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Hung TM, Son HX, Bang LVN, Van Duyet L. Characteristics of Cervical Cancer Caused by the Human Papillomavirus 18 and Its Genetic Variations in Vietnamese Women. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 117:105546. [PMID: 38176603 DOI: 10.1016/j.meegid.2023.105546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/21/2023] [Accepted: 12/26/2023] [Indexed: 01/06/2024]
Abstract
BACKGROUND The involvement of HPV18 in cervical cancer pathogenesis, as well as its high oncogenic potential and influence on the variation of cervical cancer distribution in different geographical regions, makes assessing the characteristics of cervical cancer and its variants the basis for considering potential carcinogenic HPV18 sequence variations and vaccine strategies. METHODS A prospective study was conducted at Vietnam Central Obstetrics Hospital from January 1, 2019 to December 31, 2020. HPV18 infection was confirmed in cervical cancer patients using molecular diagnostics. Nucleotide sequences of the HPV18 E6, E7, and L1 genes were used to analyze genetic variations. The demographic, clinical, and laboratory data of the patients were collected and statistically analyzed. RESULTS Among 48 patients with HPV18-infected cervical cancer, 79.2% were between the ages of 35-54; while only 20.8% were < 35 and > 54 years old. 100% of patients have been pregnant at some point in their lives, with ≥3 pregnancies accounting for 83.3%. Patients with cervical cancer caused by HPV18 infection were predominantly in stages 0 and I, with no patients in stages II, III, or IV. A single HPV18 infection generates much more cervical cancer cases than multiple HPV18 infections. Symptoms such as lower abdomen pain, unusual anginal discharge, and vaginal bleeding were observed in both stages 0 and I; however, vaginal bleeding after sex was only detected in women with stage I cervical cancer. Cervicitis, cervical ectropion, and ulcers are reported in cervical status stages 0 and I; however, warts and ulcers were only present in stage I. Magnetic resonance imaging produces far superior outcomes than ultrasound. All cytology and pathology tests confirmed L/HSIL, SCC, AC, and CIS. On the other hand, a single HPV18 infection was associated with a significantly higher risk of L/HSIL, SCC, AC, and CIS than multiple HPV18 infections. Nulceotide sequences of the E6, E7, and L1 genes revealed 20 mutations, including three (E6), five (E7), and twelve (L1) mutations. High-frequency mutations (95.8%-100% of HPV18 samples had mutations) occur at the following positions: C287G - P61P (E6 gene), G5503A - R25Q, C5701G - P91R, C6460G - P344R, C6625G - P399R, and C6842G - P471R (L1 gene). A phylogenetic tree based on the E6/E7/L1 gene sequence revealed that 100% belonged to A lineage, with 97.9% belonging AA (Asian Amerindian - A1) and 2.1% belonging to the E (European - A5). CONCLUSION Patients with a single HPV18 infection have a higher risk of cervical cancer than those infected with HPV18 and other high-risk strains simultaneously. HPV18 single-infection, on the other hand, had considerably higher incidences of L/HSIL, SCC, AC, and CIS than HPV18 co-infection. The HPV18 strain that was found in Vietnam belonged to lineage A (A1 and A5), which contains several oncogene mutations.
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Affiliation(s)
- Than Manh Hung
- Emergency Department, National Hospital for Tropical Diseases, 78 Giai Phong, Dong Da, Hanoi, Viet Nam; Infectious Department, University of Medicine and Pharmacy, Vietnam National University, 144 Xuan Thuy, Cau Giay, Hanoi, Viet Nam
| | - Hoang Xuan Son
- Departments of obstetrics and gynecology, Cho Moi District General Hospital, Na Mo village, Dong Tam town, Cho Moi district, Bac Kan province, Viet Nam
| | - Le Van Nguyen Bang
- Luong The Vinh High School, 35 Dinh Nup, Trung Hoa, Cau Giay, Hanoi, Viet Nam
| | - Le Van Duyet
- Micobiology and Moclecular Biology Department, National Hospital for Tropical Diseases, 78 Giai Phong, Dong Da, Hanoi, Viet Nam.
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2
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Bertagnin C, Messa L, Pavan M, Celegato M, Sturlese M, Mercorelli B, Moro S, Loregian A. A small molecule targeting the interaction between human papillomavirus E7 oncoprotein and cellular phosphatase PTPN14 exerts antitumoral activity in cervical cancer cells. Cancer Lett 2023; 571:216331. [PMID: 37532093 DOI: 10.1016/j.canlet.2023.216331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/21/2023] [Accepted: 07/30/2023] [Indexed: 08/04/2023]
Abstract
Human papillomavirus (HPV)-induced cancers still represent a major health issue for worldwide population and lack specific therapeutic regimens. Despite substantial advancements in anti-HPV vaccination, the incidence of HPV-related cancers remains high, thus there is an urgent need for specific anti-HPV drugs. The HPV E7 oncoprotein is a major driver of carcinogenesis that acts by inducing the degradation of several host factors. A target is represented by the cellular phosphatase PTPN14 and its E7-mediated degradation was shown to be crucial in HPV oncogenesis. Here, by exploiting the crystal structure of E7 bound to PTPN14, we performed an in silico screening of small-molecule compounds targeting the C-terminal CR3 domain of E7 involved in the interaction with PTPN14. We discovered a compound able to inhibit the E7/PTPN14 interaction in vitro and to rescue PTPN14 levels in cells, leading to a reduction in viability, proliferation, migration, and cancer-stem cell potential of HPV-positive cervical cancer cells. Mechanistically, as a consequence of PTPN14 rescue, treatment of cancer cells with this compound altered the Yes-associated protein (YAP) nuclear-cytoplasmic shuttling and downstream signaling. Notably, this compound was active against cervical cancer cells transformed by different high-risk (HR)-HPV genotypes indicating a potential broad-spectrum activity. Overall, our study reports the first-in-class inhibitor of E7/PTPN14 interaction and provides the proof-of-principle that pharmacological inhibition of this interaction by small-molecule compounds could be a feasible therapeutic strategy for the development of novel antitumoral drugs specific for HPV-associated cancers.
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Affiliation(s)
- Chiara Bertagnin
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Lorenzo Messa
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Matteo Pavan
- Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Marta Celegato
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Mattia Sturlese
- Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | | | - Stefano Moro
- Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Arianna Loregian
- Department of Molecular Medicine, University of Padua, Padua, Italy.
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Hidayatullah A, Putra WE, Sustiprijatno S, Rifa'i M, Widiastuti D, Heikal MF, Permatasari GW. Concatenation of molecular docking and dynamics simulation of human papillomavirus type 16 E7 oncoprotein targeted ligands: In quest of cervical cancer's treatment. AN ACAD BRAS CIENC 2023; 95:e20220633. [PMID: 37466536 DOI: 10.1590/0001-3765202320220633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/23/2022] [Indexed: 07/20/2023] Open
Abstract
The Human papillomaviruses type 16 E7 oncoprotein is a 98-amino-acid, 11-kilodalton acidic oncoprotein with three conserved portions. Due to its interaction with the pRb-E2F complex, CKII, CKI (mostly p21), and even HDAC1, it possesses strong transformative and carcinogenic qualities that inhibit normal differentiation and cell cycle regulation. Here, we target the E7 oncoprotein using two prior research active compounds: asarinin and thiazolo[3,2-a]benzimidazole-3(2H)-one,2-(2-fluorobenzylideno)-7,8-dimethyl (thiazolo), and valproic acid as a control. We are performing molecular docking followed by molecular dynamic analysis. By acting as competitive inhibitors in the binding site, it was hypothesized that both drugs would inhibit E7-mediated pRb degradation and E7-mediated p21 degradation, resulting in decreased cell cycle progression, immortalization, and proliferation. In addition, we expect that the direct inhibitory action of valproic acid in E7 will target the CKII-mediated phosphorylation pathway necessary for destabilizing p130 and pRb. According to the results of the dynamic simulation, stable interactions exist between every compound. Despite the instability of E7 protein, stability results indicate that both natural chemicals are preferable, with thiazolo outperforming valproic acid.
