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Yu L, Majerciak V, Lobanov A, Mirza S, Band V, Liu H, Cam M, Hughes SH, Lowy DR, Zheng ZM. HPV oncogenes expressed from only one of multiple integrated HPV DNA copies drive clonal cell expansion in cervical cancer. mBio 2024; 15:e0072924. [PMID: 38624210 PMCID: PMC11077993 DOI: 10.1128/mbio.00729-24] [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: 03/12/2024] [Accepted: 03/22/2024] [Indexed: 04/17/2024] Open
Abstract
The integration of HPV DNA into human chromosomes plays a pivotal role in the onset of papillomavirus-related cancers. HPV DNA integration often occurs by linearizing the viral DNA in the E1/E2 region, resulting in the loss of a critical viral early polyadenylation signal (PAS), which is essential for the polyadenylation of the E6E7 bicistronic transcripts and for the expression of the viral E6 and E7 oncogenes. Here, we provide compelling evidence that, despite the presence of numerous integrated viral DNA copies, virus-host fusion transcripts originate from only a single integrated HPV DNA in HPV16 and HPV18 cervical cancers and cervical cancer-derived cell lines. The host genomic elements neighboring the integrated HPV DNA are critical for the efficient expression of the viral oncogenes that leads to clonal cell expansion. The fusion RNAs that are produced use a host RNA polyadenylation signal downstream of the integration site, and almost all involve splicing to host sequences. In cell culture, siRNAs specifically targeting the host portion of the virus-host fusion transcripts effectively silenced viral E6 and E7 expression. This, in turn, inhibited cell growth and promoted cell senescence in HPV16+ CaSki and HPV18+ HeLa cells. Showing that HPV E6 and E7 expression from a single integration site is instrumental in clonal cell expansion sheds new light on the mechanisms of HPV-induced carcinogenesis and could be used for the development of precision medicine tailored to combat HPV-related malignancies. IMPORTANCE Persistent oncogenic HPV infections lead to viral DNA integration into the human genome and the development of cervical, anogenital, and oropharyngeal cancers. The expression of the viral E6 and E7 oncogenes plays a key role in cell transformation and tumorigenesis. However, how E6 and E7 could be expressed from the integrated viral DNA which often lacks a viral polyadenylation signal in the cancer cells remains unknown. By analyzing the integrated HPV DNA sites and expressed HPV RNAs in cervical cancer tissues and cell lines, we show that HPV oncogenes are expressed from only one of multiple chromosomal HPV DNA integrated copies. A host polyadenylation signal downstream of the integrated viral DNA is used for polyadenylation and stabilization of the virus-host chimeric RNAs, making the oncogenic transcripts targetable by siRNAs. This observation provides further understanding of the tumorigenic mechanism of HPV integration and suggests possible therapeutic strategies for the development of precision medicine for HPV cancers.
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Affiliation(s)
- Lulu Yu
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Vladimir Majerciak
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Alexei Lobanov
- CCR Collaborative Bioinformatics Resource (CCBR), National Cancer Institute, Bethesda, Maryland, USA
| | - Sameer Mirza
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Vimla Band
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Haibin Liu
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Maggie Cam
- CCR Collaborative Bioinformatics Resource (CCBR), National Cancer Institute, Bethesda, Maryland, USA
| | - Stephen H. Hughes
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Douglas R. Lowy
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
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Wei L, Huang K, Han H, Liu RY. Human Papillomavirus Infection in Penile Cancer: Multidimensional Mechanisms and Vaccine Strategies. Int J Mol Sci 2023; 24:16808. [PMID: 38069131 PMCID: PMC10706305 DOI: 10.3390/ijms242316808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/19/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Penile cancer (PC) is a rare male malignant tumor, with early lymph node metastasis and poor prognosis. Human papillomavirus (HPV) plays a key role in the carcinogenesis of PC. This review aims to summarize the association between HPV infection and PC in terms of virus-host genome integration patterns (the disrupted regions in the HPV and PC genome), genetic alterations, and epigenetic regulation (methylation and microRNA modification) occurring in HPV and PC DNA, as well as tumor immune microenvironment reprogramming. In addition, the potential of HPV vaccination strategies for PC prevention and treatment is discussed. Understanding of the HPV-related multidimensional mechanisms and the application of HPV vaccines will promote rational and novel management of PC.
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Affiliation(s)
- Lichao Wei
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; (L.W.); (K.H.)
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Kangbo Huang
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; (L.W.); (K.H.)
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Hui Han
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; (L.W.); (K.H.)
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Ran-yi Liu
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; (L.W.); (K.H.)
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Gunder LC, Johnson HR, Yao E, Moyer TH, Green HA, Sherer N, Zhang W, Carchman EH. Topical Protease Inhibitor Decreases Anal Carcinogenesis in a Transgenic Mouse Model of HPV Anal Disease. Viruses 2023; 15:v15041013. [PMID: 37112993 PMCID: PMC10146494 DOI: 10.3390/v15041013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
Anal cancer is a major health problem. This study seeks to determine if the topical protease inhibitor Saquinavir (SQV), is effective at the prevention of anal cancer in transgenic mice with established anal dysplasia. K14E6/E7 mice were entered into the study when the majority spontaneously developed high-grade anal dysplasia. To ensure carcinoma development, a subset of the mice was treated with a topical carcinogen: 7,12-Dimethylbenz[a]anthracene (DMBA). Treatment groups included: no treatment, DMBA only, and topical SQV with/without DMBA. After 20 weeks of treatment, anal tissue was harvested and evaluated histologically. SQV was quantified in the blood and anal tissue, and tissue samples underwent analysis for E6, E7, p53, and pRb. There was minimal systemic absorption of SQV in the sera despite high tissue concentrations. There were no differences in tumor-free survival between SQV-treated and respective control groups but there was a lower grade of histological disease in the mice treated with SQV compared to those untreated. Changes in E6 and E7 levels with SQV treatment suggest that SQV may function independently of E6 and E7. Topical SQV decreased histological disease progression in HPV transgenic mice with or without DMBA treatment without local side effects or significant systemic absorption.
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Affiliation(s)
- Laura C Gunder
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA
| | - Hillary R Johnson
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA
| | - Evan Yao
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA
| | - Tyra H Moyer
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA
| | - Heather A Green
- Carbone Cancer Center, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705, USA
| | - Nathan Sherer
- McArdle Laboratory for Cancer Research and Institute for Molecular Virology, University of Wisconsin, 1111 Highland Avenue, Madison, WI 53706, USA
| | - Wei Zhang
- Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin, 3170 UW Medical Foundation Centennial Building (MFCB), 1685 Highland Avenue, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, 2500 Overlook Terrace, Madison, WI 53705, USA
| | - Evie H Carchman
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA
- Carbone Cancer Center, School of Medicine and Public Health, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, 2500 Overlook Terrace, Madison, WI 53705, USA
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Hany D, Zoetemelk M, Bhattacharya K, Nowak-Sliwinska P, Picard D. Network-informed discovery of multidrug combinations for ERα+/HER2-/PI3Kα-mutant breast cancer. Cell Mol Life Sci 2023; 80:80. [PMID: 36869202 PMCID: PMC10032341 DOI: 10.1007/s00018-023-04730-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/20/2023] [Accepted: 02/19/2023] [Indexed: 03/05/2023]
Abstract
Breast cancer is a persistent threat to women worldwide. A large proportion of breast cancers are dependent on the estrogen receptor α (ERα) for tumor progression. Therefore, targeting ERα with antagonists, such as tamoxifen, or estrogen deprivation by aromatase inhibitors remain standard therapies for ERα + breast cancer. The clinical benefits of monotherapy are often counterbalanced by off-target toxicity and development of resistance. Combinations of more than two drugs might be of great therapeutic value to prevent resistance, and to reduce doses, and hence, decrease toxicity. We mined data from the literature and public repositories to construct a network of potential drug targets for synergistic multidrug combinations. With 9 drugs, we performed a phenotypic combinatorial screen with ERα + breast cancer cell lines. We identified two optimized low-dose combinations of 3 and 4 drugs of high therapeutic relevance to the frequent ERα + /HER2-/PI3Kα-mutant subtype of breast cancer. The 3-drug combination targets ERα in combination with PI3Kα and cyclin-dependent kinase inhibitor 1 (p21). In addition, the 4-drug combination contains an inhibitor for poly (ADP-ribose) polymerase 1 (PARP1), which showed benefits in long-term treatments. Moreover, we validated the efficacy of the combinations in tamoxifen-resistant cell lines, patient-derived organoids, and xenograft experiments. Thus, we propose multidrug combinations that have the potential to overcome the standard issues of current monotherapies.
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Affiliation(s)
- Dina Hany
- Département de Biologie Moléculaire et Cellulaire, Université de Genève, Sciences III, Quai Ernest-Ansermet 30, 1211, Genève 4, Switzerland
- On leave from: Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, 21311, Egypt
| | - Marloes Zoetemelk
- Groupe de Pharmacologie Moléculaire, Section des Sciences Pharmaceutiques, Université de Genève, Genève, Switzerland
- Institut des Sciences Pharmaceutiques de Suisse Occidentale, Université de Genève, Genève, Switzerland
- Centre de Recherche Translationnelle en Onco-hématologie, Université de Genève, Genève, Switzerland
| | - Kaushik Bhattacharya
- Département de Biologie Moléculaire et Cellulaire, Université de Genève, Sciences III, Quai Ernest-Ansermet 30, 1211, Genève 4, Switzerland
| | - Patrycja Nowak-Sliwinska
- Groupe de Pharmacologie Moléculaire, Section des Sciences Pharmaceutiques, Université de Genève, Genève, Switzerland
- Institut des Sciences Pharmaceutiques de Suisse Occidentale, Université de Genève, Genève, Switzerland
- Centre de Recherche Translationnelle en Onco-hématologie, Université de Genève, Genève, Switzerland
| | - Didier Picard
- Département de Biologie Moléculaire et Cellulaire, Université de Genève, Sciences III, Quai Ernest-Ansermet 30, 1211, Genève 4, Switzerland.
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Saleh T, Khasawneh AI, Himsawi N, Abu-Raideh J, Ejeilat V, Elshazly AM, Gewirtz DA. Senolytic Therapy: A Potential Approach for the Elimination of Oncogene-Induced Senescent HPV-Positive Cells. Int J Mol Sci 2022; 23:ijms232415512. [PMID: 36555154 PMCID: PMC9778669 DOI: 10.3390/ijms232415512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
Senescence represents a unique cellular stress response characterized by a stable growth arrest, macromolecular alterations, and wide spectrum changes in gene expression. Classically, senescence is the end-product of progressive telomeric attrition resulting from the repetitive division of somatic cells. In addition, senescent cells accumulate in premalignant lesions, in part, as a product of oncogene hyperactivation, reflecting one element of the tumor suppressive function of senescence. Oncogenic processes that induce senescence include overexpression/hyperactivation of H-Ras, B-Raf, and cyclin E as well as inactivation of PTEN. Oncogenic viruses, such as Human Papilloma Virus (HPV), have also been shown to induce senescence. High-risk strains of HPV drive the immortalization, and hence transformation, of cervical epithelial cells via several mechanisms, but primarily via deregulation of the cell cycle, and possibly, by facilitating escape from senescence. Despite the wide and successful utilization of HPV vaccines in reducing the incidence of cervical cancer, this measure is not effective in preventing cancer development in individuals already positive for HPV. Accordingly, in this commentary, we focus on the potential contribution of oncogene and HPV-induced senescence (OIS) in cervical cancer. We further consider the potential utility of senolytic agents for the elimination of HPV-harboring senescent cells as a strategy for reducing HPV-driven transformation and the risk of cervical cancer development.
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Affiliation(s)
- Tareq Saleh
- Department of Pharmacology and Public Health, Faculty of Medicine, The Hashemite University, Zarqa 13133, Jordan
- Correspondence: (T.S.); (D.A.G.)
| | - Ashraf I. Khasawneh
- Department of Microbiology, Pathology, and Forensic Medicine, Faculty of Medicine, The Hashemite University, Zarqa 13133, Jordan
| | - Nisreen Himsawi
- Department of Microbiology, Pathology, and Forensic Medicine, Faculty of Medicine, The Hashemite University, Zarqa 13133, Jordan
| | - Jumana Abu-Raideh
- Department of Microbiology, Pathology, and Forensic Medicine, Faculty of Medicine, The Hashemite University, Zarqa 13133, Jordan
| | - Vera Ejeilat
- Department of Anatomy and Histology, Faculty of Medicine, The University of Jordan, Amman 11942, Jordan
| | - Ahmed M. Elshazly
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh 33516, Egypt
| | - David A. Gewirtz
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
- Correspondence: (T.S.); (D.A.G.)
