1
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Demirden SF, Kimiz-Gebologlu I, Oncel SS. Animal Cell Lines as Expression Platforms in Viral Vaccine Production: A Post Covid-19 Perspective. ACS OMEGA 2024; 9:16904-16926. [PMID: 38645343 PMCID: PMC11025085 DOI: 10.1021/acsomega.3c10484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/11/2024] [Accepted: 03/20/2024] [Indexed: 04/23/2024]
Abstract
Vaccines are considered the most effective tools for preventing diseases. In this sense, with the Covid-19 pandemic, the effects of which continue all over the world, humanity has once again remembered the importance of the vaccine. Also, with the various epidemic outbreaks that occurred previously, the development processes of effective vaccines against these viral pathogens have accelerated. By these efforts, many different new vaccine platforms have been approved for commercial use and have been introduced to the commercial landscape. In addition, innovations have been made in the production processes carried out with conventionally produced vaccine types to create a rapid response to prevent potential epidemics or pandemics. In this situation, various cell lines are being positioned at the center of the production processes of these new generation viral vaccines as expression platforms. Therefore, since the main goal is to produce a fast, safe, and effective vaccine to prevent the disease, in addition to existing expression systems, different cell lines that have not been used in vaccine production until now have been included in commercial production for the first time. In this review, first current viral vaccine types in clinical use today are described. Then, the reason for using cell lines, which are the expression platforms used in the production of these viral vaccines, and the general production processes of cell culture-based viral vaccines are mentioned. Also, selection parameters for animal cell lines as expression platforms in vaccine production are explained by considering bioprocess efficiency and current regulations. Finally, all different cell lines used in cell culture-based viral vaccine production and their properties are summarized, with an emphasis on the current and future status of cell cultures in industrial viral vaccine production.
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Affiliation(s)
| | | | - Suphi S. Oncel
- Ege University, Bioengineering Department, Izmir, 35100, Turkiye
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2
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Önay Uçar E, Şengelen A, Mertoğlu Kamalı E. Hsp27, Hsp60, Hsp70, or Hsp90 depletion enhances the antitumor effects of resveratrol via oxidative and ER stress response in human glioblastoma cells. Biochem Pharmacol 2023; 208:115409. [PMID: 36603687 DOI: 10.1016/j.bcp.2022.115409] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/22/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023]
Abstract
Therapeutic resistance of gliomas is still a crucial issue and closely related to induced heat shock response (HSR). Resveratrol (RSV) is a promising experimental agent for glioblastoma (GB) therapy. However, the role of heat shock protein (Hsp)27, Hsp60, Hsp70, and Hsp90 on the therapeutic efficacy of RSV remains unclear in gliomas. Herein, small interfering (si)RNA transfection was performed to block Hsp expressions. RSV treatments reduced glioma cells' viability dose- and time-dependent while keeping HEK-293 normal cells alive. Furthermore, a low dose of RSV (15 µM/48 h) offered protection against oxidative stress and apoptosis due to Hsp depletion in healthy cells. On the contrary, in glioma cells, RSV (15 µM/48 h) increased ROS (reactive oxygen species) production, led to autophagy and induced endoplasmic reticulum (ER) stress and apoptosis, and reduced 2D- and 3D-clonogenic survival. Hsp27, Hsp60, Hsp70, or Hsp90 depletion also resulted in cell death through ER stress response and ROS burst. Remarkably, the heat shock response (increased HSF1 levels) due to Hsp depletion was attenuated by RSV in glioma cells. Collectively, our data show that these Hsp silencings make glioma cells more sensitive to RSV treatment, indicating that these Hsps are potential therapeutic targets for GB treatment.
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Affiliation(s)
- Evren Önay Uçar
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Istanbul, Turkey.
| | - Aslıhan Şengelen
- Department of Molecular Biology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, Istanbul, Turkey.
| | - Elif Mertoğlu Kamalı
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Istanbul, Turkey.
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3
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Mosaheb MM, Brown MC, Dobrikova EY, Dobrikov MI, Gromeier M. Harnessing virus tropism for dendritic cells for vaccine design. Curr Opin Virol 2020; 44:73-80. [PMID: 32771959 DOI: 10.1016/j.coviro.2020.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 07/17/2020] [Indexed: 01/13/2023]
Abstract
Dendritic cells (DCs) are pivotal stimulators of T cell responses. They provide essential signals (epitope presentation, proinflammatory cytokines, co-stimulation) to T cells and prime adaptive immunity. Therefore, they are paramount to immunization strategies geared to generate T cell immunity. The inflammatory signals DCs respond to, classically occur in the context of acute virus infection. Yet, enlisting viruses for engaging DCs is hampered by their penchant for targeting DCs with sophisticated immune evasive and suppressive ploys. In this review, we discuss our work on devising vectors based on a recombinant polio:rhinovirus chimera for effectively targeting and engaging DCs. We are juxtaposing this approach with commonly used, recently studied dsDNA virus vector platforms.
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Affiliation(s)
- Mubeen M Mosaheb
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Michael C Brown
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Elena Y Dobrikova
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Mikhail I Dobrikov
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Matthias Gromeier
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States.
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4
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Mosaheb MM, Dobrikova EY, Brown MC, Yang Y, Cable J, Okada H, Nair SK, Bigner DD, Ashley DM, Gromeier M. Genetically stable poliovirus vectors activate dendritic cells and prime antitumor CD8 T cell immunity. Nat Commun 2020; 11:524. [PMID: 31988324 PMCID: PMC6985231 DOI: 10.1038/s41467-019-13939-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 12/06/2019] [Indexed: 12/20/2022] Open
Abstract
Viruses naturally engage innate immunity, induce antigen presentation, and mediate CD8 T cell priming against foreign antigens. Polioviruses can provide a context optimal for generating antigen-specific CD8 T cells, as they have natural tropism for dendritic cells, preeminent inducers of CD8 T cell immunity; elicit Th1-promoting inflammation; and lack interference with innate or adaptive immunity. However, notorious genetic instability and underlying neuropathogenicity has hampered poliovirus-based vector applications. Here we devised a strategy based on the polio:rhinovirus chimera PVSRIPO, devoid of viral neuropathogenicity after intracerebral inoculation in human subjects, for stable expression of exogenous antigens. PVSRIPO vectors infect, activate, and induce epitope presentation in DCs in vitro; they recruit and activate DCs with Th1-dominant cytokine profiles at the injection site in vivo. They efficiently prime tumor antigen-specific CD8 T cells in vivo, induce CD8 T cell migration to the tumor site, delay tumor growth and enhance survival in murine tumor models. Experimental PVSRIPO oncolytic virus therapy of glioblastoma has shown long-term efficacy in a subset of patients. Here the authors engineer the virus to enable incorporation of tumor-specific antigens, and show proof-of-principle evidence that this modification increases anti-tumor immunity and extends survival in mice.
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Affiliation(s)
- Mubeen M Mosaheb
- Department of Molecular Genetics & Microbiology, Duke University Medical School, Durham, NC, 27701, USA
| | - Elena Y Dobrikova
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Michael C Brown
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Yuanfan Yang
- Department of Pathology, Duke University Medical School, Durham, NC, 27701, USA
| | - Jana Cable
- Department of Molecular Genetics & Microbiology, Duke University Medical School, Durham, NC, 27701, USA
| | - Hideho Okada
- Parker Institute for Cancer Immunotherapy, University of California at San Francisco, San Francisco, CA, 94129, USA.,Department of Neurological Surgery, University of California at San Francisco, San Francisco, CA, 94129, USA
| | - Smita K Nair
- Department of Surgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Darell D Bigner
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - David M Ashley
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Matthias Gromeier
- Department of Molecular Genetics & Microbiology, Duke University Medical School, Durham, NC, 27701, USA. .,Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA.
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5
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Thompson EM, Brown M, Dobrikova E, Ramaswamy V, Taylor MD, McLendon R, Sanks J, Chandramohan V, Bigner D, Gromeier M. Poliovirus Receptor (CD155) Expression in Pediatric Brain Tumors Mediates Oncolysis of Medulloblastoma and Pleomorphic Xanthoastrocytoma. J Neuropathol Exp Neurol 2019; 77:696-702. [PMID: 29878245 DOI: 10.1093/jnen/nly045] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Poliovirus oncolytic immunotherapy is a putatively novel approach to treat pediatric brain tumors. This work sought to determine expression of the poliovirus receptor (PVR), CD155, in low-grade and malignant pediatric brain tumors and its ability to infect, propagate, and inhibit cell proliferation. CD155 expression in pleomorphic xanthoastrocytoma (PXA), medulloblastoma, atypical teratoid rhabdoid tumor, primitive neuroectodermal tumor, and anaplastic ependymoma specimens was assessed. The ability of the polio: rhinovirus recombinant, PVSRIPO, to infect PXA (645 [BRAF V600E mutation], 2363) and medulloblastoma (D283, D341) cells were determined by viral propagation measurement and cell proliferation. PVR mRNA expression was evaluated in 763 medulloblastoma and 1231 normal brain samples. CD155 was expressed in all 12 patient specimens and in PXA and medulloblastoma cell lines. One-step growth curves at a multiplicity of infection of 10 demonstrated productive infection and peak plaque formation units at 5-10 hours. PVSRIPO infection significantly decreased cellular proliferation in 2363, 645, and D341 cell lines at 48 hours (p < 0.05) and resulted in cell death. PVR expression was highest in medulloblastoma subtypes Group 3γ, WNTα, and WNTβ (p < 0.001). This proof-of-concept in vitro study demonstrates that PVSRIPO is capable of infecting, propagating, prohibiting cell proliferation, and killing PXA and Group 3 medulloblastoma.
