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Ji J, Xu S, Xu X, Man Y, Yao L, Xie Q, Bi Y. Transcriptome-wide N6-methyladenosine modification and microRNA jointly regulate the infection of avian leukosis virus subgroup J in vitro. Poult Sci 2024; 103:103671. [PMID: 38569240 PMCID: PMC10999702 DOI: 10.1016/j.psj.2024.103671] [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: 02/06/2024] [Revised: 03/07/2024] [Accepted: 03/14/2024] [Indexed: 04/05/2024] Open
Abstract
N6-methyladenosine (m6A) methylation in transcripts has been suggested to influence tumorigenesis in liver tumors caused by the avian leukosis virus subgroup J (ALV-J). However, m6A modifications during ALV-J infection in vitro remain unclear. Herein, we performed m6A and RNA sequencing in ALV-J-infected chicken fibroblasts (DF-1). A total of 51 differentially expressed genes containing differentially methylated peaks were identified, which were markedly enriched in microRNAs (miRNAs) in cancer cells as well as apoptosis, mitophagy and autophagy, RNA degradation, and Hippo and MAPK signaling pathways. Correlation analysis indicated that YTHDC1 (m6A-reader gene) plays a key role in m6A modulation during ALV-J infection. The env gene of ALV-J harbored the strongest peak, and untranslated regions and long terminal repeats also contained peaks of different degrees. To the best of our knowledge, this is the first thorough analysis of m6A patterns in ALV-J-infected DF-1 cells. Combined with miRNA profiles, this study provides a useful basis for future research into the key pathways of ALV-J infection associated with m6A alteration.
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Affiliation(s)
- Jun Ji
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang 473061, PR China.
| | - Shuqi Xu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang 473061, PR China
| | - Xin Xu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang 473061, PR China
| | - Yuanzhuo Man
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang 473061, PR China
| | - Lunguang Yao
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang 473061, PR China
| | - Qingmei Xie
- College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
| | - Yingzuo Bi
- College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
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Ji J, Mu X, Xu S, Xu X, Zhang Z, Yao L, Xie Q, Bi Y. Conservation and distribution of the DRACH motif for potential m 6A sites in avian leukosis virus subgroup J. Front Vet Sci 2024; 11:1374430. [PMID: 38681855 PMCID: PMC11046932 DOI: 10.3389/fvets.2024.1374430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/03/2024] [Indexed: 05/01/2024] Open
Abstract
N6-methyladenosine (m6A) methylation is an internal post-transcriptional modification that has been linked to viral multiplication and pathogenicity. To elucidate the conservation patterns of potential 5'-DRACH-3' motifs in avian leukosis virus subgroup J (ALV-J), 149 ALV-J strains (139 isolates from China; ALV-J prototype HPRS-103 from the UK; and 9 strains from the USA, Russia, India, and Pakistan) available in GenBank before December 2023 were retrieved. According to the prediction results of the SRAMP web-server, these ALV-J genomes contained potential DRACH motifs, with the total number ranging from 43 to 64, which were not determined based on the isolation region and time. Conservative analysis suggested that 37 motifs exhibited a conservation of >80%, including 17 motifs with a grading above "high confidence." Although these motifs were distributed in the U5 region of LTRs and major coding regions, they were enriched in the coding regions of p27, p68, p32, and gp85. The most common m6A-motif sequence of the DRACH motif in the ALV-J genome was GGACU. The RNA secondary structure of each conserved motif predicted by SRAMP and RNAstructure web-server was mainly of two types-A-U pair (21/37) and hairpin loop (16/37)-based on the core adenosine. Considering the systematic comparative analysis performed in this study, future thorough biochemical research is warranted to determine the role of m6A modification during the replication and infection of ALV-J. These conservation and distribution analysis of the DRACH motif for potential m6A sites in ALV-J would provide a foundation for the future intervention of ALV-J infection and m6A modification.
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Affiliation(s)
- Jun Ji
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China
| | - Xinhao Mu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China
| | - Shuqi Xu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China
| | - Xin Xu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China
| | - Zhibin Zhang
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China
| | - Lunguang Yao
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China
| | - Qingmei Xie
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yingzuo Bi
- College of Animal Science, South China Agricultural University, Guangzhou, China
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Gemayel J, Chebly A, Kourie H, Hanna C, Mheidly K, Mhanna M, Karam F, Ghoussaini D, Najjar PE, Khalil C. Genome Engineering as a Therapeutic Approach in Cancer Therapy: A Comprehensive Review. ADVANCED GENETICS (HOBOKEN, N.J.) 2024; 5:2300201. [PMID: 38465225 PMCID: PMC10919288 DOI: 10.1002/ggn2.202300201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Indexed: 03/12/2024]
Abstract
Cancer is one of the foremost causes of mortality. The human genome remains stable over time. However, human activities and environmental factors have the power to influence the prevalence of certain types of mutations. This goes to the excessive progress of xenobiotics and industrial development that is expanding the territory for cancers to develop. The mechanisms involved in immune responses against cancer are widely studied. Genome editing has changed the genome-based immunotherapy process in the human body and has opened a new era for cancer treatment. In this review, recent cancer immunotherapies and the use of genome engineering technology are largely focused on.