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Affiliation(s)
- Arief Hidayatullah
- United Nations Development Programme Indonesia, Health Governance Initiative, Eijkman-RSCM Building, Jakarta, 10430, Indonesia
| | - Wira E Putra
- Universitas Negeri Malang, Biotechnology Study Program, Department of Applied Sciences, Faculty of Mathematics and Natural Sciences, East Java 65145, Indonesia
| | - Sustiprijatno Sustiprijatno
- National Research and Innovation Agency, Research Center for Plant Conservation, Botanic Gardens and Forestry, Cibinong-Bogor, West Java 45262, Indonesia
| | - Muhaimin Rifa'i
- Brawijaya University, Department of Biology, Faculty of Mathematics and Natural Sciences, East Java, 65145, Indonesia
| | - Diana Widiastuti
- Universitas Pakuan, Department of Chemistry, Faculty of Mathematics and Natural Science, West Java, 45262, Indonesia
| | - Muhammad F Heikal
- Khon Kaen University, Tropical Medicine International Program, Faculty of Medicine, Khon Kaen 40000, Thailand
| | - Galuh W Permatasari
- Indonesian Research Institute for Biotechnology and Bioindustry, Bogor, West Java, 45262, Indonesia
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ZER1 Contributes to the Carcinogenic Activity of High-Risk HPV E7 Proteins. mBio 2022; 13:e0203322. [PMID: 36346242 PMCID: PMC9765665 DOI: 10.1128/mbio.02033-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Human papillomavirus (HPV) E7 proteins bind to host cell proteins to facilitate virus replication. Interactions between HPV E7 and host cell proteins can also drive cancer progression. We hypothesize that HPV E7-host protein interactions specific for high-risk E7 contribute to the carcinogenic activity of high-risk HPV. The cellular protein ZER1 interacts with the E7 protein from HPV16, the genotype most frequently associated with human cancers. The HPV16 E7-ZER1 interaction is unique among HPV E7 tested to date. Other E7 proteins, even from closely related HPV genotypes, do not bind ZER1, which is a substrate specificity factor for a CUL2-RING ubiquitin ligase. In the present study, we investigated the contribution of ZER1 to the carcinogenic activity of HPV16 E7. First, we mapped the ZER1 binding site to specific residues on the C terminus of HPV16 E7. We showed that the mutant HPV16 E7 that cannot bind ZER1 is impaired in the ability to promote the growth of primary keratinocytes. We found that ZER1 and CUL2 contribute to, but are not required for, HPV16 E7 to degrade RB1. Cancer dependency data show that ZER1 is an essential gene in most HPV-positive, but not HPV-negative, cancer cell lines. Depleting ZER1 impaired the growth of primary keratinocytes expressing HPV16 E7 or HPV18 E7 and of HPV16-and HPV18-positive cervical cancer cell lines. Taken together, our work demonstrates that ZER1 contributes to HPV-mediated carcinogenesis and is essential for the growth of HPV-positive cells. IMPORTANCE HPV16 is highly carcinogenic and is the most predominant HPV genotype associated with human cancers. The mechanisms that underlie differences between high-risk HPV genotypes are currently unknown, but many of these differences are likely attributable to the activities of the oncogenic HPV proteins, including E7. The HPV E7 oncoprotein is essential for HPV-mediated carcinogenesis. A large number of HPV E7 targets have been identified. However, it is unclear which of these many interactions contributes to the carcinogenic activity of HPV E7. Here, we characterized the interaction between HPV16 E7 and the host cell protein ZER1, testing whether this genotype-specific interaction could enable some of the carcinogenic activity of HPV16 E7. We found that ZER1 binding contributes to the growth-promoting activity of HPV16 E7 and to the growth of HPV-positive cervical cancer cells. We propose that ZER1 makes an important contribution to HPV-mediated carcinogenesis.
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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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Risør MW, Jansma AL, Medici N, Thomas B, Dyson HJ, Wright PE. Characterization of the High-Affinity Fuzzy Complex between the Disordered Domain of the E7 Oncoprotein from High-Risk HPV and the TAZ2 Domain of CBP. Biochemistry 2021; 60:3887-3898. [PMID: 34905914 PMCID: PMC8865373 DOI: 10.1021/acs.biochem.1c00669] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The intrinsically disordered N-terminal region of the E7 protein from high-risk human papillomavirus (HPV) strains is responsible for oncogenic transformation of host cells through its interaction with a number of cellular factors, including the TAZ2 domain of the transcriptional coactivator CREB-binding protein. Using a variety of spectroscopic and biochemical tools, we find that despite its nanomolar affinity, the HPV16 E7 complex with TAZ2 is disordered and highly dynamic. The disordered domain of HPV16 E7 protein does not adopt a single conformation on the surface of TAZ2 but engages promiscuously with its target through multiple interactions involving two conserved motifs, termed CR1 and CR2, that occupy an extensive binding surface on TAZ2. The fuzzy nature of the complex is a reflection of the promiscuous binding repertoire of viral proteins, which must efficiently dysregulate host cell processes by binding to a variety of host factors in the cellular environment.
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Affiliation(s)
- Michael W. Risør
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, U.S.A.,Joint first author
| | - Ariane L. Jansma
- Department of Chemistry, Point Loma Nazarene University, San Diego, California, 92106, U.S.A.,Joint first author
| | - Natasha Medici
- Department of Chemistry, Point Loma Nazarene University, San Diego, California, 92106, U.S.A
| | - Brittany Thomas
- Department of Chemistry, Point Loma Nazarene University, San Diego, California, 92106, U.S.A
| | - H. Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, U.S.A.,Author for correspondence: H. Jane Dyson, Phone: 1-858-784-2223, , Peter E. Wright, Phone: 1-858-784-9721,
| | - Peter E. Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, U.S.A.,Author for correspondence: H. Jane Dyson, Phone: 1-858-784-2223, , Peter E. Wright, Phone: 1-858-784-9721,
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Basukala O, Banks L. The Not-So-Good, the Bad and the Ugly: HPV E5, E6 and E7 Oncoproteins in the Orchestration of Carcinogenesis. Viruses 2021; 13:1892. [PMID: 34696321 PMCID: PMC8541208 DOI: 10.3390/v13101892] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 12/15/2022] Open
Abstract
Infection with HPV starts with the access of the viral particles to basal cells in the epidermis, potentially via microtraumas to the skin. The basal cells are able to keep away these pathogens in normal circumstances through a robust immune response from the host, as HPV infections are, in general, cleared within 2 to 3 weeks. However, the rare instances of persistent infection and/or in cases where the host immune system is compromised are major risk factors for the development of lesions potentially leading to malignancy. Evolutionarily, obligatory pathogens such as HPVs would not be expected to risk exposing the host to lethal cancer, as this would entail challenging their own life cycle, but infection with these viruses is highly correlated with cancer and malignancy-as in cancer of the cervix, which is almost always associated with these viruses. Despite this key associative cause and the availability of very effective vaccines against these viruses, therapeutic interventions against HPV-induced cancers are still a challenge, indicating the need for focused translational research. In this review, we will consider the key roles that the viral proteins play in driving the host cells to carcinogenesis, mainly focusing on events orchestrated by early proteins E5, E6 and E7-the not-so-good, the bad and the ugly-and discuss and summarize the major events that lead to these viruses mechanistically corrupting cellular homeostasis, giving rise to cancer and malignancy.