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Affiliation(s)
- Eric M Thompson
- Department of Neurosurgery, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University, Durham, North Carolina
| | - Michael Brown
- Department of Neurosurgery, Duke University, Durham, North Carolina
| | - Elena Dobrikova
- Department of Neurosurgery, Duke University, Durham, North Carolina
| | - Vijay Ramaswamy
- Division of Haematology/Oncology, The Arthur and Sonia Labatt Brain Tumour Research Centre, Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael D Taylor
- Division of Neurosurgery, The Arthur and Sonia Labatt Brain Tumour Research Centre, Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Roger McLendon
- Department of Pathology, Duke University, Durham, North Carolina
| | - Jennifer Sanks
- Department of Pathology, Duke University, Durham, North Carolina
| | - Vidya Chandramohan
- Preston Robert Tisch Brain Tumor Center, Duke University, Durham, North Carolina.,Department of Pathology, Duke University, Durham, North Carolina
| | - Darell Bigner
- Preston Robert Tisch Brain Tumor Center, Duke University, Durham, North Carolina.,Department of Pathology, Duke University, Durham, North Carolina
| | - Matthias Gromeier
- Department of Neurosurgery, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University, Durham, North Carolina
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6
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Abstract
Mechanisms to elicit antiviral immunity, a natural host response to viral pathogen challenge, are of eminent relevance to cancer immunotherapy. "Oncolytic" viruses, naturally existing or genetically engineered viral agents with cell type-specific propagation in malignant cells, were ostensibly conceived for their tumor cytotoxic properties. Yet, their true therapeutic value may rest in their ability to provoke antiviral signals that engage antitumor immune responses within the immunosuppressive tumor microenvironment. Coopting oncolytic viral agents to instigate antitumor immunity is not an easy feat. In the course of coevolution with their hosts, viruses have acquired sophisticated strategies to block inflammatory signals, intercept innate antiviral interferon responses, and prevent antiviral effector responses, e.g., by interfering with antigen presentation and T cell costimulation. The resulting struggle of host innate inflammatory and antiviral responses versus viral immune evasion and suppression determines the potential for antitumor immunity to occur. Moreover, paradigms of early host:virus interaction established in normal immunocompetent organisms may not hold in the profoundly immunosuppressive tumor microenvironment. In this review, we explain the mechanisms of recombinant nonpathogenic poliovirus, PVSRIPO, which is currently in phase I clinical trials against recurrent glioblastoma. We focus on an unusual host:virus relationship defined by the simple and cytotoxic replication strategy of poliovirus, which generates inflammatory perturbations conducive to tumor antigen-specific immune priming.
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Affiliation(s)
- Matthias Gromeier
- Department of Neurosurgery.,Department of Molecular Genetics and Microbiology
| | - Smita K Nair
- Department of Surgery.,Department of Pathology, Duke University School of Medicine, Durham, North Carolina 27710;
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7
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Kučan Brlić P, Lenac Roviš T, Cinamon G, Tsukerman P, Mandelboim O, Jonjić S. Targeting PVR (CD155) and its receptors in anti-tumor therapy. Cell Mol Immunol 2019; 16:40-52. [PMID: 30275538 PMCID: PMC6318332 DOI: 10.1038/s41423-018-0168-y] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 08/20/2018] [Indexed: 12/22/2022] Open
Abstract
Poliovirus receptor (PVR, CD155) has recently been gaining scientific interest as a therapeutic target in the field of tumor immunology due to its prominent endogenous and immune functions. In contrast to healthy tissues, PVR is expressed at high levels in several human malignancies and seems to have protumorigenic and therapeutically attractive properties that are currently being investigated in the field of recombinant oncolytic virotherapy. More intriguingly, PVR participates in a considerable number of immunoregulatory functions through its interactions with activating and inhibitory immune cell receptors. These functions are often modified in the tumor microenvironment, contributing to tumor immunosuppression. Indeed, increasing evidence supports the rationale for developing strategies targeting these interactions, either in terms of checkpoint therapy (i.e., targeting inhibitory receptors) or in adoptive cell therapy, which targets PVR as a tumor marker.
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Affiliation(s)
- Paola Kučan Brlić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51 000, Rijeka, Croatia.
| | - Tihana Lenac Roviš
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51 000, Rijeka, Croatia
| | - Guy Cinamon
- Nectin Therapeutics Ltd., Hi-Tech Campus Givat Ram, POB 39135, 91390, Jerusalem, Israel
| | - Pini Tsukerman
- Nectin Therapeutics Ltd., Hi-Tech Campus Givat Ram, POB 39135, 91390, Jerusalem, Israel
| | - Ofer Mandelboim
- The Lautenberg Center for General and Tumor Immunology, The Faculty of Medicine, IMRIC, The Hebrew University Medical School, Jerusalem, Israel
| | - Stipan Jonjić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51 000, Rijeka, Croatia.
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8
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Holl EK, Brown MC, Boczkowski D, McNamara MA, George DJ, Bigner DD, Gromeier M, Nair SK. Recombinant oncolytic poliovirus, PVSRIPO, has potent cytotoxic and innate inflammatory effects, mediating therapy in human breast and prostate cancer xenograft models. Oncotarget 2018; 7:79828-79841. [PMID: 27806313 PMCID: PMC5346754 DOI: 10.18632/oncotarget.12975] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/13/2016] [Indexed: 12/31/2022] Open
Abstract
Intratumoral inoculation of viruses with tumor-selective cytotoxicity may induce cancer cell death and, thereby, shrink neoplastic lesions. It is unlikely, however, that viral tumor cell killing alone could produce meaningful, durable clinical responses, as clinically suitable ‘oncolytic’ viruses are severely attenuated and their spread and propagation are opposed by host immunity. Thus, a more propitious event in this context is the innate antiviral response to intratumoral virus administration, in particular for recruiting durable adaptive immune effector responses. It may represent a double-edged sword, as innate immune activation may eliminate infected tumor cells early, intercept viral spread and block any meaningful therapeutic response. The innate response to viral infection of tumors may be very different from that in non-malignant target tissues, owing to the unusual composition/tissue properties of tumor stroma. In this work, we report investigations of the innate immune response to the oncolytic poliovirus recombinant, PVSRIPO, in two mouse xenotransplantation models for breast and prostate cancer. Our observations indicate short-term virus persistence in infected tumors and virus recovery indicative of modest intratumoral propagation and persistence. Yet, a powerful innate inflammatory response coincided with chemokine induction and myeloid cell infiltration into tumors that was, interestingly, dominated by neutrophils. The combined effect of PVSRIPO tumor infection and the innate response it elicits was significant tumor regression in both models.
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Affiliation(s)
- Eda K Holl
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Michael C Brown
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - David Boczkowski
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Megan A McNamara
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Daniel J George
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Darell D Bigner
- Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Matthias Gromeier
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Smita K Nair
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
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9
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Brown MC, Holl EK, Boczkowski D, Dobrikova E, Mosaheb M, Chandramohan V, Bigner DD, Gromeier M, Nair SK. Cancer immunotherapy with recombinant poliovirus induces IFN-dominant activation of dendritic cells and tumor antigen-specific CTLs. Sci Transl Med 2017; 9:eaan4220. [PMID: 28931654 PMCID: PMC6034685 DOI: 10.1126/scitranslmed.aan4220] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 04/10/2017] [Accepted: 08/07/2017] [Indexed: 12/11/2022]
Abstract
Tumors thrive in an immunosuppressive microenvironment that impedes antitumor innate and adaptive immune responses. Thus, approaches that can overcome immunosuppression and engage antitumor immunity are needed. This study defines the adjuvant and cancer immunotherapy potential of the recombinant poliovirus/rhinovirus chimera PVSRIPO. PVSRIPO is currently in clinical trials against recurrent World Health Organization grade IV malignant glioma, a notoriously treatment-refractory cancer. Cytopathogenic infection of neoplastic cells releases the proteome and exposes pathogen- and damage-associated molecular patterns. At the same time, sublethal infection of antigen-presenting cells, such as dendritic cells and macrophages, yields potent, sustained type I interferon-dominant activation in an immunosuppressed microenvironment and promotes the development of tumor antigen-specific T cell responses in vitro and antitumor immunity in vivo. PVSRIPO's immune adjuvancy stimulates canonical innate anti-pathogen inflammatory responses within the tumor microenvironment that culminate in dendritic cell and T cell infiltration. Our findings provide mechanistic evidence that PVSRIPO functions as a potent intratumor immune adjuvant that generates tumor antigen-specific cytotoxic T lymphocyte responses.
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Affiliation(s)
- Michael C Brown
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Eda K Holl
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - David Boczkowski
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Elena Dobrikova
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mubeen Mosaheb
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Vidya Chandramohan
- Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Darell D Bigner
- Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Matthias Gromeier
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710, USA.
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Smita K Nair
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA.
- Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
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10
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Bowers JR, Readler JM, Sharma P, Excoffon KJDA. Poliovirus Receptor: More than a simple viral receptor. Virus Res 2017; 242:1-6. [PMID: 28870470 DOI: 10.1016/j.virusres.2017.09.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 12/27/2022]
Abstract
The human poliovirus receptor (PVR) is a cell surface protein with a multitude of functions in human biology. PVR was initially identified as the receptor for the human poliovirus and recent discoveries have given a greater insight into both its morphology and its function. Alternative splicing of the PVR gene results in a total of 4 alternatively spliced isoforms. Two of these isoforms lack a complete transmembrane domain and are considered soluble and block viral infection; the remaining two transmembrane isoforms differ only at their extreme C-terminal domains resulting in differential localization in epithelia and polarity of viral infection. In addition to its role as a receptor for the human poliovirus, several native biological functions have also been uncovered. PVR is an important cell adhesion protein and is involved in the transendothelial migration of leukocytes. Through its interactions with CD226 and TIGIT, transmembrane proteins found on leukocytes, PVR is a key regulator of the cell-mediated immune response. As PVR is differentially regulated in a broad spectrum of cancers, it has a strong potential for clinical use as a biomarker. PVR is also a possible target for novel cancer therapies. Utilizing its natural tropism for PVR, a genetically modified form of the live attenuated poliovirus vaccine is currently being tested for its ability to locate and destroy certain tumors. These recent studies emphasize the importance of PVR in human biology and demonstrate its utility beyond being a viral receptor protein.