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Affiliation(s)
- Jack Gemayel
- Faculty of SciencesBalamand UniversityBeirutLebanon
- FMPS Holding BIOTECKNO s.a.l. Research and Quality SolutionsNaccashBeirut60 247Lebanon
| | - Alain Chebly
- Center Jacques Loiselet for Medical Genetics and Genomics (CGGM), Faculty of MedicineSaint Joseph UniversityBeirutLebanon
- Higher Institute of Public HealthSaint Joseph UniversityBeirutLebanon
| | - Hampig Kourie
- Center Jacques Loiselet for Medical Genetics and Genomics (CGGM), Faculty of MedicineSaint Joseph UniversityBeirutLebanon
- Faculty of MedicineSaint Joseph UniversityBeirutLebanon
| | - Colette Hanna
- Faculty of MedicineLebanese American University Medical CenterRizk HospitalBeirutLebanon
| | | | - Melissa Mhanna
- Faculty of MedicineParis Saclay University63 Rue Gabriel PériLe Kremlin‐Bicêtre94270France
| | - Farah Karam
- Faculty of MedicineBalamand UniversityBeirutLebanon
| | | | - Paula El Najjar
- FMPS Holding BIOTECKNO s.a.l. Research and Quality SolutionsNaccashBeirut60 247Lebanon
- Department of Agricultural and Food Engineering, School of EngineeringHoly Spirit University of KaslikJounieh446Lebanon
| | - Charbel Khalil
- Reviva Regenerative Medicine CenterBsalimLebanon
- Bone Marrow Transplant UnitBurjeel Medical CityAbu DhabiUAE
- Lebanese American University School of MedicineBeirutLebanon
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Stricker E, Peckham-Gregory EC, Scheurer ME. CancerHERVdb: Human Endogenous Retrovirus (HERV) Expression Database for Human Cancer Accelerates Studies of the Retrovirome and Predictions for HERV-Based Therapies. J Virol 2023; 97:e0005923. [PMID: 37255431 PMCID: PMC10308937 DOI: 10.1128/jvi.00059-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 05/10/2023] [Indexed: 06/01/2023] Open
Abstract
In this study, we sought to create a database summarizing the expression of human endogenous retroviruses (HERVs) in various human cancers. HERVs are suitable therapeutic targets due to their abundance in the human genome, overexpression in various malignancies, and involvement in various cancer pathways. We identified articles on HERVs from PubMed and then prescreened and automatically categorized them using the portable document format (PDF) data extractor (PDE) R package. We discovered 196 primary research articles with HERV expression data from cancer tissues or cancer cell lines. HERV RNA and protein expression was reported in brain, breast, cervical, colorectal, endocrine, gastrointestinal, kidney/renal/pelvis, liver, lung, genital, oral cavity, pharynx, ovary, pancreas, prostate, skin, testicular, urinary/bladder, and uterus cancers, leukemias, lymphomas, and myelomas. Additionally, we discovered reports of HERV RNA-only overexpression in soft tissue cancers including heart, thyroid, bone, and joint cancers. The CancerHERVdb database is hosted in the form of interactive visualizations of the expression data and a summary data table at https://erikstricker.shinyapps.io/cancerHERVdb/. The user can filter the findings according to cancer type, HERV family, HERV gene, or a combination thereof and easily export the results with the corresponding reference list. In our report, we provide examples of potential uses of the CancerHERVdb, such as identification of cancers suitable for off-target treatment with the multiple sclerosis-associated retrovirus (MSRV)-Env-targeting antibody GNbAC1 (now named temelimab) currently in phase 2b clinical trials for multiple sclerosis or the discovery of cancers overexpressing HERV-H long terminal repeat-associating 2 (HHLA2), a newly emerging immune checkpoint. In summary, the CancerHERVdb allows cross-study comparisons, encourages data exploration, and informs about potential off-target effects of HERV-targeting treatments. IMPORTANCE Human endogenous retroviruses (HERVs), which in the past have inserted themselves in various regions of the human genome, are to various degrees activated in virtually every cancer type. While a centralized naming system and resources summarizing HERV levels in cancers are lacking, the CancerHERVdb database provides a consolidated resource for cross-study comparisons, data exploration, and targeted searches of HERV activation. The user can access data extracted from hundreds of articles spanning 25 human cancer categories. Therefore, the CancerHERVdb database can aid in the identification of prognostic and risk markers, drivers of cancer, tumor-specific targets, multicancer spanning signals, and targets for immune therapies. Consequently, the CancerHERVdb database is of direct relevance for clinical as well as basic research.
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Affiliation(s)
- Erik Stricker
- Baylor College of Medicine, Department of Molecular Virology and Microbiology, Houston, Texas, USA
- Baylor College of Medicine, Department of Pediatrics, Houston, Texas, USA
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Stricker E, Peckham-Gregory EC, Scheurer ME. HERVs and Cancer-A Comprehensive Review of the Relationship of Human Endogenous Retroviruses and Human Cancers. Biomedicines 2023; 11:936. [PMID: 36979914 PMCID: PMC10046157 DOI: 10.3390/biomedicines11030936] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
Genomic instability and genetic mutations can lead to exhibition of several cancer hallmarks in affected cells such as sustained proliferative signaling, evasion of growth suppression, activated invasion, deregulation of cellular energetics, and avoidance of immune destruction. Similar biological changes have been observed to be a result of pathogenic viruses and, in some cases, have been linked to virus-induced cancers. Human endogenous retroviruses (HERVs), once external pathogens, now occupy more than 8% of the human genome, representing the merge of genomic and external factors. In this review, we outline all reported effects of HERVs on cancer development and discuss the HERV targets most suitable for cancer treatments as well as ongoing clinical trials for HERV-targeting drugs. We reviewed all currently available reports of the effects of HERVs on human cancers including solid tumors, lymphomas, and leukemias. Our review highlights the central roles of HERV genes, such as gag, env, pol, np9, and rec in immune regulation, checkpoint blockade, cell differentiation, cell fusion, proliferation, metastasis, and cell transformation. In addition, we summarize the involvement of HERV long terminal repeat (LTR) regions in transcriptional regulation, creation of fusion proteins, expression of long non-coding RNAs (lncRNAs), and promotion of genome instability through recombination.
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Affiliation(s)
- Erik Stricker
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77047, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77047, USA
| | | | - Michael E. Scheurer
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77047, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77047, USA
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Diakite M, Shaw-Saliba K, Lau CY. Malignancy and viral infections in Sub-Saharan Africa: A review. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2023; 3:1103737. [PMID: 37476029 PMCID: PMC10358275 DOI: 10.3389/fviro.2023.1103737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
The burden of malignancy related to viral infection is increasing in Sub-Saharan Africa (SSA). In 2018, approximately 2 million new cancer cases worldwide were attributable to infection. Prevention or treatment of these infections could reduce cancer cases by 23% in less developed regions and about 7% in developed regions. Contemporaneous increases in longevity and changes in lifestyle have contributed to the cancer burden in SSA. African hospitals are reporting more cases of cancer related to infection (e.g., cervical cancer in women and stomach and liver cancer in men). SSA populations also have elevated underlying prevalence of viral infections compared to other regions. Of 10 infectious agents identified as carcinogenic by the International Agency for Research on Cancer, six are viruses: hepatitis B and C viruses (HBV and HCV, respectively), Epstein-Barr virus (EBV), high-risk types of human papillomavirus (HPV), Human T-cell lymphotropic virus type 1 (HTLV-1), and Kaposi's sarcoma herpesvirus (KSHV, also known as human herpesvirus type 8, HHV-8). Human immunodeficiency virus type 1 (HIV) also facilitates oncogenesis. EBV is associated with lymphomas and nasopharyngeal carcinoma; HBV and HCV are associated with hepatocellular carcinoma; KSHV causes Kaposi's sarcoma; HTLV-1 causes T-cell leukemia and lymphoma; HPV causes carcinoma of the oropharynx and anogenital squamous cell cancer. HIV-1, for which SSA has the greatest global burden, has been linked to increasing risk of malignancy through immunologic dysregulation and clonal hematopoiesis. Public health approaches to prevent infection, such as vaccination, safer injection techniques, screening of blood products, antimicrobial treatments and safer sexual practices could reduce the burden of cancer in Africa. In SSA, inequalities in access to cancer screening and treatment are exacerbated by the perception of cancer as taboo. National level cancer registries, new screening strategies for detection of viral infection and public health messaging should be prioritized in SSA's battle against malignancy. In this review, we discuss the impact of carcinogenic viruses in SSA with a focus on regional epidemiology.