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Lou H, Boland JF, Li H, Burk R, Yeager M, Anderson SK, Wentzensen N, Schiffman M, Mirabello L, Dean M. HPV16 E7 Nucleotide Variants Found in Cancer-Free Subjects Affect E7 Protein Expression and Transformation. Cancers (Basel) 2022; 14:4895. [PMID: 36230818 PMCID: PMC9562847 DOI: 10.3390/cancers14194895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/23/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
The human papillomavirus (HPV) type 16 E7 oncogene is critical to carcinogenesis and highly conserved. Previous studies identified a preponderance of non-synonymous E7 variants amongst HPV16-positive cancer-free controls compared to those with cervical cancer. To investigate the function of E7 variants, we constructed full-length HPV16 E7 genes and tested variants at positions H9R, D21N, N29S, E33K, T56I, D62N, S63F, S63P, T64M, E80K, D81N, P92L, and P92S (found only in controls); D14E, N29H cervical intraepithelial neoplasia (CIN2), and P6L, H51N, R77S (CIN3). We determined the steady-state level of cytoplasmic and nuclear HPV16 E7 protein. All variants from controls showed a reduced level of E7 protein, with 7/13 variants having lower protein levels. In contrast, 2/3 variants from the CIN3 precancer group had near-wild type E7 levels. We assayed the activity of representative variants in stably transfected NIH3T3 cells. The H9R, E33K, P92L, and P92S variants found in control subjects had lower transforming activity than D14E and N29H variants (CIN2), and the R77S (CIN3) had activity only slightly reduced from wild-type E7. In addition, R77S and WT E7 caused increased migration of NIH3T3 cells in a wound-healing assay compared with H9R, E33K, P92L, and P92S (controls) and D14E (CIN2). These data provide evidence that the E7 variants found in HPV16-positive cancer-free women are partially defective for transformation and cell migration, further demonstrating the importance of fully active E7 in cancer development.
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Affiliation(s)
- Hong Lou
- Cancer Genetics Research Laboratory, Division of Cancer Epidemiology and Genetics, Frederick National Laboratory for Cancer Research, Rockville, MD 20850, USA
| | - Joseph F. Boland
- Cancer Genetics Research Laboratory, Division of Cancer Epidemiology and Genetics, Frederick National Laboratory for Cancer Research, Rockville, MD 20850, USA
| | - Hongchuan Li
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Robert Burk
- Departments of Pediatrics, Microbiology and Immunology, and Obstetrics & Gynecology and Women’s Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Meredith Yeager
- Cancer Genetics Research Laboratory, Division of Cancer Epidemiology and Genetics, Frederick National Laboratory for Cancer Research, Rockville, MD 20850, USA
| | - Stephen K. Anderson
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Nicolas Wentzensen
- Laboratory of Cancer Genetics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD 20850, USA
| | - Mark Schiffman
- Laboratory of Cancer Genetics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD 20850, USA
| | - Lisa Mirabello
- Laboratory of Cancer Genetics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD 20850, USA
| | - Michael Dean
- Laboratory of Translational Genomics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD 20850, USA
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Kisseljova NP, Fedorova MD, Zaikina AE, Elkina NV, Goldobina EE, Elkin DS, Abramov PM, Pavlova LS, Vinokurova SV. [Identification regulatory noncoding RNAs of human papilloma virus type 16 (Papillomaviridae: Alphapapillomavirus: Human papillomavirus) in cervical tumors]. Vopr Virusol 2022; 67:217-226. [PMID: 35831964 DOI: 10.36233/0507-4088-108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
INTRODUCTION High carcinogenic-risk human papillomaviruses (hrHPVs) are recognized as etiological agents of cervical cancer. Constant expression of the viral oncoproteins, E6 and E7, is required for maintenance of the malignant phenotype of tumor cells. The exact mechanism of regulation of viral oncogenes expression in tumor cells is not fully elucidated. THE PURPOSE identification of viral noncoding RNAs (ncRNAs) in HPV16-positve cervical cancer. MATERIALS AND METHODS The reverse transcription polymerase chain reactions were used to detect viral ncRNAs in HPV16-positve primary cervical squamous cell carcinomas and SiHa and CasKi cell lines. The knockdown technique with oligonucleotides complementary to ncRNAs was used to elucidate their functions. RESULTS We have identified ncRNAs transcribed in the upstream regulatory region of HPV16 in the cervical carcinoma cell lines and in 32 out 32 cervical squamous cell carcinomas with episomal or integrated forms of HPV16 DNA. Knockdown of sense or antisense strains of ncRNAs by oligonucleotides results in a decrease or increase of the E6 and E7 oncogenes mRNA levels in cells, respectively. These changes of oncogenes mRNA levels are accompanied by the modulation of the levels of the p53 protein, the main target of the E6 oncoprotein. CONCLUSION The presence of regulatory ncRNAs in all examined tumors and cell lines revealed for the first time indicates their necessity for maintenance of constant expression of E6 and E7 oncogenes in them. The findings can be useful for understanding of the fundamental aspects of the viral expression regulation in HPV16-positive tumors.
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Affiliation(s)
- N P Kisseljova
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - M D Fedorova
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - A E Zaikina
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - N V Elkina
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - E E Goldobina
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - D S Elkin
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - P M Abramov
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - L S Pavlova
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
| | - S V Vinokurova
- FSBI «National Medical Research Center of Oncology named after N.N. Blokhin» of the Ministry of Health of Russia
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Cell death mechanisms in head and neck cancer cells in response to low and high-LET radiation. Expert Rev Mol Med 2022. [DOI: 10.1017/erm.2021.31] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AbstractHead and neck squamous cell carcinoma (HNSCC) is a common malignancy that develops in or around the throat, larynx, nose, sinuses and mouth, and is mostly treated with a combination of chemo- and radiotherapy (RT). The main goal of RT is to kill enough of the cancer cell population, whilst preserving the surrounding normal and healthy tissue. The mechanisms by which conventional photon RT achieves this have been extensively studied over several decades, but little is known about the cell death pathways that are activated in response to RT of increasing linear energy transfer (LET), including proton beam therapy and heavy ions. Here, we provide an up-to-date review on the observed radiobiological effects of low- versus high-LET RT in HNSCC cell models, particularly in the context of specific cell death mechanisms, including apoptosis, necrosis, autophagy, senescence and mitotic death. We also detail some of the current therapeutic strategies targeting cell death pathways that have been investigated to enhance the radiosensitivity of HNSCC cells in response to RT, including those that may present with clinical opportunities for eventual patient benefit.
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Abstract
Etiologically, 5% of all cancers worldwide are caused by the high-risk human papillomaviruses (hrHPVs). These viruses encode two oncoproteins (E6 and E7) whose expression is required for cancer initiation and maintenance. Among their cellular targets are the p53 and the retinoblastoma tumor suppressor proteins. Inhibition of the hrHPV E6-mediated ubiquitylation of p53 through the E6AP ubiquitin ligase results in the stabilization of p53, leading to cellular apoptosis. We utilized a live cell high throughput screen to determine whether exogenous microRNA (miRNA) transfection had the ability to stabilize p53 in hrHPV-positive cervical cancer cells expressing a p53-fluorescent protein as an in vivo reporter of p53 stability. Among the miRNAs whose transfection resulted in the greatest p53 stabilization was 375-3p that has previously been reported to stabilize p53 in HeLa cells, providing validation of the screen. The top 32 miRNAs in addition to 375-3p were further assessed using a second cell-based p53 stability reporter system as well as in non-reporter HeLa cells to examine their effects on endogenous p53 protein levels, resulting in the identification of 23 miRNAs whose transfection increased p53 levels in HeLa cells. While a few miRNAs that stabilized p53 led to decreases in E6AP protein levels, all targeted HPV oncoprotein expression. We further examined subsets of these miRNAs for their abilities to induce apoptosis and determined whether it was p53-mediated. The introduction of specific miRNAs revealed surprisingly heterogeneous responses in different cell lines. Nonetheless, some of the miRNAs described here have potential as therapeutics for treating HPV-positive cancers. Importance Human papillomaviruses cause approximately 5% of all cancers worldwide and encode genes that contribute to both the initiation and maintenance of these cancers. The viral oncoprotein E6 is expressed in all HPV-positive cancers and functions by targeting the degradation of p53 through the engagement of the cellular ubiquitin ligase E6AP. Inhibiting the degradation of p53 leads to apoptosis in HPV-positive cancer cells. Using a high throughput live cell assay we identified several miRNAs whose transfection stabilize p53 in HPV-positive cells. These miRNAs have the potential to be used in the treatment of HPV-positive cancers.
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Delineating the Switch between Senescence and Apoptosis in Cervical Cancer Cells under Ciclopirox Treatment. Cancers (Basel) 2021; 13:cancers13194995. [PMID: 34638479 PMCID: PMC8508512 DOI: 10.3390/cancers13194995] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/26/2021] [Indexed: 01/09/2023] Open
Abstract
Simple Summary Novel treatment options for cervical cancer are urgently required. Ciclopirox (CPX), an iron chelator, has shown promising anti-tumorigenic potential in several preclinical tumor models, including cervical cancer cells. In these cells, CPX can induce apoptosis, a form of cell death, or senescence, an irreversible cellular growth arrest. These different phenotypic outcomes may influence therapy response. Here, we show that the decision of cervical cancer cells to induce apoptosis or senescence is strongly dependent on glucose availability: CPX induces apoptosis under limited glucose availability, whereas under increased glucose supply, CPX treatment results in senescence. Further, we link the pro-apoptotic and pro-senescent activities of CPX to its capacity to block oxidative phosphorylation and to chelate iron, respectively. In addition, we show that the combined treatment of CPX and glycolysis inhibitors blocks the proliferation of cervical cancer cells in a synergistic manner. Collectively, we provide novel insights into the anti-proliferative activities of CPX in cervical cancer cells, elucidate the cellular decision between apoptosis or senescence induction, and provide a rationale to combine CPX with glycolysis inhibitors. Abstract The iron-chelating drug ciclopirox (CPX) may possess therapeutic potential for cancer treatment, including cervical cancer. As is observed for other chemotherapeutic drugs, CPX can induce senescence or apoptosis in cervical cancer cells which could differently affect their therapy response. The present study aims to gain insights into the determinants which govern the switch between senescence and apoptosis in cervical cancer cells. We performed proteome analyses, proliferation studies by live-cell imaging and colony formation assays, senescence and apoptosis assays, and combination treatments of CPX with inhibitors of oxidative phosphorylation (OXPHOS) or glycolysis. We found that CPX downregulates OXPHOS factors and facilitates the induction of apoptosis under limited glucose availability, an effect which is shared by classical OXPHOS inhibitors. Under increased glucose availability, however, CPX-induced apoptosis is prevented and senescence is induced, an activity which is not exerted by classical OXPHOS inhibitors, but by other iron chelators. Moreover, we show that the combination of CPX with glycolysis inhibitors blocks cervical cancer proliferation in a synergistic manner. Collectively, our results reveal that the phenotypic response of cervical cancer cells towards CPX is strongly dependent on glucose availability, link the pro-apoptotic and pro-senescent activities of CPX to its bifunctionality as an OXPHOS inhibitor and iron chelator, respectively, and provide a rationale for combining CPX with glycolysis inhibitors.
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Inturi R, Jemth P. CRISPR/Cas9-based inactivation of human papillomavirus oncogenes E6 or E7 induces senescence in cervical cancer cells. Virology 2021; 562:92-102. [PMID: 34280810 DOI: 10.1016/j.virol.2021.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/02/2021] [Accepted: 07/08/2021] [Indexed: 01/10/2023]
Abstract
Human papillomaviruses (HPVs) such as HPV16 and HPV18 can cause cancers of the cervix, anogenital and oropharyngeal sites. Continuous expression of the HPV oncoproteins E6 and E7 are essential for transformation and maintenance of cancer cells. Therefore, therapeutic targeting of E6 or E7 genes can potentially treat HPV-related cancers. Here we report that CRISPR/Cas9-based knockout of E6 or E7 can trigger cellular senescence in HPV18 immortalized HeLa cells. Specifically, E6 or E7-inactivated HeLa cells exhibited characteristic senescence markers like enlarged cell surface area, increased β-galactosidase expression and loss of lamin B1. Since E6 and E7 are bicistronic transcripts, inactivation of HPV18 E6 resulted in knockout of both E6 and E7 and increasing levels of p53/p21 and pRb/p21, respectively. Knockout of HPV18 E7 resulted in decreased E6 expression with activation of pRb/p21 pathway. Taken together, our study demonstrates cellular senescence as an alternative outcome of HPV oncogene inactivation by CRISPR/Cas9.
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Affiliation(s)
- Raviteja Inturi
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-75123, Uppsala, Sweden.
| | - Per Jemth
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-75123, Uppsala, Sweden.