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Affiliation(s)
- Jonathan R Bowers
- Department of Biological Sciences, Wright State University, Dayton, OH, 45435, United States
| | - James M Readler
- Department of Biological Sciences, Wright State University, Dayton, OH, 45435, United States
| | - Priyanka Sharma
- Department of Biological Sciences, Wright State University, Dayton, OH, 45435, United States
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11
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Gardeck AM, Sheehan J, Low WC. Immune and viral therapies for malignant primary brain tumors. Expert Opin Biol Ther 2017; 17:457-474. [DOI: 10.1080/14712598.2017.1296132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Andrew M. Gardeck
- Departments of Neurosurgery, University of Minnesota, Minneapolis, MN, USA
| | - Jordan Sheehan
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Walter C. Low
- Departments of Neurosurgery, University of Minnesota, Minneapolis, MN, USA
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
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12
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Transcriptional Elongation Regulator 1 Affects Transcription and Splicing of Genes Associated with Cellular Morphology and Cytoskeleton Dynamics and Is Required for Neurite Outgrowth in Neuroblastoma Cells and Primary Neuronal Cultures. Mol Neurobiol 2016; 54:7808-7823. [PMID: 27844289 DOI: 10.1007/s12035-016-0284-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/31/2016] [Indexed: 12/22/2022]
Abstract
TCERG1 is a highly conserved human protein implicated in interactions with the transcriptional and splicing machinery that is associated with neurodegenerative disorders. Biochemical, neuropathological, and genetic evidence suggests an important role for TCERG1 in Huntington's disease (HD) pathogenesis. At present, the molecular mechanism underlying TCERG1-mediated neuronal effects is unknown. Here, we show that TCERG1 depletion led to widespread alterations in mRNA processing that affected different types of alternative transcriptional or splicing events, indicating that TCERG1 plays a broad role in the regulation of alternative splicing. We observed considerable changes in the transcription and alternative splicing patterns of genes involved in cytoskeleton dynamics and neurite outgrowth. Accordingly, TCERG1 depletion in the neuroblastoma SH-SY5Y cell line and primary mouse neurons affected morphogenesis and resulted in reduced dendritic outgrowth, with a major effect on dendrite ramification and branching complexity. These defects could be rescued by ectopic expression of TCERG1. Our results indicate that TCERG1 affects expression of multiple mRNAs involved in neuron projection development, whose misregulation may be involved in TCERG1-linked neurological disorders.
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13
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Li Y, Bor YC, Fitzgerald MP, Lee KS, Rekosh D, Hammarskjold ML. An NXF1 mRNA with a retained intron is expressed in hippocampal and neocortical neurons and is translated into a protein that functions as an Nxf1 cofactor. Mol Biol Cell 2016; 27:3903-3912. [PMID: 27708137 PMCID: PMC5170612 DOI: 10.1091/mbc.e16-07-0515] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/14/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022] Open
Abstract
A small Nxf1 protein, expressed from an NXF1 mRNA with a retained intron is highly expressed in rodent hippocampal and neocortical neurons, colocalizes with Staufen2 proteins in neuronal RNA granules, is present in polysomes, and replaces Nxt1 as an Nxf1 cofactor in export and expression of mRNA with retained introns. The Nxf1 protein is a major nuclear export receptor for the transport of mRNA, and it also is essential for export of retroviral mRNAs with retained introns. In the latter case, it binds to RNA elements known as constitutive transport elements (CTEs) and functions in conjunction with a cofactor known as Nxt1. The NXF1 gene also regulates expression of its own intron-containing RNA through the use of a functional CTE within intron 10. mRNA containing this intron is exported to the cytoplasm, where it can be translated into the 356–amino acid short Nxf1(sNxf1) protein, despite the fact that it is a prime candidate for nonsense-mediated decay (NMD). Here we demonstrate that sNxf1 is highly expressed in nuclei and dendrites of hippocampal and neocortical neurons in rodent brain. Additionally, we show that sNxf1 localizes in RNA granules in neurites of differentiated N2a mouse neuroblastoma cells, where it shows partial colocalization with Staufen2 isoform SS, a protein known to play a role in dendritic mRNA trafficking. We also show that sNxf1 forms heterodimers in conjunction with the full-length Nxf1 and that sNxf1 can replace Nxt1 to enhance the expression of CTE-containing mRNA and promote its association with polyribosomes.
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Affiliation(s)
- Ying Li
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Yeou-Cherng Bor
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Mark P Fitzgerald
- Departments of Neuroscience and Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Kevin S Lee
- Departments of Neuroscience and Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - David Rekosh
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Marie-Louise Hammarskjold
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
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14
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Zhang Y, Cao J, Zhang S, Lee AJ, Sun G, Larsen CN, Zhao H, Gu Z, He S, Klem EB, Scheuermann RH. Genetic changes found in a distinct clade of Enterovirus D68 associated with paralysis during the 2014 outbreak. Virus Evol 2016; 2:vew015. [PMID: 28512577 PMCID: PMC5426007 DOI: 10.1093/ve/vew015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Enterovirus D68 (EV-D68) caused a severe respiratory illness outbreak in the United States in 2014. Reports of acute flaccid myelitis (AFM)/paralysis (AFP) in several independent epidemiological clusters of children with detectable EV-D68 have raised concerns that genetic changes in EV-D68 could be causing increased disease severity and neurological symptoms. To explore the potential link between EV-D68 genetic variations and symptom changes, we performed a series of comparative genomic analyses of EV-D68 2014 outbreak isolate sequences using data and analytical tools in the Virus Pathogen Resource (ViPR; www.viprbrc.org). Our results suggest that (1) three distinct lineages of EV-D68 were co-circulating in 2013 and 2014; (2) isolates associated with AFM/AFP belong to a single phylogenetic subclade - B1; (3) the majority of isolates from the B1 subclade have 21 unique substitutions that distinguish them from other isolates, including amino acid substitutions in the VP1, VP2, and VP3 capsid proteins and the 3D RNA-dependent RNA polymerase, and nucleotide substitutions in the internal ribosome entry sequence (IRES); (4) at 12 of these positions, B1 isolates carry the same residues observed at equivalent positions in paralysis-causing enteroviruses, including poliovirus, EV-D70 and EV-A71. Based on these results, we hypothesize that unique B1 substitutions may be responsible for the apparent increased incidence of neuropathology associated with the 2014 outbreak.
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Affiliation(s)
- Yun Zhang
- J. Craig Venter Institute, La Jolla, CA, USA
| | - Jing Cao
- Department of Statistical Science, Southern Methodist University, Dallas, TX, USA
| | - Song Zhang
- Department of Clinical Science, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | | | | | - Hongtao Zhao
- Northrop Grumman Health Solutions, Rockville, MD, USA
| | - Zhiping Gu
- Northrop Grumman Health Solutions, Rockville, MD, USA
| | - Sherry He
- Northrop Grumman Health Solutions, Rockville, MD, USA
| | - Edward B Klem
- Northrop Grumman Health Solutions, Rockville, MD, USA
| | - Richard H Scheuermann
- J. Craig Venter Institute, La Jolla, CA, USA.,Department of Pathology, University of California, San Diego, La Jolla, CA, USA
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15
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Stepanenko A, Dmitrenko V. HEK293 in cell biology and cancer research: phenotype, karyotype, tumorigenicity, and stress-induced genome-phenotype evolution. Gene 2015; 569:182-90. [DOI: 10.1016/j.gene.2015.05.065] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/11/2015] [Accepted: 05/26/2015] [Indexed: 01/18/2023]
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16
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Brown MC, Gromeier M. Cytotoxic and immunogenic mechanisms of recombinant oncolytic poliovirus. Curr Opin Virol 2015; 13:81-5. [PMID: 26083317 DOI: 10.1016/j.coviro.2015.05.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 12/12/2022]
Abstract
An oncolytic virus (OV) based on poliovirus (PV), the highly attenuated polio/rhinovirus recombinant PVSRIPO, may deliver targeted inflammatory cancer cell killing; a principle that is showing promise in clinical trials for recurrent glioblastoma (GBM). The two decisive factors in PVSRIPO anti-tumor efficacy are selective cytotoxicity and its in situ immunogenic imprint. While our work is focused on what constitutes PVSRIPO cancer cytotoxicity, we are also studying how this engenders host immune responses that are vital to tumor regression. We hypothesize that PVSRIPO cytotoxicity and immunogenicity are inextricably linked in essential, complimentary roles that define the anti-neoplastic response. Herein we delineate mechanisms we unraveled to decipher the basis for PVSRIPO cytotoxicity and its immunotherapeutic potential.
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Affiliation(s)
- Michael C Brown
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Box 3020, Research Drive, Durham, NC 27710, USA; Department of Neurosurgery, Duke University Medical Center, Box 3020, Research Drive, Durham, NC 27710, USA
| | - Matthias Gromeier
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Box 3020, Research Drive, Durham, NC 27710, USA; Department of Neurosurgery, Duke University Medical Center, Box 3020, Research Drive, Durham, NC 27710, USA.
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17
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Brown MC, Gromeier M. Oncolytic immunotherapy through tumor-specific translation and cytotoxicity of poliovirus. DISCOVERY MEDICINE 2015; 19:359-365. [PMID: 26105699 PMCID: PMC4780852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Achieving tumor-specific, robust, and durable effector cytotoxic immune responses is key to successful immunotherapy. This has been accomplished with adoptive cell transfer of ex vivo-expanded autologous tumor-infiltrating or engineered T cells, or with immune checkpoint inhibitors, enhancing inherent T cell reactivity. A natural ability to recruit effector responses makes tumor-targeting ('oncolytic') viruses attractive as immunotherapy vehicles. However, most viruses actively block inflammatory and immunogenic events; or, host innate immune responses may prevent immune initiating events in the first place. Moreover, the mechanisms of how virus infection can produce effector responses against host (tumor) neo-antigens are unclear. We are pioneering oncolytic immunotherapy based on poliovirus, which has no specific mechanism to interfere with host immune activation, exhibits lytic cytotoxicity in the presence of an antiviral interferon response and pre-existing immunity, and engages a powerful innate immune sensor implicated in recruiting cytotoxic T cell responses. Central to this approach is a unique confluence of factors that drive tumor-specific viral translation and cytotoxicity.
