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Updated: Aug 24, 2026
Growth, Purification, and Titration of Oncolytic Herpes Simplex Virus
Published on: May 13, 2021
Effect of murine liver cell proliferation on herpes viral behavior: implications for oncolytic viral therapy
Keith A Delman1, Jonathan S Zager, Amit Bhargava
1Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
Abstract:
Replication-competent herpes simplex oncolytic viruses are promising anticancer agents that partly target increased DNA synthesis in tumor cells. Investigators have proposed that these DNA viruses may be combined with liver resection to enhance killing of liver malignancies. Whether or not the cellular alterations associated with hepatic regeneration affect the efficacy and toxicity of these promising anticancer agents is unknown. This study examined the behavior of two oncolytic viruses, NV1020 and G207, during liver regeneration. When delivered during the peak of liver regeneration, replication and appearance of both G207 and NV1020 in hepatic tissue are enhanced as demonstrated by histochemical staining for the marker gene lac Z, immunohistochemical staining, and quantitative polymerase chain reaction. This increased appearance of virus in liver tissue correlates with increases in cellular ribonucleotide reductase activity and DNA synthesis and is also associated with increased viral binding. However, increased viral presence is transient, and viral detection declines to baseline within 7 days. When these viruses were delivered to animals even as early as 7 days after hepatectomy, there proved to be no measurable viral replication in any organ and no increased morbidity or mortality. In conclusion, the early stages of hepatic regeneration after resection provide an environment suitable for viral replication. Administration of replication-competent herpes simplex virus during the peak of hepatocyte regeneration (24-48 hours) permits viral productivity in tissue that otherwise does not support viral growth. The increase in hepatotoxicity after hepatectomy is short-lived and can be predicted by peak hepatocyte DNA synthesis.
Insights
Oncolytic herpes simplex viruses show enhanced replication in regenerating liver tissue after resection. This effect is transient and occurs during peak hepatocyte regeneration, suggesting a window for enhanced oncolytic virotherapy.
Area of Science:
- Oncolytic virotherapy
- Hepatocellular carcinoma treatment
- Viral oncology
Background:
- Replication-competent oncolytic viruses are promising anticancer agents targeting tumor cell DNA synthesis.
- Combining oncolytic viruses with liver resection is proposed for enhanced liver malignancy treatment.
- The impact of hepatic regeneration on oncolytic virus efficacy and toxicity remains unclear.
Purpose of the Study:
- To investigate the behavior of oncolytic viruses (NV1020 and G207) during liver regeneration.
- To determine if hepatic regeneration influences the efficacy and toxicity of these oncolytic viruses.
Main Methods:
- Administration of NV1020 and G207 to animals undergoing liver resection.
- Assessment of viral replication and presence using histochemical staining (lac Z), immunohistochemistry, and quantitative PCR.
- Measurement of cellular ribonucleotide reductase activity and DNA synthesis.
- Monitoring of morbidity and mortality.
Main Results:
- Viral replication and presence in hepatic tissue were enhanced when viruses were delivered during peak liver regeneration (24-48 hours post-hepatectomy).
- Increased viral presence correlated with elevated cellular ribonucleotide reductase activity, DNA synthesis, and viral binding.
- Enhanced viral detection was transient, declining to baseline within 7 days, with no significant viral replication or increased toxicity observed at 7 days post-hepatectomy.
Conclusions:
- Early hepatic regeneration stages create a favorable environment for oncolytic herpes simplex virus replication.
- Administering replication-competent herpes simplex virus during peak hepatocyte regeneration enhances viral productivity in liver tissue.
- Increased hepatotoxicity post-hepatectomy is temporary and linked to peak hepatocyte DNA synthesis.