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Affiliation(s)
- Mahamadou Diakite
- University Clinical Research Center, University of Sciences, Techniques, and Technologies, Bamako, Mali
| | - Kathryn Shaw-Saliba
- Collaborative Clinical Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Chuen-Yen Lau
- HIV Dynamics and Replication Program, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, United States
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Egan KM, Kim Y, Bender N, Hodge JM, Coghill AE, Smith-Warner SA, Rollison DE, Teras LR, Grimsrud TK, Waterboer T. Prospective investigation of polyomavirus infection and the risk of adult glioma. Sci Rep 2021; 11:9642. [PMID: 33953301 PMCID: PMC8100283 DOI: 10.1038/s41598-021-89133-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/16/2021] [Indexed: 12/23/2022] Open
Abstract
Glioma is an aggressive primary tumor of the brain with a poorly understood etiology. We studied the association of 4 human polyomaviruses (HPyV)—JC virus (JCV), BK virus (BKV), human polyomavirus 6 (HPyV6), and Merkel cell polyomavirus (MCPyV) with glioma risk within the Cancer Prevention Study II in the US (CPS-II) and the Janus Serum Bank in Norway. Cohort participants subsequently diagnosed with glioma from the CPS-II (n = 37) and Janus Serum Bank (n = 323), a median of 6.9 and 15.4 years after blood collection, respectively, were matched to individual controls on age, sex, and date of blood draw. Serum antibodies to the major viral capsid protein (VP1) were used to establish infection history for each polyomavirus. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. In the Janus Serum Bank, MCPyV infection was associated with a higher risk of glioma overall (OR: 1.56; 95% CI 1.10, 2.19). A modest, nonsignificant positive association with MCPyV infection was also observed in CPS-II (OR: 1.29; 95% CI 0.54, 3.08). In both cohorts, glioma risk was not significantly related to infection with JCV, BKV or HPyV6. The present study suggests that MCPyV infection may increase glioma risk.
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Affiliation(s)
- Kathleen M Egan
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL, 33612, USA.
| | - Youngchul Kim
- Department of Biostatistics, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Noemi Bender
- Infections and Cancer Epidemiology, German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ), 69120, Heidelberg, Germany
| | - James M Hodge
- Department of Population Science, American Cancer Society, Atlanta, GA, 30303, USA
| | - Anna E Coghill
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL, 33612, USA
| | - Stephanie A Smith-Warner
- Departments of Nutrition and Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Dana E Rollison
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL, 33612, USA
| | - Lauren R Teras
- Department of Population Science, American Cancer Society, Atlanta, GA, 30303, USA
| | - Tom K Grimsrud
- Department of Research, Cancer Registry of Norway, 0379, Oslo, Norway
| | - Tim Waterboer
- Infections and Cancer Epidemiology, German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ), 69120, Heidelberg, Germany
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Kristensen MK, Christensen T. Regulation of the expression of human endogenous retroviruses: elements in fetal development and a possible role in the development of cancer and neurological diseases. APMIS 2021; 129:241-253. [PMID: 33683784 DOI: 10.1111/apm.13130] [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: 11/10/2020] [Accepted: 03/03/2021] [Indexed: 12/14/2022]
Abstract
Human endogenous retroviruses (HERVs) are remnants of ancient retroviral germline infections. Most HERV sequences are silenced in somatic cells, but interest is emerging on the involvement of HERV derived transcripts and proteins in human physiology and disease. A HERV-W encoded protein, syncytin-1, has been co-opted into fetal physiology, where it plays a role in trophoblast formation. Altered HERV transcription and expression of HERV derived proteins are associated with various cancer types and neurological diseases such as multiple sclerosis (MS). The implication of HERVs as potential mediators of both health and disease suggests important roles of regulatory mechanisms and alterations of these in physiological and pathological processes. The regulation of HERV sequences is mediated by a wide variety of mechanisms, and the focus of this review is on selected aspects of these, including epigenetic mechanisms such as CpG methylation and histone modifications of the HP1-H3K9me axis, viral transactivation events, and regulatory perspectives of transient stimuli in the microenvironment. Increasing knowledge of the regulation of HERV sequences will not only contribute to the understanding of complex pathogeneses, but also may pinpoint potential targets for better diagnosis and treatment in complex diseases as MS.
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Isaguliants M, Bayurova E, Avdoshina D, Kondrashova A, Chiodi F, Palefsky JM. Oncogenic Effects of HIV-1 Proteins, Mechanisms Behind. Cancers (Basel) 2021; 13:305. [PMID: 33467638 PMCID: PMC7830613 DOI: 10.3390/cancers13020305] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/28/2020] [Accepted: 01/04/2021] [Indexed: 02/08/2023] Open
Abstract
People living with human immunodeficiency virus (HIV-1) are at increased risk of developing cancer, such as Kaposi sarcoma (KS), non-Hodgkin lymphoma (NHL), cervical cancer, and other cancers associated with chronic viral infections. Traditionally, this is linked to HIV-1-induced immune suppression with depletion of CD4+ T-helper cells, exhaustion of lymphopoiesis and lymphocyte dysfunction. However, the long-term successful implementation of antiretroviral therapy (ART) with an early start did not preclude the oncological complications, implying that HIV-1 and its antigens are directly involved in carcinogenesis and may exert their effects on the background of restored immune system even when present at extremely low levels. Experimental data indicate that HIV-1 virions and single viral antigens can enter a wide variety of cells, including epithelial. This review is focused on the effects of five viral proteins: envelope protein gp120, accessory protein negative factor Nef, matrix protein p17, transactivator of transcription Tat and reverse transcriptase RT. Gp120, Nef, p17, Tat, and RT cause oxidative stress, can be released from HIV-1-infected cells and are oncogenic. All five are in a position to affect "innocent" bystander cells, specifically, to cause the propagation of (pre)existing malignant and malignant transformation of normal epithelial cells, giving grounds to the direct carcinogenic effects of HIV-1.
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Affiliation(s)
- Maria Isaguliants
- Gamaleya Research Center for Epidemiology and Microbiology, 123098 Moscow, Russia; (E.B.); (D.A.)
- M.P. Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, 108819 Moscow, Russia;
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177 Stockholm, Sweden;
- Department of Research, Riga Stradins University, LV-1007 Riga, Latvia
| | - Ekaterina Bayurova
- Gamaleya Research Center for Epidemiology and Microbiology, 123098 Moscow, Russia; (E.B.); (D.A.)
- M.P. Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, 108819 Moscow, Russia;
| | - Darya Avdoshina
- Gamaleya Research Center for Epidemiology and Microbiology, 123098 Moscow, Russia; (E.B.); (D.A.)
- M.P. Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, 108819 Moscow, Russia;
| | - Alla Kondrashova
- M.P. Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, 108819 Moscow, Russia;
| | - Francesca Chiodi
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177 Stockholm, Sweden;
| | - Joel M. Palefsky
- Department of Medicine, University of California, San Francisco, CA 94117, USA;
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Abstract
Approximately, 1.4 million virus-induced cancers occur annually, representing roughly 10% of the worldwide cancer burden, with the majority (> 85%) occurring in the lower- and middle-income countries. The viruses associated with the greatest number of cancer cases are human papillomaviruses (HPVs), which cause cervical cancer and several other epithelial malignancies, and hepatitis viruses HBV and HCV, which are responsible for the majority of hepatocellular cancer. Other oncoviruses include Epstein-Barr virus (EBV), Kaposi's sarcoma herpesvirus (KSHV), human T-cell leukemia virus (HTLV-I), and Merkel cell polyoma virus (MCPyV). These oncoviruses include various classes of DNA and RNA viruses and induce cancer by a variety of mechanisms. However, cancers develop in a minority of infected individuals and almost always after chronic infection of many year's duration. Identification of the oncoviruses has provided critical insights in human carcinogenesis and led to several interventions that may reduce the risk of developing the tumors they induce. These interventions include preventive vaccines against HBV and HPV, screening for persistent HPV and HCV infections, antivirals for the treatment of chronic HBV and HCV infection, and screening the blood supply for the presence of HBV and HCV. Further efforts to identify additional oncogenic viruses in human cancers and new insights into etiology and pathogenesis of virally induced cancers would likely lead to new approaches for prophylactic and therapeutic interventions.