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12
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Martínez-Noël G, Vieira VC, Szajner P, Lilienthal EM, Kramer RE, Boyland KA, Smith JA, Howley PM. Live cell, image-based high-throughput screen to quantitate p53 stabilization and viability in human papillomavirus positive cancer cells. Virology 2021; 560:96-109. [PMID: 34051479 DOI: 10.1016/j.virol.2021.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/16/2021] [Accepted: 05/16/2021] [Indexed: 11/16/2022]
Abstract
Approximately 5% of cancers are caused by high-risk human papillomaviruses. Although very effective preventive vaccines will reduce this cancer burden significantly over the next several decades, they have no therapeutic effect for those already infected and remaining at risk for malignant progression of hrHPV lesions. HPV-associated cancers are dependent upon the expression of the viral E6 and E7 oncogenes. The oncogenic function of hrHPV E6 relies partially on its ability to induce p53 degradation. Since p53 is generally wildtype in hrHPV-associated cancers, p53 stabilization arrests proliferation, induces apoptosis and/or results in senescence. Here we describe a live cell, image-based high-throughput screen to identify compounds that stabilize p53 and/or affect viability in HPV-positive cancer HeLa cells. We validate the robustness and potential of this screening assay by assessing the activities of approximately 6,500 known bioactive compounds, illustrating its capability to function as a platform to identify novel therapeutics for hrHPV.
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Affiliation(s)
- Gustavo Martínez-Noël
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Valdimara Corrêa Vieira
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Patricia Szajner
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Erin M Lilienthal
- ICCB-Longwood Screening Facility, Harvard Medical School, 250 Longwood Avenue, Boston, MA, 02115, USA
| | - Rebecca E Kramer
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Kathleen A Boyland
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Jennifer A Smith
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA; ICCB-Longwood Screening Facility, Harvard Medical School, 250 Longwood Avenue, Boston, MA, 02115, USA
| | - Peter M Howley
- Department of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA.
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13
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The Role of Senescent Cells in Acquired Drug Resistance and Secondary Cancer in BRAFi-Treated Melanoma. Cancers (Basel) 2021; 13:cancers13092241. [PMID: 34066966 PMCID: PMC8125319 DOI: 10.3390/cancers13092241] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/30/2021] [Accepted: 05/02/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Advances in melanoma treatment include v-Raf murine sarcoma viral oncogene homolog B (BRAF) inhibitors that target the predominant oncogenic mutation found in malignant melanoma. Despite initial success of the BRAF inhibitor (BRAFi) therapies, resistance and secondary cancer often occur. Mechanisms of resistance and secondary cancer rely on upregulation of pro-survival pathways that circumvent senescence. The repeated identification of a cellular senescent phenotype throughout melanoma progression demonstrates the contribution of senescent cells in resistance and secondary cancer development. Incorporating senotherapeutics in melanoma treatment may offer a novel approach for potentially improving clinical outcome. Abstract BRAF is the most common gene mutated in malignant melanoma, and predominately it is a missense mutation of codon 600 in the kinase domain. This oncogenic BRAF missense mutation results in constitutive activation of the mitogen-activate protein kinase (MAPK) pro-survival pathway. Several BRAF inhibitors (BRAFi) have been developed to specifically inhibit BRAFV600 mutations that improve melanoma survival, but resistance and secondary cancer often occur. Causal mechanisms of BRAFi-induced secondary cancer and resistance have been identified through upregulation of MAPK and alternate pro-survival pathways. In addition, overriding of cellular senescence is observed throughout the progression of disease from benign nevi to malignant melanoma. In this review, we discuss melanoma BRAF mutations, the genetic mechanism of BRAFi resistance, and the evidence supporting the role of senescent cells in melanoma disease progression, drug resistance and secondary cancer. We further highlight the potential benefit of targeting senescent cells with senotherapeutics as adjuvant therapy in combating melanoma.
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14
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Hoppe-Seyler K, Herrmann AL, Däschle A, Kuhn BJ, Strobel TD, Lohrey C, Bulkescher J, Krijgsveld J, Hoppe-Seyler F. Effects of Metformin on the virus/host cell crosstalk in human papillomavirus-positive cancer cells. Int J Cancer 2021; 149:1137-1149. [PMID: 33844847 DOI: 10.1002/ijc.33594] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/17/2021] [Accepted: 04/06/2021] [Indexed: 12/14/2022]
Abstract
Oncogenic types of human papillomaviruses (HPVs) are major human carcinogens. The viral E6/E7 oncogenes maintain the malignant growth of HPV-positive cancer cells. Targeted E6/E7 inhibition results in efficient induction of cellular senescence, which could be exploited for therapeutic purposes. Here we show that viral E6/E7 expression is strongly downregulated by Metformin in HPV-positive cervical cancer and head and neck cancer cells, both at the transcript and protein level. Metformin-induced E6/E7 repression is glucose and PI3K-dependent but-other than E6/E7 repression under hypoxia-AKT-independent. Proteome analyses reveal that Metformin-induced HPV oncogene repression is linked to the downregulation of cellular factors associated with E6/E7 expression in HPV-positive cancer biopsies. Notably, despite efficient E6/E7 repression, Metformin induces only a reversible proliferative stop in HPV-positive cancer cells and enables them to evade senescence. Metformin also efficiently blocks senescence induction in HPV-positive cancer cells in response to targeted E6/E7 inhibition by RNA interference. Moreover, Metformin treatment enables HPV-positive cancer cells to escape from chemotherapy-induced senescence. These findings uncover profound effects of Metformin on the virus/host cell interactions and the phenotype of HPV-positive cancer cells with implications for therapy-induced senescence, for attempts to repurpose Metformin as an anticancer agent and for the development of E6/E7-inhibitory therapeutic strategies.
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Affiliation(s)
- Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Anja L Herrmann
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Antonia Däschle
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Bianca J Kuhn
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany.,Division of Proteomics of Stem Cells and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Tobias D Strobel
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Claudia Lohrey
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Julia Bulkescher
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jeroen Krijgsveld
- Division of Proteomics of Stem Cells and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
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15
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Park S, Auyeung A, Lee DL, Lambert PF, Carchman EH, Sherer NM. HIV-1 Protease Inhibitors Slow HPV16-Driven Cell Proliferation through Targeted Depletion of Viral E6 and E7 Oncoproteins. Cancers (Basel) 2021; 13:949. [PMID: 33668328 PMCID: PMC7956332 DOI: 10.3390/cancers13050949] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/09/2021] [Accepted: 02/20/2021] [Indexed: 02/05/2023] Open
Abstract
High-risk human papillomavirus strain 16 (HPV16) causes oral and anogenital cancers through the activities of two viral oncoproteins, E6 and E7, that dysregulate the host p53 and pRb tumor suppressor pathways, respectively. The maintenance of HPV16-positive cancers requires constitutive expression of E6 and E7. Therefore, inactivating these proteins could provide the basis for an anticancer therapy. Herein we demonstrate that a subset of aspartyl protease inhibitor drugs currently used to treat HIV/AIDS cause marked reductions in HPV16 E6 and E7 protein levels using two independent cell culture models: HPV16-transformed CaSki cervical cancer cells and NIKS16 organotypic raft cultures (a 3-D HPV16-positive model of epithelial pre-cancer). Treatment of CaSki cells with some (lopinavir, ritonavir, nelfinavir, and saquinavir) but not other (indinavir and atazanavir) protease inhibitors reduced E6 and E7 protein levels, correlating with increased p53 protein levels and decreased cell viability. Long-term (>7 day) treatment of HPV16-positive NIKS16 raft cultures with saquinavir caused epithelial atrophy with no discernible effects on HPV-negative rafts, demonstrating selectivity. Saquinavir also reduced HPV16's effects on markers of the cellular autophagy pathway in NIKS16 rafts, a hallmark of HPV-driven pre-cancers. Taken together, these data suggest HIV-1 protease inhibitors be studied further in the context of treating or preventing HPV16-positive cancers.
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Affiliation(s)
- Soyeong Park
- McArdle Laboratory for Cancer Research, Deptartment of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (S.P.); (D.L.L.); (P.F.L.)
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (A.A.); (E.H.C.)
| | - Andrew Auyeung
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (A.A.); (E.H.C.)
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA
| | - Denis L. Lee
- McArdle Laboratory for Cancer Research, Deptartment of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (S.P.); (D.L.L.); (P.F.L.)
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (A.A.); (E.H.C.)
| | - Paul F. Lambert
- McArdle Laboratory for Cancer Research, Deptartment of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (S.P.); (D.L.L.); (P.F.L.)
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (A.A.); (E.H.C.)
| | - Evie H. Carchman
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (A.A.); (E.H.C.)
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA
| | - Nathan M. Sherer
- McArdle Laboratory for Cancer Research, Deptartment of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (S.P.); (D.L.L.); (P.F.L.)
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; (A.A.); (E.H.C.)
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16
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Biological Pathways of HPV-Induced Carcinogenesis. Sex Transm Infect 2020. [DOI: 10.1007/978-3-030-02200-6_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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17
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Braun JA, Herrmann AL, Blase JI, Frensemeier K, Bulkescher J, Scheffner M, Galy B, Hoppe-Seyler K, Hoppe-Seyler F. Effects of the antifungal agent ciclopirox in HPV-positive cancer cells: Repression of viral E6/E7 oncogene expression and induction of senescence and apoptosis. Int J Cancer 2019; 146:461-474. [PMID: 31603527 DOI: 10.1002/ijc.32709] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/05/2019] [Accepted: 09/18/2019] [Indexed: 01/02/2023]
Abstract
The malignant growth of human papillomavirus (HPV)-positive cancer cells is dependent on the continuous expression of the viral E6/E7 oncogenes. Here, we examined the effects of iron deprivation on the phenotype of HPV-positive cervical cancer cells. We found that iron chelators, such as the topical antifungal agent ciclopirox (CPX), strongly repress HPV E6/E7 oncogene expression, both at the transcript and protein level. CPX efficiently blocks the proliferation of HPV-positive cancer cells by inducing cellular senescence. Although active mTOR signaling is considered to be critical for the cellular senescence response towards a variety of prosenescent agents, CPX-induced senescence occurs under conditions of severely impaired mTOR signaling. Prolonged CPX treatment leads to p53-independent Caspase-3/7 activation and induction of apoptosis. CPX also eliminates HPV-positive cancer cells under hypoxic conditions through induction of apoptosis. Taken together, these results show that iron deprivation exerts profound antiviral and antiproliferative effects in HPV-positive cancer cells and suggest that iron chelators, such as CPX, possess therapeutic potential as HPV-inhibitory, prosenescent and proapoptotic agents in both normoxic and hypoxic environments.
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Affiliation(s)
- Julia A Braun
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Anja L Herrmann
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Johanna I Blase
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Kristin Frensemeier
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Julia Bulkescher
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin Scheffner
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Bruno Galy
- Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), Heidelberg, Germany
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18
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PI3K/AKT/mTOR Signaling Regulates the Virus/Host Cell Crosstalk in HPV-Positive Cervical Cancer Cells. Int J Mol Sci 2019; 20:ijms20092188. [PMID: 31058807 PMCID: PMC6539191 DOI: 10.3390/ijms20092188] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 04/26/2019] [Accepted: 04/30/2019] [Indexed: 12/15/2022] Open
Abstract
Human papillomavirus (HPV)-induced cancers will remain a significant clinical challenge for decades. Thus, the development of novel treatment strategies is urgently required, which should benefit from improving our understanding of the mechanisms of HPV-induced cell transformation. This should also include analyses of hypoxic tumor cells, which represent a major problem for cancer therapy. Recent evidence indicates that the PI3K/AKT/mTOR network plays a key role for the virus/host cell crosstalk in both normoxic and hypoxic HPV-positive cancer cells. In normoxic cells, the efficacy of the senescence induction upon experimental E6/E7 repression depends on active mTORC1 signaling. Under hypoxia, however, HPV-positive cancer cells can evade senescence due to hypoxic impairment of mTORC1 signaling, albeit the cells strongly downregulate E6/E7. Hypoxic repression of E6/E7 is mediated by the AKT kinase, which is activated under hypoxia by its canonical upstream regulators mTORC2 and PI3K. This review highlights our current knowledge about the oxygen-dependent crosstalk of the PI3K/AKT/mTOR signaling circuit with the HPV oncogenes and the phenotypic state of the host cell. Moreover, since the PI3K/AKT/mTOR pathway is considered to be a promising target for anticancer therapy, we discuss clinical implications for the treatment of HPV-positive cervical and head and neck squamous cell carcinomas.