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Affiliation(s)
| | - Lawrence Banks
- Tumour Virology Laboratory, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34149 Trieste, Italy;
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Modeling and Molecular Dynamics of the 3D Structure of the HPV16 E7 Protein and Its Variants. Int J Mol Sci 2021; 22:ijms22031400. [PMID: 33573298 PMCID: PMC7866783 DOI: 10.3390/ijms22031400] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/12/2021] [Accepted: 01/26/2021] [Indexed: 01/21/2023] Open
Abstract
The oncogenic potential of high-risk human papillomavirus (HPV) is predicated on the production of the E6 and E7 oncoproteins, which are responsible for disrupting the control of the cell cycle. Epidemiological studies have proposed that the presence of the N29S and H51N variants of the HPV16 E7 protein is significantly associated with cervical cancer. It has been suggested that changes in the amino acid sequence of E7 variants may affect the oncoprotein 3D structure; however, this remains uncertain. An analysis of the structural differences of the HPV16 E7 protein and its variants (N29S and H51N) was performed through homology modeling and structural refinement by molecular dynamics simulation. We propose, for the first time, a 3D structure of the E7 reference protein and two of Its variants (N29S and H51N), and conclude that the mutations induced by the variants in N29S and H51N have a significant influence on the 3D structure of the E7 protein of HPV16, which could be related to the oncogenic capacity of this protein.
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Epitope Mapping and Computational Analysis of Anti-HPV16 E6 and E7 Antibodies in Single-Chain Format for Clinical Development as Antitumor Drugs. Cancers (Basel) 2020; 12:cancers12071803. [PMID: 32640530 PMCID: PMC7408665 DOI: 10.3390/cancers12071803] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 11/17/2022] Open
Abstract
Human Papillomavirus 16-associated cancer, affecting primarily the uterine cervix but, increasingly, other body districts, including the head–neck area, will long be a public health problem, despite there being a vaccine. Since the virus oncogenic activity is fully ascribed to the viral E6 and E7 oncoproteins, one of the therapeutic approaches for HPV16 cancer is based on specific antibodies in single-chain format targeting the E6/E7 activity. We analyzed the Complementarity Determining Regions, repositories of antigen-binding activity, of four anti-HPV16 E6 and -HPV16 E7 scFvs, to highlight possible conformity to biophysical properties, recognized to be advantageous for therapeutic use. By epitope mapping, using E7 mutants with amino acid deletions or variations, we investigated differences among the anti-16E7 scFvs in terms of antigen-binding capacity. We also performed computational analyses to determine whether length, total net charge, surface hydrophobicity, polarity and charge distribution conformed well to those of the antibodies that had already reached clinical use, through the application of developability guidelines derived from recent literature on clinical-stage antibodies, and the Therapeutic Antibodies Profiler software. Overall, our findings show that the scFvs investigated may represent valid candidates to be developed as therapeutic molecules for clinical use, and highlight characteristics that could be improved by molecular engineering.
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10
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Suppression of a Subset of Interferon-Induced Genes by Human Papillomavirus Type 16 E7 via a Cyclin Dependent Kinase 8-Dependent Mechanism. Viruses 2020; 12:v12030311. [PMID: 32183180 PMCID: PMC7150855 DOI: 10.3390/v12030311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
Persistent infection by human papillomaviruses (HPVs), small, double-stranded DNA viruses that infect keratinocytes of the squamous epithelia, can lead to the development of cervical and other cancers. The viral oncoprotein E7 contributes to viral persistence in part by regulating host gene expression through binding host transcriptional regulators, although mechanisms responsible for E7-mediated transcriptional regulation are incompletely understood. Type I IFN signaling promotes the expression of anti-viral genes, called interferon-stimulated genes (ISGs), through the phosphorylation and activation of STAT1. In this study, we have observed that the CR3 domain of E7 contributes to the episomal maintenance of viral genomes. Transcriptome analysis revealed that E7 transcriptionally suppresses a subset of ISGs but not through regulation of STAT1 activation. Instead, we discovered that E7 associates with Mediator kinase CDK8 and this is correlated with the recruitment of CDK8 to ISG promoters and reduced ISG expression. E7 fails to suppress ISGs in the absence of CDK8, indicating that CDK8 function contributes to the suppression of ISGs by E7. Altogether, E7/CDK8 association may be a novel mechanism by which E7 inhibits innate immune signaling.
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Human papillomavirus E7 oncoprotein targets RNF168 to hijack the host DNA damage response. Proc Natl Acad Sci U S A 2019; 116:19552-19562. [PMID: 31501315 DOI: 10.1073/pnas.1906102116] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
High-risk human papillomaviruses (HR-HPVs) promote cervical cancer as well as a subset of anogenital and head and neck cancers. Due to their limited coding capacity, HPVs hijack the host cell's DNA replication and repair machineries to replicate their own genomes. How this host-pathogen interaction contributes to genomic instability is unknown. Here, we report that HPV-infected cancer cells express high levels of RNF168, an E3 ubiquitin ligase that is critical for proper DNA repair following DNA double-strand breaks, and accumulate high numbers of 53BP1 nuclear bodies, a marker of genomic instability induced by replication stress. We describe a mechanism by which HPV E7 subverts the function of RNF168 at DNA double-strand breaks, providing a rationale for increased homology-directed recombination in E6/E7-expressing cervical cancer cells. By targeting a new regulatory domain of RNF168, E7 binds directly to the E3 ligase without affecting its enzymatic activity. As RNF168 knockdown impairs viral genome amplification in differentiated keratinocytes, we propose that E7 hijacks the E3 ligase to promote the viral replicative cycle. This study reveals a mechanism by which tumor viruses reshape the cellular response to DNA damage by manipulating RNF168-dependent ubiquitin signaling. Importantly, our findings reveal a pathway by which HPV may promote the genomic instability that drives oncogenesis.
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12
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Yun HY, Kim MW, Lee HS, Kim W, Shin JH, Kim H, Shin HC, Park H, Oh BH, Kim WK, Bae KH, Lee SC, Lee EW, Ku B, Kim SJ. Structural basis for recognition of the tumor suppressor protein PTPN14 by the oncoprotein E7 of human papillomavirus. PLoS Biol 2019; 17:e3000367. [PMID: 31323018 PMCID: PMC6668832 DOI: 10.1371/journal.pbio.3000367] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 07/31/2019] [Accepted: 07/08/2019] [Indexed: 12/28/2022] Open
Abstract
Human papillomaviruses (HPVs) are causative agents of various diseases associated with cellular hyperproliferation, including cervical cancer, one of the most prevalent tumors in women. E7 is one of the two HPV-encoded oncoproteins and directs recruitment and subsequent degradation of tumor-suppressive proteins such as retinoblastoma protein (pRb) via its LxCxE motif. E7 also triggers tumorigenesis in a pRb-independent pathway through its C-terminal domain, which has yet been largely undetermined, with a lack of structural information in a complex form with a host protein. Herein, we present the crystal structure of the E7 C-terminal domain of HPV18 belonging to the high-risk HPV genotypes bound to the catalytic domain of human nonreceptor-type protein tyrosine phosphatase 14 (PTPN14). They interact directly and potently with each other, with a dissociation constant of 18.2 nM. Ensuing structural analysis revealed the molecular basis of the PTPN14-binding specificity of E7 over other protein tyrosine phosphatases and also led to the identification of PTPN21 as a direct interacting partner of E7. Disruption of HPV18 E7 binding to PTPN14 by structure-based mutagenesis impaired E7’s ability to promote keratinocyte proliferation and migration. Likewise, E7 binding-defective PTPN14 was resistant for degradation via proteasome, and it was much more effective than wild-type PTPN14 in attenuating the activity of downstream effectors of Hippo signaling and negatively regulating cell proliferation, migration, and invasion when examined in HPV18-positive HeLa cells. These results therefore demonstrated the significance and therapeutic potential of the intermolecular interaction between HPV E7 and host PTPN14 in HPV-mediated cell transformation and tumorigenesis. Human papillomaviruses cause various diseases associated with cellular hyperproliferation, including cervical cancer. Structural, biochemical, and cellular analyses reveal the molecular basis and significance of the intermolecular interaction between the E7 protein of human papillomavirus 18 and the human tumor suppressor protein PTPN14.