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Affiliation(s)
- Michael C Brown
- Department of Surgery Division of Neurosurgery and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Matthias Gromeier
- Department of Surgery Division of Neurosurgery and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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18
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Peredo J, Villacé P, Ortín J, de Lucas S. Human Staufen1 associates to miRNAs involved in neuronal cell differentiation and is required for correct dendritic formation. PLoS One 2014; 9:e113704. [PMID: 25423178 PMCID: PMC4244161 DOI: 10.1371/journal.pone.0113704] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 10/27/2014] [Indexed: 11/19/2022] Open
Abstract
Double-stranded RNA-binding proteins are key elements in the intracellular localization of mRNA and its local translation. Staufen is a double-stranded RNA binding protein involved in the localised translation of specific mRNAs during Drosophila early development and neuronal cell fate. The human homologue Staufen1 forms RNA-containing complexes that include proteins involved in translation and motor proteins to allow their movement within the cell, but the mechanism underlying translation repression in these complexes is poorly understood. Here we show that human Staufen1-containing complexes contain essential elements of the gene silencing apparatus, like Ago1-3 proteins, and we describe a set of miRNAs specifically associated to complexes containing human Staufen1. Among these, miR-124 stands out as particularly relevant because it appears enriched in human Staufen1 complexes and is over-expressed upon differentiation of human neuroblastoma cells in vitro. In agreement with these findings, we show that expression of human Staufen1 is essential for proper dendritic arborisation during neuroblastoma cell differentiation, yet it is not necessary for maintenance of the differentiated state, and suggest potential human Staufen1 mRNA targets involved in this process.
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Affiliation(s)
- Joan Peredo
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
| | - Patricia Villacé
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
| | - Juan Ortín
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
- * E-mail: (JO); (SdL)
| | - Susana de Lucas
- Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
- * E-mail: (JO); (SdL)
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19
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Induction of viral, 7-methyl-guanosine cap-independent translation and oncolysis by mitogen-activated protein kinase-interacting kinase-mediated effects on the serine/arginine-rich protein kinase. J Virol 2014; 88:13135-48. [PMID: 25187541 DOI: 10.1128/jvi.01883-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Protein synthesis, the most energy-consuming process in cells, responds to changing physiologic priorities, e.g., upon mitogen- or stress-induced adaptations signaled through the mitogen-activated protein kinases (MAPKs). The prevailing status of protein synthesis machinery is a viral pathogenesis factor, particularly for plus-strand RNA viruses, where immediate translation of incoming viral RNAs shapes host-virus interactions. In this study, we unraveled signaling pathways centered on the ERK1/2 and p38α MAPK-interacting kinases MNK1/2 and their role in controlling 7-methyl-guanosine (m(7)G) "cap"-independent translation at enterovirus type 1 internal ribosomal entry sites (IRESs). Activation of Raf-MEK-ERK1/2 signals induced viral IRES-mediated translation in a manner dependent on MNK1/2. This effect was not due to MNK's known functions as eukaryotic initiation factor (eIF) 4G binding partner or eIF4E(S209) kinase. Rather, MNK catalytic activity enabled viral IRES-mediated translation/host cell cytotoxicity through negative regulation of the Ser/Arg (SR)-rich protein kinase (SRPK). Our investigations suggest that SRPK activity is a major determinant of type 1 IRES competency, host cell cytotoxicity, and viral proliferation in infected cells. IMPORTANCE We are targeting unfettered enterovirus IRES activity in cancer with PVSRIPO, the type 1 live-attenuated poliovirus (PV) (Sabin) vaccine containing a human rhinovirus type 2 (HRV2) IRES. A phase I clinical trial of PVSRIPO with intratumoral inoculation in patients with recurrent glioblastoma (GBM) is showing early promise. Viral translation proficiency in infected GBM cells is a core requirement for the antineoplastic efficacy of PVSRIPO. Therefore, it is critically important to understand the mechanisms controlling viral cap-independent translation in infected host cells.
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20
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Brown MC, Dobrikova EY, Dobrikov MI, Walton RW, Gemberling SL, Nair SK, Desjardins A, Sampson JH, Friedman HS, Friedman AH, Tyler DS, Bigner DD, Gromeier M. Oncolytic polio virotherapy of cancer. Cancer 2014; 120:3277-86. [PMID: 24939611 DOI: 10.1002/cncr.28862] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/13/2014] [Indexed: 01/23/2023]
Abstract
Recently, the century-old idea of targeting cancer with viruses (oncolytic viruses) has come of age, and promise has been documented in early stage and several late-stage clinical trials in a variety of cancers. Although originally prized for their direct tumor cytotoxicity (oncolytic virotherapy), recently, the proinflammatory and immunogenic effects of viral tumor infection (oncolytic immunotherapy) have come into focus. Indeed, a capacity for eliciting broad, sustained antineoplastic effects stemming from combined direct viral cytotoxicity, innate antiviral activation, stromal proinflammatory stimulation, and recruitment of adaptive immune effector responses is the greatest asset of oncolytic viruses. However, it also is the source for enormous mechanistic complexity that must be considered for successful clinical translation. Because of fundamentally different relationships with their hosts (malignant or not), diverse replication strategies, and distinct modes of tumor cytotoxicity/killing, oncolytic viruses should not be referred to collectively. These agents must be evaluated based on their individual merits. In this review, the authors highlight key mechanistic principles of cancer treatment with the polio:rhinovirus chimera PVSRIPO and their implications for oncolytic immunotherapy in the clinic.
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Affiliation(s)
- Michael C Brown
- Department of Surgery, Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina; Division of Neurosurgery Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina; Department of Molecular Genetics and Microbiology, Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
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21
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Lin JY, Shih SR. Cell and tissue tropism of enterovirus 71 and other enteroviruses infections. J Biomed Sci 2014; 21:18. [PMID: 24602216 PMCID: PMC3995930 DOI: 10.1186/1423-0127-21-18] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 02/26/2014] [Indexed: 02/04/2023] Open
Abstract
Enterovirus 71 (EV71) is a member of Picornaviridae that causes mild and self-limiting hand, foot, and mouth disease (HFMD). However, EV71 infections can progress to polio-like paralysis, neurogenic pulmonary edema, and fatal encephalitis in infants and young children. Large EV71 outbreaks have been reported in Taiwan, China, Japan, Malaysia, Singapore, and Australia. This virus is considered a critical emerging public health threat. EV71 is an important crucial neurotropic enterovirus for which there is currently no effective antiviral drug or vaccine. The mechanism by which EV71 causes severe central nervous system complications remains unclear. The interaction between the virus and the host is vital for viral replication, virulence, and pathogenicity. SCARB2 or PSGL-1 receptor binding is the first step in the development of viral infections, and viral factors (e.g., 5' UTR, VP1, 3C, 3D, 3' UTR), host factors and environments (e.g., ITAFs, type I IFN) are also involved in viral infections. The tissue tropism and pathogenesis of viruses are determined by a combination of several factors. This review article provides a summary of host and virus factors affecting cell and tissue tropism and the pathogenesis of enteroviruses.
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Affiliation(s)
| | - Shin-Ru Shih
- Research Center for Emerging Viral Infections, Chang Gung University, Tao-Yuan, Taiwan.
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22
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Vlecken DH, Pelgrim RP, Ruminski S, Bakker WA, van der Pol LA. Comparison of initial feasibility of host cell lines for viral vaccine production. J Virol Methods 2013; 193:28-41. [DOI: 10.1016/j.jviromet.2013.04.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 04/17/2013] [Accepted: 04/29/2013] [Indexed: 12/28/2022]
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23
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Burns CC, Shaw J, Jorba J, Bukbuk D, Adu F, Gumede N, Pate MA, Abanida EA, Gasasira A, Iber J, Chen Q, Vincent A, Chenoweth P, Henderson E, Wannemuehler K, Naeem A, Umami RN, Nishimura Y, Shimizu H, Baba M, Adeniji A, Williams AJ, Kilpatrick DR, Oberste MS, Wassilak SG, Tomori O, Pallansch MA, Kew O. Multiple independent emergences of type 2 vaccine-derived polioviruses during a large outbreak in northern Nigeria. J Virol 2013; 87:4907-22. [PMID: 23408630 PMCID: PMC3624331 DOI: 10.1128/jvi.02954-12] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 02/07/2013] [Indexed: 01/15/2023] Open
Abstract
Since 2005, a large poliomyelitis outbreak associated with type 2 circulating vaccine-derived poliovirus (cVDPV2) has occurred in northern Nigeria, where immunization coverage with trivalent oral poliovirus vaccine (tOPV) has been low. Phylogenetic analysis of P1/capsid region sequences of isolates from each of the 403 cases reported in 2005 to 2011 resolved the outbreak into 23 independent type 2 vaccine-derived poliovirus (VDPV2) emergences, at least 7 of which established circulating lineage groups. Virus from one emergence (lineage group 2005-8; 361 isolates) was estimated to have circulated for over 6 years. The population of the major cVDPV2 lineage group expanded rapidly in early 2009, fell sharply after two tOPV rounds in mid-2009, and gradually expanded again through 2011. The two major determinants of attenuation of the Sabin 2 oral poliovirus vaccine strain (A481 in the 5'-untranslated region [5'-UTR] and VP1-Ile143) had been replaced in all VDPV2 isolates; most A481 5'-UTR replacements occurred by recombination with other enteroviruses. cVDPV2 isolates representing different lineage groups had biological properties indistinguishable from those of wild polioviruses, including efficient growth in neuron-derived HEK293 cells, the capacity to cause paralytic disease in both humans and PVR-Tg21 transgenic mice, loss of the temperature-sensitive phenotype, and the capacity for sustained person-to-person transmission. We estimate from the poliomyelitis case count and the paralytic case-to-infection ratio for type 2 wild poliovirus infections that ∼700,000 cVDPV2 infections have occurred during the outbreak. The detection of multiple concurrent cVDPV2 outbreaks in northern Nigeria highlights the risks of cVDPV emergence accompanying tOPV use at low rates of coverage in developing countries.
