A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.

To generate a novel oncolytic vaccinia virus with improved safety and productivity, the genome of smallpox vaccine strain LC16m8 was modified by a bacterial artificial chromosome system. By using LC16m8, a replicating virus homologous to the target virus, as a helper virus for the bacterial artifici...

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Main Authors: Go Okita, Kiyotaka Suenaga, Masashi Sakaguchi, Toshio Murakami
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0312205
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author Go Okita
Kiyotaka Suenaga
Masashi Sakaguchi
Toshio Murakami
author_facet Go Okita
Kiyotaka Suenaga
Masashi Sakaguchi
Toshio Murakami
author_sort Go Okita
collection DOAJ
description To generate a novel oncolytic vaccinia virus with improved safety and productivity, the genome of smallpox vaccine strain LC16m8 was modified by a bacterial artificial chromosome system. By using LC16m8, a replicating virus homologous to the target virus, as a helper virus for the bacterial artificial chromosome system, we successfully recovered genome-edited infectious viruses. Oncolytic viruses with limited growth in normal cells were obtained by deleting the genes for vaccinia virus growth factor (VGF), extracellular signal-regulated kinase-activating protein (O1L), and ribonucleotide reductase (RNR) present in the viral genome. Furthermore, the amino acid residues of seven proteins involved in extracellular enveloped virus virion formation were replaced to the IHD-J strain sequence, which is known to highly express extracellular enveloped virus. In cultured cancer cells (HeLa), these modified viruses showed cytotoxicity and increased productivity, but it was confirmed that the cytotoxicity was suppressed in normal cells (normal human dermal fibroblasts). For in vivo safety evaluation, a modified virus (MD-RVV-ΔRR-EEV6) in which the VGF, O1L, and RNR genes of LC16m8 were deleted and the genes of six extracellular enveloped virus-associated proteins were replaced with sequences derived from IHD-J strain, and another modified virus (MD-RVV) lacking only the VGF and O1L were administered intravenously to severe combined immunodeficiency mice. In the MD-RVV administration, animals in all dose groups died by 40 days after virus administration. On the other hand, after MD-RVV-ΔRR-EEV6 administration, 3 out of 5 animals in the high and medium dose groups and all animals in the low dose group were still alive by day 71, the end of the observation period. These results demonstrate that genome editing of oncolytic vaccinia virus can delete genes involved in viral replication to improve safety in normal cells, while replacing genes involved in maturation improves proliferative potential in cancer cells.
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spelling doaj-art-1210e82dd2f14ccdb68d5c614e5362042025-08-20T03:52:46ZengPublic Library of Science (PLoS)PLoS ONE1932-62032025-01-01203e031220510.1371/journal.pone.0312205A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.Go OkitaKiyotaka SuenagaMasashi SakaguchiToshio MurakamiTo generate a novel oncolytic vaccinia virus with improved safety and productivity, the genome of smallpox vaccine strain LC16m8 was modified by a bacterial artificial chromosome system. By using LC16m8, a replicating virus homologous to the target virus, as a helper virus for the bacterial artificial chromosome system, we successfully recovered genome-edited infectious viruses. Oncolytic viruses with limited growth in normal cells were obtained by deleting the genes for vaccinia virus growth factor (VGF), extracellular signal-regulated kinase-activating protein (O1L), and ribonucleotide reductase (RNR) present in the viral genome. Furthermore, the amino acid residues of seven proteins involved in extracellular enveloped virus virion formation were replaced to the IHD-J strain sequence, which is known to highly express extracellular enveloped virus. In cultured cancer cells (HeLa), these modified viruses showed cytotoxicity and increased productivity, but it was confirmed that the cytotoxicity was suppressed in normal cells (normal human dermal fibroblasts). For in vivo safety evaluation, a modified virus (MD-RVV-ΔRR-EEV6) in which the VGF, O1L, and RNR genes of LC16m8 were deleted and the genes of six extracellular enveloped virus-associated proteins were replaced with sequences derived from IHD-J strain, and another modified virus (MD-RVV) lacking only the VGF and O1L were administered intravenously to severe combined immunodeficiency mice. In the MD-RVV administration, animals in all dose groups died by 40 days after virus administration. On the other hand, after MD-RVV-ΔRR-EEV6 administration, 3 out of 5 animals in the high and medium dose groups and all animals in the low dose group were still alive by day 71, the end of the observation period. These results demonstrate that genome editing of oncolytic vaccinia virus can delete genes involved in viral replication to improve safety in normal cells, while replacing genes involved in maturation improves proliferative potential in cancer cells.https://doi.org/10.1371/journal.pone.0312205
spellingShingle Go Okita
Kiyotaka Suenaga
Masashi Sakaguchi
Toshio Murakami
A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.
PLoS ONE
title A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.
title_full A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.
title_fullStr A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.
title_full_unstemmed A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.
title_short A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells.
title_sort novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells
url https://doi.org/10.1371/journal.pone.0312205
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