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MESH Headings
- Amino Acid Sequence
- Cell Line
- Cell Line, Tumor
- Cell Transformation, Neoplastic
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Female
- HEK293 Cells
- HeLa Cells
- Humans
- Models, Molecular
- Oncogene Proteins, Viral/chemistry
- Oncogene Proteins, Viral/genetics
- Oncogene Proteins, Viral/metabolism
- Protein Binding
- Protein Domains
- Protein Tyrosine Phosphatases, Non-Receptor/chemistry
- Protein Tyrosine Phosphatases, Non-Receptor/genetics
- Protein Tyrosine Phosphatases, Non-Receptor/metabolism
- Retinoblastoma Protein/chemistry
- Retinoblastoma Protein/genetics
- Retinoblastoma Protein/metabolism
- Sequence Homology, Amino Acid
- Uterine Cervical Neoplasms/genetics
- Uterine Cervical Neoplasms/metabolism
- Uterine Cervical Neoplasms/pathology
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Affiliation(s)
- Hye-Yeoung Yun
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Bioscience, University of Science and Technology KRIBB School, Daejeon, Republic of Korea
| | - Min Wook Kim
- Department of Bioscience, University of Science and Technology KRIBB School, Daejeon, Republic of Korea
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Hye Seon Lee
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Biology, Chungnam National University, Daejeon, Republic of Korea
| | - Wantae Kim
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Biochemistry, Chungnam National University, Daejeon, Republic of Korea
| | - Ji Hye Shin
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Hyunmin Kim
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Ho-Chul Shin
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Hwangseo Park
- Department of Bioscience and Biotechnology, Sejong University, Seoul, Republic of Korea
| | - Byung-Ha Oh
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Won Kon Kim
- Department of Bioscience, University of Science and Technology KRIBB School, Daejeon, Republic of Korea
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Kwang-Hee Bae
- Department of Bioscience, University of Science and Technology KRIBB School, Daejeon, Republic of Korea
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Sang Chul Lee
- Department of Bioscience, University of Science and Technology KRIBB School, Daejeon, Republic of Korea
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Eun-Woo Lee
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- * E-mail: (E-WL); (BK); (SJK)
| | - Bonsu Ku
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- * E-mail: (E-WL); (BK); (SJK)
| | - Seung Jun Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Bioscience, University of Science and Technology KRIBB School, Daejeon, Republic of Korea
- * E-mail: (E-WL); (BK); (SJK)
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13
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Alvarez-Paggi D, Lorenzo JR, Camporeale G, Montero L, Sánchez IE, de Prat Gay G, Alonso LG. Topology Dictates Evolution of Regulatory Cysteines in a Family of Viral Oncoproteins. Mol Biol Evol 2019; 36:1521-1532. [DOI: 10.1093/molbev/msz085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
| | - Juan Ramiro Lorenzo
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Laboratorio de Fisiología de Proteínas, Buenos Aires, Argentina
| | - Gabriela Camporeale
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Luciano Montero
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Ignacio E Sánchez
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Laboratorio de Fisiología de Proteínas, Buenos Aires, Argentina
| | - Gonzalo de Prat Gay
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Leonardo G Alonso
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
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14
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Lai TO, Boon SS, Law PT, Chen Z, Thomas M, Banks L, Chan PK. Oncogenicitiy Comparison of Human Papillomavirus Type 52 E6 Variants. J Gen Virol 2019; 100:484-496. [PMID: 30676312 DOI: 10.1099/jgv.0.001222] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human papillomavirus (HPV) infection contributes to virtually all cases of cervical cancer, the fourth most common cancer affecting women worldwide. The oncogenicity of HPV is mainly attributable to the E6 and E7 oncoproteins. HPV-52 is the seventh most common HPV type globally, but it has a remarkably high prevalence in East Asia. In previous studies it has been speculated that the oncogenicity might vary among different HPV-52 variants. In the present study, we compared the oncogenicity of E6 derived from the HPV-52 prototype and three commonly found variants, V1 (K93R), V2 (E14D/V92L) and V3 (K93R/N122K), through molecular and phenotypic approaches. We demonstrated that cells containing V1 achieved higher colony formation and showed greater cell migration ability when compared to other variants, but no difference in cell immortalization ability was observed. At the molecular level, the three variants formed complexes with E6-associated protein (E6AP) and p53 as efficiently as the prototype. They degraded p53 and PSD95/Dlg/ZO-1(PDZ) proteins, including MAGI-1c and Dlg, to a similar extent. They also exhibited a similar subcellular localization, and shared a half-life of approximately 45 min. Our findings provide a clearer picture of HPV-52 E6 variant oncogenicity, which is important for further studies aiming to understand the unusually high prevalence of HPV-52 among cervical cancers in East Asia.
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Affiliation(s)
- Tsz On Lai
- 1Department of Microbiology, Faulty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Siaw Shi Boon
- 1Department of Microbiology, Faulty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Priscilla Ty Law
- 1Department of Microbiology, Faulty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Zigui Chen
- 1Department of Microbiology, Faulty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
| | - Miranda Thomas
- 2International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Lawrence Banks
- 2International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Paul Ks Chan
- 1Department of Microbiology, Faulty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
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15
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The PTPN14 Tumor Suppressor Is a Degradation Target of Human Papillomavirus E7. J Virol 2017; 91:JVI.00057-17. [PMID: 28100625 DOI: 10.1128/jvi.00057-17] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 12/13/2022] Open
Abstract
Activation of signaling pathways ensuring cell growth is essential for the proliferative competence of human papillomavirus (HPV)-infected cells. Tyrosine kinases and phosphatases are key regulators of cellular growth control pathways. A recently identified potential cellular target of HPV E7 is the cytoplasmic protein tyrosine phosphatase PTPN14, which is a potential tumor suppressor and is linked to the control of the Hippo and Wnt/beta-catenin signaling pathways. In this study, we show that the E7 proteins of both high-risk and low-risk mucosal HPV types can interact with PTPN14. This interaction is independent of retinoblastoma protein (pRb) and involves residues in the carboxy-terminal region of E7. We also show that high-risk E7 induces proteasome-mediated degradation of PTPN14 in cells derived from cervical tumors. This degradation appears to be independent of cullin-1 or cullin-2 but most likely involves the UBR4/p600 ubiquitin ligase. The degree to which E7 downregulates PTPN14 would suggest that this interaction is important for the viral life cycle and potentially also for the development of malignancy. In support of this we find that overexpression of PTPN14 decreases the ability of HPV-16 E7 to cooperate with activated EJ-ras in primary cell transformation assays.IMPORTANCE This study links HPV E7 to the deregulation of protein tyrosine phosphatase signaling pathways. PTPN14 is classified as a potential tumor suppressor protein, and here we show that it is very susceptible to HPV E7-induced proteasome-mediated degradation. Intriguingly, this appears to use a mechanism that is different from that employed by E7 to target pRb. Therefore, this study has important implications for our understanding of the molecular basis for E7 function and also sheds important light on the potential role of PTPN14 as a tumor suppressor.
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16
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Nogueira MO, Hošek T, Calçada EO, Castiglia F, Massimi P, Banks L, Felli IC, Pierattelli R. Monitoring HPV-16 E7 phosphorylation events. Virology 2017; 503:70-75. [PMID: 28126639 DOI: 10.1016/j.virol.2016.12.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/28/2016] [Indexed: 11/25/2022]
Abstract
HPV-16 E7 is one of the key proteins that, by interfering with the host metabolism through many protein-protein interactions, hijacks cell regulation and contributes to malignancy. Here we report the high resolution investigation of the CR3 region of HPV-16 E7, both as an isolated domain and in the full-length protein. This opens the way to the atomic level study of the many interactions in which HPV-16 E7 is involved. Along these lines we show here the effect of one of the key post-translational modifications of HPV-16 E7, the phosphorylation by casein kinase II.