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19
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Preciado C, Vallejo Janeta P. Situation of Human Papilloma Virus: Generalities and current treatments. BIONATURA 2019. [DOI: 10.21931/rb/cs/2019.02.01.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Human papillomavirus represents the commonest STD, and it is the principal causative agent of different genital lesions, including genital warts and cervical cancer. Two high-risk HPV genotypes are responsible for the 70% of cervical cancer, and the prevalence of these types reaches alarming levels in many developing countries (e.g., 43.58% in Ecuador). However, the information about HPV in developing countries is limited, becoming an obstacle for breakthrough treatments or prevention strategies. Current strategies include the development of new vaccines, combined chemo- and radiotherapy, and the use of CRISPR/Cas9. Moreover, HPV can be used to treat other non-related cancers, such as ovarian cancer. The present review aims to describe the different prevention strategies and treatments for HPV available worldwide, cover the usage of HPV for the treatment of other diseases, as well as comment on their possible application in Ecuador.
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Affiliation(s)
- Cristhian Preciado
- School of Biological Sciences and Engineering, YachayTech, Urcuquí. Ecuador
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20
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Repression of Human Papillomavirus Oncogene Expression under Hypoxia Is Mediated by PI3K/mTORC2/AKT Signaling. mBio 2019; 10:mBio.02323-18. [PMID: 30755508 PMCID: PMC6372795 DOI: 10.1128/mbio.02323-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Oncogenic HPV types are major human carcinogens. Under hypoxia, HPV-positive cancer cells can repress the viral E6/E7 oncogenes and induce a reversible growth arrest. This response could contribute to therapy resistance, immune evasion, and tumor recurrence upon reoxygenation. Here, we uncover evidence that HPV oncogene repression is mediated by hypoxia-induced activation of canonical PI3K/mTORC2/AKT signaling. AKT-dependent downregulation of E6/E7 is only observed under hypoxia and occurs, at least in part, at the transcriptional level. Quantitative proteome analyses identify additional factors as candidates to be involved in AKT-dependent E6/E7 repression and/or hypoxic PI3K/mTORC2/AKT activation. These results connect PI3K/mTORC2/AKT signaling with HPV oncogene regulation, providing new mechanistic insights into the cross talk between oncogenic HPVs and their host cells. Hypoxia is linked to therapeutic resistance and poor clinical prognosis for many tumor entities, including human papillomavirus (HPV)-positive cancers. Notably, HPV-positive cancer cells can induce a dormant state under hypoxia, characterized by a reversible growth arrest and strong repression of viral E6/E7 oncogene expression, which could contribute to therapy resistance, immune evasion and tumor recurrence. The present work aimed to gain mechanistic insights into the pathway(s) underlying HPV oncogene repression under hypoxia. We show that E6/E7 downregulation is mediated by hypoxia-induced stimulation of AKT signaling. Ablating AKT function in hypoxic HPV-positive cancer cells by using chemical inhibitors efficiently counteracts E6/E7 repression. Isoform-specific activation or downregulation of AKT1 and AKT2 reveals that both AKT isoforms contribute to hypoxic E6/E7 repression and act in a functionally redundant manner. Hypoxic AKT activation and consecutive E6/E7 repression is dependent on the activities of the canonical upstream AKT regulators phosphoinositide 3-kinase (PI3K) and mechanistic target of rapamycin (mTOR) complex 2 (mTORC2). Hypoxic downregulation of E6/E7 occurs, at least in part, at the transcriptional level. Modulation of E6/E7 expression by the PI3K/mTORC2/AKT cascade is hypoxia specific and not observed in normoxic HPV-positive cancer cells. Quantitative proteome analyses identify additional factors as candidates to be involved in hypoxia-induced activation of the PI3K/mTORC2/AKT signaling cascade and in the AKT-dependent repression of the E6/E7 oncogenes under hypoxia. Collectively, these data uncover a functional key role of the PI3K/mTORC2/AKT signaling cascade for viral oncogene repression in hypoxic HPV-positive cancer cells and provide new insights into the poorly understood cross talk between oncogenic HPVs and their host cells under hypoxia.
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21
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Wei W, Ji S. Cellular senescence: Molecular mechanisms and pathogenicity. J Cell Physiol 2018; 233:9121-9135. [PMID: 30078211 DOI: 10.1002/jcp.26956] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022]
Abstract
Cellular senescence is the arrest of normal cell division. Oncogenic genes and oxidative stress, which cause genomic DNA damage and generation of reactive oxygen species, lead to cellular senescence. The senescence-associated secretory phenotype is a distinct feature of senescence. Senescence is normally involved in the embryonic development. Senescent cells can communicate with immune cells to invoke an immune response. Senescence emerges during the aging process in several tissues and organs. In fact, increasing evidence shows that cellular senescence is implicated in aging-related diseases, such as nonalcoholic fatty liver disease, obesity and diabetes, pulmonary hypertension, and tumorigenesis. Cellular senescence can also be induced by microbial infection. During cellular senescence, several signaling pathways, including those of p53, nuclear factor-κB (NF-κB), mammalian target of rapamycin, and transforming growth factor-beta, play important roles. Accumulation of senescent cells can trigger chronic inflammation, which may contribute to the pathological changes in the elderly. Given the variety of deleterious effects caused by cellular senescence in humans, strategies have been proposed to control senescence. In this review, we will focus on recent studies to provide a brief introduction to cellular senescence, including associated signaling pathways and pathology.
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Affiliation(s)
- Wenqiang Wei
- Laboratory of Cell Signal Transduction, Basic Medical School, Henan University, Kaifeng, Henan, China.,Department of Microbiology, Basic Medical School, Henan University, Kaifeng, Henan, China
| | - Shaoping Ji
- Laboratory of Cell Signal Transduction, Basic Medical School, Henan University, Kaifeng, Henan, China
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22
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Abstract
Genetically engineered mice (GEMs) have provided valuable insights into the carcinogenic properties of various human tumor viruses, which, in aggregate, are etiologically associated with over 15% of all human cancers. This review provides an overview of seminal discoveries made through the use of GEM models for human DNA tumor viruses. Emphasis is placed on the discoveries made in the study of human papillomaviruses, Merkel cell carcinoma-associated polyomavirus, Epstein-Barr virus, and Kaposi's sarcoma-associated herpesvirus, because GEMs have contributed extensively to our understanding of how these DNA tumor viruses directly contribute to human cancers.
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Affiliation(s)
- Paul F Lambert
- McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705;
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23
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Hoppe-Seyler K, Bossler F, Braun JA, Herrmann AL, Hoppe-Seyler F. The HPV E6/E7 Oncogenes: Key Factors for Viral Carcinogenesis and Therapeutic Targets. Trends Microbiol 2017; 26:158-168. [PMID: 28823569 DOI: 10.1016/j.tim.2017.07.007] [Citation(s) in RCA: 229] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/12/2017] [Accepted: 07/28/2017] [Indexed: 10/19/2022]
Abstract
Human papillomavirus (HPV)-induced cancers are expected to remain a major health problem worldwide for decades. The growth of HPV-positive cancer cells depends on the sustained expression of the viral E6 and E7 oncogenes which act in concert with still poorly defined cellular alterations. E6/E7 constitute attractive therapeutic targets since E6/E7 inhibition rapidly induces senescence in HPV-positive cancer cells. This cellular response is linked to the reconstitution of the antiproliferative p53 and pRb pathways, and to prosenescent mTOR signaling. Hypoxic HPV-positive cancer cells could be a major obstacle for treatment strategies targeting E6/E7 since they downregulate E6/E7 but evade senescence through hypoxia-induced mTOR impairment. Prospective E6/E7 inhibitors may therefore benefit from a combination with treatment strategies directed against hypoxic tumor cells.
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Affiliation(s)
- Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Felicitas Bossler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Julia A Braun
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Anja L Herrmann
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
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24
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Telomerase Induction in HPV Infection and Oncogenesis. Viruses 2017; 9:v9070180. [PMID: 28698524 PMCID: PMC5537672 DOI: 10.3390/v9070180] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/05/2017] [Accepted: 07/07/2017] [Indexed: 12/11/2022] Open
Abstract
Telomerase extends the repetitive DNA at the ends of linear chromosomes, and it is normally active in stem cells. When expressed in somatic diploid cells, it can lead to cellular immortalization. Human papillomaviruses (HPVs) are associated with and high-risk for cancer activate telomerase through the catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT). The expression of hTERT is affected by both high-risk HPVs, E6 and E7. Seminal studies over the last two decades have identified the transcriptional, epigenetic, and post-transcriptional roles high-risk E6 and E7 have in telomerase induction. This review will summarize these findings during infection and highlight the importance of telomerase activation as an oncogenic pathway in HPV-associated cancer development and progression.
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Hoppe-Seyler K, Mändl J, Adrian S, Kuhn BJ, Hoppe-Seyler F. Virus/Host Cell Crosstalk in Hypoxic HPV-Positive Cancer Cells. Viruses 2017; 9:v9070174. [PMID: 28678198 PMCID: PMC5537666 DOI: 10.3390/v9070174] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 06/22/2017] [Accepted: 06/29/2017] [Indexed: 12/16/2022] Open
Abstract
Oncogenic types of human papillomaviruses (HPVs) are major human carcinogens. The expression of the viral E6/E7 oncogenes plays a key role for HPV-linked oncogenesis. It recently has been found that low oxygen concentrations (“hypoxia”), as present in sub-regions of HPV-positive cancers, strongly affect the interplay between the HPV oncogenes and their transformed host cell. As a result, a state of dormancy is induced in hypoxic HPV-positive cancer cells, which is characterized by a shutdown of viral oncogene expression and a proliferative arrest that can be reversed by reoxygenation. In this review, these findings are put into the context of the current concepts of both HPV-linked carcinogenesis and of the effects of hypoxia on tumor biology. Moreover, we discuss the consequences for the phenotype of HPV-positive cancer cells as well as for their clinical behavior and response towards established and prospective therapeutic strategies.
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Affiliation(s)
- Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
| | - Julia Mändl
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
- Viral Transformation Mechanisms (F030), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
| | - Svenja Adrian
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
| | - Bianca J Kuhn
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
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Abstract
INTRODUCTION MicroRNAs (miRs) are short (~20 nucleotides) non-coding ribonuecleic acids (ncRNAs) known to be involved in cellular processes such as proliferation, differentiation, immune response, pathogenicity and tumourigenesis, among many others. The regulatory mechanisms exerted by miRs have been implicated in many cancers, including Human Papillomavirus (HPV)-associated cancers. Areas covered: In this review, the authors discuss the involvement of miRs (-143, -375, -21, -200, -296 etc.) that have been shown to be dysregulated in HPV-associated cancers. This review also encompasses both intracellular and exosomal miRs, and their potential as diagnostic biomarkers in saliva and blood. The authors have also attempted to dissect the functional impact of miRs on cellular processes such as changes in cellular polarity, loss of apoptosis and tumour suppression, and unchecked and uncontrolled cell cycle regulation, all of which ultimately lead to aberrant cellular proliferation. Expert commentary: Identification of dysregulated miRs in HPV-associated cancers opens up new opportunities to develop diagnostic, therapeutic and prognostic biomarkers. Studies on global expression patterns of miRs dysregulated in HPV-associated cancers can be instrumental in developing broader therapeutic strategies. Therapies like anti-miR, miR-replacement and those based on alternative natural products targeting miRs, need to be improved and better synchronized to be cost-effective and have better treatment outcomes.
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HPV16-E2 protein modifies self-renewal and differentiation rate in progenitor cells of human immortalized keratinocytes. Virol J 2017; 14:65. [PMID: 28372578 PMCID: PMC5376701 DOI: 10.1186/s12985-017-0736-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/23/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Cervical cancer is the fourth cause of death worldwide by cancer in women and is a disease associated to persistent infection with human papillomavirus (HPV), particularly from two high-risk types HPV16 and 18. The virus initiates its replicative cycle infecting cells located in the basal layer of the epithelium, where a small population of epithelial stem cells is located performing important functions of renewal and maintenance of the tissue. Viral E2 gene is one of the first expressed after infection and plays relevant roles in the replicative cycle of the virus, modifying fundamental processes in the infected cells. Thus, the aim of the present study was to demonstrate the presence of hierarchic subpopulations in HaCaT cell line and evaluate the effect of HPV16-E2 expression, on their biological processes. METHODS HaCaT-HPV16-E2 cells were generated by transduction of HaCaT cell line with a lentiviral vector. The α6-integrin-CD71 expression profile was established by immunostaining and flow cytometric analysis. After sorting, cell subpopulations were analyzed in biological assays for self-renewal, clonogenicity and expression of stemness factors (RT-qPCR). RESULTS We identified in HaCaT cell line three different subpopulations that correspond to early differentiated cells (α6-integrindim), transitory amplifying cells (α6-integrinbri/CD71bri) and progenitor cells (α6-integrinbri/CD71dim). The last subpopulation showed stem cell characteristics, such as self-renewal ability, clonogenicity and expression of the well-known stem cell factors SOX2, OCT4 and NANOG, suggesting they are stem-like cells. Interestingly, the expression of HPV16-E2 in HaCaT cells changed its α6-integrin-CD71 immunophenotype modifying the relative abundance of the cell subpopulations, reducing significantly the percentage of α6-integrinbri/CD71dim cells. Moreover, the expression of the stem cell markers was also modified, increasing the expression of SOX2 and NANOG, but decreasing notably the expression of OCT4. CONCLUSIONS Our data demonstrated the presence of a small subpopulation with epithelial "progenitor cells" characteristics in the HaCaT cell line, and that HPV16-E2 expression on these cells induces early differentiation.
