scholarly journals Engineering and Preclinical Evaluation of Western Reserve Oncolytic Vaccinia Virus Expressing A167Y Mutant Herpes Simplex Virus Thymidine Kinase

Biomedicines ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 426
Author(s):  
S. M. Bakhtiar UL Islam ◽  
Young Mi Hong ◽  
Mefotse saha Cyrelle Ornella ◽  
Daniel Ngabire ◽  
Hyunjung Jang ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Vaccinia Virus ◽  
Cancer Cells ◽  
Thymidine Kinase ◽  
Nucleoside Analogs ◽  
Wild Type ◽  
Normal Cells ◽  
Simplex Virus ◽  
Western Reserve

Viral replication of thymidine kinase deleted (tk−) vaccinia virus (VV) is attenuated in resting normal cells, enabling cancer selectivity, however, replication potency of VV-tk− appears to be diminished in cancer cells. Previously, we found that wild-type herpes simplex virus (HSV)-tk (HSV-tk) disappeared in most of the recombinant VV after multiple screenings, and only a few recombinant VV containing naturally mutated HSV-tk remained stable. In this study, VV-tk of western reserve (WR) VV was replaced by A167Y mutated HSV-tk (HSV-tk418m), to alter nucleoside selectivity from broad spectrum to purine exclusive selectivity. WOTS-418 remained stable after numerous passages. WOTS-418 replication was significantly attenuated in normal cells, but cytotoxicity was almost similar to that of wild type WR VV in cancer cells. WOTS-418 showed no lethality following a 5 × 108 PFU intranasal injection, contrasting WR VV, which showed 100% lethality at 1 × 105 PFU. Additionally, ganciclovir (GCV) but not BvdU inhibited WOTS-418 replication, confirming specificity to purine nucleoside analogs. The potency of WOTS-418 replication inhibition by GCV was > 10-fold higher than that of our previous truncated HSV-tk recombinant OTS-412. Overall, WOTS-418 demonstrated robust oncolytic efficacy and pharmacological safety which may delegate it as a candidate for future clinical use in OV therapy.

scholarly journals A truncated herpes simplex virus thymidine kinase phosphorylates thymidine and nucleoside analogs and does not cause sterility in transgenic mice.

1995 ◽  
Vol 15 (10) ◽  
pp. 5322-5328 ◽  
Author(s):  
B Salomon ◽  
S Maury ◽  
L Loubière ◽  
M Caruso ◽  
R Onclercq ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Transgenic Mice ◽  
Thymidine Kinase ◽  
Nucleoside Analogs ◽  
Suicide Gene ◽  
Physiological Importance ◽  
Simplex Virus ◽  
High Level

Dividing eukaryotic cells expressing the herpes simplex virus type 1 thymidine kinase (TK) gene are sensitive to the cytotoxic effect of nucleoside analogs such as acyclovir or ganciclovir (GCV). Transgenic mice with cell-targeted expression of this conditional toxin have been used to create animals with temporally controlled cell-specific ablation. In these animal models, which allow the study of the physiological importance of a cell type, males are sterile. In this study, we showed that this phenomenon is due to testis-specific high-level expression of short TK transcripts initiated mainly upstream of the second internal ATG of the TK gene. This expression is DNA methylation independent. To obtain a suicide gene that does not cause male infertility, we generated and analyzed the properties of a truncated TK (delta TK) lacking the sequences upstream of the second ATG. We showed that when expressed at sufficient levels, the functional properties of delta TK are similar to those of TK in terms of thymidine or GCV phosphorylation. This translated into a similar GCV-dependent toxicity for delta TK- or TK-expressing cells, both in vitro and in transgenic mice. However, delta TK behaved differently from TK in two ways. First, it did not cause sterility in delta TK transgenic males. Second, low-level delta TK RNA expression did not confer sensitivity to GCV. The uses of delta TK in cell-specific ablation in transgenic mice and in gene therapy are discussed.

scholarly journals Engineering and Characterization of Oncolytic Vaccinia Virus Expressing Truncated Herpes Simplex Virus Thymidine Kinase

Cancers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 228
Author(s):  
S. M. Bakhtiar Ul Islam ◽  
Bora Lee ◽  
Fen Jiang ◽  
Eung-Kyun Kim ◽  
Soon Cheol Ahn ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Viral Replication ◽  
Vaccinia Virus ◽  
Thymidine Kinase ◽  
Oncolytic Viruses ◽  
Multiple Cancer ◽  
Replication Control ◽  
Tumor Selectivity ◽  
Simplex Virus