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Affiliation(s)
- Marcela O Nogueira
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, Italy
| | - Tomáš Hošek
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, Italy
| | - Eduardo O Calçada
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, Italy
| | - Francesca Castiglia
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, Italy
| | - Paola Massimi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, Trieste, Italy
| | - Lawrence Banks
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, Trieste, Italy
| | - Isabella C Felli
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, Italy.
| | - Roberta Pierattelli
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, Italy.
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17
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Lee C, Kim DH, Lee SH, Su J, Han KH. Structural investigation on the intrinsically disordered N-terminal region of HPV16 E7 protein. BMB Rep 2017; 49:431-6. [PMID: 27418281 PMCID: PMC5070730 DOI: 10.5483/bmbrep.2016.49.8.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 11/28/2022] Open
Abstract
Human papillomavirus (HPV) is the major cause of cervical cancer, a deadly threat to millions of females. The early oncogene product (E7) of the high-risk HPV16 is the primary agent associated with HPV-related cervical cancers. In order to understand how E7 contributes to the transforming activity, we investigated the structural features of the flexible N-terminal region (46 residues) of E7 by carrying out N-15 heteronuclear NMR experiments and replica exchange molecular dynamics simulations. Several NMR parameters as well as simulation ensemble structures indicate that this intrinsically disordered region of E7 contains two transient (10-20% populated) helical pre-structured motifs that overlap with important target binding moieties such as an E2F-mimic motif and a pRb-binding LXCXE segment. Presence of such target-binding motifs in HPV16 E7 provides a reasonable explanation for its promiscuous target-binding behavior associated with its transforming activity. [BMB Reports 2016; 49(8): 431-436]
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Affiliation(s)
- Chewook Lee
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Do-Hyoung Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Si-Hyung Lee
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Jiulong Su
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141; Department of Bioinformatics, University of Science and Technology, Daejeon 34113, Korea
| | - Kyou-Hoon Han
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141; Department of Bioinformatics, University of Science and Technology, Daejeon 34113, Korea
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18
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Camporeale G, Lorenzo JR, Thomas MG, Salvatierra E, Borkosky SS, Risso MG, Sánchez IE, de Prat Gay G, Alonso LG. Degenerate cysteine patterns mediate two redox sensing mechanisms in the papillomavirus E7 oncoprotein. Redox Biol 2016; 11:38-50. [PMID: 27863297 PMCID: PMC5278158 DOI: 10.1016/j.redox.2016.10.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/13/2016] [Accepted: 10/16/2016] [Indexed: 01/06/2023] Open
Abstract
Infection with oncogenic human papillomavirus induces deregulation of cellular redox homeostasis. Virus replication and papillomavirus-induced cell transformation require persistent expression of viral oncoproteins E7 and E6 that must retain their functionality in a persistent oxidative environment. Here, we dissected the molecular mechanisms by which E7 oncoprotein can sense and manage the potentially harmful oxidative environment of the papillomavirus-infected cell. The carboxy terminal domain of E7 protein from most of the 79 papillomavirus viral types of alpha genus, which encloses all the tumorigenic viral types, is a cysteine rich domain that contains two classes of cysteines: strictly conserved low reactive Zn+2 binding and degenerate reactive cysteine residues that can sense reactive oxygen species (ROS). Based on experimental data obtained from E7 proteins from the prototypical viral types 16, 18 and 11, we identified a couple of low pKa nucleophilic cysteines that can form a disulfide bridge upon the exposure to ROS and regulate the cytoplasm to nucleus transport. From sequence analysis and phylogenetic reconstruction of redox sensing states we propose that reactive cysteine acquisition through evolution leads to three separate E7s protein families that differ in the ROS sensing mechanism: non ROS-sensitive E7s; ROS-sensitive E7s using only a single or multiple reactive cysteine sensing mechanisms and ROS-sensitive E7s using a reactive-resolutive cysteine couple sensing mechanism. Transforming protein ROS-sensing. Reactive cysteine acquisition through evolution. Redox-switching mechanism. Papillomavirus-induced cancers.
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Affiliation(s)
- Gabriela Camporeale
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Juan R Lorenzo
- ULB-Neuroscience Institute, Universite Libre de Bruxelles, Bruxelles, Belgium
| | - Maria G Thomas
- RNA Cell Biology Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Edgardo Salvatierra
- Laboratory of Molecular and Cellular Therapy, Fundación Instituto Leloir-CONICET and IIBBA-CONICET, Buenos Aires, Argentina
| | - Silvia S Borkosky
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Marikena G Risso
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Ignacio E Sánchez
- Protein Physiology Laboratory, Universidad de Buenos Aires, CONICET, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
| | - Gonzalo de Prat Gay
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina.
| | - Leonardo G Alonso
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina.
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19
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Songock WK, Kim SM, Bodily JM. The human papillomavirus E7 oncoprotein as a regulator of transcription. Virus Res 2016; 231:56-75. [PMID: 27818212 DOI: 10.1016/j.virusres.2016.10.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 12/12/2022]
Abstract
High-risk human papillomaviruses (HPVs) encode oncoproteins which manipulate gene expression patterns in the host keratinocytes to facilitate viral replication, regulate viral transcription, and promote immune evasion and persistence. In some cases, oncoprotein-induced changes in host cell behavior can cause progression to cancer, but a complete picture of the functions of the viral oncoproteins in the productive HPV life cycle remains elusive. E7 is the HPV-encoded factor most responsible for maintaining cell cycle competence in differentiating keratinocytes. Through interactions with dozens of host factors, E7 has an enormous impact on host gene expression patterns. In this review, we will examine the role of E7 specifically as a regulator of transcription. We will discuss mechanisms of regulation of cell cycle-related genes by E7 as well as genes involved in immune regulation, growth factor signaling, DNA damage responses, microRNAs, and others pathways. We will also discuss some unanswered questions about how transcriptional regulation by E7 impacts the biology of HPV in both benign and malignant conditions.
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Affiliation(s)
- William K Songock
- Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Seong-Man Kim
- Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Jason M Bodily
- Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA.
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20
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Zine El Abidine A, Tomaić V, Bel Haj Rhouma R, Massimi P, Guizani I, Boubaker S, Ennaifer E, Banks L. A naturally occurring variant of HPV-16 E7 exerts increased transforming activity through acquisition of an additional phospho-acceptor site. Virology 2016; 500:218-225. [PMID: 27829177 DOI: 10.1016/j.virol.2016.10.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/20/2016] [Accepted: 10/25/2016] [Indexed: 01/23/2023]
Abstract
Human Papillomavirus E6 and E7 play critical roles in cancer development, although not all isolates of the viral oncoproteins are identical. A common E7 variant encodes an amino acid change at N29S. We show that this change increases the levels of phosphorylation by CKII by creating an additional phospho-acceptor site at S29. This confers increased phospho-dependent interaction with a number of cellular targets, including TATA Box Binding Protein (TBP) and pRb. A further consequence is an increased ability to target pRb and p130 for degradation. Biologically, these biochemical differences are reflected in an increased ability of the N29S variant to transform primary rodent cells. This is the first study to demonstrate an important biochemical change in E7 function caused by a naturally occurring variation, and we suggest that the N29S variant merits further assessment to determine whether it has an increased association with the development of HPV-associated malignancies.