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Induction of dormancy in hypoxic human papillomavirus-positive cancer cells. Proc Natl Acad Sci U S A 2017; 114:E990-E998. [PMID: 28115701 DOI: 10.1073/pnas.1615758114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Oncogenic human papillomaviruses (HPVs) are closely linked to major human malignancies, including cervical and head and neck cancers. It is widely assumed that HPV-positive cancer cells are under selection pressure to continuously express the viral E6/E7 oncogenes, that their intracellular p53 levels are reconstituted on E6/E7 repression, and that E6/E7 inhibition phenotypically results in cellular senescence. Here we show that hypoxic conditions, as are often found in subregions of cervical and head and neck cancers, enable HPV-positive cancer cells to escape from these regulatory principles: E6/E7 is efficiently repressed, yet, p53 levels do not increase. Moreover, E6/E7 repression under hypoxia does not result in cellular senescence, owing to hypoxia-associated impaired mechanistic target of rapamycin (mTOR) signaling via the inhibitory REDD1/TSC2 axis. Instead, a reversible growth arrest is induced that can be overcome by reoxygenation. Impairment of mTOR signaling also interfered with the senescence response of hypoxic HPV-positive cancer cells toward prosenescent chemotherapy in vitro. Collectively, these findings indicate that hypoxic HPV-positive cancer cells can induce a reversible state of dormancy, with decreased viral antigen synthesis and increased therapeutic resistance, and may serve as reservoirs for tumor recurrence on reoxygenation.
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Carchman EH, Matkowskyj KA, Meske L, Lambert PF. Dysregulation of Autophagy Contributes to Anal Carcinogenesis. PLoS One 2016; 11:e0164273. [PMID: 27706233 PMCID: PMC5051741 DOI: 10.1371/journal.pone.0164273] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/22/2016] [Indexed: 01/01/2023] Open
Abstract
Introduction Autophagy is an intracellular catabolic process that removes and recycles unnecessary/dysfunctional cellular components, contributing to cellular health and survival. Autophagy is a highly regulated cellular process that responds to several intracellular signals, many of which are deregulated by human papillomavirus (HPV) infection through the expression of HPV-encoded oncoproteins. This adaptive inhibitory response helps prevent viral clearance. A strong correlation remains between HPV infection and the development of squamous cell carcinoma (SCC) of the anus, particularly in HIV positive and other immunosuppressed patients. We hypothesize that autophagy is inhibited by HPV–encoded oncoproteins thereby promoting anal carcinogenesis (Fig 1). Materials and Methods HPV16 transgenic mice (K14E6/E7) and non-transgenic mice (FVB/N), both of which do not spontaneously develop anal tumors, were treated topically with the chemical carcinogen, 7,12-Dimethylbenz[a]anthracene (DMBA), to induce anal cancer. The anuses at different time points of treatment (5, 10, 15 and 20 weeks) were analyzed using immunofluorescence (IF) for two key autophagy marker proteins (LC3β and p62) in addition to histological grading. The anuses from the K14E6/E7 mice were also analyzed for visual evidence of autophagic activity by electron microscopy (EM). To see if there was a correlation to humans, archival anal specimens were assessed histologically for grade of dysplasia and then analyzed for LC3β and p62 protein content. To more directly examine the effect of autophagic inhibition on anal carcinogenesis, nontransgenic mice that do not develop anal cancer with DMBA treatment were treated with a known pharmacologic inhibitor of autophagy, chloroquine, and examined for tumor development and analyzed by IF for autophagic proteins. Results Histologically, we observed the progression of normal anoderm to invasive SCC with DMBA treatment in K14E6/E7 mice but not in nontransgenic, syngeneic FVB/N background control mice. With the development of low-grade dysplasia in the K14E6/E7 mice, there was an increase in both punctate LC3β and p62 expression while EM revealed increased autophagosomes without evidence of autophagolysosomes. These observations are consistent with autophagy being inhibited at a later stage in the autophagic process. In contrast, in high-grade dysplasia and SCC in the DMBA-treated K14E6/E7 mice, there were decreased levels of p62 with a continued increase in punctate LC3β expression by IF, while autophagolysosomes were seen on EM, consistent with the process of autophagy proceeded to completion. Similar findings, including histological grade dependent changes in LC3β and p62 expression, were noted with human samples upon analysis of IF. Finally, with pharmacologic inhibition of autophagy in DMBA-treated, nontrangenic FVB/N mice, there was a significant increase in anal cancer development similar to that observed in DMBA- treated K14E6/E7 mice. Conclusion Autophagic dysregulation is noted early on in HPV-associated anal carcinogenesis (low-grade dysplasia), with normalization of the autophagic process arising in late stages of HPV-associated anal carcinogenesis (high-grade dysplasia and invasive carcinoma).
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/adverse effects
- Animals
- Anus Neoplasms/chemically induced
- Anus Neoplasms/metabolism
- Anus Neoplasms/pathology
- Anus Neoplasms/virology
- Autophagy
- Carcinoma, Squamous Cell/chemically induced
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Carcinoma, Squamous Cell/virology
- Gene Expression Regulation, Neoplastic
- Human papillomavirus 16/genetics
- Human papillomavirus 16/metabolism
- Human papillomavirus 16/pathogenicity
- Humans
- Mice
- Mice, Transgenic
- Microtubule-Associated Proteins/metabolism
- Oncogene Proteins, Viral/genetics
- Oncogene Proteins, Viral/metabolism
- Papillomavirus E7 Proteins/genetics
- Papillomavirus E7 Proteins/metabolism
- Papillomavirus Infections/metabolism
- Papillomavirus Infections/pathology
- RNA-Binding Proteins/metabolism
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Affiliation(s)
- Evie H. Carchman
- Department of Surgery, University of Wisconsin, Madison, WI, United States of America
- * E-mail:
| | - Kristina A. Matkowskyj
- Department of Pathology and Laboratory, University of Wisconsin, Madison, WI, United States of America
| | - Louise Meske
- Department of Surgery, University of Wisconsin, Madison, WI, United States of America
| | - Paul F. Lambert
- Department of Oncology, University of Wisconsin, Madison, WI, United States of America
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Tandemly Integrated HPV16 Can Form a Brd4-Dependent Super-Enhancer-Like Element That Drives Transcription of Viral Oncogenes. mBio 2016; 7:mBio.01446-16. [PMID: 27624132 PMCID: PMC5021809 DOI: 10.1128/mbio.01446-16] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In cancer cells associated with human papillomavirus (HPV) infections, the viral genome is very often found integrated into the cellular genome. The viral oncogenes E6 and E7 are transcribed from the viral promoter, and integration events that alter transcriptional regulation of this promoter contribute to carcinogenic progression. In this study, we detected highly enriched binding of the super-enhancer markers Brd4, MED1, and H3K27ac, visible as a prominent nuclear focus by immunofluorescence, at the tandemly integrated copies of HPV16 in cells of the cervical neoplasia cell line W12 subclone 20861. Tumor cells are often addicted to super-enhancer-driven oncogenes and are particularly sensitive to disruption of transcription factor binding to the enhancers. Treatment of 20861 cells with bromodomain inhibitors displaced Brd4 from the HPV integration site, greatly decreased E6/E7 transcription, and inhibited cellular proliferation. Thus, Brd4 activates viral transcription at this integration site, and strong selection for E6/E7 expression can drive the formation of a super-enhancer-like element to promote oncogenesis. Oncogenic human papillomaviruses play an essential role in the development of cervical cancer, and growth of these cancer cells requires continued expression of the viral E6 and E7 oncogenes. Integration of the virus into the host genome often results in deregulation of E6 and E7 expression, which provides a selective growth advantage and increases genetic instability of infected cells. We show here that tandemly integrated copies of the viral genome can form a super-enhancer-like element that drives E6/E7 transcription. Targeted disruption of factors binding to this element decreases viral transcription and causes cell death. Thus, cancer cells that harbor integrated HPV could be targeted by therapeutics that disrupt super-enhancer function.
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Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice. mBio 2016; 7:mBio.00628-16. [PMID: 27190216 PMCID: PMC4895109 DOI: 10.1128/mbio.00628-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. IMPORTANCE : Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an accumulation of DNA damage. We hypothesize, therefore, that DNA damage induced by HPV leads to an accumulation of mutations in patients with FA deficiency and that such mutations allow HPV-driven cancers to become independent of the viral oncogenes. Consistent with this hypothesis, we found that cervical cancers arising in HPV16 transgenic mice with FA deficiency frequently escape from dependency on the HPV16 oncogene that drove its development. Our report provides further support for vaccination of FA patients against HPVs and argues for the need to define mutational profiles of SCCs arising in FA patients in order to inform precision medicine-based approaches to treating these patients.
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Natarajan T, Anandhi M, Aiswarya D, Ramkumar R, Kumar S, Perumal P. Idaein chloride induced p53 dependent apoptosis in cervical cancer cells through inhibition of viral oncoproteins. Biochimie 2015; 121:13-20. [PMID: 26586108 DOI: 10.1016/j.biochi.2015.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 11/09/2015] [Indexed: 01/30/2023]
Abstract
Host dependent expression of early HPV oncoproteins, E6 and E7 play central role in the formation of cervical carcinoma. Presently, we have shown that the cyanidin analog, idaein chloride treatment induced dose dependent apoptosis (IC50 = 2.579 μg/ml) in HPV positive - HeLa cells. Flow cytometric analysis showed arrest of cell cycle at G1 phase with an increased sub G1 cell population on 12th h of exposure. The recorded reduced expression levels of cell cycle proteins - cyclin D, cdk 4 and cdk 6 confirmed the occurrence of cell cycle arrest at G1 phase. In addition, the idaein chloride significantly inhibited the expression of E6 and E7 proteins, resulting in p53 re-expression and hence triggering of p53 dependent apoptosis. This has been further supported by the recorded variations in the expression patterns of p21/WAF, pRb and E2F regulatory proteins. In case of mitochondrial apoptotic markers, the expression of Bax was restored and Bcl-2 level got decreased at 12th h. Cleaved caspases 3 & 9 and PARP were also observed after 3 h of treatment. Interestingly, the epigenetic regulatory enzymes (DNMTs) were inhibited by idaein chloride. Thus, idaein chloride could be a potent source for developing a drug against cervical carcinoma.
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Affiliation(s)
- Thillainathan Natarajan
- Department of Biotechnology, School of Biosciences, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - Manickam Anandhi
- Department of Biotechnology, School of Biosciences, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - Dilipkumar Aiswarya
- Department of Biotechnology, School of Biosciences, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - Rajendiran Ramkumar
- Department of Biotechnology, Padmavani Arts and Science College for Women, Salem, 636 011, Tamil Nadu, India
| | - Subramanian Kumar
- Department of Internal Medicine (Oncology Division), University of the Witwatersrand Medical School, Private bag 3, WITS 2050, Johannesburg, South Africa
| | - Pachiappan Perumal
- Department of Biotechnology, School of Biosciences, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India.
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Zhang C, Deng Z, Pan X, Uehara T, Suzuki M, Xie M. Effects of Methylation Status of CpG Sites within the HPV16 Long Control Region on HPV16-Positive Head and Neck Cancer Cells. PLoS One 2015; 10:e0141245. [PMID: 26509736 PMCID: PMC4625038 DOI: 10.1371/journal.pone.0141245] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/05/2015] [Indexed: 12/31/2022] Open
Abstract
Objective To map comprehensively the methylation status of the CpG sites within the HPV16 long control region (LCR) in HPV-positive cancer cells, and to explore further the effects of methylation status of HPV16 LCR on cell bioactivity and E6 and E7 expression. In addition, to analyze the methylation status of the LCR in HPV-positive oropharyngeal squamous cell carcinoma (OPSCC) patients. Methods and Materials Methylation patterns of HPV16 LCR in UM-SCC47, CaSki, and SiHa cells and HPV16-positiive OPSCC specimens were detected by bisulfite-sequencing PCR and TA cloning. For cells treated with 5-aza-2′-deoxycytidine and E6 and E7 knockdown, MTS and trypan blue staining, annexin-V and 7-AAD staining, and prodidium iodide were used to evaluate cell growth and cell proliferation, cell apoptosis, and cell cycle arrest, respectively. E6 and E7 mRNA and protein expression were analyzed by quantitative real-time PCR and immunocytochemistry, respectively. Results Hypermethylation status of the LCR in UM-SCC47 (79.8%) and CaSki cells (90.0%) and unmethylation status of the LCR in SiHa cells (0%) were observed. Upon demethylation, the cells with different methylation levels responded differently during growth, apoptosis, and cell cycle arrest, as well as in terms of their E6 and E7 expression. In HPV16-positive OPSCC patients, the methylation rates were 9.5% in the entire LCR region, 13.9% in the 5′-LCR, 6.0% in the E6 enhancer, and 9.5% in the p97 promoter, and hypermethylation of p97 promoter was found in a subset of cases (20.0%, 2/10). Conclusions Our study revealed two different methylation levels of the LCR in HPV16-positive cancer cells and OPSCC patients, which may represent different carcinogenesis mechanisms of HPV-positive cancers cells. Demethylating the meCpGs in HPV16 LCR might be a potential target for a subgroup of HPV16-positive patients with head and neck squamous cell carcinoma.