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Affiliation(s)
- Cara C Burns
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
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24
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Jahan N, Wimmer E, Mueller S. Polypyrimidine tract binding protein-1 (PTB1) is a determinant of the tissue and host tropism of a human rhinovirus/poliovirus chimera PV1(RIPO). PLoS One 2013; 8:e60791. [PMID: 23593313 PMCID: PMC3617181 DOI: 10.1371/journal.pone.0060791] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 03/03/2013] [Indexed: 01/08/2023] Open
Abstract
The internal ribosomal entry site (IRES) of picornavirus genomes serves as the nucleation site of a highly structured ribonucleoprotein complex essential to the binding of the 40S ribosomal subunit and initiation of viral protein translation. The transition from naked RNA to a functional "IRESome" complex are poorly understood, involving the folding of secondary and tertiary RNA structure, facilitated by a tightly concerted binding of various host cell proteins that are commonly referred to as IRES trans-acting factors (ITAFs). Here we have investigated the influence of one ITAF, the polypyrimidine tract-binding protein 1 (PTB1), on the tropism of PV1(RIPO), a chimeric poliovirus in which translation of the poliovirus polyprotein is under the control of a human rhinovirus type 2 (HRV2) IRES element. We show that PV1(RIPO)'s growth defect in restrictive mouse cells is partly due to the inability of its IRES to interact with endogenous murine PTB. Over-expression of human PTB1 stimulated the HRV2 IRES-mediated translation, resulting in increased growth of PV1(RIPO) in murine cells and human neuronal SK-N-MC cells. Mutations within the PV1(RIPO) IRES, selected to grow in restrictive mouse cells, eliminated the human PTB1 supplementation requirement, by restoring the ability of the IRES to interact with endogenous murine PTB. In combination with our previous findings these results give a compelling insight into the thermodynamic behavior of IRES structures. We have uncovered three distinct thermodynamic aspects of IRES formation which may independently contribute to overcome the observed PV1(RIPO) IRES block by lowering the free energy δG of the IRESome formation, and stabilizing the correct and functional structure: 1) lowering the growth temperature, 2) modifying the complement of ITAFs in restricted cells, or 3) selection of adaptive mutations. All three mechanisms can conceivably modulate the thermodynamics of RNA folding, and thus facilitate and stabilize the functional IRES structure.
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Affiliation(s)
- Nusrat Jahan
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, New York, United States of America
| | - Eckard Wimmer
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, New York, United States of America
| | - Steffen Mueller
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, New York, United States of America
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25
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Andreev DE, Hirnet J, Terenin IM, Dmitriev SE, Niepmann M, Shatsky IN. Glycyl-tRNA synthetase specifically binds to the poliovirus IRES to activate translation initiation. Nucleic Acids Res 2012; 40:5602-14. [PMID: 22373920 PMCID: PMC3384309 DOI: 10.1093/nar/gks182] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Adaptation to the host cell environment to efficiently take-over the host cell's machinery is crucial in particular for small RNA viruses like picornaviruses that come with only small RNA genomes and replicate exclusively in the cytosol. Their Internal Ribosome Entry Site (IRES) elements are specific RNA structures that facilitate the 5′ end-independent internal initiation of translation both under normal conditions and when the cap-dependent host protein synthesis is shut-down in infected cells. A longstanding issue is which host factors play a major role in this internal initiation. Here, we show that the functionally most important domain V of the poliovirus IRES uses tRNAGly anticodon stem–loop mimicry to recruit glycyl-tRNA synthetase (GARS) to the apical part of domain V, adjacent to the binding site of the key initiation factor eIF4G. The binding of GARS promotes the accommodation of the initiation region of the IRES in the mRNA binding site of the ribosome, thereby greatly enhancing the activity of the IRES at the step of the 48S initiation complex formation. Moonlighting functions of GARS that may be additionally needed for other events of the virus–host cell interaction are discussed.
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Affiliation(s)
- Dmitri E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Building 40, Moscow 119991, Russian Federation
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26
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Attenuation of neurovirulence, biodistribution, and shedding of a poliovirus:rhinovirus chimera after intrathalamic inoculation in Macaca fascicularis. J Virol 2011; 86:2750-9. [PMID: 22171271 DOI: 10.1128/jvi.06427-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A dependence of poliovirus on an unorthodox translation initiation mode can be targeted selectively to drive viral protein synthesis and cytotoxicity in malignant cells. Transformed cells are naturally susceptible to poliovirus, due to widespread ectopic upregulation of the poliovirus receptor, Necl-5, in ectodermal/neuroectodermal cancers. Viral tumor cell killing and the host immunologic response it engenders produce potent, lasting antineoplastic effects in animal tumor models. Clinical application of this principle depends on unequivocal demonstration of safety in primate models for paralytic poliomyelitis. We conducted extensive dose-range-finding, toxicity, biodistribution, shedding, and neutralizing antibody studies of the prototype oncolytic poliovirus recombinant, PVS-RIPO, after intrathalamic inoculation in Macaca fascicularis. These studies suggest that intracerebral PVS-RIPO inoculation does not lead to viral propagation in the central nervous system (CNS), does not cause histopathological CNS lesions or neurological symptoms that can be attributed to the virus, is not associated with extraneural virus dissemination or replication and does not induce shedding of virus with stool. Intrathalamic PVS-RIPO inoculation induced neutralizing antibody responses against poliovirus serotype 1 in all animals studied.
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27
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Modification of the untranslated regions of human enterovirus 71 impairs growth in a cell-specific manner. J Virol 2011; 86:542-52. [PMID: 22031931 DOI: 10.1128/jvi.00069-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human enterovirus 71 (HEV71) is the causative agent of hand, foot, and mouth disease and associated acute neurological disease. At present, little is known about the genetic determinants of HEV71 neurovirulence. Studies of related enteroviruses have indicated that the untranslated regions (UTRs), which control virus-directed translation and replication, also exert significant influence on neurovirulence. We used an infectious cDNA clone of a subgenogroup B3 strain to construct and characterize chimeras with 5'- and 3'-UTR modifications. Replacement of the entire HEV71 5' UTR with that of human rhinovirus 2 (HRV2) resulted in a small reduction in growth efficiency in cells of both nonneuronal (rhabdomyosarcoma) and neuronal (SH-SY5Y) origin due to reduced translational efficiency. However, the introduction of a 17-nucleotide deletion into the proximal region of the 3' UTR significantly decreased the growth of HEV71-HRV2 in SH-SY5Y cells. This observation is similar to that made with stem-loop domain Z (SLD Z)-deleted coxsackievirus B3-HRV2 5'-UTR chimeras reported previously and provides the first evidence of a potentially functional SLD Z in the 3' UTR in human enterovirus A species viruses. We further showed that the cell-specific growth impairment was caused by the synergistic effects of cis-acting UTR control elements on different stages of the virus life cycle. These chimeras will further improve our understanding of the control of HEV71 replication and its relationship to neurovirulence.
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28
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Goetz C, Dobrikova E, Shveygert M, Dobrikov M, Gromeier M. Oncolytic poliovirus against malignant glioma. Future Virol 2011; 6:1045-1058. [PMID: 21984883 DOI: 10.2217/fvl.11.76] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In cancerous cells, physiologically tight regulation of protein synthesis is lost, contributing to uncontrolled growth and proliferation. We describe a novel experimental cancer therapy approach based on genetically recombinant poliovirus that targets an intriguing aberration of translation control in malignancy. This strategy is based on the confluence of several factors enabling specific and efficacious cancer cell targeting. Poliovirus naturally targets the vast majority of ectodermal/neuroectodermal cancers expressing its cellular receptor. Evidence from glioblastoma patients suggests that the poliovirus receptor is ectopically upregulated on tumor cells and may be associated with stem cell-like cancer cell populations and proliferating tumor vasculature. We exploit poliovirus' reliance on an unorthodox mechanism of protein synthesis initiation to selectively drive viral translation, propagation and cytotoxicity in glioblastoma. PVSRIPO, a prototype nonpathogenic poliovirus recombinant, is scheduled to enter clinical investigation against glioblastoma.
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Affiliation(s)
- Christian Goetz
- Division of Neurosurgery, Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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29
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A host-specific, temperature-sensitive translation defect determines the attenuation phenotype of a human rhinovirus/poliovirus chimera, PV1(RIPO). J Virol 2011; 85:7225-35. [PMID: 21561914 DOI: 10.1128/jvi.01804-09] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
By using a rhinosvirus/poliovirus type 1 chimera, PV1(RIPO), with the cognate internal ribosome entry site (IRES) of human rhinovirus type 2 (HRV2), we set out to shed light on the mechanism by which this variant expresses its attenuated phenotype in poliovirus-sensitive, CD155 transgenic (tg) mice and cynomolgus monkeys. Here we report that replication of PV1(RIPO) is restricted not only in human cells of neuronal origin, as was reported previously, but also in cells of murine origin at physiological temperature. This block in replication was enhanced at 39.5°C but, remarkably, it was absent at 33°C. PV1(RIPO) variants that overcame the replication block were derived by serial passage under restrictive conditions in either mouse cells or human neuronal cells. All adapting mutations mapped to the 5'-nontranslated region of PV1(RIPO). Variants selected in mouse cells, but not in human neuronal cells, exhibited increased mouse neurovirulence in vivo. The observed strong mouse-specific defect of PV1(RIPO) at nonpermissive temperature correlated with the translational activity of the HRV2 IRES in this chimeric virus. These unexpected results must be kept in mind when poliovirus variants are tested in CD155 tg mice for their neurovirulent potential, particularly in assays of live attenuated oral poliovirus vaccine lots. Virulence may be masked by adverse species-specific conditions in mouse cells that may not allow accurate prediction of neurovirulence in the human host. Thus, novel poliovirus variants in line for possible development of human vaccines must be tested in nonhuman primates.
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Goetz C, Everson RG, Zhang LC, Gromeier M. MAPK signal-integrating kinase controls cap-independent translation and cell type-specific cytotoxicity of an oncolytic poliovirus. Mol Ther 2010; 18:1937-46. [PMID: 20648000 DOI: 10.1038/mt.2010.145] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Many animal viruses exhibit proficient growth in transformed cells, a property that has been harnessed for the development of novel therapies against cancer. Despite overwhelming evidence for this phenomenon, understanding of the molecular mechanisms enabling tumor-cell killing is rudimentary for most viruses. We report here that growth and cytotoxicity of the prototype oncolytic poliovirus (PV), PVSRIPO, in glioblastoma multiforme (GBM) is promoted by mitogen-activated protein kinases (MAPKs) converging on the MAPK signal-integrating kinase 1 (Mnk1) and its primary substrate, the eukaryotic initiation factor (eIF) 4E. Inducing Mnk1-catalyzed eIF4E phosphorylation through expression of oncogenic Ras substantially enhanced PVSRIPO translation, replication, and cytotoxicity in resistant cells. This effect was mimicked by expression of constitutively active forms of Mnk1 and correlated with enhanced translation of subgenomic reporter RNAs. Our findings implicate Mnk1 activity in stimulation of PVSRIPO cap-independent translation, an effect that can be synergistically enhanced by inhibition of the phosphoinositide-3 kinase (PI3K).