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Affiliation(s)
- John T Schiller
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA.
| | - Douglas R Lowy
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
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11
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Wilhelm C, Scherzad A, Bregenzer M, Meyer T, Gehrke T, Kleinsasser N, Hagen R, Hackenberg S. Interaction of head and neck squamous cell carcinoma cells and mesenchymal stem cells under hypoxia and normoxia. Oncol Lett 2020; 20:229. [PMID: 32968451 DOI: 10.3892/ol.2020.12092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 07/23/2020] [Indexed: 02/06/2023] Open
Abstract
Mesenchymal stem cells (MSCs) exhibit strong tropism towards tumor tissue. While MSCs generally surround tumors, they can also infiltrate tumors and thereby influence their proliferation. Interactions between MSCs and tumor cells are usually tested under normoxia, but the majority of solid tumors, including head and neck squamous cell carcinoma (HNSCC), are also characterized by hypoxic areas. Hence, the present study aimed to assess the interaction between MSCs and tumor cells under hypoxic conditions. MSCs were cultivated under normoxia and hypoxia, and conditioned media were used to cultivate the HNSCC cell line FaDu. The cell cycle distribution and viability of MSCs and the proliferation of FaDu cells were analyzed under normoxia and hypoxia, and changes in cytokine levels in the conditioned media were evaluated. No cell cycle changes were observed for MSCs after 24 h of cultivation under hypoxia, but the cell viability had declined. Hypoxia also led to a decrease in the proliferation of FaDu cells; however, FaDu cells proliferated faster after 48 h under hypoxia compared with normoxic conditions. This effect was reversed after incubation under normoxia for 72 h and hypoxia for 72 h. While these changes constituted a trend, these differences were not statistically significant. A cytokine assay showed an increase in interleukin (IL)-6 in the hypoxic medium. Overall, the results indicated that there was an interaction between MSCs and tumor cells. The presence or absence of oxygen seemed to influence the functionality of MSCs and their protumorigenic properties, in which IL-6 was identified as a potential mediator. Since MSCs are a component of the tumor stroma, further in vitro and in vivo studies are needed to investigate this interaction in order to develop novel approaches for tumor therapy.
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Affiliation(s)
- Christian Wilhelm
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Agmal Scherzad
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Maximilian Bregenzer
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Till Meyer
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Thomas Gehrke
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Norbert Kleinsasser
- Department of Otorhinolaryngology, Head and Neck Surgery, Kepler University, A-4020 Linz, Austria
| | - Rudolf Hagen
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Stephan Hackenberg
- Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, Julius Maximilian University of Wuerzburg, D-97080 Wuerzburg, Germany
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12
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Loyola L, Achuthan V, Gilroy K, Borland G, Kilbey A, Mackay N, Bell M, Hay J, Aiyer S, Fingerman D, Villanueva RA, Cameron E, Kozak CA, Engelman AN, Neil J, Roth MJ. Disrupting MLV integrase:BET protein interaction biases integration into quiescent chromatin and delays but does not eliminate tumor activation in a MYC/Runx2 mouse model. PLoS Pathog 2019; 15:e1008154. [PMID: 31815961 PMCID: PMC6974304 DOI: 10.1371/journal.ppat.1008154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 01/21/2020] [Accepted: 10/22/2019] [Indexed: 02/06/2023] Open
Abstract
Murine leukemia virus (MLV) integrase (IN) lacking the C-terminal tail peptide (TP) loses its interaction with the host bromodomain and extraterminal (BET) proteins and displays decreased integration at promoter/enhancers and transcriptional start sites/CpG islands. MLV lacking the IN TP via an altered open reading frame was used to infect tumorigenesis mouse model (MYC/Runx2) animals to observe integration patterns and phenotypic effects, but viral passage resulted in the restoration of the IN TP through small deletions. Mice subsequently infected with an MLV IN lacking the TP coding sequence (TP-) showed an improved median survival by 15 days compared to wild type (WT) MLV infection. Recombination with polytropic endogenous retrovirus (ERV), Pmv20, was identified in seven mice displaying both fast and slow tumorigenesis, highlighting the strong selection within the mouse to maintain the full-length IN protein. Mapping the genomic locations of MLV in tumors from an infected mouse with no observed recombination with ERVs, TP-16, showed fewer integrations at TSS and CpG islands, compared to integrations observed in WT tumors. However, this mouse succumbed to the tumor in relatively rapid fashion (34 days). Analysis of the top copy number integrants in the TP-16 tumor revealed their proximity to known MLV common insertion site genes while maintaining the MLV IN TP- genotype. Furthermore, integration mapping in K562 cells revealed an insertion preference of MLV IN TP- within chromatin profile states associated with weakly transcribed heterochromatin with fewer integrations at histone marks associated with BET proteins (H3K4me1/2/3, and H3K27Ac). While MLV IN TP- showed a decreased overall rate of tumorigenesis compared to WT virus in the MYC/Runx2 model, MLV integration still occurred at regions associated with oncogenic driver genes independently from the influence of BET proteins, either stochastically or through trans-complementation by functional endogenous Gag-Pol protein. Many different retroviruses, including murine leukemia virus (MLV), are used as vectors for human gene therapy and cancer immunotherapies (CAR-T) because of their stable and efficient delivery of genetic material into the host DNA. However, this process can result in activation and/or disruption of cellular genes, which has resulted in the outgrowth of tumors in previous clinical trials. Of critical importance is the preferred location within the host genome at which the retrovirus integrates. Our study presents a modified MLV virus that has lost the ability to bind to the host BET proteins, the drivers of insertion at promoter/enhancer regions of highly activated genes. This is the first direct study within an animal model to examine whether infection with this type of modified MLV virus affects tumor progression. We found that the modified virus improved the survival of the well-characterized MYC/Runx2 mouse compared to infections with the wild-type MLV. Most modified viral integrants mapped into less active regions of the genome, but some integration events still occurred near cancer-related genes. Thus, while the modified MLV virus can be a safer vector than the wildtype virus, it still maintains the potential to activate oncogenes. This study provides new insights on how to improve the safety of MLV retroviral vectors.