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Affiliation(s)
- Chunlin Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- Department of Otorhinolaryngology, Head and Neck Surgery, University of the Ryukyus, Okinawa, Japan
- Department of Otorhinolaryngology, Head and Neck Surgery, Affiliated hospital of Zunyi Medical University, Zunyi, China
| | - Zeyi Deng
- Department of Otorhinolaryngology, Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- Department of Otorhinolaryngology, Head and Neck Surgery, University of the Ryukyus, Okinawa, Japan
| | - Xiaoli Pan
- Department of Otorhinolaryngology, Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- Department of Otorhinolaryngology, Head and Neck Surgery, University of the Ryukyus, Okinawa, Japan
- Department of Otorhinolaryngology, Head and Neck Surgery, The First People’s Hospital of Guangzhou, Guangzhou, China
| | - Takayuki Uehara
- Department of Otorhinolaryngology, Head and Neck Surgery, University of the Ryukyus, Okinawa, Japan
| | - Mikio Suzuki
- Department of Otorhinolaryngology, Head and Neck Surgery, University of the Ryukyus, Okinawa, Japan
- * E-mail: (MX); (MS)
| | - Minqiang Xie
- Department of Otorhinolaryngology, Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- * E-mail: (MX); (MS)
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Gonzalez LC, Ghadaouia S, Martinez A, Rodier F. Premature aging/senescence in cancer cells facing therapy: good or bad? Biogerontology 2015; 17:71-87. [DOI: 10.1007/s10522-015-9593-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/22/2015] [Indexed: 01/07/2023]
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Reuschenbach M, Huebbers CU, Prigge ES, Bermejo JL, Kalteis MS, Preuss SF, Seuthe IMC, Kolligs J, Speel EJM, Olthof N, Kremer B, Wagner S, Klussmann JP, Vinokurova S, von Knebel Doeberitz M. Methylation status of HPV16 E2-binding sites classifies subtypes of HPV-associated oropharyngeal cancers. Cancer 2015; 121:1966-76. [PMID: 25731880 DOI: 10.1002/cncr.29315] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/19/2014] [Accepted: 01/13/2015] [Indexed: 01/25/2023]
Abstract
BACKGROUND The human papillomavirus (HPV) E2 protein is a transcriptional repressor of the oncogenes E6/E7 and loss of E2 function is considered a key step in carcinogenesis. Integration of HPV into the host genome may disrupt the E2 gene. Furthermore, methylation of CpG dinucleotides in E2-binding sites (E2BSs) in the HPV upstream regulatory region may interfere with transcriptional repression of E6 and E7 by E2. The authors hypothesized that the CpG methylation status of E2BS identifies subtypes of HPV type 16 (HPV16)-associated oropharyngeal squamous cell cancers (OPSCC) in association with E2 gene integrity and viral integration. METHODS Methylation of 10 CpG dinucleotides within the upstream regulatory region, encompassing E2BSs 1, 2, 3, and 4, was quantitatively analyzed by bisulfite pyrosequencing in 57 HPV16-associated OPSCC cases. E2 status was analyzed by gene amplification and quantitative real-time reverse transcriptase-polymerase chain reaction. Viral integration was determined by integration-specific polymerase chain reaction methods. RESULTS Three subgroups with differential methylation at E2BS3 and E2BS 4 were identified: 1) complete methylation (>80%) associated with the presence of integrated HPV genomes with an intact E2 gene; 2) intermediate methylation levels (20%-80%) with predominantly episomal HPV genomes with intact E2; and 3) no methylation (<20%) with a disrupted E2 gene. Patients with high methylation levels tended to have a worse 5-year overall survival compared with patients with intermediate methylation (hazard ratio, 3.23; 95% confidence interval, 1.13-9.24 [P = .06]). CONCLUSIONS Methylation of E2BS3 and E2BS4 in OPSCC is associated with E2 integrity and viral physical status. It might explain deregulated viral oncogene expression in the presence of E2. The prognostic significance of E2BS methylation for patients with HPV-associated OPSCC needs to be analyzed further.
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Affiliation(s)
- Miriam Reuschenbach
- Department of Applied Tumor Biology, Institute of Pathology, University of Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
| | - Christian U Huebbers
- Jean-Uhrmacher Institute for Oto-Rhino-Laryngological Research, University of Cologne, Cologne, Germany
| | - Elena-Sophie Prigge
- Department of Applied Tumor Biology, Institute of Pathology, University of Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
| | - Justo Lorenzo Bermejo
- Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
| | - Martin S Kalteis
- Department of Applied Tumor Biology, Institute of Pathology, University of Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
| | - Simon F Preuss
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital of Cologne, Cologne, Germany
| | - Inga M C Seuthe
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital of Cologne, Cologne, Germany
| | - Jutta Kolligs
- Jean-Uhrmacher Institute for Oto-Rhino-Laryngological Research, University of Cologne, Cologne, Germany
| | - Ernst-Jan M Speel
- Department of Pathology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Nadine Olthof
- Department of Otorhinolaryngology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Bernd Kremer
- Department of Otorhinolaryngology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Steffen Wagner
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Giessen, Giessen, Germany
| | - Jens P Klussmann
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Giessen, Giessen, Germany
| | - Svetlana Vinokurova
- Department of Applied Tumor Biology, Institute of Pathology, University of Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
| | - Magnus von Knebel Doeberitz
- Department of Applied Tumor Biology, Institute of Pathology, University of Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
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Honegger A, Schilling D, Bastian S, Sponagel J, Kuryshev V, Sültmann H, Scheffner M, Hoppe-Seyler K, Hoppe-Seyler F. Dependence of intracellular and exosomal microRNAs on viral E6/E7 oncogene expression in HPV-positive tumor cells. PLoS Pathog 2015; 11:e1004712. [PMID: 25760330 PMCID: PMC4356518 DOI: 10.1371/journal.ppat.1004712] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 01/28/2015] [Indexed: 02/07/2023] Open
Abstract
Specific types of human papillomaviruses (HPVs) cause cervical cancer. Cervical cancers exhibit aberrant cellular microRNA (miRNA) expression patterns. By genome-wide analyses, we investigate whether the intracellular and exosomal miRNA compositions of HPV-positive cancer cells are dependent on endogenous E6/E7 oncogene expression. Deep sequencing studies combined with qRT-PCR analyses show that E6/E7 silencing significantly affects ten of the 52 most abundant intracellular miRNAs in HPV18-positive HeLa cells, downregulating miR-17-5p, miR-186-5p, miR-378a-3p, miR-378f, miR-629-5p and miR-7-5p, and upregulating miR-143-3p, miR-23a-3p, miR-23b-3p and miR-27b-3p. The effects of E6/E7 silencing on miRNA levels are mainly not dependent on p53 and similarly observed in HPV16-positive SiHa cells. The E6/E7-regulated miRNAs are enriched for species involved in the control of cell proliferation, senescence and apoptosis, suggesting that they contribute to the growth of HPV-positive cancer cells. Consistently, we show that sustained E6/E7 expression is required to maintain the intracellular levels of members of the miR-17~92 cluster, which reduce expression of the anti-proliferative p21 gene in HPV-positive cancer cells. In exosomes secreted by HeLa cells, a distinct seven-miRNA-signature was identified among the most abundant miRNAs, with significant downregulation of let-7d-5p, miR-20a-5p, miR-378a-3p, miR-423-3p, miR-7-5p, miR-92a-3p and upregulation of miR-21-5p, upon E6/E7 silencing. Several of the E6/E7-dependent exosomal miRNAs have also been linked to the control of cell proliferation and apoptosis. This study represents the first global analysis of intracellular and exosomal miRNAs and shows that viral oncogene expression affects the abundance of multiple miRNAs likely contributing to the E6/E7-dependent growth of HPV-positive cancer cells.
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Affiliation(s)
- Anja Honegger
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniela Schilling
- Cancer Genome Research (B063), German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Sandra Bastian
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jasmin Sponagel
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Vladimir Kuryshev
- Cancer Genome Research (B063), German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Holger Sültmann
- Cancer Genome Research (B063), German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Martin Scheffner
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center (DKFZ), Heidelberg, Germany
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Re-expression of HPV16 E2 in SiHa (human cervical cancer) cells potentiates NF-κB activation induced by TNF-α concurrently increasing senescence and survival. Biosci Rep 2015; 35:BSR20140160. [PMID: 25572145 PMCID: PMC4340273 DOI: 10.1042/bsr20140160] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Re-expression of E2 in human papillomavirus (HPV) transformed tumour cells can induce apoptosis; however, some evidences also attribute an important role to E2 in sustaining tumorigenesis. In the present paper, we studied the effects of tumour necrosis factor (TNF)-α-mediated NF-κB (nuclear factor kappa-light-chain-enhancer of activated B-cells) activation on E2-induced senescence in HPV16-integrated SiHa cells. The results show that E2 inhibits endogenous E6 gene expression and sensitizes SiHa cells to TNF-α-induced NF-κB activation. Under this condition there was an increase in the expression of senescent proteins p53, p21, p27 and p16 and senescence-associated (SA)-β-galactosidase activity indicating that TNF-α augments E2-mediated senescence. Re-expression of E2 expression with TNF-α treatment resulted in an increase in the expression of anti-apoptotic Bcl2 (B-cell lymphoma 2) protein and other pro-survival genes like cyclin D1 (cyc D1), survivin and hTERT (human telomerase reverse transcriptase). Concomitantly, E2 + TNF-α combination increased the survival of SiHa cells by positive changes in viability, proliferation and colony formation. E2-induced apoptotic tendency shifted towards senescence in presence of TNF-α by arresting the cells at both G0/G1 and G2/M phases, thus enhancing cell survival. Another observation in the present study is the significant up-regulation of key senescence messaging factors regulated by NF-κB namely interleukin (IL)-6, IL-8, high-mobility group protein A (HMGA)1 and B (HMGB)1 in E2-transfected cells treated with TNF-α. Our data provide a mechanistic basis and a new insight for the role of TNF-α and E2 in linking cellular senescence, tumorigenesis and HPV re-infection. Human papillomavirus (HPV)16 E2 potentiates NF-κB (nuclear factor kappa-light-chain-enhancer of activated B-cells) activation induced by tumour necrosis factor (TNF)-α in SiHa (human cervical cancer) cells and significantly influences cell viability, apoptosis and expression of pro-survival genes regulated by NF-κB.
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Lillsunde Larsson G, Helenius G, Sorbe B, Karlsson MG. Viral load, integration and methylation of E2BS3 and 4 in human papilloma virus (HPV) 16-positive vaginal and vulvar carcinomas. PLoS One 2014; 9:e112839. [PMID: 25393237 PMCID: PMC4231157 DOI: 10.1371/journal.pone.0112839] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/17/2014] [Indexed: 12/19/2022] Open
Abstract
Objective To investigate if viral load, integration and methylation of E2BS3 and 4 represent different ways of tumor transformation in vaginal and vulvar carcinoma and to elucidate its clinical impact. Methods Fifty-seven samples, positive for HPV16, were selected for the study. Detection of viral load was made with realtime-PCR using copy numbers of E6 and integration was calculated from comparing E2 to E6-copies. Methylation of E2BS3 and 4 was analysed using bisulphite treatment of tumor DNA, followed by PCR and pyrosequencing. Results Vaginal tumors were found to have a higher viral load (p = 0.024) compared to vulvar tumors but a high copy number (> median value, 15 000) as well as high methylation (>50%) was significantly (p = 0.010 and p = 0.045) associated with a worse cancer-specific survival rate in vulvar carcinoma, but not in vaginal carcinoma. Four groups could be defined for the complete series using a Cluster Two step analysis; (1) tumors holding episomal viral DNA, viral load below 150 000 copies not highly methylated (n = 25, 46.3%); (2) tumors harboring episomal viral DNA and being highly methylated (>50%; n = 6, 11.1%); (3) tumors with viral DNA fully integrated (n = 11, 20.4%), and (4) tumors harboring episomal viral DNA and being medium- or unmethylated (<50%) and having a high viral load (> total mean value 150 000; n = 12, 22.2%). The completely integrated tumors were found to be distinct group, whilst some overlap between the groups with high methylation and high viral load was observed. Conclusion HPV16- related integration, methylation in E2BS3 and 4 and viral load may represent different viral characteristics driving vaginal and vulvar carcinogenesis. HPV16- related parameters were found to be of clinical importance in the vulvar series only.