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Affiliation(s)
- Amira Zine El Abidine
- Laboratory of Molecular Epidemiology and Experimental Pathology Applied to Infectious Diseases/ LR11IPT04, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia; Department of Human and Experimental Pathology, Institut Pasteur de Tunis, Université Tunis el Manar, Tunis, Tunisia
| | - Vjekoslav Tomaić
- Tumour Virology Laboratory, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste, Italy; Division of Molecular Medicine, Rudjer Boskovic Institute, 10000 Zagreb, Croatia
| | - Rahima Bel Haj Rhouma
- Laboratory of Molecular Epidemiology and Experimental Pathology Applied to Infectious Diseases/ LR11IPT04, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Paola Massimi
- Tumour Virology Laboratory, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste, Italy
| | - Ikram Guizani
- Laboratory of Molecular Epidemiology and Experimental Pathology Applied to Infectious Diseases/ LR11IPT04, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Samir Boubaker
- Department of Human and Experimental Pathology, Institut Pasteur de Tunis, Université Tunis el Manar, Tunis, Tunisia
| | - Emna Ennaifer
- Laboratory of Molecular Epidemiology and Experimental Pathology Applied to Infectious Diseases/ LR11IPT04, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia; Department of Human and Experimental Pathology, Institut Pasteur de Tunis, Université Tunis el Manar, Tunis, Tunisia
| | - Lawrence Banks
- Tumour Virology Laboratory, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste, Italy
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21
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The Human Papillomavirus 16 E7 Oncoprotein Attenuates AKT Signaling To Promote Internal Ribosome Entry Site-Dependent Translation and Expression of c-MYC. J Virol 2016; 90:5611-5621. [PMID: 27030265 DOI: 10.1128/jvi.00411-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/23/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED While the role of high-risk human papillomavirus (HPV) oncoproteins E6 and E7 in targeting p53 and retinoblastoma (Rb) has been intensively studied, how E6 and E7 manipulate cellular signaling cascades to promote the viral life cycle and cancer development is less understood. Keratinocytes containing the episomal HPV-16 genome had decreased activation of AKT, which was phenocopied by HPV-16 E7 expression alone. Attenuation of phosphorylated AKT (pAKT) by E7 was independent of the Rb degradation function of E7 but could be ablated by a missense mutation in the E7 carboxy terminus, H73E, thereby defining a novel structure-function phenotype for E7. Downstream of AKT, reduced phosphorylation of p70 S6K and 4E-BP1 was also observed in E7-expressing keratinocytes, which coincided with an increase in internal ribosomal entry site (IRES)-dependent translation that enhanced the expression of several cellular proteins, including MYC, Bax, and the insulin receptor. The decrease in pAKT mediated by E7 is in contrast to the widely observed increase of pAKT in invasive cervical cancers, suggesting that the activation of AKT signaling could be acquired during the progression from initial productive infections to invasive carcinomas. IMPORTANCE HPV causes invasive cervical cancers through the dysregulation of the cell cycle regulators p53 and Rb, which are degraded by the viral oncoproteins E6 and E7, respectively. Signaling cascades contribute to cancer progression and cellular differentiation, and how E6 and E7 manipulate those pathways remains unclear. The phosphoinositol 3-kinase (PI3K)/AKT pathway regulates cellular processes, including proliferation, cell survival, and cell differentiation. Surprisingly, we found that HPV-16 decreased the phosphorylation of AKT (pAKT) and that this is a function of E7 that is independent of the Rb degradation function. This is in contrast to the observed increase in AKT signaling in nearly 80% of cervical cancers, which typically show an acquired mutation within the PI3K/AKT cascade leading to constitutive activation of the pathway. Our observations suggest that multiple changes in the activation and effects of AKT signaling occur in the progression from productive HPV infections to invasive cervical cancers.
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22
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E6^E7, a novel splice isoform protein of human papillomavirus 16, stabilizes viral E6 and E7 oncoproteins via HSP90 and GRP78. mBio 2015; 6:e02068-14. [PMID: 25691589 PMCID: PMC4337564 DOI: 10.1128/mbio.02068-14] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transcripts of human papillomavirus 16 (HPV16) E6 and E7 oncogenes undergo alternative RNA splicing to produce multiple splice isoforms. However, the importance of these splice isoforms is poorly understood. Here we report a critical role of E6^E7, a novel isoform containing the 41 N-terminal amino acid (aa) residues of E6 and the 38 C-terminal aa residues of E7, in the regulation of E6 and E7 stability. Through mass spectrometric analysis, we identified that HSP90 and GRP78, which are frequently upregulated in cervical cancer tissues, are two E6^E7-interacting proteins responsible for the stability and function of E6^E7, E6, and E7. Although GRP78 and HSP90 do not bind each other, GRP78, but not HSP90, interacts with E6 and E7. E6^E7 protein, in addition to self-binding, interacts with E6 and E7 in the presence of GRP78 and HSP90, leading to the stabilization of E6 and E7 by prolonging the half-life of each protein. Knocking down E6^E7 expression in HPV16-positive CaSki cells by a splice junction-specific small interfering RNA (siRNA) destabilizes E6 and E7 and prevents cell growth. The same is true for the cells with a GRP78 knockdown or in the presence of an HSP90 inhibitor. Moreover, mapping and alignment analyses for splicing elements in 36 alpha-HPVs (α-HPVs) suggest the possible expression of E6^E7 mostly by other oncogenic or possibly oncogenic α-HPVs (HPV18, -30, -31, -39, -42, -45, -56, -59, -70, and -73). HPV18 E6^E7 is detectable in HPV18-positive HeLa cells and HPV18-infected raft tissues. All together, our data indicate that viral E6^E7 and cellular GRP78 or HSP90 might be novel targets for cervical cancer therapy. HPV16 is the most prevalent HPV genotype, being responsible for 60% of invasive cervical cancer cases worldwide. What makes HPV16 so potent in the development of cervical cancer remains a mystery. We discovered in this study that, besides producing two well-known oncoproteins, E6 and E7, seen in other high-risk HPVs, HPV16 produces E6^E7, a novel splice isoform of E6 and E7. E6^E7, in addition to self-interacting, binds cellular chaperone proteins, HSP90 and GRP78, and viral E6 and E7 to increase the steady-state levels and half-lives of viral oncoproteins, leading to cell proliferation. The splicing cis elements in the regulation of HPV16 E6^E7 production are highly conserved in 11 oncogenic or possibly oncogenic HPVs, and we confirmed the production of HPV18 E6^E7 in HPV18-infected cells. This study provides new insight into the mechanism of splicing, the interplay between different products of the polycistronic viral message, and the role of the host chaperones as they function.
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Jansma AL, Martinez-Yamout MA, Liao R, Sun P, Dyson HJ, Wright PE. The high-risk HPV16 E7 oncoprotein mediates interaction between the transcriptional coactivator CBP and the retinoblastoma protein pRb. J Mol Biol 2014; 426:4030-4048. [PMID: 25451029 DOI: 10.1016/j.jmb.2014.10.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/25/2014] [Accepted: 10/29/2014] [Indexed: 11/24/2022]
Abstract
The oncoprotein E7 from human papillomavirus (HPV) strains that confer high cancer risk mediates cell transformation by deregulating host cellular processes and activating viral gene expression through recruitment of cellular proteins such as the retinoblastoma protein (pRb) and the cyclic-AMP response element binding binding protein (CBP) and its paralog p300. Here we show that the intrinsically disordered N-terminal region of E7 from high-risk HPV16 binds the TAZ2 domain of CBP with greater affinity than E7 from low-risk HPV6b. HPV E7 and the tumor suppressor p53 compete for binding to TAZ2. The TAZ2 binding site in E7 overlaps the LxCxE motif that is crucial for interaction with pRb. While TAZ2 and pRb compete for binding to a monomeric E7 polypeptide, the full-length E7 dimer mediates an interaction between TAZ2 and pRb by promoting formation of a ternary complex. Cell-based assays show that expression of full-length HPV16 E7 promotes increased pRb acetylation and that this response depends both on the presence of CBP/p300 and on the ability of E7 to form a dimer. These observations suggest a model for the oncogenic effect of high-risk HPV16 E7. The disordered region of one E7 molecule in the homodimer interacts with the pocket domain of pRb, while the same region of the other E7 molecule binds the TAZ2 domain of CBP/p300. Through its ability to dimerize, E7 recruits CBP/p300 and pRb into a ternary complex, bringing the histone acetyltransferase domain of CBP/p300 into proximity to pRb and promoting acetylation, leading to disruption of cell cycle control.