Oncolytic viruses are a promising class of anti-tumor agents; however, concerns regarding uncontrolled viral replication have led to the development of a replication-controllable oncolytic vaccinia virus (OVV). The engineering involves replacing the native thymidine kinase (VV-tk) gene, in a Wyeth strain vaccinia backbone, with the herpes simplex virus thymidine kinase (HSV-tk) gene, which allows for viral replication control via ganciclovir (GCV, an antiviral/cytotoxic pro-drug). Adding the wild-type HSV-tk gene might disrupt the tumor selectivity of VV-tk deleted OVVs; therefore, only engineered viruses that lacked tk activity were selected as candidates. Ultimately, OTS-412, which is an OVV containing a mutant HSV-tk, was chosen for characterization regarding tumor selectivity, sensitivity to GCV, and the influence of GCV on OTS-412 anti-tumor effects. OTS-412 demonstrated comparable replication and cytotoxicity to VVtk- (control, a VV-tk deleted OVV) in multiple cancer cell lines. In HCT 116 mouse models, OTS-412 replication in tumors was reduced by >50% by GCV (p = 0.004); additionally, combination use of GCV did not compromise the anti-tumor effects of OTS-412. This is the first report of OTS-412, a VV-tk deleted OVV containing a mutant HSV-tk transgene, which demonstrates tumor selectivity and sensitivity to GCV. The HSV-tk/GCV combination provides a safety mechanism for future clinical applications of OTS-412.

scholarly journals Competition and complementation between thymidine kinase-negative and wild-type herpes simplex virus during co-infection of mouse trigeminal ganglia

2006 ◽  
Vol 87 (12) ◽  
pp. 3495-3502 ◽  
Author(s):  
Shih-Heng Chen ◽  
Yu-Wen Lin ◽  
Anthony Griffiths ◽  
Wen-Yen Huang ◽  
Shun-Hua Chen
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Antiviral Drug ◽  
Wild Type Virus ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Viral Genomes ◽  
Simplex Virus

Laboratory strains of herpes simplex virus lacking thymidine kinase (TK) cannot replicate acutely to detectable levels in mouse trigeminal ganglia and do not reactivate from latency. However, many pathogenic clinical isolates that are resistant to the antiviral drug acyclovir are heterogeneous populations of TK-negative (TK−) and TK-positive (TK+) viruses. To recapitulate this in vivo, mice were infected with mixtures of wild-type virus and a recombinant TK− mutant in various ratios. Following co-infection, the replication, number of latent viral genomes and reactivation efficiency of TK+ virus in trigeminal ganglia were reduced in a manner related to the amount of TK− virus in the inoculum. TK+ virus did not always complement the acute replication or increase the number of latent viral genomes of TK− mutant in mouse ganglia. Even so, TK+ virus could still confer the pathogenic phenotype to a TK− mutant, somehow providing sufficient TK activity in trans to permit a TK− mutant to reactivate from latently infected ganglia.

scholarly journals Accumulation of Viral Transcripts and DNA during Establishment of Latency by Herpes Simplex Virus

1998 ◽  
Vol 72 (2) ◽  
pp. 1177-1185 ◽  
Author(s):  
Martha F. Kramer ◽  
Shun-Hua Chen ◽  
David M. Knipe ◽  
Donald M. Coen
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Latent Infection ◽  
Acute Infection ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Wild Type ◽  
Simplex Virus

ABSTRACT Latent infection of mice with wild-type herpes simplex virus is established during an acute phase of ganglionic infection in which there is abundant viral replication and productive-cycle gene expression. Thymidine kinase-negative mutants establish latent infections but are severely impaired for acute ganglionic replication and productive-cycle gene expression. Indeed, by in situ hybridization assays, acute infection by these mutants resembles latency. To assess events during establishment of latency by wild-type and thymidine kinase-negative viruses, we quantified specific viral nucleic acid sequences in mouse trigeminal ganglia during acute ganglionic infection by using sensitive PCR-based assays. Through 32 h postinfection, viral DNA and transcripts representative of the three kinetic classes of productive-cycle genes accumulated to comparable levels in wild-type- and mutant-infected ganglia. At 48 and 72 h, although latency-associated transcripts accumulated to comparable levels in ganglia infected with wild-type or mutant virus, levels of DNA accumulating in wild-type-infected ganglia exceeded those in mutant-infected ganglia by 2 to 3 orders of magnitude. Coincident with this increase in DNA, wild-type-infected ganglia exhibited abundant expression of productive-cycle genes and high titers of infectious progeny. Nevertheless, the levels of productive-cycle RNAs expressed by mutant virus during acute infection greatly exceeded those expressed by wild-type virus during latency. The results thus distinguish acute infection of ganglia by a replication-compromised mutant from latent infection and may have implications for mechanisms of latency.

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