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Affiliation(s)
- Lorenz Loyola
- Rutgers-Robert Wood Johnson Medical School, Dept of Pharmacology, Piscataway, New Jersey, United States of America
| | - Vasudevan Achuthan
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Department of Medicine, Boston, Massachusetts, United States of America
| | - Kathryn Gilroy
- Beatson Institute for Cancer Research, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gillian Borland
- MRC Univ. of Glasgow Centre for Virus Research, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anna Kilbey
- MRC Univ. of Glasgow Centre for Virus Research, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Nancy Mackay
- MRC Univ. of Glasgow Centre for Virus Research, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Margaret Bell
- Univ. of Glasgow School of Veterinary Medicine, Department of Veterinary Pathology Bearsden, United Kingdom
| | - Jodie Hay
- MRC Univ. of Glasgow Centre for Virus Research, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sriram Aiyer
- Rutgers-Robert Wood Johnson Medical School, Dept of Pharmacology, Piscataway, New Jersey, United States of America
| | - Dylan Fingerman
- Rutgers-Robert Wood Johnson Medical School, Dept of Pharmacology, Piscataway, New Jersey, United States of America
| | - Rodrigo A. Villanueva
- Rutgers-Robert Wood Johnson Medical School, Dept of Pharmacology, Piscataway, New Jersey, United States of America
| | - Ewan Cameron
- Univ. of Glasgow School of Veterinary Medicine, Department of Veterinary Pathology Bearsden, United Kingdom
| | | | - Alan N. Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Department of Medicine, Boston, Massachusetts, United States of America
| | - James Neil
- MRC Univ. of Glasgow Centre for Virus Research, College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Monica J. Roth
- Rutgers-Robert Wood Johnson Medical School, Dept of Pharmacology, Piscataway, New Jersey, United States of America
- * E-mail:
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13
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Minarovits J, Niller HH. Truncated oncoproteins of retroviruses and hepatitis B virus: A lesson in contrasts. INFECTION GENETICS AND EVOLUTION 2019; 73:342-357. [DOI: 10.1016/j.meegid.2019.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/14/2019] [Accepted: 05/27/2019] [Indexed: 02/07/2023]
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14
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Broecker F, Moelling K. What viruses tell us about evolution and immunity: beyond Darwin? Ann N Y Acad Sci 2019; 1447:53-68. [PMID: 31032941 PMCID: PMC6850104 DOI: 10.1111/nyas.14097] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/09/2019] [Accepted: 03/20/2019] [Indexed: 12/14/2022]
Abstract
We describe mechanisms of genetic innovation mediated by viruses and related elements that, during evolution, caused major genetic changes beyond what was anticipated by Charles Darwin. Viruses and related elements introduced genetic information and have shaped the genomes and immune systems of all cellular life forms. None of these mechanisms contradict Darwin's theory of evolution but extend it by means of sequence information that has recently become available. Not only do small increments of genetic information contribute to evolution, but also do major events such as infection by viruses or bacteria, which can supply new genetic information to a host by horizontal gene transfer. Thereby, viruses and virus-like elements act as major drivers of evolution.
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Affiliation(s)
- Felix Broecker
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Karin Moelling
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.,Max Planck Institute for Molecular Genetics, Berlin, Germany
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15
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Zhang M, Liang JQ, Zheng S. Expressional activation and functional roles of human endogenous retroviruses in cancers. Rev Med Virol 2019; 29:e2025. [PMID: 30614117 PMCID: PMC6590502 DOI: 10.1002/rmv.2025] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 10/26/2018] [Accepted: 11/05/2018] [Indexed: 12/26/2022]
Abstract
Human endogenous retroviruses (HERVs) are widely believed to be remnants of ancestral germ line infections by exogenous retroviruses. Although HERVs are deemed as “nonfunctional DNAs” due to loss of most of their viral protein coding capacity during evolution as part of the human genome, cumulative evidences are showing the expressional activation and potential roles of HERVs in diseases especially cancers. Work by other researchers and us has observed the dysregulation of HERVs in cancers, identified new HERV‐related genes, and revealed their potential importance in cancer development. Here, we summarized the current knowledge on the mechanisms of the expressional activation and functional roles of HERVs, with a focus on the H family HERV (HERV‐H), in carcinogenesis. HERV expression is regulated by external chemical or physical substances and exogenous virus infection, as well as host factors such as epigenetic DNA methylation, transcription factors, cytokines, and small RNAs. Diverse roles of HERVs have been proposed by acting in the forms of noncoding RNAs, proteins, and transcriptional regulators during carcinogenesis. However, much remains to be learnt about the contributions of HERVs to human cancers. More investigation is warranted to elucidate the functions of these “fossil remnants” yet important viral DNAs in the human genome.
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Affiliation(s)
- Mengwen Zhang
- The Department of Plastic and Reconstructive Surgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Cancer Institute, Second Affiliated Hospital, and Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, China
| | - Jessie Qiaoyi Liang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Shu Zheng
- Cancer Institute, Second Affiliated Hospital, and Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, China.,The Department of surgical oncology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
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16
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Balestrieri E, Argaw-Denboba A, Gambacurta A, Cipriani C, Bei R, Serafino A, Sinibaldi-Vallebona P, Matteucci C. Human Endogenous Retrovirus K in the Crosstalk Between Cancer Cells Microenvironment and Plasticity: A New Perspective for Combination Therapy. Front Microbiol 2018; 9:1448. [PMID: 30013542 PMCID: PMC6036167 DOI: 10.3389/fmicb.2018.01448] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/11/2018] [Indexed: 12/24/2022] Open
Abstract
Abnormal activation of human endogenous retroviruses (HERVs) has been associated with several diseases such as cancer, autoimmunity, and neurological disorders. In particular, in cancer HERV activity and expression have been specifically associated with tumor aggressiveness and patient outcomes. Cancer cell aggressiveness is intimately linked to the acquisition of peculiar plasticity and heterogeneity based on cell stemness features, as well as on the crosstalk between cancer cells and the microenvironment. The latter is a driving factor in the acquisition of aggressive phenotypes, associated with metastasis and resistance to conventional cancer therapies. Remarkably, in different cell types and stages of development, HERV expression is mainly regulated by epigenetic mechanisms and is subjected to a very precise temporal and spatial regulation according to the surrounding microenvironment. Focusing on our research experience with HERV-K involvement in the aggressiveness and plasticity of melanoma cells, this perspective aims to highlight the role of HERV-K in the crosstalk between cancer cells and the tumor microenvironment. The implications for a combination therapy targeted at HERVs with standard approaches are discussed.
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Affiliation(s)
- Emanuela Balestrieri
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Ayele Argaw-Denboba
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Alessandra Gambacurta
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Chiara Cipriani
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Roberto Bei
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Annalucia Serafino
- Institute of Translational Pharmacology, National Research Council, Rome, Italy
| | - Paola Sinibaldi-Vallebona
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy.,Institute of Translational Pharmacology, National Research Council, Rome, Italy
| | - Claudia Matteucci
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
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17
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Mullins JI, Frenkel LM. Clonal Expansion of Human Immunodeficiency Virus-Infected Cells and Human Immunodeficiency Virus Persistence During Antiretroviral Therapy. J Infect Dis 2017; 215:S119-S127. [PMID: 28520966 DOI: 10.1093/infdis/jiw636] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The latent HIV-1 reservoir in blood decays very slowly, even during prolonged suppression of viral replication by antiretroviral therapy (ART). Mechanisms for reservoir persistence include replenishment through low-level viral replication, longevity and homeostatic proliferation of memory T cells, and most recently appreciated, clonal expansion of HIV-infected cells. Clonally expanded cells make up a large and increasing fraction of the residual infected cell population on ART, and insertion of HIV proviruses into certain host cellular genes has been associated with this proliferation. That the vast majority of proviruses are defective clouds our assessment of the degree to which clonally expanded cells harbor infectious viruses, and thus the extent to which they contribute to reservoirs relevant to curing infection. This review summarizes past studies that have defined our current understanding and the gaps in our knowledge of the mechanisms by which proviral integration and clonal expansion sustain the HIV reservoir.
