.00560-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 03/18/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The E1 helicase from anogenital human papillomavirus (HPV) types interacts with the cellular WD repeat-containing protein UAF1 in complex with the deubiquitinating enzyme USP1, USP12, or USP46. This interaction stimulates viral DNA replication and is required for maintenance of the viral episome in keratinocytes. E1 associates with UAF1 through a short UAF1-binding site (UBS) located within the N-terminal 40 residues of the protein. Here, we investigated if the E1 UBS could be replaced by the analogous domain from an unrelated protein, the pleckstrin homology domain and leucine-rich repeat protein phosphatase 1 (PHLPP1). We found that PHLPP1 and E1 interact with UAF1 in a mutually exclusive manner and mapped the minimal PHLPP1 UBS (PUBS) to a 100-amino-acid region sufficient for assembly into UAF1-USP complexes. Similarly to the E1 UBS, overexpression of PUBS in trans inhibited HPV DNA replication, albeit less efficiently. Characterization of a PHLPP1-E1 chimeric helicase revealed that PUBS could partially substitute for the E1 UBS in enhancing viral DNA replication and that the stimulatory effect of PUBS likely involves recruitment of UAF1-USP complexes, as it was abolished by mutations that weaken UAF1-binding and by overexpression of catalytically inactive USPs. Although functionally similar to the E1 UBS, PUBS is larger in size and requires both the WD repeat region and C-terminal ubiquitin-like domain of UAF1 for interaction, in contrast to E1, which does not contact the latter. Overall, this comparison of two heterologous UBSs indicates that these domains function as transferable protein interaction modules and provide further evidence that the association of E1 with UAF1-containing deubiquitinating complexes stimulates HPV DNA replication. IMPORTANCE The E1 protein from anogenital HPV types interacts with the UAF1-associated deubiquitinating enzymes USP1, USP12, and USP46 to stimulate replication of the viral genome. Little is known about the molecular nature of the E1-UAF1 interaction and, more generally, how UAF1-USP complexes recognize their substrate proteins. To address this question, we characterized the UAF1-binding site (UBS) of PHLPP1, a protein unrelated to E1. Using a PHLPP1-E1 chimeric helicase, we show that the PHLPP1 UBS (PUBS) can partially substitute for the E1 UBS in stimulating HPV DNA replication. This stimulation required conserved sequences in PUBS that meditate its interaction with UAF1, including a motif common to the E1 UBS. These results indicate that UAF1-binding sequences function as transferable protein interaction modules and provide further evidence that UAF1-USP complexes stimulate HPV DNA replication.
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The transcription map of human papillomavirus type 18 during genome replication in U2OS cells. PLoS One 2014; 9:e116151. [PMID: 25548925 PMCID: PMC4280167 DOI: 10.1371/journal.pone.0116151] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 12/04/2014] [Indexed: 11/19/2022] Open
Abstract
The human osteosarcoma cell line U2OS is useful for studying genome replication of human papillomavirus (HPVs) subtypes that belong to different phylogenetic genera. In this study, we defined the HPV18 transcription map in U2OS cells during transient replication, stable maintenance and vegetative amplification by identifying viral promoter regions, transcription polyadenylation and splicing sites during HPV18 genome replication. Mapping of the HPV18 transcription start sites in U2OS cells revealed five distinct promoter regions (P102, P520, P811, P1193 and P3000). With the exception of P3000, all of these regions have been previously identified during productive HPV18 infection. Collectively, the data suggest that U2OS cells are suitable for studying the replication and transcription properties of HPVs and to serve as a platform for conducting high-throughput drug screens to identify HPV replication inhibitors. In addition, we have identified mRNA species that are initiated from the promoter region P3000, which can encode two E2C regulator proteins that contain only the C-terminal hinge and DNA-binding and dimerization domains of E2. We show that these proteins regulate the initial amplification of HPV18 by modulating viral transcription. Moreover, we show that one of these proteins can act as a transcriptional activator of promoter P102.
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Tsakogiannis D, Kyriakopoulou Z, Ruether IGA, Amoutzias GD, Dimitriou TG, Diamantidou V, Kotsovassilis C, Markoulatos P. Determination of human papillomavirus 16 physical status through E1/E6 and E2/E6 ratio analysis. J Med Microbiol 2014; 63:1716-1723. [DOI: 10.1099/jmm.0.076810-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Human papillomavirus (HPV) 16 genome integration into the host chromosome is a crucial event during the life cycle of the virus and a major step towards carcinogenesis. The integration of HPV16 DNA promotes a constitutive high expression level of E6 and E7 oncoproteins, resulting in the extensive proliferation of the infected epithelial cells. In the present report the physical status of the HPV16 genome was studied, through determination of E1/E6 and E2/E6 DNA copy number ratios in 61 cervical samples of low- and high-grade malignancy and 8 cervical cancer samples, all of them associated with HPV16 infection. The selection of E1, E2 and E6 amplification target regions was performed according to the most prevalent deleted/disrupted sites of E1 and E2 genes. For this target selection we also considered the most conserved regions of E1, E2 and E6 genes among the same HPV16 isolates that were recently reported by our group. The analysis of HPV16 DNA form revealed a significant association among the mixed DNA forms in low-grade and high-grade malignancies, (χ2, P<0.01). The comparative analysis of E1/E6 and E2/E6 in the same cervical samples provides an accurate picture of HPV16 DNA form and may reveal whether different HPV16 DNA integrants coexist in the same cervical sample or not. This study proposes that E1/E6 and E2/E6 ratios determine with accuracy the HPV16 DNA integration pattern and may predict multiple integration events in the examined sample, thus providing significant information about the progression of cervical dysplasia.
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Affiliation(s)
- Dimitris Tsakogiannis
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Zaharoula Kyriakopoulou
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Irina Georgia Anna Ruether
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Grigoris D. Amoutzias
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Tilemachos G. Dimitriou
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Valentina Diamantidou
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
| | | | - Panayotis Markoulatos
- Microbiology–Virology Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece
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