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Affiliation(s)
- Gabriella Lillsunde Larsson
- Department of Laboratory Medicine, Örebro University Hospital, Örebro, Sweden
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden
- * E-mail:
| | - Gisela Helenius
- Department of Laboratory Medicine, Örebro University Hospital, Örebro, Sweden
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden
| | - Bengt Sorbe
- Department of Oncology, Örebro University Hospital, Örebro, Sweden
| | - Mats G. Karlsson
- Department of Laboratory Medicine, Örebro University Hospital, Örebro, Sweden
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden
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Zanier K, Stutz C, Kintscher S, Reinz E, Sehr P, Bulkescher J, Hoppe-Seyler K, Travé G, Hoppe-Seyler F. The E6AP binding pocket of the HPV16 E6 oncoprotein provides a docking site for a small inhibitory peptide unrelated to E6AP, indicating druggability of E6. PLoS One 2014; 9:e112514. [PMID: 25383876 PMCID: PMC4226571 DOI: 10.1371/journal.pone.0112514] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/03/2014] [Indexed: 12/11/2022] Open
Abstract
The HPV E6 oncoprotein maintains the malignant phenotype of HPV-positive cancer cells and represents an attractive therapeutic target. E6 forms a complex with the cellular E6AP ubiquitin ligase, ultimately leading to p53 degradation. The recently elucidated x-ray structure of a HPV16 E6/E6AP complex showed that HPV16 E6 forms a distinct binding pocket for E6AP. This discovery raises the question whether the E6AP binding pocket is druggable, i. e. whether it provides a docking site for functional E6 inhibitors. To address these issues, we performed a detailed analysis of the HPV16 E6 interactions with two small peptides: (i) E6APpep, corresponding to the E6 binding domain of E6AP, and (ii) pep11**, a peptide that binds to HPV16 E6 and, in contrast to E6APpep, induces apoptosis, specifically in HPV16-positive cancer cells. Surface plasmon resonance, NMR chemical shift perturbation, and mammalian two-hybrid analyses coupled to mutagenesis indicate that E6APpep contacts HPV16 E6 amino acid residues within the E6AP pocket, both in vitro and intracellularly. Many of these amino acids were also important for binding to pep11**, suggesting that the binding sites for the two peptides on HPV16 E6 overlap. Yet, few E6 amino acids were differentially involved which may contribute to the higher binding affinity of pep11**. Data from the HPV16 E6/pep11** interaction allowed the rational design of single amino acid exchanges in HPV18 and HPV31 E6 that enabled their binding to pep11**. Taken together, these results suggest that E6 molecular surfaces mediating E6APpep binding can also accommodate pro-apoptotic peptides that belong to different sequence families. As proof of concept, this study provides the first experimental evidence that the E6AP binding pocket is druggable, opening new possibilities for rational, structure-based drug design.
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Affiliation(s)
- Katia Zanier
- Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 67412, Illkirch, France
- * E-mail: (KZ); (FHS)
| | - Christina Stutz
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Susanne Kintscher
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Eileen Reinz
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Peter Sehr
- EMBL-DKFZ Chemical Biology Core Facility, European Molecular Biology Laboratory (EMBL), 69117, Heidelberg, Germany
| | - Julia Bulkescher
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Gilles Travé
- Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 67412, Illkirch, France
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
- * E-mail: (KZ); (FHS)
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Smith JA, Haberstroh FS, White EA, Livingston DM, DeCaprio JA, Howley PM. SMCX and components of the TIP60 complex contribute to E2 regulation of the HPV E6/E7 promoter. Virology 2014; 468-470:311-321. [PMID: 25222147 PMCID: PMC4252969 DOI: 10.1016/j.virol.2014.08.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 06/19/2014] [Accepted: 08/22/2014] [Indexed: 11/28/2022]
Abstract
An important step in the malignant progression of HPV-associated lesions is the dysregulation of expression of the viral E6 and E7 oncogenes. This is often achieved through the loss of expression of E2, which represses the HPV LCR promoter and E6/E7 expression. Our previous studies confirmed a role for Brd4 in mediating the E2 transcriptional repression function, and identified JARID1C/SMCX and EP400 as contributors to E2-mediated repression. Here we show that TIP60, a component of the TIP60/TRRAP histone acetyltransferase complex, also contributes to the E2 repression function, and we extend our studies on SMCX. Di- and tri-methyl marks on histone H3K4 are reduced in the presence of E2 and SMCX, suggesting a mechanism by which SMCX contributes to E2-mediated repression of the HPV LCR. Together, these findings lead us to hypothesize that E2 recruits histone-modifying cellular proteins to the HPV LCR, resulting in transcriptional repression of E6 and E7.
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Affiliation(s)
- Jennifer A Smith
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States
| | - Friederike S Haberstroh
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States
| | - Elizabeth A White
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States
| | - David M Livingston
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States; Department of Medicine, Brigham and Women׳s Hospital, Boston, MA 02115 and Harvard Medical School, Boston, MA 02115, United States
| | - James A DeCaprio
- Department of Medicine, Brigham and Women׳s Hospital, Boston, MA 02115 and Harvard Medical School, Boston, MA 02115, United States; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, United States
| | - Peter M Howley
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States.
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Donalisio M, Massari S, Argenziano M, Manfroni G, Cagno V, Civra A, Sabatini S, Cecchetti V, Loregian A, Cavalli R, Lembo D, Tabarrini O. Ethyl 1,8-Naphthyridone-3-carboxylates Downregulate Human Papillomavirus-16 E6 and E7 Oncogene Expression. J Med Chem 2014; 57:5649-63. [DOI: 10.1021/jm500340h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manuela Donalisio
- Department
of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
| | - Serena Massari
- Department
of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Monica Argenziano
- Department
of Drug Science and Technology, University of Torino, 10125 Torino, Italy
| | - Giuseppe Manfroni
- Department
of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Valeria Cagno
- Department
of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
| | - Andrea Civra
- Department
of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
| | - Stefano Sabatini
- Department
of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Violetta Cecchetti
- Department
of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Arianna Loregian
- Department
of Molecular Medicine, University of Padova, 35121 Padova, Italy
| | - Roberta Cavalli
- Department
of Drug Science and Technology, University of Torino, 10125 Torino, Italy
| | - David Lembo
- Department
of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
| | - Oriana Tabarrini
- Department
of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
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HPV-16 E2 physical status and molecular evolution in vivo in cervical carcinomas. Int J Biol Markers 2014; 29:e78-85. [PMID: 24170557 DOI: 10.5301/jbm.5000051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2013] [Indexed: 11/20/2022]
Abstract
A key event in the development of cervical carcinoma is the deregulated expression of high-risk human papillomavirus (HR-HPV) oncogenes, most commonly due to HPV integration into host DNA. Here we explored whether HPV-16 E2 gene integrity is a biomarker of progressive disease with oncogenes expression. HPV-16 genome disruption was assessed by amplification of the entire E2 gene, while mRNA expression patterns of the E1, E2, E6, and E7 genes were evaluated by reverse transcription PCR (RT-PCR). As expected, E2 disruption was significantly higher among patients with cervical cancers than subjects with benign lesions (p=0.02). The status of the E2 gene correlated with tumorogenesis, and seemed also to correlate with the stage of the carcinomas, since integrated HPV-16 DNA was frequently detected in patients with advanced cancer stages (75% of stage III vs 60% stages I and II). In bivariate analysis, the lesions’ grade was most significantly associated with HPV-16 DNA disruption (p<0.05). In cervical carcinoma the deletion pattern involved more frequently the E2 gene rather than the E1 gene (62.5% vs 45.8%). The prevalence of the E6/E7 HPV-16 transcripts in cervical carcinoma specimens and in benign cervical lesions were detected with frequencies of, respectively, 91.6% and 45.4%. The mRNA levels of the HPV-16 E6/E7 genes were expressed at approximately the same levels in each physical state. We consistently observed that E6/E7 were absent or weakly detectable in the presence of E2. However, in the absence of E2 the levels of E6/E7 markedly increased (p<0.05). This study underscores the significance of investigating alternative mechanisms of E2 expression and oncogenes E6/E7 transcripts in vivo as biomarkers for disease severity in cervical carcinomas.
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Leitz J, Reuschenbach M, Lohrey C, Honegger A, Accardi R, Tommasino M, Llano M, von Knebel Doeberitz M, Hoppe-Seyler K, Hoppe-Seyler F. Oncogenic human papillomaviruses activate the tumor-associated lens epithelial-derived growth factor (LEDGF) gene. PLoS Pathog 2014; 10:e1003957. [PMID: 24604027 PMCID: PMC3946365 DOI: 10.1371/journal.ppat.1003957] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 01/13/2014] [Indexed: 12/20/2022] Open
Abstract
The expression of the human papillomavirus (HPV) E6/E7 oncogenes is crucial for HPV-induced malignant cell transformation. The identification of cellular targets attacked by the HPV oncogenes is critical for our understanding of the molecular mechanisms of HPV-associated carcinogenesis and may open novel therapeutic opportunities. Here, we identify the Lens Epithelial-Derived Growth Factor (LEDGF) gene as a novel cellular target gene for the HPV oncogenes. Elevated LEDGF expression has been recently linked to human carcinogenesis and can protect tumor cells towards different forms of cellular stress. We show that intracellular LEDGF mRNA and protein levels in HPV-positive cancer cells are critically dependent on the maintenance of viral oncogene expression. Ectopic E6/E7 expression stimulates LEDGF transcription in primary keratinocytes, at least in part via activation of the LEDGF promoter. Repression of endogenous LEDGF expression by RNA interference results in an increased sensitivity of HPV-positive cancer cells towards genotoxic agents. Immunohistochemical analyses of cervical tissue specimens reveal a highly significant increase of LEDGF protein levels in HPV-positive lesions compared to histologically normal cervical epithelium. Taken together, these results indicate that the E6/E7-dependent maintenance of intracellular LEDGF expression is critical for protecting HPV-positive cancer cells against various forms of cellular stress, including DNA damage. This could support tumor cell survival and contribute to the therapeutic resistance of cervical cancers towards genotoxic treatment strategies in the clinic. Specific types of human papillomaviruses (HPVs) are closely linked to the development of malignant tumors, such as cervical cancer. Virtually all cervical cancers contain HPV DNA and the tumorigenic growth behavior of cervical cancer cells is dependent on the activity of two viral oncogenes, called E6 and E7. It is important to study the activities by which the HPV oncogenes can support the growth of tumor cells. This should allow new insights into the molecular mechanisms of virus-induced carcinogenesis and could also be useful for developing novel approaches for cancer therapy. We here show that the HPV oncogenes stimulate and maintain expression of the cellular LEDGF gene in HPV-positive cancer cells. Consistently, pre-malignant and malignant lesions of the cervix exhibit significantly increased LEDGF protein levels. LEDGF is crucial for the protection of tumor cells against various forms of cellular stress, including DNA damage. LEDGF stimulation by the viral oncogenes could be a critical survival mechanism by which HPVs support the growth of cervical cancer cells and provide resistance towards chemo- and radiotherapy in the clinic.