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Affiliation(s)
- James I Mullins
- Departments of Microbiology, Medicine, Global Health and Laboratory Medicine, University of Washington, Seattle, WA, US
| | - Lisa M Frenkel
- Departments of Pediatrics, Medicine, Global Health and Laboratory Medicine, University of Washington, Seattle, WA, US.,Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, US
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18
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Babaian A, Mager DL. Endogenous retroviral promoter exaptation in human cancer. Mob DNA 2016; 7:24. [PMID: 27980689 PMCID: PMC5134097 DOI: 10.1186/s13100-016-0080-x] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/11/2016] [Indexed: 12/13/2022] Open
Abstract
Cancer arises from a series of genetic and epigenetic changes, which result in abnormal expression or mutational activation of oncogenes, as well as suppression/inactivation of tumor suppressor genes. Aberrant expression of coding genes or long non-coding RNAs (lncRNAs) with oncogenic properties can be caused by translocations, gene amplifications, point mutations or other less characterized mechanisms. One such mechanism is the inappropriate usage of normally dormant, tissue-restricted or cryptic enhancers or promoters that serve to drive oncogenic gene expression. Dispersed across the human genome, endogenous retroviruses (ERVs) provide an enormous reservoir of autonomous gene regulatory modules, some of which have been co-opted by the host during evolution to play important roles in normal regulation of genes and gene networks. This review focuses on the “dark side” of such ERV regulatory capacity. Specifically, we discuss a growing number of examples of normally dormant or epigenetically repressed ERVs that have been harnessed to drive oncogenes in human cancer, a process we term onco-exaptation, and we propose potential mechanisms that may underlie this phenomenon.
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Affiliation(s)
- Artem Babaian
- Terry Fox Laboratory, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, BC V5Z1L3 Canada ; Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
| | - Dixie L Mager
- Terry Fox Laboratory, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, BC V5Z1L3 Canada ; Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
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19
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Abstract
Worldwide, increasing numbers of patients are developing end-stage renal disease, and at present, the only treatment options are dialysis or kidney transplantation. Dialysis is associated with increased morbidity and mortality, poor life quality and high economic costs. Transplantation is by far the better option, but there are insufficient numbers of donor kidneys available. Therefore, there is an urgent need to explore alternative approaches. In this review, we discuss how this problem could potentially be addressed by using autologous cells and appropriate scaffolds to develop 'bioengineered' kidneys for transplantation. In particular, we will highlight recent breakthroughs in pluripotent stem cell biology that have led to the development of autologous renal progenitor cells capable of differentiating to all renal cell types and will discuss how these cells could be combined with appropriate scaffolds to develop a bioengineered kidney.
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Affiliation(s)
- Bettina Wilm
- Institute of Translational Medicine, Centre for Preclinical Imaging, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - Riccardo Tamburrini
- Department of Surgery, Section of Transplantation, Wake Forest School of Medicine,Wake Forest Baptist Hospital, Medical Center Blvd, Winston Salem, NC 27157 USA
| | - Giuseppe Orlando
- Department of Surgery, Section of Transplantation, Wake Forest School of Medicine,Wake Forest Baptist Hospital, Medical Center Blvd, Winston Salem, NC 27157 USA
| | - Patricia Murray
- Institute of Translational Medicine, Centre for Preclinical Imaging, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
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20
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Hosseinkhani H, Abedini F, Ou KL, Domb AJ. Polymers in gene therapy technology. POLYM ADVAN TECHNOL 2014. [DOI: 10.1002/pat.3432] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Hossein Hosseinkhani
- Graduate Institute of Biomedical Engineering; National Taiwan University of Science and Technology (Taiwan Tech); Taipei 10607 Taiwan
- Center of Excellence in Nanomedicine; National Taiwan University of Science and Technology (Taiwan Tech); Taipei 10607 Taiwan
- Research Center for Biomedical Devices and Prototyping Production, Research Center for Biomedical Implants and Microsurgery Devices, Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Department of Dentistry; Taipei Medical University-Shuang Ho Hospital; Taipei 235 Taiwan
| | - Fatemeh Abedini
- Razi Vaccine and Serum Research Institute; Karaj Alborz IRAN
| | - Keng-Liang Ou
- Research Center for Biomedical Devices and Prototyping Production, Research Center for Biomedical Implants and Microsurgery Devices, Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Department of Dentistry; Taipei Medical University-Shuang Ho Hospital; Taipei 235 Taiwan
| | - Abraham J. Domb
- Institute of Drug Research, The Center for Nanoscience and Nanotechnology, School of Pharmacy-Faculty of Medicine; The Hebrew University of Jerusalem; Jerusalem 91120 Israel
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21
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Turan S, Qiao J, Madden S, Benham C, Kotz M, Schambach A, Bode J. Expanding Flp-RMCE options: the potential of Recombinase Mediated Twin-Site Targeting (RMTT). Gene 2014; 546:135-44. [DOI: 10.1016/j.gene.2014.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 06/02/2014] [Indexed: 01/02/2023]
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22
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Wagner TA, McLaughlin S, Garg K, Cheung CYK, Larsen BB, Styrchak S, Huang HC, Edlefsen PT, Mullins JI, Frenkel LM. HIV latency. Proliferation of cells with HIV integrated into cancer genes contributes to persistent infection. Science 2014; 345:570-3. [PMID: 25011556 DOI: 10.1126/science.1256304] [Citation(s) in RCA: 509] [Impact Index Per Article: 50.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Antiretroviral treatment (ART) of HIV infection suppresses viral replication. Yet if ART is stopped, virus reemerges because of the persistence of infected cells. We evaluated the contribution of infected-cell proliferation and sites of proviral integration to HIV persistence. A total of 534 HIV integration sites (IS) and 63 adjacent HIV env sequences were derived from three study participants over 11.3 to 12.7 years of ART. Each participant had identical viral sequences integrated at the same position in multiple cells, demonstrating infected-cell proliferation. Integrations were overrepresented in genes associated with cancer and favored in 12 genes across multiple participants. Over time on ART, a greater proportion of persisting proviruses were in proliferating cells. HIV integration into specific genes may promote proliferation of HIV-infected cells, slowing viral decay during ART.
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Affiliation(s)
- Thor A Wagner
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA. University of Washington, Seattle, WA, USA
| | - Sherry McLaughlin
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA. University of Washington, Seattle, WA, USA
| | - Kavita Garg
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | | | - Sheila Styrchak
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA
| | - Hannah C Huang
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA
| | - Paul T Edlefsen
- University of Washington, Seattle, WA, USA. Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Lisa M Frenkel
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA. University of Washington, Seattle, WA, USA.