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Affiliation(s)
- Christian Goetz
- Division of Neurosurgery, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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Abstract
Over the past decade, Human enterovirus (HEV)71 has emerged as a highly significant cause of viral encephalitis in the south-east Asian region. A pattern of increased epidemic activity has been observable since 1997, the cause of which is unclear. Ongoing investigations into the molecular basis of HEV71 infection and virulence, in particular viral translation and replication, have confirmed similarities between HEV71 and other enteroviruses, including the prototype species Poliovirus, but more work is required in this field. Although several putative receptors for HEV71 have been identified, it remains likely that other, as yet unidentified, receptors exist. Work in several established animal models for HEV71 infection has confirmed the protective efficacy of several inactivated vaccines. As more information emerges regarding the molecular processes involved in HEV71 infection, further advances may lead to the development of more effective antiviral treatments and, ultimately, a vaccine protection strategy.
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Affiliation(s)
- Emily J Bek
- Infectious Diseases & Immunology, Sydney Medical School, Blackburn Building D06, The University of Sydney, NSW 2006, Australia
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Goetz C, Gromeier M. Preparing an oncolytic poliovirus recombinant for clinical application against glioblastoma multiforme. Cytokine Growth Factor Rev 2010; 21:197-203. [PMID: 20299272 DOI: 10.1016/j.cytogfr.2010.02.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PVS-RIPO is a genetically recombinant, non-pathogenic poliovirus chimera with a tumor-specific conditional replication phenotype. Consisting of the genome of the live attenuated poliovirus type 1 (Sabin) vaccine with its cognate IRES element replaced with that of human rhinovirus type 2, PVS-RIPO displays an inability to translate its genome in untransformed neuronal cells, but effectively does so in cells originating from primary tumors in the central nervous system or other cancers. Hence, PVS-RIPO unleashes potent cytotoxic effects on infected cancer cells and produces sustained anti-tumoral responses in animal tumor models. PVS-RIPO presents a novel approach to the treatment of patients with glioblastoma multiforme, based on conditions favoring an unconventional viral translation initiation mechanism in cancerous cells. In this review we summarize advances in the understanding of major molecular determinants of PVS-RIPO oncolytic efficacy and safety and discuss their implications for upcoming clinical investigations.
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Affiliation(s)
- Christian Goetz
- Division of Neurosurgery, Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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Brunner JE, Ertel KJ, Rozovics JM, Semler BL. Delayed kinetics of poliovirus RNA synthesis in a human cell line with reduced levels of hnRNP C proteins. Virology 2010; 400:240-7. [PMID: 20189623 PMCID: PMC2844484 DOI: 10.1016/j.virol.2010.01.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 10/21/2009] [Accepted: 01/27/2010] [Indexed: 02/08/2023]
Abstract
The hnRNP C heterotetramer [(C13)C2] binds RNA polymerase II transcripts in the nucleus, along with other proteins of the core hnRNP complex, and plays an important role in mRNA biogenesis and transport. Infection of HeLa cells with poliovirus causes hnRNP C to re-localize from the nucleus, where it is normally retained during interphase, to the cytoplasm. We have proposed that in the cytoplasm, the protein isoforms of hnRNP C participate in the recognition of viral specific RNAs by the poliovirus replication proteins and/or in the assembly of membrane-bound RNA replication complexes. In SK-OV-3 cells, which express reduced levels of hnRNP C compared to HeLa cells or 293 cells, the kinetics of poliovirus replication are delayed. hnRNP C is also re-localized from the nucleus to the cytoplasm in SK-OV-3 cells infected with poliovirus. Increased expression of hnRNP C in SK-OV-3 cells by transient transfection increases the rate of virus production and overall yield over that seen in mock-transfected cells. We propose that hnRNP C interacts with poliovirus RNA and replication proteins to increase the efficiency of viral genomic RNA synthesis.
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Affiliation(s)
- Jo Ellen Brunner
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, CA 92697, USA
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Amadesi S, Grant AD, Cottrell GS, Vaksman N, Poole DP, Rozengurt E, Bunnett NW. Protein kinase D isoforms are expressed in rat and mouse primary sensory neurons and are activated by agonists of protease-activated receptor 2. J Comp Neurol 2009; 516:141-56. [PMID: 19575452 DOI: 10.1002/cne.22104] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Serine proteases generated during injury and inflammation cleave protease-activated receptor 2 (PAR(2)) on primary sensory neurons to induce neurogenic inflammation and hyperalgesia. Hyperalgesia requires sensitization of transient receptor potential vanilloid (TRPV) ion channels by mechanisms involving phospholipase C and protein kinase C (PKC). The protein kinase D (PKD) serine/threonine kinases are activated by diacylglycerol and PKCs and can phosphorylate TRPV1. Thus, PKDs may participate in novel signal transduction pathways triggered by serine proteases during inflammation and pain. However, it is not known whether PAR(2) activates PKD, and the expression of PKD isoforms by nociceptive neurons is poorly characterized. By using HEK293 cells transfected with PKDs, we found that PAR(2) stimulation promoted plasma membrane translocation and phosphorylation of PKD1, PKD2, and PKD3, indicating activation. This effect was partially dependent on PKCepsilon. By immunofluorescence and confocal microscopy, with antibodies against PKD1/PKD2 and PKD3 and neuronal markers, we found that PKDs were expressed in rat and mouse dorsal root ganglia (DRG) neurons, including nociceptive neurons that expressed TRPV1, PAR(2), and neuropeptides. PAR(2) agonist induced phosphorylation of PKD in cultured DRG neurons, indicating PKD activation. Intraplantar injection of PAR(2) agonist also caused phosphorylation of PKD in neurons of lumbar DRG, confirming activation in vivo. Thus, PKD1, PKD2, and PKD3 are expressed in primary sensory neurons that mediate neurogenic inflammation and pain transmission, and PAR(2) agonists activate PKDs in HEK293 cells and DRG neurons in culture and in intact animals. PKD may be a novel component of a signal transduction pathway for protease-induced activation of nociceptive neurons and an important new target for antiinflammatory and analgesic therapies.
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Affiliation(s)
- Silvia Amadesi
- Center for Neurobiology of Digestive Diseases, University of California, San Francisco, San Francisco, California 94143-0660, USA
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Characterization of genotype-specific carboxyl-terminal cleavage sites of hepatitis B virus e antigen precursor and identification of furin as the candidate enzyme. J Virol 2009; 83:3507-17. [PMID: 19193799 DOI: 10.1128/jvi.02348-08] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Hepatitis B e antigen (HBeAg) is a secreted version of hepatitis B virus (HBV) core protein that promotes immune tolerance and persistent infection. It is derived from a translation product of the precore/core gene by two proteolytic cleavage events: removal of the amino-terminal signal peptide and removal of the carboxyl-terminal arginine-rich sequence. Four RXXR motifs are present at the carboxyl terminus of the HBeAg precursor, with the first two fused as (151)RRGRSPR(157). Genotype A possesses two extra amino acids at the first motif ((151)RRDRGRSPR(159)), which weakens the first motif and separates it from the second one. Western blot analysis of patient sera revealed a single HBeAg form for genotypes B to D but two additional forms of larger sizes for genotype A. Site-directed mutagenesis and transfection experiments with human hepatoma cell lines indicated that HBeAg of genotype B is derived from cleavage at the first ((151)RRGR(154)) motif. The major HBeAg form of genotype A corresponds to cleavage at the second ((156)RSPR(159)) motif, and the other two forms are cleavage products of the first ((151)RRDR(154)) and third ((166)RRRR(169)) motifs, respectively. Only the cleavage product of the third motif of genotype A was observed in furin-deficient LoVo cells, and an inhibitor of furin-like proprotein convertases blocked cleavage of the first and second motifs in human hepatoma cells. In conclusion, our study reveals genotypic differences in HBeAg processing and implicates furin as the major enzyme involved in the cleavage of the first and second RXXR motifs.
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Attenuation of rabies virus replication and virulence by picornavirus internal ribosome entry site elements. J Virol 2008; 83:1911-9. [PMID: 19073737 DOI: 10.1128/jvi.02055-08] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Gene expression of nonsegmented negative-strand RNA viruses is regulated at the transcriptional level and relies on the canonical 5'-end-dependent translation of capped viral mRNAs. Here, we have used internal ribosome entry sites (IRES) from picornaviruses to control the expression level of the phosphoprotein P of the neurotropic rabies virus (RV; Rhabdoviridae), which is critically required for both viral replication and escape from the host interferon response. In a dual luciferase reporter RV, the IRES elements of poliovirus (PV) and human rhinovirus type 2 (HRV2) were active in a variety of cell lines from different host species. While a generally lower activity of the HRV2 IRES was apparent compared to the PV IRES, specific deficits of the HRV2 IRES in neuronal cell lines were not observed. Recombinant RVs expressing P exclusively from a bicistronic nucleoprotein (N)-IRES-P mRNA showed IRES-specific reduction of replication in cell culture and in neurons of organotypic brain slice cultures, an increased activation of the beta interferon (IFN-beta) promoter, and increased sensitivity to IFN. Intracerebral infection revealed a complete loss of virulence of both PV- and HRV2 IRES-controlled RV for wild-type mice and for transgenic mice lacking a functional IFN-alpha receptor (IFNAR(-/-)). The virulence of HRV2 IRES-controlled RV was most severely attenuated and could be demonstrated only in newborn IFNAR(-/-) mice. Translational control of individual genes is a promising strategy to attenuate replication and virulence of live nonsegmented negative-strand RNA viruses and vectors and to study the function of IRES elements in detail.
