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Riederer S, Del Canizo A, Navas J, Peter MG, Link EK, Sutter G, Rojas JJ. Improving poxvirus-mediated antitumor immune responses by deleting viral cGAMP-specific nuclease. Cancer Gene Ther 2023:10.1038/s41417-023-00610-5. [PMID: 37016144 DOI: 10.1038/s41417-023-00610-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 02/21/2023] [Accepted: 03/21/2023] [Indexed: 04/06/2023]
Abstract
cGAMP-specific nucleases (poxins) are a recently described family of proteins dedicated to obstructing cyclic GMP-AMP synthase signaling (cGAS), an important sensor triggered by cytoplasmic viral replication that activates type I interferon (IFN) production. The B2R gene of vaccinia viruses (VACV) codes for one of these nucleases. Here, we evaluated the effects of inactivating the VACV B2 nuclease in the context of an oncolytic VACV. VACV are widely used as anti-cancer vectors due to their capacity to activate immune responses directed against tumor antigens. We aimed to elicit robust antitumor immunity by preventing viral inactivation of the cGAS/STING/IRF3 pathway after infection of cancer cells. Activation of such a pathway is associated with a dominant T helper 1 (Th1) cell differentiation of the response, which benefits antitumor outcomes. Deletion of the B2R gene resulted in enhanced IRF3 phosphorylation and type I IFN expression after infection of tumor cells, while effective VACV replication remained unimpaired, both in vitro and in vivo. In syngeneic mouse tumor models, the absence of the VACV cGAMP-specific nuclease translated into improved antitumor activity, which was associated with antitumor immunity directed against tumor epitopes.
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Affiliation(s)
- Stephanie Riederer
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Munich, Germany
| | - Ana Del Canizo
- Immunology Unit, Department of Pathology and Experimental Therapies, School of Medicine, University of Barcelona-UB, Barcelona, Spain
- Immunity, Inflammation, and Cancer Group, Oncobell Program, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Javier Navas
- Immunology Unit, Department of Pathology and Experimental Therapies, School of Medicine, University of Barcelona-UB, Barcelona, Spain
- Immunity, Inflammation, and Cancer Group, Oncobell Program, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Marlowe G Peter
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Munich, Germany
| | - Ellen K Link
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Munich, Germany
| | - Gerd Sutter
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Munich, Germany.
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany.
| | - Juan J Rojas
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Munich, Germany.
- Immunology Unit, Department of Pathology and Experimental Therapies, School of Medicine, University of Barcelona-UB, Barcelona, Spain.
- Immunity, Inflammation, and Cancer Group, Oncobell Program, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain.
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Riederer S, Fux R, Lehmann MH, Volz A, Sutter G, Rojas JJ. Activation of interferon regulatory factor 3 by replication-competent vaccinia viruses improves antitumor efficacy mediated by T cell responses. MOLECULAR THERAPY-ONCOLYTICS 2021; 22:399-409. [PMID: 34553028 PMCID: PMC8430050 DOI: 10.1016/j.omto.2021.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 06/01/2021] [Indexed: 11/16/2022]
Abstract
Recently, oncolytic vaccinia viruses (VACVs) have shown their potential to provide for clinically effective cancer treatments. The reason for this clinical usefulness is not only the direct destruction of infected cancer cells but also activation of immune responses directed against tumor antigens. For eliciting a robust antitumor immunity, a dominant T helper 1 (Th1) cell differentiation of the response is preferred, and such polarization can be achieved by activating the Toll-like receptor 3 (TLR3)-interferon regulatory factor 3 (IRF3) signaling pathway. However, current VACVs used as oncolytic viruses to date still encode several immune evasion proteins involved in the inhibition of this signaling pathway. By inactivating genes of selected regulatory virus proteins, we aimed for a candidate virus with increased potency to activate cellular antitumor immunity but at the same time with a fully maintained replicative capacity in cancer cells. The removal of up to three key genes (C10L, N2L, and C6L) from VACV did not reduce the strength of viral replication, both in vitro and in vivo, but resulted in the rescue of IRF3 phosphorylation upon infection of cancer cells. In syngeneic mouse tumor models, this activation translated to enhanced cytotoxic T lymphocyte (CTL) responses directed against tumor-associated antigens and neo-epitopes and improved antitumor activity.
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Affiliation(s)
- Stephanie Riederer
- Division of Virology, Department of Veterinary Sciences, LMU Munich, 80539 Munich, Germany
| | - Robert Fux
- Division of Virology, Department of Veterinary Sciences, LMU Munich, 80539 Munich, Germany
| | - Michael H Lehmann
- Division of Virology, Department of Veterinary Sciences, LMU Munich, 80539 Munich, Germany
| | - Asisa Volz
- Division of Virology, Department of Veterinary Sciences, LMU Munich, 80539 Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, 80539 Munich, Germany
| | - Gerd Sutter
- Division of Virology, Department of Veterinary Sciences, LMU Munich, 80539 Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, 80539 Munich, Germany
| | - Juan J Rojas
- Division of Virology, Department of Veterinary Sciences, LMU Munich, 80539 Munich, Germany.,Department of Pathology and Experimental Therapies, IDIBELL, University of Barcelona, 08907 L'Hospitalet de Llobregat, Spain
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Ectromelia virus lacking the E3L ortholog is replication-defective and nonpathogenic but does induce protective immunity in a mouse strain susceptible to lethal mousepox. Virology 2018; 518:335-348. [PMID: 29602068 DOI: 10.1016/j.virol.2018.03.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 01/16/2023]
Abstract
All known orthopoxviruses, including ectromelia virus (ECTV), contain a gene in the E3L family. The protein product of this gene, E3, is a double-stranded RNA-binding protein. It can impact host range and is used by orthopoxviruses to combat cellular defense pathways, such as PKR and RNase L. In this work, we constructed an ECTV mutant with a targeted disruption of the E3L open reading frame (ECTVΔE3L). Infection with this virus resulted in an abortive replication cycle in all cell lines tested. We detected limited transcription of late genes but no significant translation of these mRNAs. Notably, the replication defects of ECTVΔE3L were rescued in human and mouse cells lacking PKR. ECTVΔE3L was nonpathogenic in BALB/c mice, a strain susceptible to lethal mousepox disease. However, infection with ECTVΔE3L induced protective immunity upon subsequent challenge with wild-type virus. In summary, E3L is an essential gene for ECTV.
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Albarnaz JD, Torres AA, Smith GL. Modulating Vaccinia Virus Immunomodulators to Improve Immunological Memory. Viruses 2018; 10:E101. [PMID: 29495547 PMCID: PMC5869494 DOI: 10.3390/v10030101] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 12/14/2022] Open
Abstract
The increasing frequency of monkeypox virus infections, new outbreaks of other zoonotic orthopoxviruses and concern about the re-emergence of smallpox have prompted research into developing antiviral drugs and better vaccines against these viruses. This article considers the genetic engineering of vaccinia virus (VACV) to enhance vaccine immunogenicity and safety. The virulence, immunogenicity and protective efficacy of VACV strains engineered to lack specific immunomodulatory or host range proteins are described. The ultimate goal is to develop safer and more immunogenic VACV vaccines that induce long-lasting immunological memory.
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Affiliation(s)
- Jonas D Albarnaz
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Alice A Torres
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Geoffrey L Smith
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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