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23
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Kassiotis G. Endogenous retroviruses and the development of cancer. THE JOURNAL OF IMMUNOLOGY 2014; 192:1343-9. [PMID: 24511094 DOI: 10.4049/jimmunol.1302972] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mammalian genomes include a considerable number of endogenous retroviruses (ERVs), relics of ancestral infectious retroviruses, whose proviruses have invaded the germ-line. The documented ability of infectious retroviruses to cause cancer has greatly contributed to the discovery of ERVs. It also reinforced the concept that ERVs are causative agents of many cancers, a notion that historically has not always stood up to experimental scrutiny. The recent greater appreciation of the complexity of ERV biology and the identification of dedicated host mechanisms controlling ERV activity have revealed novel interactions between ERVs and their hosts, with the potential to cause or contribute to disease. In this review, the involvement of ERVs in cancer initiation and progression is discussed, as well as their contribution to our understanding of the process of transformation and to the invention of innovative preventive and therapeutic cancer treatments.
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Affiliation(s)
- George Kassiotis
- Division of Immunoregulation, Medical Research Council National Institute for Medical Research, London NW7 1AA, United Kingdom
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24
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Presence of viral DNA in whole-genome sequencing of brain tumor tissues from the cancer genome atlas. J Virol 2014; 88:774. [PMID: 24353289 DOI: 10.1128/jvi.02725-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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25
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Abstract
It is now estimated that approximately 10 % of worldwide cancers are attributable to viral infection, with the vast majority (>85 %) occurring in the developing world. Oncogenic viruses include various classes of DNA and RNA viruses and induce cancer by a variety of mechanisms. A unifying theme is that cancer develops in a minority of infected individuals and only after chronic infection of many years duration. The viruses associated with the greatest number of cancer cases are the human papillomaviruses (HPVs), which cause cervical cancer and several other epithelial malignancies, and the hepatitis viruses HBV and HCV, which are responsible for the majority of hepatocellular cancer. Other oncoviruses include Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpes virus (KSHV), human T-cell leukemia virus (HTLV-I), and Merkel cell polyomavirus (MCPyV). Identification of the infectious cause has led to several interventions that may reduce the risk of developing these tumors. These include preventive vaccines against HBV and HPV, HPV-based testing for cervical cancer screening, anti-virals for the treatment of chronic HBV and HCV infection, and screening the blood supply for the presence of HBV and HCV. Successful efforts to identify additional oncogenic viruses in human cancer may lead to further insight into etiology and pathogenesis as well as to new approaches for therapeutic and prophylactic intervention.
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Affiliation(s)
- John T Schiller
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA,
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26
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Pathological and evolutionary implications of retroviruses as mobile genetic elements. Genes (Basel) 2013; 4:573-82. [PMID: 24705263 PMCID: PMC3927575 DOI: 10.3390/genes4040573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/27/2013] [Accepted: 10/08/2013] [Indexed: 11/17/2022] Open
Abstract
Retroviruses, a form of mobile genetic elements, have important roles in disease and primate evolution. Exogenous retroviruses, such as human immunodeficiency virus (HIV), have significant pathological implications that have created a massive public health challenge in recent years. Endogenous retroviruses (ERVs), which are the primary focus of this review, can also be pathogenic, as well as being beneficial to a host in some cases. Furthermore, retroviruses may have played a key role in primate evolution that resulted in the incorporation of these elements into the human genome. Retroviruses are mobile genetic elements that have important roles in disease and primate evolution. We will further discuss the pathogenic potential of retroviruses, including their role in cancer biology, and will briefly summarize their evolutionary implications.
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27
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Owens JB, Mauro D, Stoytchev I, Bhakta MS, Kim MS, Segal DJ, Moisyadi S. Transcription activator like effector (TALE)-directed piggyBac transposition in human cells. Nucleic Acids Res 2013; 41:9197-207. [PMID: 23921635 PMCID: PMC3799441 DOI: 10.1093/nar/gkt677] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/09/2013] [Accepted: 07/10/2013] [Indexed: 12/13/2022] Open
Abstract
Insertional therapies have shown great potential for combating genetic disease and safer methods would undoubtedly broaden the variety of possible illness that can be treated. A major challenge that remains is reducing the risk of insertional mutagenesis due to random insertion by both viral and non-viral vectors. Targetable nucleases are capable of inducing double-stranded breaks to enhance homologous recombination for the introduction of transgenes at specific sequences. However, off-target DNA cleavages at unknown sites can lead to mutations that are difficult to detect. Alternatively, the piggyBac transposase is able perform all of the steps required for integration; therefore, cells confirmed to contain a single copy of a targeted transposon, for which its location is known, are likely to be devoid of aberrant genomic modifications. We aimed to retarget transposon insertions by comparing a series of novel hyperactive piggyBac constructs tethered to a custom transcription activator like effector DNA-binding domain designed to bind the first intron of the human CCR5 gene. Multiple targeting strategies were evaluated using combinations of both plasmid-DNA and transposase-protein relocalization to the target sequence. We demonstrated user-defined directed transposition to the CCR5 genomic safe harbor and isolated single-copy clones harboring targeted integrations.
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Affiliation(s)
- Jesse B. Owens
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
| | - Damiano Mauro
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
| | - Ilko Stoytchev
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
| | - Mital S. Bhakta
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
| | - Moon-Soo Kim
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
| | - David J. Segal
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
| | - Stefan Moisyadi
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA, Genome Center, Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA and Manoa BioSciences, Honolulu, HI 96819, USA
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Dabrowska MJ, Ejegod D, Lassen LB, Johnsen HE, Wabl M, Pedersen FS, Dybkær K. Gene expression profiling of murine T-cell lymphoblastic lymphoma identifies deregulation of S-phase initiating genes. Leuk Res 2013; 37:1383-90. [PMID: 23896059 DOI: 10.1016/j.leukres.2013.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 03/24/2013] [Accepted: 04/08/2013] [Indexed: 12/11/2022]
Abstract
In a search for genes and pathways implicated in T-cell lymphoblastic lymphoma (T-LBL) development, we used a murine lymphoma model, where mice of the NMRI-inbred strain were inoculated with murine leukemia virus mutants. The resulting tumors were analyzed by integration analysis and global gene expression profiling to determine the effect of the retroviral integrations on the nearby genes, and the deregulated pathways in the tumors. Gene expression profiling identified increased expression of genes involved in the minichromosome maintenance and origin of recognition pathway as well as downregulation in negative regulators of G1/S transition, indicating increased S-phase initiation in murine T-LBLs.