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Affiliation(s)
- Jenny Leitz
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Miriam Reuschenbach
- Department of Applied Tumor Biology, Institute of Pathology, University of Heidelberg, Heidelberg, Germany
| | - Claudia Lohrey
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Anja Honegger
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Rosita Accardi
- International Agency for Research on Cancer, World Health Organization, Lyon, France
| | - Massimo Tommasino
- International Agency for Research on Cancer, World Health Organization, Lyon, France
| | - Manuel Llano
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | | | - Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
- * E-mail: (KHS); (FHS)
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers (F065), Program Infection and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
- * E-mail: (KHS); (FHS)
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Masterson L, Moualed D, Masood A, Dwivedi RC, Benson R, Sterling JC, Rhodes KM, Sudhoff H, Jani P, Goon P. De-escalation treatment protocols for human papillomavirus-associated oropharyngeal squamous cell carcinoma. Cochrane Database Syst Rev 2014; 2014:CD010271. [PMID: 24532092 PMCID: PMC10654373 DOI: 10.1002/14651858.cd010271.pub2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Human papillomavirus-associated oropharyngeal squamous cell carcinomas are a distinct subgroup of tumours that may have a better prognosis than traditional tobacco/alcohol-related disease. Iatrogenic complications, associated with conventional practice, are estimated to cause mortality of approximately 2% and high morbidity. As a result, clinicians are actively investigating the de-escalation of treatment protocols for disease with a proven viral aetiology. OBJECTIVES To summarise the available evidence regarding de-escalation treatment protocols for human papillomavirus-associated, locally advanced oropharyngeal squamous cell carcinoma. SEARCH METHODS We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials; PubMed; EMBASE; CINAHL; Web of Science; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 25 June 2013. SELECTION CRITERIA Randomised controlled trials investigating de-escalation treatment protocols for human papillomavirus-associated, locally advanced oropharyngeal carcinoma. Specific de-escalation categories were: 1) bioradiotherapy (experimental) versus chemoradiotherapy (control); 2) radiotherapy (experimental) versus chemoradiotherapy (control); and 3) low-dose (experimental) versus standard-dose radiotherapy (control). The outcomes of interest were overall and disease-specific survival, treatment-related morbidity, quality of life and cost. DATA COLLECTION AND ANALYSIS Three authors independently selected studies from the search results and extracted data. We planned to use the Cochrane 'Risk of bias' tool to assess study quality. MAIN RESULTS We did not identify any completed randomised controlled trials that could be included in the current version of this systematic review. We did, however, identify seven ongoing trials that will meet our inclusion criteria. These studies will report from 2014 onwards. We excluded 30 studies on methodological grounds (seven randomised trials with post hoc analysis by human papillomavirus status, 11 prospective trials and 12 ongoing studies). AUTHORS' CONCLUSIONS There is currently insufficient high-quality evidence for, or against, de-escalation of treatment for human papillomavirus-associated oropharyngeal carcinoma. Future trials should be multicentre to ensure adequate power. Adverse events, morbidity associated with treatment, quality of life outcomes and cost analyses should be reported in a standard format to facilitate comparison with other studies.
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Affiliation(s)
- Liam Masterson
- Cambridge University Hospitals NHS Foundation TrustENT DepartmentCambridgeUKCB2 0QQ
| | - Daniel Moualed
- Great Western Hospitals NHS Foundation TrustENT DepartmentSwindonUK
| | - Ajmal Masood
- Norfolk and Norwich University HospitalENT DepartmentNorwichUK
| | - Raghav C Dwivedi
- Cambridge University Hospitals NHS Foundation TrustENT DepartmentCambridgeUKCB2 0QQ
| | - Richard Benson
- Addenbrooke's HospitalOncology CentreBox 193CambridgeUKCB2 2QQ
| | - Jane C Sterling
- Addenbrooke's HospitalDepartment of DermatologyBox 46CambridgeUKCB2 2QQ
| | - Kirsty M Rhodes
- University of CambridgeMRC Biostatistics UnitNewnham CollegeSidgwick AvenueCambridgeCambridgeshireUKCB3 DF
| | - Holger Sudhoff
- Bielefeld Academic Teaching HospitalDepartment of Otolaryngology, Head and Neck SurgeryTeutoburger Str. 50BielefeldGermany33604
| | - Piyush Jani
- Cambridge University Hospitals NHS Foundation TrustENT DepartmentCambridgeUKCB2 0QQ
| | - Peter Goon
- University of CambridgeDepartment of PathologyCambridgeUK
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Cherry JJ, Rietz A, Malinkevich A, Liu Y, Xie M, Bartolowits M, Davisson VJ, Baleja JD, Androphy EJ. Structure based identification and characterization of flavonoids that disrupt human papillomavirus-16 E6 function. PLoS One 2013; 8:e84506. [PMID: 24376816 PMCID: PMC3871595 DOI: 10.1371/journal.pone.0084506] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 11/20/2013] [Indexed: 02/07/2023] Open
Abstract
Expression and function of the human papillomavirus (HPV) early protein 6 (E6) is necessary for viral replication and oncogenesis in cervical cancers. HPV E6 targets the tumor suppressor protein p53 for degradation. To achieve this, "high-risk" HPV E6 proteins bind to and modify the target specificity of the ubiquitin ligase E6AP (E6 associated protein). This E6-dependent loss of p53 enables the virus to bypass host cell defenses and facilitates virally induced activation of the cell cycle progression during viral replication. Disruption of the interaction between E6 and E6AP and stabilization of p53 should decrease viability and proliferation of HPV positive cells. A new in vitro high-throughput binding assay was developed to assay binding between HPV-16 E6 and E6AP and to identify compounds that inhibit this interaction. The compound luteolin emerged from the screen and a library of novel flavones based on its structure was synthesized and characterized using this in vitro binding assay. The compounds identified in this study disrupt the E6/E6AP interaction, increase the levels of p53 and p21(Cip1/Waf1), and decrease proliferation of HPV positive cell lines. The new class of flavonoid E6 inhibitors displays a high degree of specificity for HPV positive cells. Docking analyses suggest that these compounds bind in a hydrophobic pocket at the interface between E6 and E6AP and mimic the leucines in the conserved α-helical motif of E6AP. The activity and specificity of these compounds represent a promising new lead for development as an antiviral therapy in the treatment of HPV infection and cervical cancer.
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Affiliation(s)
- Jonathan J. Cherry
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Anne Rietz
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Anna Malinkevich
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Yuqi Liu
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Meng Xie
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Matthew Bartolowits
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana, United States of America
| | - V. Jo Davisson
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana, United States of America
| | - James D. Baleja
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Elliot J. Androphy
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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46
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Jiang P, Yue Y. Human papillomavirus oncoproteins and apoptosis (Review). Exp Ther Med 2013; 7:3-7. [PMID: 24348754 PMCID: PMC3860870 DOI: 10.3892/etm.2013.1374] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/21/2013] [Indexed: 12/22/2022] Open
Abstract
The aim of this study was to review the literature and identify the association between human papillomavirus (HPV) oncoproteins and apoptosis. HPV-associated apoptosis may be primarily blocked by a number of oncoproteins, including E5, E6 and E7. E5 protein protects cells from tumor necrosis factor-associated apoptosis; the oncoprotein E6 predominantly inhibits apoptosis through the p53 pathway; and oncoprotein E7 is involved in apoptosis activation and inhibition. In addition, HPV oncoproteins are involved in activating or repressing the transcription of E6/E7. In conclusion, HPV oncoproteins, including E5, E6 and E7 protein, may interfere with apoptosis via certain regulatory principles.
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Affiliation(s)
- Peiyue Jiang
- Department of Gynecological Oncology, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Ying Yue
- Department of Gynecological Oncology, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
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47
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Fischer M, Quaas M, Wintsche A, Müller GA, Engeland K. Polo-like kinase 4 transcription is activated via CRE and NRF1 elements, repressed by DREAM through CDE/CHR sites and deregulated by HPV E7 protein. Nucleic Acids Res 2013; 42:163-80. [PMID: 24071582 PMCID: PMC3874167 DOI: 10.1093/nar/gkt849] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Infection by oncogenic viruses is a frequent cause for tumor formation as observed in cervical cancer. Viral oncoproteins cause inactivation of p53 function and false transcriptional regulation of central cell cycle genes. Here we analyze the regulation of Plk4, serving as an example of many cell cycle- and p53-regulated genes. Cell cycle genes are often repressed via CDE and CHR elements in their promoters and activated by NF-Y binding to CCAAT-boxes. In contrast, general activation of Plk4 depends on NRF1 and CRE sites. Bioinformatic analyses imply that NRF1 and CRE are central elements of the transcriptional network controlling cell cycle genes. We identify CDE and CHR sites in the Plk4 promoter, which are necessary for binding of the DREAM (DP, RB-like, E2F4 and MuvB) complex and for mediating repression in G0/G1. When cells progress to G2 and mitosis, DREAM is replaced by the MMB (Myb-MuvB) complex that only requires the CHR element for binding. Plk4 expression is downregulated by the p53-p21WAF1/CIP1-DREAM signaling pathway through the CDE and CHR sites. Cell cycle- and p53-dependent repression is abrogated by HPV E7 oncoprotein. Together with genome-wide analyses our results imply that many cell cycle genes upregulated in tumors by viral infection are bound by DREAM through CDE/CHR sites.
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Affiliation(s)
- Martin Fischer
- Molecular Oncology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103 Leipzig, Germany and Computational EvoDevo Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany
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48
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Honegger A, Leitz J, Bulkescher J, Hoppe-Seyler K, Hoppe-Seyler F. Silencing of human papillomavirus (HPV)E6/E7oncogene expression affects both the contents and the amounts of extracellular microvesicles released from HPV-positive cancer cells. Int J Cancer 2013; 133:1631-42. [DOI: 10.1002/ijc.28164] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/14/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Anja Honegger
- Molecular Therapy of Virus-Associated Cancers; German Cancer Research Center (DKFZ); Heidelberg; Germany
| | - Jenny Leitz
- Molecular Therapy of Virus-Associated Cancers; German Cancer Research Center (DKFZ); Heidelberg; Germany
| | - Julia Bulkescher
- Molecular Therapy of Virus-Associated Cancers; German Cancer Research Center (DKFZ); Heidelberg; Germany
| | - Karin Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers; German Cancer Research Center (DKFZ); Heidelberg; Germany
| | - Felix Hoppe-Seyler
- Molecular Therapy of Virus-Associated Cancers; German Cancer Research Center (DKFZ); Heidelberg; Germany
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49
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Li C, Johnson DE. Liberation of functional p53 by proteasome inhibition in human papilloma virus-positive head and neck squamous cell carcinoma cells promotes apoptosis and cell cycle arrest. Cell Cycle 2013; 12:923-34. [PMID: 23421999 DOI: 10.4161/cc.23882] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human papilloma virus (HPV) infection represents an emerging risk factor in head and neck squamous cell carcinoma (HNSCC). In contrast to HPV-negative HNSCC, most cases of HPV-positive HNSCC encode wild-type p53, although the p53 protein in these cells is rapidly degraded via HPV E6-mediated ubiquitination and subsequent proteasomal degradation. This unique feature of HPV-positive HNSCC has raised hope that liberation of wild-type p53 from the E6 protein may have therapeutic benefit in this disease. Indeed, suppression of E6 expression promotes apoptosis in HPV-positive HNSCC cell lines. However, the role of p53 in mediating this cell death has not been determined. Here, we demonstrate that siRNAs targeting the E6/E7 RNA, or treatment with the proteasome inhibitor bortezomib, resulted in upregulation of functional p53 and p53 gene targets in three HPV-positive HNSCC cell lines, but not in HPV-negative HNSCC cells. Apoptosis induced by E6/E7 siRNA in HPV-positive cells was found to be dependent on p53, while bortezomib-induced cell death was modestly p53-dependent. Treatment with subtoxic doses of bortezomib led to cell cycle arrest in HPV-positive, but not HPV-negative HNSCC cells. Moreover, this cell cycle arrest was mediated by p53 and the cell cycle inhibitor p21, the product of a p53 target gene. Collectively, these findings establish that wild-type p53 encoded by HPV-positive HNSCC cells, once liberated from HPV E6, can play important roles in promoting apoptosis and cell cycle arrest.
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Affiliation(s)
- Changyou Li
- Department of Medicine, University of Pittsburgh and the University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
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50
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The transcription factors TBX2 and TBX3 interact with human papillomavirus 16 (HPV16) L2 and repress the long control region of HPVs. J Virol 2013; 87:4461-74. [PMID: 23388722 DOI: 10.1128/jvi.01803-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The minor capsid protein L2 of human papillomaviruses (HPVs) has multiple functions during the viral life cycle. Although L2 is required for effective invasion and morphogenesis, only a few cellular interaction partners are known so far. Using yeast two-hybrid screening, we identified the transcription factor TBX2 as a novel interaction partner of HPV type 16 (HPV16) L2. Coimmunoprecipitations and immunofluorescence analyses confirmed the L2-TBX2 interaction and revealed that L2 also interacts with TBX3, another member of the T-box family. Transcription of the early genes during HPV infection is under the control of an upstream enhancer and early promoter region, the long control region (LCR). In promoter-reporter gene assays, we observed that TBX2 and TBX3 repress transcription from the LCR and that this effect is enhanced by L2. Repression of the HPV LCR by TBX2/3 seems to be a conserved mechanism, as it was also observed with the LCRs of different HPV types. Finally, interaction of TBX2 with the LCR was detected by chromatin immunoprecipitation, and we found a strong colocalization of L2 and TBX2 in HPV16-positive cervical intraepithelial neoplasia (CIN) I-II tissue sections. These results suggest that TBX2/3 might play a role in the regulation of HPV gene expression during the viral life cycle.
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