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Yang X, Chen E, Jiang H, Muszynski K, Harris RD, Giardina SL, Gromeier M, Mitra G, Soman G. Evaluation of IRES-mediated, cell-type-specific cytotoxicity of poliovirus using a colorimetric cell proliferation assay. J Virol Methods 2008; 155:44-54. [PMID: 18951922 DOI: 10.1016/j.jviromet.2008.09.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 09/10/2008] [Accepted: 09/22/2008] [Indexed: 12/14/2022]
Abstract
PVS-RIPO is a recombinant oncolytic poliovirus designed for clinical application to target CD155 expressing malignant gliomas and other malignant diseases. PVS-RIPO does not replicate in healthy neurons and is therefore non-pathogenic in rodent and non-human primate models of poliomyelitis. A tetrazolium salt dye-based cellular assay was developed and qualified to define the cytotoxicity of virus preparations on susceptible cells and to explore the target cell specificity of PVS-RIPO. In this assay, PVS-RIPO inhibited proliferation of U87-MG astrocytoma cells in a dose-dependent manner. However, HEK293 cells were much less susceptible to cell killing by PVS-RIPO. In contrast, the Sabin type 1 live attenuated poliovirus vaccine strain (PV(1)S) was cytotoxic to both HEK293 and U87-MG cells. The correlation between expression of CD155 and cytotoxicity was also explored using six different cell lines. There was little or no expression of CD155 and PVS-RIPO-induced cytotoxicity in Jurkat and Daudi cells. HEK293 was the only cell line tested that showed CD155 expression and resistance to PVS-RIPO cytotoxicity. The results indicate that differential cytotoxicity measured by the colorimetric assay can be used to evaluate the cytotoxicity and cell-type specificity of recombinant strains of poliovirus and to demonstrate lot to lot consistency during the manufacture of viruses intended for clinical use.
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Affiliation(s)
- Xiaoyi Yang
- Bioanalytical Development Laboratory, Biopharmaceutical Development Program, SAIC-Frederick, Inc., NCI Frederick, USA
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Dobrikova EY, Broadt T, Poiley-Nelson J, Yang X, Soman G, Giardina S, Harris R, Gromeier M. Recombinant oncolytic poliovirus eliminates glioma in vivo without genetic adaptation to a pathogenic phenotype. Mol Ther 2008; 16:1865-72. [PMID: 18766173 DOI: 10.1038/mt.2008.184] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Many viruses, either naturally occurring or as a result of genetic manipulation, exhibit conditional replication in transformed cells. This principle is the basis for experimental therapeutic approaches exploiting the oncolytic potential of such agents without the danger of collateral damage to resistant normal tissues. One of the potential obstacles to these approaches is the possibility of genetic adaptation of oncolytic viruses upon replication in susceptible tumor tissues. Genetic variation can reverse genetic manipulations of parental viral genomes that determine attenuation of virulence, selective tumor cell tropism or other desirable traits. Alternatively, it may convey new properties not originally associated with parental strains, e.g., adaptation to a human host range. We examined genetic stability of an oncolytic nonpathogenic poliovirus recombinant considered for therapy of recurrent glioblastoma multiforme (GBM). This was done by serial passage experiments in glioma xenografts in vivo and investigation of phenotypic and genotypic markers of attenuation. Intratumoral inoculation of oncolytic poliovirus produced efficient tumor regress and elimination without altering temperature-sensitive growth, selective cytotoxicity, or genetic markers of attenuation of virus recovered from inoculated animals. Our studies demonstrate that active viral oncolysis of malignant glioma does not alter the conditional replication properties of oncolytic nonpathogenic poliovirus recombinants.
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Affiliation(s)
- Elena Y Dobrikova
- Division of Neurosurgery, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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Zoll J, Heus HA, van Kuppeveld FJM, Melchers WJG. The structure-function relationship of the enterovirus 3'-UTR. Virus Res 2008; 139:209-16. [PMID: 18706945 DOI: 10.1016/j.virusres.2008.07.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 07/02/2008] [Indexed: 12/25/2022]
Abstract
Essential processes in living cells are carried out by large complex assemblies, which typically consist of a large number of proteins and frequently also contain nucleic acids, mostly RNA [Alberts, B., 1998. The cell as a collection of protein machines: preparing the next generation of molecular biologists. Cell 92, 291-294]. These large biomolecular complexes carry out biological processes in highly sophisticated ways: molecules do not move around randomly in the cell and interact by chance, but are guided to these "macromolecular machines", in which the number of possible collisions is restricted to a few possibilities, based, e.g., on the specificity of protein-RNA recognition. While the coding capacity of RNA lies within its sequence, the shape of an RNA molecule determines other functionalities such as stability, intra- and intermolecular interactions, catalytic activity, regulation of cellular processes, etc. [Doudna, J.A., 2000. Structural genomics of RNA. Nat. Struct. Biol. 7, 954-956; Cech, T.R. 2000. Structural biology. The ribosome is a ribozyme. Science 289, 878-879]. RNA structures in macromolecular machines are important features in assembly, target recognition and activity. Viral RNA molecules contain cis- and/or trans-acting control elements that, as exemplified by internal ribosomal entry sites and origins of genome replication, consist of complex multidomain structures [Andino, R., Rieckhof, G.E., Achacoso, P.L., Baltimore D., 1993. Poliovirus RNA synthesis utilizes an RNP complex formed around the 5'-end of viral RNA. EMBO J. 12, 3587-3598; Melchers, W.J.G., Hoenderop, J.G.J., Bruins Slot, H.J., Pleij, C.W.A., Pilipenko, E.V., Agol, V.I., Galama, J.M.D., 1997. Kissing of the two predominant hairpin loops in the coxsackie B virus 3' untranslated region is the essential structural feature of the origin of replication required for negative-strand RNA synthesis. J. Virol. 71, 686-696]. The formation of these structures is involved in the specific recognition of ligands or serves to support the structural integrity of the whole element. The replication of the enterovirus RNA is carried out by a large biomolecular complex formed by cis-acting RNA elements found in the 5'- and 3'-UTR of the virus genome and several cellular and viral proteins. This review will focus on RNA elements in the 3'-UTR of enteroviruses.
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Affiliation(s)
- Jan Zoll
- Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Department of Medical Microbiology, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
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Cello J, Toyoda H, Dejesus N, Dobrikova EY, Gromeier M, Wimmer E. Growth phenotypes and biosafety profiles in poliovirus-receptor transgenic mice of recombinant oncolytic polio/human rhinoviruses. J Med Virol 2008; 80:352-9. [PMID: 18098139 DOI: 10.1002/jmv.21063] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The use of oncolytic recombinant polioviruses has an important therapeutic potential in the treatment of human gliomas. This study was carried out to assess parameters of the utility of the oncolytic poliovirus/human rhinovirus type 2 chimeras (PV/HRV2). The prototype PV/HRV2 chimera was constructed containing the complete genome of wild-type PV type 1 (Mahoney) [PV1(M)] in which the cognate IRES was replaced with that of HRV2 [called PV1(RIPO)]. A derivative of PV1(RIPO) is PV1(RIPOS) in which the capsid coding region (P1) was replaced with the capsid-coding region of the PV type 1 (Sabin) [PV1(S)] vaccine strain. In addition, a third PV/HRV2 chimera was constructed containing the complete genome of PV1(S) in which the cognate IRES was replaced with that of HRV2 [termed PVS(RIPO)]. To analyze the growth phenotypes of PV/HRV2 recombinants [PV1(RIPO), PV1(RIPOS), PVS(RIPO)], one-step growth experiments were performed in four human cell lines at three different temperatures. To address the safety profile, PVS(RIPO) was injected into the brain of CD155 tg mice at the dose 10(7) PFU. Then, clinical signs, persistence of the virus in the CNS and genetic stability of PVS(RIPO) replicating in the CNS were evaluated. The data obtained in the present study suggest (i) a correlation between temperature-sensitive (ts) phenotype in both neuronal and non-neuronal cell lines and neuroattenuation in experimental animals, (ii) that PVS (RIPO) is genetically stable on replication in the CNS of poliovirus-susceptible mice. These findings highlight the safety of intracerebral inoculation of PVS(RIPO) for the treatment of human glioma.
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Affiliation(s)
- Jeronimo Cello
- Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, NY 11794-5222, USA.
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Anderson EC, Hunt SL, Jackson RJ. Internal initiation of translation from the human rhinovirus-2 internal ribosome entry site requires the binding of Unr to two distinct sites on the 5' untranslated region. J Gen Virol 2007; 88:3043-3052. [PMID: 17947529 DOI: 10.1099/vir.0.82463-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Internal initiation of translation from the human rhinovirus-2 (HRV-2) internal ribosome entry site (IRES) is dependent upon host cell trans-acting factors. The multiple cold shock domain protein Unr and the polypyrimidine tract-binding protein have been identified as synergistic activators of HRV-2 IRES-driven translation. In order to investigate the mechanism by which Unr acts in this process, we have mapped the binding sites of Unr to two distinct secondary structure domains of the HRV-2 IRES, and have identified specific nucleotides that are involved in the binding of Unr to the IRES. The data suggest that Unr acts as an RNA chaperone to maintain a complex tertiary IRES structure required for translational competency.