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Yang Y, Xiao F, Lu Z, Li Z, Zuo H, Zhang Q, Li Q, Wang H, Wang LS. Development of a novel adenovirus-alphavirus hybrid vector with RNA replicon features for malignant hematopoietic cell transduction. Cancer Gene Ther 2013; 20:429-36. [PMID: 23827880 DOI: 10.1038/cgt.2013.37] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/24/2013] [Accepted: 06/02/2013] [Indexed: 01/06/2023]
Abstract
To improve the expression levels of transgenes in malignant hematopoietic cells, we developed a novel adenoviral-alphavirus hybrid vector Ad5/F11p-SFV-GFP that contains a Semliki Forest Virus (SFV) replicon and chimeric fibers of Ad5 and Ad11p. Ad5/F11p-SFV-GFP infected >95% of K562, U937 or Jurkat cells and 23.65% of HL-60 cells, and led to moderate Enhanced Green Fluorescent Protein (EGFP) transgene expression intensity. The infection efficiency of Ad5/F11p-SFV-GFP in primary human leukemia cells ranged from 9.34-89.63% (median, 28.58%) at a multiplicity of infection (MOI) of 100, compared with only 3.37-44.54% (median, 10.42%) in cells infected by Ad5/F11p-GFP. Importantly, Ad5/F11p-SFV-GFP led to a significantly higher transgene expression level in primary leukemia cells, as indicated by the relative fluorescence intensity, compared to cells infected with Ad5/F11p-GFP. The increased expression of EGFP in Ad5/F11p-SFV-GFP-infected cells was associated with the accumulation of abundant subgenomic mRNA. Additionally, infection of K562, U937 or Jurkat cells by Ad5/F11p-SFV-GFP was significantly inhibited by blocking CD46 receptor; however, other factors may affect the gene-transfer efficiency of Ad5/F11p-SFV-GFP in primary leukemia cells. In conclusion, we successfully developed a novel adenoviral-alphavirus hybrid vector with RNA replicon features, which represents a promising vector for gene modifications during the production of cell-based vaccines for leukemia patients.
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Affiliation(s)
- Y Yang
- Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China
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Shimizu A, Kobayashi N, Shimada K, Oura K, Tanaka T, Okamoto A, Kondo K. Novel gene therapy viral vector using non-oncogenic lymphotropic herpesvirus. PLoS One 2013; 8:e56027. [PMID: 23409116 PMCID: PMC3569415 DOI: 10.1371/journal.pone.0056027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/04/2013] [Indexed: 01/26/2023] Open
Abstract
Despite the use of retroviral vectors, efficiently introducing target genes into immunocytes such as T cells is difficult. In addition, retroviral vectors carry risks associated with the oncogenicity of the native virus and the potential for introducing malignancy in recipients due to genetic carryover from immortalized cells used during vector production. To address these issues, we have established a new virus vector that is based on human herpesvirus 6 (HHV-6), a non-oncogenic lymphotropic herpesvirus that infects CD4+ T cells, macrophages, and dendritic cells. In the present study, we have altered the cell specificity of the resulting recombinant HHV-6 by knocking out the U2–U8 genes. The resulting virus proliferated only in activated cord blood cells and not in peripheral blood cells. Umbilical cord blood cells produced replication-defective recombinant virus in sufficiently high titer to omit the use of immortalized cells during vector production. HHV-6 vectors led to high rates (>90%) of gene transduction in both CD4+ and CD8+ T cells. These viruses showed low-level replication of viral DNA that supported greater expression of the induced genes than that of other methods but that was insufficient to support the production of replication-competent virus. Furthermore, HHV-6 vectors containing short hairpin RNAs against CD4 and HIV Gag remarkably inhibited the production of these proteins and HIV particles. Here we demonstrate the utility of HHV-6 as a new non-carcinogenic viral vector for immunologic diseases and immunotherapy.
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Affiliation(s)
- Akihiro Shimizu
- Department of Virology, The Jikei University School of Medicine, Tokyo, Japan
| | - Nobuyuki Kobayashi
- Department of Virology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kazuya Shimada
- Department of Virology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kuniaki Oura
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Tadao Tanaka
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Aikou Okamoto
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kazuhiro Kondo
- Department of Virology, The Jikei University School of Medicine, Tokyo, Japan
- * E-mail:
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Recombinase-mediated cassette exchange (RMCE) — A rapidly-expanding toolbox for targeted genomic modifications. Gene 2013. [DOI: 10.1016/j.gene.2012.11.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Nellåker C, Keane TM, Yalcin B, Wong K, Agam A, Belgard TG, Flint J, Adams DJ, Frankel WN, Ponting CP. The genomic landscape shaped by selection on transposable elements across 18 mouse strains. Genome Biol 2012; 13:R45. [PMID: 22703977 PMCID: PMC3446317 DOI: 10.1186/gb-2012-13-6-r45] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/25/2012] [Accepted: 06/15/2012] [Indexed: 12/20/2022] Open
Abstract
Background Transposable element (TE)-derived sequence dominates the landscape of mammalian genomes and can modulate gene function by dysregulating transcription and translation. Our current knowledge of TEs in laboratory mouse strains is limited primarily to those present in the C57BL/6J reference genome, with most mouse TEs being drawn from three distinct classes, namely short interspersed nuclear elements (SINEs), long interspersed nuclear elements (LINEs) and the endogenous retrovirus (ERV) superfamily. Despite their high prevalence, the different genomic and gene properties controlling whether TEs are preferentially purged from, or are retained by, genetic drift or positive selection in mammalian genomes remain poorly defined. Results Using whole genome sequencing data from 13 classical laboratory and 4 wild-derived mouse inbred strains, we developed a comprehensive catalogue of 103,798 polymorphic TE variants. We employ this extensive data set to characterize TE variants across the Mus lineage, and to infer neutral and selective processes that have acted over 2 million years. Our results indicate that the majority of TE variants are introduced though the male germline and that only a minority of TE variants exert detectable changes in gene expression. However, among genes with differential expression across the strains there are twice as many TE variants identified as being putative causal variants as expected. Conclusions Most TE variants that cause gene expression changes appear to be purged rapidly by purifying selection. Our findings demonstrate that past TE insertions have often been highly deleterious, and help to prioritize TE variants according to their likely contribution to gene expression or phenotype variation.
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Affiliation(s)
- Christoffer Nellåker
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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An optogenetic approach in epilepsy. Neuropharmacology 2012; 69:89-95. [PMID: 22698957 DOI: 10.1016/j.neuropharm.2012.05.049] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 05/28/2012] [Accepted: 05/29/2012] [Indexed: 12/14/2022]
Abstract
Optogenetic tools comprise a variety of different light-sensitive proteins from single-cell organisms that can be expressed in mammalian neurons and effectively control their excitability. Two main classes of optogenetic tools allow to either depolarize or hyperpolarize, and respectively generate or inhibit action potentials in selective populations of neurons. This opens unprecedented possibilities for delineating the role of certain neuronal populations in brain processing and diseases. Moreover, optogenetics may be considered for developing potential treatment strategies for brain diseases, particularly for excitability disorders such as epilepsy. Expression of the inhibitory halorhodopsin NpHR in hippocampal principal cells has been recently used as a tool to effectively control chemically and electrically induced epileptiform activity in slice preparations, and to reduce in vivo spiking induced by tetanus toxin injection in the motor cortex. In this review we give a comprehensive summary of what has been achieved so far in the field of epilepsy using optogenetics, and discuss some of the possible strategies that could be envisaged in the future. We also point out some of the challenges and pitfalls in relation to possible outcomes of using optogenetics for controlling network excitability, and associated brain diseases. This article is part of the Special Issue entitled 'New Targets and Approaches to the Treatment of Epilepsy'.
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Fan H. Cell transformation by RNA viruses: an overview. Viruses 2011; 3:858-60. [PMID: 21994757 PMCID: PMC3185770 DOI: 10.3390/v3060858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 06/14/2011] [Indexed: 12/16/2022] Open
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