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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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Eaglesham JB, McCarty KL, Kranzusch PJ. Structures of diverse poxin cGAMP nucleases reveal a widespread role for cGAS-STING evasion in host-pathogen conflict. eLife 2020; 9:e59753. [PMID: 33191912 PMCID: PMC7688311 DOI: 10.7554/elife.59753] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/12/2020] [Indexed: 02/06/2023] Open
Abstract
DNA viruses in the family Poxviridae encode poxin enzymes that degrade the immune second messenger 2'3'-cGAMP to inhibit cGAS-STING immunity in mammalian cells. The closest homologs of poxin exist in the genomes of insect viruses suggesting a key mechanism of cGAS-STING evasion may have evolved outside of mammalian biology. Here we use a biochemical and structural approach to discover a broad family of 369 poxins encoded in diverse viral and animal genomes and define a prominent role for 2'3'-cGAMP cleavage in metazoan host-pathogen conflict. Structures of insect poxins reveal unexpected homology to flavivirus proteases and enable identification of functional self-cleaving poxins in RNA-virus polyproteins. Our data suggest widespread 2'3'-cGAMP signaling in insect antiviral immunity and explain how a family of cGAS-STING evasion enzymes evolved from viral proteases through gain of secondary nuclease activity. Poxin acquisition by poxviruses demonstrates the importance of environmental connections in shaping evolution of mammalian pathogens.
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Affiliation(s)
- James B Eaglesham
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Department of Cancer Immunology and Virology, Dana-Farber Cancer InstituteBostonUnited States
- Harvard PhD Program in Virology, Division of Medical Sciences, Harvard UniversityBostonUnited States
| | - Kacie L McCarty
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Department of Cancer Immunology and Virology, Dana-Farber Cancer InstituteBostonUnited States
| | - Philip J Kranzusch
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Department of Cancer Immunology and Virology, Dana-Farber Cancer InstituteBostonUnited States
- Harvard PhD Program in Virology, Division of Medical Sciences, Harvard UniversityBostonUnited States
- Parker Institute for Cancer Immunotherapy at Dana-Farber Cancer InstituteBostonUnited States
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