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Affiliation(s)
- Ariane L Jansma
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Maria A Martinez-Yamout
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Rong Liao
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Peiqing Sun
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - H Jane Dyson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Ajiro M, Zheng ZM. Oncogenes and RNA splicing of human tumor viruses. Emerg Microbes Infect 2014; 3:e63. [PMID: 26038756 PMCID: PMC4185361 DOI: 10.1038/emi.2014.62] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/29/2014] [Accepted: 06/29/2014] [Indexed: 02/07/2023]
Abstract
Approximately 10.8% of human cancers are associated with infection by an oncogenic virus. These viruses include human papillomavirus (HPV), Epstein–Barr virus (EBV), Merkel cell polyomavirus (MCV), human T-cell leukemia virus 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), hepatitis C virus (HCV) and hepatitis B virus (HBV). These oncogenic viruses, with the exception of HCV, require the host RNA splicing machinery in order to exercise their oncogenic activities, a strategy that allows the viruses to efficiently export and stabilize viral RNA and to produce spliced RNA isoforms from a bicistronic or polycistronic RNA transcript for efficient protein translation. Infection with a tumor virus affects the expression of host genes, including host RNA splicing factors, which play a key role in regulating viral RNA splicing of oncogene transcripts. A current prospective focus is to explore how alternative RNA splicing and the expression of viral oncogenes take place in a cell- or tissue-specific manner in virus-induced human carcinogenesis.
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Affiliation(s)
- Masahiko Ajiro
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, MD 21702, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, MD 21702, USA
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Chemes LB, Camporeale G, Sánchez IE, de Prat-Gay G, Alonso LG. Cysteine-rich positions outside the structural zinc motif of human papillomavirus E7 provide conformational modulation and suggest functional redox roles. Biochemistry 2014; 53:1680-96. [PMID: 24559112 DOI: 10.1021/bi401562e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The E7 protein from high-risk human papillomavirus is essential for cell transformation in cervical, oropharyngeal, and other HPV-related cancers, mainly through the inactivation of the retinoblastoma (Rb) tumor suppressor. Its high cysteine content (~7%) and the observation that HPV-transformed cells are under oxidative stress prompted us to investigate the redox properties of the HPV16 E7 protein under biologically compatible oxidative conditions. The seven cysteines in HPV16 E7 remain reduced in conditions resembling the basal reduced state of a cell. However, under oxidative stress, a stable disulfide bridge forms between cysteines 59 and 68. Residue 59 has a protective effect on the other cysteines, and its mutation leads to an overall increase in the oxidation propensity of E7, including cysteine 24 central to the Rb binding motif. Gluthationylation of Cys 24 abolishes Rb binding, which is reversibly recovered upon reduction. Cysteines 59 and 68 are located 18.6 Å apart, and the formation of the disulfide bridge leads to a large structural rearrangement while retaining strong Zn association. These conformational and covalent changes are fully reversible upon restoration of the reductive environment. In addition, this is the first evidence of an interaction between the N-terminal intrinsically disordered and the C-terminal globular domains, known to be highly and separately conserved among human papillomaviruses. The significant conservation of such noncanonical cysteines in HPV E7 proteins leads us to propose a functional redox activity. Such an activity adds to the previously discovered chaperone activity of E7 and supports the picture of a moonlighting pathological role of this paradigmatic viral oncoprotein.
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Affiliation(s)
- Lucía B Chemes
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina
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Human papillomavirus E7 oncoprotein increases production of the anti-inflammatory interleukin-18 binding protein in keratinocytes. J Virol 2014; 88:4173-9. [PMID: 24478434 DOI: 10.1128/jvi.02546-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Human papillomavirus (HPV) can successfully evade the host immune response to establish a persistent infection. We show here that expression of the E7 oncoprotein in primary human keratinocytes results in increased production of interleukin-18 (IL-18) binding protein (IL-18BP). This anti-inflammatory cytokine binding protein is a natural antagonist of IL-18 and is necessary for skin homeostasis. We map increased IL-18BP production to the CR3 region of E7 and demonstrate that this ability is shared among E7 proteins from different HPV types. Furthermore, mutagenesis shows that increased IL-18BP production is mediated by a gamma-activated sequence (GAS) in the IL-18BP promoter. Importantly, the increased IL-18BP levels seen in E7-expressing keratinocytes are capable of diminishing IL-18-mediated CD4 lymphocyte activation. This study provides the first evidence for a virus protein that targets IL-18BP and further validates E7 as a key component of the HPV immune evasion armor. IMPORTANCE Infection with human papillomavirus is a leading cause of morbidity and mortality worldwide. This study demonstrates that the E7 protein increases production of the anti-inflammatory IL-18BP, a major regulator of epithelial homeostasis. A number of E7 proteins can increase IL-18BP production, and a region within the CR3 of E7 is necessary for mediating the increase. A consequence of increased IL-18BP production is a reduction in CD4-positive lymphocyte activation in response to IL-18 costimulation. These findings may shed light on the immune evasion abilities of HPV.
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The human papillomavirus E7 proteins associate with p190RhoGAP and alter its function. J Virol 2014; 88:3653-63. [PMID: 24403595 DOI: 10.1128/jvi.03263-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Using mass spectrometry, we identified p190RhoGAP (p190) as a binding partner of human papillomavirus 16 (HPV16) E7. p190 belongs to the GTPase activating protein (GAP) family and is one of the primary GAPs for RhoA. GAPs stimulate the intrinsic GTPase activity of the Rho proteins, leading to Rho inactivation and influencing numerous biological processes. RhoA is one of the best-characterized Rho proteins and is specifically involved in formation of focal adhesions and stress fibers, thereby regulating cell migration and cell spreading. Since this is the first report that E7 associates with p190, we carried out detailed interaction studies. We show that E7 proteins from other HPV types also bind p190. Furthermore, we found that conserved region 3 (CR3) of E7 and the middle domain of p190 are important for this interaction. More specifically, we identified two residues in CR3 of E7 that are necessary for p190 binding and used mutants of E7 with mutations of these residues to determine the biological consequences of the E7-p190 interaction. Our data suggest that the interaction of E7 with p190 dysregulates this GAP and alters the actin cytoskeleton. We also found that this interaction negatively regulates cell spreading on a fibronectin substrate and therefore likely contributes to important aspects of the HPV life cycle or HPV-induced tumorigenesis. IMPORTANCE This study identifies p190RhoGAP as a novel cellular binding partner for the human papillomavirus (HPV) E7 protein. Our study shows that a large number of different HPV E7 proteins bind p190RhoGAP, and it identifies regions in both E7 and p190RhoGAP which are important for the interaction to occur. This study also highlights the likelihood that the E7-p190RhoGAP interaction may have important biological consequences related to actin organization in the infected cell. These changes could be an important contributor to the viral life cycle and during progression to cancer in HPV-infected cells. Importantly, this work also emphasizes the need for further study in a field which has largely been unexplored as it relates to the HPV life cycle and HPV-induced transformation.
