Trichostatin A and oncolytic HSV combination therapy shows enhanced antitumoral and antiangiogenic effects

Area of Science:

• Oncology
• Virology
• Molecular Biology

Background:

• Oncolytic herpes simplex viruses (HSVs) demonstrate oncolytic and antiangiogenic properties for cancer treatment.
• The efficacy of HSVs as single agents requires improvement for broader clinical application.

Purpose of the Study:

• To investigate the synergistic efficacy of combining oncolytic HSV (G47Delta) with histone deacetylase inhibitor trichostatin A (TSA) for enhanced cancer therapy.
• To elucidate the mechanisms underlying the synergistic effects of the combination therapy.

Main Methods:

• In vitro studies assessed the synergistic effects of TSA and G47Delta on proliferating endothelial cells and various cancer cell lines.
• Isogenic cell systems were used to determine the role of cellular cyclin D1 in the combination's efficacy.
• Animal models were employed to evaluate the in vivo antiangiogenic and antitumoral effects of concurrent systemic TSA and intratumoral G47Delta administration.

Main Results:

• TSA and G47Delta exhibited strong synergy against proliferating endothelial cells and significant synergy against most cancer cell lines.
• Synergy was dependent on viral replication and high cellular cyclin D1 levels but not on dosing sequence or viral kinetics.
• The combination treatment enhanced the inhibition of cyclin D1 and vascular endothelial growth factor (VEGF) in tumor cells and proliferating endothelial cells.
• In vivo studies demonstrated enhanced antiangiogenesis and antitumoral efficacy with concurrent systemic TSA and intratumoral G47Delta administration.

Conclusions:

• Combination therapy of oncolytic HSV with TSA offers a novel and enhanced approach to cancer treatment.
• The synergistic effect is linked to the inhibition of cyclin D1 and VEGF, highlighting a potential therapeutic strategy targeting tumor vasculature and cancer cells simultaneously.