Vaccinia Virus Shuffling: deVV5, a Novel Chimeric Poxvirus with Improved Oncolytic Potency

Area of Science:

• Virology
• Oncology
• Genetic Engineering

Background:

• Oncolytic virus (OV) therapy offers a promising, potentially less toxic cancer treatment alternative.
• While Vaccinia virus (VACV)-derived OVs show safety, their monotherapy efficacy can be limited.
• Improving OV potency and tumor selectivity is crucial for enhanced cancer treatment.

Purpose of the Study:

• To generate a novel recombinant poxvirus with enhanced oncolytic properties using directed evolution.
• To improve the tumor selectivity and anti-tumor activity of the derived virus.
• To evaluate the therapeutic potential of engineered viruses for cancer therapy.

Main Methods:

• Directed evolution by pooling different Vaccinia virus strains (Copenhagen, Western Reserve, Wyeth) and MVA.
• Selection under pressure to derive a chimeric VACV (deVV5) with increased in vitro oncolytic potency and tumor selectivity.
• Generation of a thymidine kinase (TK)-deleted chimeric virus (deVV5-fcu1) armed with the suicide gene FCU1.

Main Results:

• A chimeric VACV, deVV5, was successfully generated with enhanced cancer cell killing capacity and tumor selectivity.
• The TK-deleted deVV5-fcu1 virus demonstrated efficient replication in human tumor cells.
• deVV5-fcu1 showed significant attenuation in normal primary cells, indicating improved safety.

Conclusions:

• Directed evolution is an effective strategy for generating recombinant poxviruses with superior oncolytic potency.
• The engineered virus deVV5-fcu1 exhibits enhanced tumor selectivity and replication efficiency.
• These findings highlight the potential of engineered OVs with a high therapeutic index to advance cancer therapy.