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Affiliation(s)
- Emma C Anderson
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Sarah L Hunt
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Richard J Jackson
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
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Florez de Sessions P, Dobrikova E, Gromeier M. Genetic adaptation to untranslated region-mediated enterovirus growth deficits by mutations in the nonstructural proteins 3AB and 3CD. J Virol 2007; 81:8396-405. [PMID: 17537861 PMCID: PMC1951365 DOI: 10.1128/jvi.00321-07] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 05/22/2007] [Indexed: 12/17/2022] Open
Abstract
Both untranslated regions (UTRs) of plus-strand RNA virus genomes jointly control translation and replication of viral genomes. In the case of the Enterovirus genus of the Picornaviridae family, the 5'UTR consists of a cloverleaf-like terminus preceding the internal ribosomal entry site (IRES) and the 3' terminus is composed of a structured 3'UTR and poly(A). The IRES and poly(A) have been implicated in translation control, and all UTR structures, in addition to cis-acting genetic elements mapping to the open reading frame, have been assigned roles in RNA replication. Viral UTRs are recognized by viral and host cell RNA-binding proteins that may co-determine genome stability, translation, plus- and minus-strand RNA replication, and scaffolding of viral replication complexes within host cell substructures. In this report, we describe experiments with coxsackie B viruses with a cell type-specific propagation deficit in Sk-N-Mc neuroblastoma cells conferred by the combination of a heterologous IRES and altered 3'UTR. Serial passage of these constructs in Sk-N-Mc cells yielded genetic adaptation by mutations within the viral nonstructural proteins 3A and 3C. Our data implicate 3A and/or 3C or their precursors 3AB and/or 3CD in a functional complex with the IRES and 3'UTR that drives viral propagation. Adaptation to neuroblastoma cells suggests an involvement of cell type-specific host factors or the host cell cytoplasmic milieu in this phenomenon.
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Affiliation(s)
- Paola Florez de Sessions
- Division of Neurological Surgery, Department of Surgery, Duke University Medical Center, Box 3020, Durham, NC 27710, USA
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Zoll J, Tessari M, Van Kuppeveld FJM, Melchers WJG, Heus HA. Breaking pseudo-twofold symmetry in the poliovirus 3'-UTR Y-stem by restoring Watson-Crick base pairs. RNA (NEW YORK, N.Y.) 2007; 13:781-92. [PMID: 17449731 PMCID: PMC1852819 DOI: 10.1261/rna.375607] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The previously described NMR structure of a 5'-CU-3'/5'-UU-3' motif, which is highly conserved within the 3'-UTR Y-stem of poliovirus-like enteroviruses, revealed striking regularities of the local helix geometry, thus retaining the pseudo-twofold symmetry of the RNA helix. A mutant virus with both pyrimidine base pairs changed into Watson-Crick replicated as wild type, indicating the functional importance of this symmetry relation in viral RNA replication. Here we investigated the effect of changing only one of the two pyrimidine base pairs to Watson-Crick. We determined the NMR structures of two Y-stem variants: one containing the 5'-CU-3'/5'-AU-3' motif, which has been found in wild-type virus isolates as well, and the other containing a 5'-CU-3'/5'-UG-3' motif, which is not present in any enterovirus sequenced to date. Both structures show single pyrimidine mismatches with intercalated bases. In the 5'-CU-3'/5'-AU-3' motif a C-U Watson-Crick-type base pair is formed that retains the pseudo-twofold symmetry, while in the 5'-CU-3'/5'-UG-3' motif a single asymmetric U-U mismatch breaks the twofold symmetry. Surprisingly, for the nonnatural variant no effect of the single base-pair replacement was observed on polioviral RNA replication using an in vitro replicon assay.
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Affiliation(s)
- Jan Zoll
- Institute for Molecules and Materials, Laboratory of Biophysical Chemistry, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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Arita M, Nagata N, Sata T, Miyamura T, Shimizu H. Quantitative analysis of poliomyelitis-like paralysis in mice induced by a poliovirus replicon. J Gen Virol 2006; 87:3317-3327. [PMID: 17030866 DOI: 10.1099/vir.0.82172-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Poliovirus (PV) infection causes severe paralysis, typically of the legs, by destruction of the motor neurons in the spinal cord. In this study, the relationship between PV replication in the spinal cord, damage in the motor neurons and poliomyelitis-like paralysis was analysed in transgenic mice expressing the human PV receptor (TgPVR21). First, a PV replicon encoding firefly luciferase in place of the capsid genes (PV-Fluc mc) was trans-encapsidated in 293T cells and the trans-encapsidated PV-Fluc mc (TE-PV-Fluc mc) was then inoculated into the spinal cords of TgPVR21 mice. TE-PV-Fluc mc was recovered with a titre of 6.3 x 10(7) infectious units ml(-1), which was comparable to those of PV1 strains. TgPVR21 mice inoculated with TE-PV-Fluc mc showed non-lethal paralysis of the hindlimbs, with severity ranging from a decline in grip strength to complete flaccid paralysis. The replication of TE-PV-Fluc mc in the spinal cord reached peak levels at 10 h post-inoculation (p.i.), followed by the appearance of paralysis at as early as 12 h p.i., reaching a plateau at 16 h p.i. Histological analysis showed a correlation between the lesion and the severity of the clinical symptoms in most mice. However, severe paralysis could also be observed with an apparently low lesion score, where as few as 5.3 x 10(2) motor neurons (1.4 % of the susceptible cells in the lumbar cord) were infected by TE-PV-Fluc mc. These results indicate that PV replication in a small population of the motor neurons was critical for severe residual poliomyelitis-like paralysis in TgPVR21 mice.
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Affiliation(s)
- Minetaro Arita
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Noriyo Nagata
- Department of Pathology, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Tetsutaro Sata
- Department of Pathology, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Tatsuo Miyamura
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Hiroyuki Shimizu
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
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Campbell SA, Mulvey M, Mohr I, Gromeier M. Attenuation of herpes simplex virus neurovirulence with picornavirus cis-acting genetic elements. J Virol 2006; 81:791-9. [PMID: 17079296 PMCID: PMC1797477 DOI: 10.1128/jvi.00714-06] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral pathogenesis depends on a suitable milieu in target host cells permitting viral gene expression, propagation, and spread. In many instances, viral genomes can be manipulated to select for propagation in certain tissues or cell types. This has been achieved for the neurotropic poliovirus (PV) by exchange of the internal ribosomal entry site (IRES), which is responsible for translation of the uncapped plus-strand RNA genome. The IRES of human rhinovirus type 2 (HRV2) confers neuron-specific replication deficits to PV but has no effect on viral propagation in malignant glioma cells. We report here that placing the critical gamma(1)34.5 virulence genes of herpes simplex virus type 1 (HSV) under translation control of the HRV2 IRES results in neuroattenuation in mice. In contrast, IRES insertion permits HSV propagation in malignant glioma cell lines that do not support replication of HSV recombinants carrying gamma(1)34.5 deletions. Our observations indicate that the conditions for alternative translation initiation at the HRV2 IRES in malignant glioma cells differ from those in normal central nervous system (CNS) cells. Picornavirus regulatory sequences mediating cell type-specific gene expression in the CNS can be utilized to target cancerous cells at the level of translation regulation outside their natural context.
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Affiliation(s)
- Stephanie A Campbell
- Division of Neurological Surgery, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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Merrill MK, Gromeier M. The double-stranded RNA binding protein 76:NF45 heterodimer inhibits translation initiation at the rhinovirus type 2 internal ribosome entry site. J Virol 2006; 80:6936-42. [PMID: 16809299 PMCID: PMC1489066 DOI: 10.1128/jvi.00243-06] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Poliovirus (PV) plus-strand RNA genomes initiate translation in a cap-independent manner via an internal ribosome entry site (IRES) in their 5' untranslated region. Viral translation is codetermined by cellular IRES trans-acting factors, which can influence viral propagation in a cell-type-specific manner. Engineering of a poliovirus recombinant devoid of neuropathogenic properties but highly lytic in malignant glioma cells was accomplished by exchange of the cognate poliovirus IRES with its counterpart from human rhinovirus type 2 (HRV2), generating PV-RIPO. Neuroblast:glioma heterokaryon analyses revealed that loss of neurovirulence is due to trans-dominant repression of PV-RIPO propagation in neuronal cells. The double-stranded RNA binding protein 76 (DRBP76) was previously identified to bind to the HRV2 IRES in neuronal cells and to inhibit PV-RIPO translation and propagation (M. Merrill, E. Dobrikova, and M. Gromeier, J. Virol. 80:3347-3356, 2006). The results of size exclusion chromatography indicate that DRBP76 heterodimerizes with nuclear factor of activated T cells, 45 kDa (NF45), in neuronal but not in glioma cells. The DRBP76:NF45 heterodimer binds to the HRV2 IRES in neuronal but not in glioma cells. Ribosomal profile analyses show that the heterodimer preferentially associates with the translation apparatus in neuronal cells and arrests translation at the HRV2 IRES, preventing PV-RIPO RNA assembly into polysomes. Results of this study suggest that the DRBP76:NF45 heterodimer selectively blocks HRV2 IRES-driven translation initiation in neuron-derived cells.
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Affiliation(s)
- Melinda K Merrill
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Box 3020, Durham, NC 27710, USA
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Merrill MK, Dobrikova EY, Gromeier M. Cell-type-specific repression of internal ribosome entry site activity by double-stranded RNA-binding protein 76. J Virol 2006; 80:3147-56. [PMID: 16537583 PMCID: PMC1440377 DOI: 10.1128/jvi.80.7.3147-3156.2006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Translation of picornavirus plus-strand RNA genomes occurs via internal ribosomal entry at highly structured 5' untranslated regions. In addition to canonical translation factors, translation rate is likely influenced by supplementary host and viral trans-acting factors. We previously reported that insertion of a heterologous human rhinovirus type 2 internal ribosomal entry site (IRES) into the poliovirus (PV) genome, generating the chimeric virus PV-RIPO, selectively abrogates viral translation and propagation in neurons, which eliminate poliovirus's signature neuropathogenicity. While severely deficient in cells of neuronal lineage, the rhinovirus IRES promotes efficient propagation of PV-RIPO in cancer cells. Tumor-specific IRES function can be therapeutically exploited to direct viral cytotoxicity to cancer cells. Neuron-glioma heterokaryon analysis implicates neuronal trans-dominant inhibition in this effect, suggesting that host trans-acting factors repress IRES function in a cell-type-specific manner. We identified a set of proteins from neuronal cells with affinity for the rhinovirus IRES, including double-stranded RNA-binding protein 76 (DRBP76). DRBP76 associates with the IRES in neuronal but not in malignant glioma cells. Moreover, DRBP76 depletion in neuronal cells enhances rhinovirus IRES-driven translation and virus propagation. Our observations suggest that cell-type-specific association of DRBP76 with the rhinovirus IRES represses PV-RIPO translation and propagation in neuronal cells.
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Affiliation(s)
- Melinda K Merrill
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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