Simultaneous Expression of Different Therapeutic Genes by Infection with Multiple Oncolytic HSV-1 Vectors

Area of Science:

• Oncolytic virology
• Cancer immunotherapy
• Gene therapy

Background:

• Oncolytic viruses (OVs) are engineered viruses that selectively infect and kill cancer cells while stimulating an anti-tumor immune response.
• Enhancing OV efficacy often involves arming them with immunomodulatory factors to improve anti-tumor immunity.
• Cancer's complexity necessitates combinatorial strategies, potentially involving co-expression of multiple therapeutic molecules for greater effectiveness than monotherapies.

Purpose of the Study:

• To investigate the feasibility of simultaneously expressing multiple therapeutic proteins in triple-negative breast cancer (TNBC) cells using a combination of oncolytic herpes simplex virus type 1 (oHSV1) vectors.
• To assess the impact of viral particle dosage on protein expression levels.
• To evaluate the efficacy and replication kinetics of recombinant oHSV1s in both single and multiple infection settings for TNBC treatment.

Main Methods:

• Generation of recombinant oHSV1s, each encoding a single transgene.
• Co-infection of TNBC cells with a panel of these oHSV1 vectors.
• Quantification of protein expression levels based on viral particle input.
• Assessment of viral replication kinetics and cancer cell killing efficacy in vitro.

Main Results:

• Simultaneous expression of different proteins in TNBC cells was successfully achieved through co-infection with multiple oHSV1 vectors.
• Protein expression levels were directly correlated with the multiplicity of infection (number of viral particles used).
• All recombinant oHSV1s demonstrated comparable efficacy in killing TNBC cells and exhibited similar replication kinetics, regardless of single or multiple infections.

Conclusions:

• A combinatorial strategy utilizing co-infection with a panel of oHSV1s represents a promising therapeutic approach for TNBC.
• This multi-targeting strategy holds potential for treating other solid tumors and warrants further investigation in advanced preclinical models.
• The ability to achieve dose-dependent, simultaneous expression of multiple therapeutic agents via oHSV1 co-infection offers a flexible platform for combinatorial cancer therapy.