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Calçada EO, Felli IC, Hošek T, Pierattelli R. The Heterogeneous Structural Behavior of E7 from HPV16 Revealed by NMR Spectroscopy. Chembiochem 2013; 14:1876-82. [DOI: 10.1002/cbic.201300172] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Indexed: 12/19/2022]
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Abstract
E7 is an accessory protein that is not encoded by all papillomaviruses. The E7 amino terminus contains two regions of similarity to conserved regions 1 and 2 of the adenovirus E1A protein, which are also conserved in the simian vacuolating virus 40 large tumor antigen. The E7 carboxyl terminus consists of a zinc-binding motif, which is related to similar motifs in E6 proteins. E7 proteins play a central role in the human papillomavirus life cycle, reprogramming the cellular environment to be conducive to viral replication. E7 proteins encoded by the cancer-associated alpha human papillomaviruses have potent transforming activities, which together with E6, are necessary but not sufficient to render their host squamous epithelial cell tumorigenic. This article strives to provide a comprehensive summary of the published research studies on human papillomavirus E7 proteins.
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Shen M, Ding X, Li T, Chen G, Zhou X. Sequence variation analysis of HPV-18 isolates in southwest China. PLoS One 2013; 8:e56614. [PMID: 23451059 PMCID: PMC3581518 DOI: 10.1371/journal.pone.0056614] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 01/15/2013] [Indexed: 11/29/2022] Open
Abstract
Intratypic variations of HPV-18 are known to differ in the persistence of the infection, frequency of carcinogenesis and the progression of precursor lesions to advanced cervical cancer. This study was designed to analyze sequence variations of HPV-18 isolates in order to discover novel HPV-18 variants and to evaluate the variations among infected women in southwest China. Cervical biopsies from 56 HPV-18-positive women with cervical neoplasia were assayed by PCR amplification and sequencing of all eight genes (E1, E2, E4, E5, E6, E7, L1, L2) of the HPV-18 genome. The most frequently observed variation was a C to G transversion at nucleotide 287 of E6, which was found in 48.2% of samples. Analysis of E7 revealed only one specimen as having sequence variations. In addition, we have identified several novel variations: A551C in E6, G6906A in L1, and C4915T and C5147A in L2. The mutations in E6 and L2 are silent, while the E7 mutation results in a single amino acid change. This study complements and expands on previous descriptions of HPV-18 variants. The sequence variation data presented here provides a foundation for future research on HPV-induced oncogenesis and may prove valuable for developing diagnostic probes and in the design of HPV vaccines for targeted populations.
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Affiliation(s)
- Mengjie Shen
- Bio-resource Research and Utilization Joint Key Laboratory of Sichuan and Chongqing, Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
- Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
| | - Xianping Ding
- Bio-resource Research and Utilization Joint Key Laboratory of Sichuan and Chongqing, Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
- Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
| | - Tianjun Li
- Bio-resource Research and Utilization Joint Key Laboratory of Sichuan and Chongqing, Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
- Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
| | - Gangyi Chen
- Bio-resource Research and Utilization Joint Key Laboratory of Sichuan and Chongqing, Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
- Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
| | - Xiao Zhou
- Bio-resource Research and Utilization Joint Key Laboratory of Sichuan and Chongqing, Institute of Medical Genetics, College of Life Science, Sichuan University, Chengdu, People’s Republic of China
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Zhang EY, Tang XD. Human Papillomavirus Type 16/18 Oncoproteins: Potential Therapeutic Targets in Non-smoking Associated Lung Cancer. Asian Pac J Cancer Prev 2012; 13:5363-9. [DOI: 10.7314/apjcp.2012.13.11.5363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Chemes LB, Glavina J, Alonso LG, Marino-Buslje C, de Prat-Gay G, Sánchez IE. Sequence evolution of the intrinsically disordered and globular domains of a model viral oncoprotein. PLoS One 2012; 7:e47661. [PMID: 23118886 PMCID: PMC3485249 DOI: 10.1371/journal.pone.0047661] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 09/14/2012] [Indexed: 12/11/2022] Open
Abstract
In the present work, we have used the papillomavirus E7 oncoprotein to pursue structure-function and evolutionary studies that take into account intrinsic disorder and the conformational diversity of globular domains. The intrinsically disordered (E7N) and globular (E7C) domains of E7 show similar degrees of conservation and co-evolution. We found that E7N can be described in terms of conserved and coevolving linear motifs separated by variable linkers, while sequence evolution of E7C is compatible with the known homodimeric structure yet suggests other activities for the domain. Within E7N, inter-residue relationships such as residue co-evolution and restricted intermotif distances map functional coupling and co-occurrence of linear motifs that evolve in a coordinate manner. Within E7C, additional cysteine residues proximal to the zinc-binding site may allow redox regulation of E7 function. Moreover, we describe a conserved binding site for disordered domains on the surface of E7C and suggest a putative target linear motif. Both homodimerization and peptide binding activities of E7C are also present in the distantly related host PHD domains, showing that these two proteins share not only structural homology but also functional similarities, and strengthening the view that they evolved from a common ancestor. Finally, we integrate the multiple activities and conformations of E7 into a hierarchy of structure-function relationships.
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Affiliation(s)
- Lucía B. Chemes
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Juliana Glavina
- Protein Physiology Laboratory, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | - Leonardo G. Alonso
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Cristina Marino-Buslje
- Structural Bioinformatics Laboratory. Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Gonzalo de Prat-Gay
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina
| | - Ignacio E. Sánchez
- Protein Physiology Laboratory, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
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Conserved region 3 of human papillomavirus 16 E7 contributes to deregulation of the retinoblastoma tumor suppressor. J Virol 2012; 86:13313-23. [PMID: 23015707 DOI: 10.1128/jvi.01637-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The human papillomavirus (HPV) E7 oncoprotein binds cellular factors, preventing or retargeting their function and thereby making the infected cell conducive for viral replication. A key target of E7 is the product of the retinoblastoma susceptibility locus (pRb). This interaction results in the release of E2F transcription factors and drives the host cell into the S phase of the cell cycle. E7 binds pRb via a high-affinity binding site in conserved region 2 (CR2) and also targets a portion of cellular pRb for degradation via the proteasome. Evidence suggests that a secondary binding site exists in CR3, and that this interaction influences pRb deregulation. Additionally, evidence suggests that CR3 also participates in the degradation of pRb. We have systematically analyzed the molecular mechanisms by which CR3 contributes to deregulation of the pRb pathway by utilizing a comprehensive series of mutations in residues predicted to be exposed on the surface of HPV16 E7 CR3. Despite differences in the ability to interact with cullin 2, all CR3 mutants degrade pRb comparably to wild-type E7. We identified two specific patches of residues on the surface of CR3 that contribute to pRb binding independently of the high-affinity CR2 binding site. Mutants within CR3 that affect pRb binding are less effective than the wild-type E7 in overcoming pRb-induced cell cycle arrest. This demonstrates that the interaction between HPV16 E7 CR3 and pRb is functionally important for alteration of the cell cycle.
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Klingelhutz AJ, Roman A. Cellular transformation by human papillomaviruses: lessons learned by comparing high- and low-risk viruses. Virology 2012; 424:77-98. [PMID: 22284986 DOI: 10.1016/j.virol.2011.12.018] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/17/2011] [Accepted: 12/27/2011] [Indexed: 12/19/2022]
Abstract
The oncogenic potential of papillomaviruses (PVs) has been appreciated since the 1930s yet the mechanisms of virally-mediated cellular transformation are still being revealed. Reasons for this include: a) the oncoproteins are multifunctional, b) there is an ever-growing list of cellular interacting proteins, c) more than one cellular protein may bind to a given region of the oncoprotein, and d) there is only limited information on the proteins encoded by the corresponding non-oncogenic PVs. The perspective of this review will be to contrast the activities of the viral E6 and E7 proteins encoded by the oncogenic human PVs (termed high-risk HPVs) to those encoded by their non-oncogenic counterparts (termed low-risk HPVs) in an attempt to sort out viral life cycle-related functions from oncogenic functions. The review will emphasize lessons learned from the cell culture studies of the HPVs causing mucosal/genital tract cancers.
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