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Updated: May 7, 2026
Paramyxoviruses for Tumor-targeted Immunomodulation: Design and Evaluation Ex Vivo
Published on: January 7, 2019
Characteristics of oncolytic vesicular stomatitis virus displaying tumor-targeting ligands
Arun Ammayappan1, Kah-Whye Peng, Stephen J Russell
1Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
Abstract:
We sought proof of principle that tumor-targeting ligands can be displayed on the surface of vesicular stomatitis virus (VSV) by engineering its glycoprotein. Here, we successfully rescued VSVs displaying tumor vasculature-targeting ligands. By using a rational approach, we investigated various feasible insertion sites on the G protein of VSV (VSV-G) for display of tumor vasculature-targeting ligands, cyclic RGD (cRGD) and echistatin. We found seven sites on VSV-G that tolerated insertion of the 9-residue cRGD peptide, two of which could tolerate insertion of the 49-amino acid echistatin domain. All of the ligand-displaying viruses replicated as well as the parental virus. In vitro studies demonstrated that the VSV-echistatin viruses specifically bound to targeted integrins. Since the low-density lipoprotein receptor (LDLR) was recently identified as a major receptor for VSV, we investigated the entry of ligand-displaying viruses after masking LDLR. The experiment showed that the modified viruses can enter the cell independently of LDLR, whereas entry of unmodified virus is significantly blocked by a specific monoclonal antibody against LDLR. Both parental and ligand-displaying viruses displayed equal oncolytic efficacies in a syngeneic mouse myeloma model. We further demonstrated that single-chain antibody fragments against tumor-specific antigens can be inserted at the N terminus of the G protein and that corresponding replication-competent VSVs can be rescued efficiently. Overall, we demonstrated that functional tumor-targeting ligands can be displayed on replication-competent VSVs without perturbing viral growth and oncolytic efficacy. This study provides a rational foundation for the future development of fully retargeted oncolytic VSVs.
Insights
Researchers engineered vesicular stomatitis virus (VSV) to display tumor-targeting ligands on its surface. These modified VSVs maintain viral growth and oncolytic efficacy, paving the way for targeted cancer therapies.
Area of Science:
- Virology
- Molecular Biology
- Oncolytic Virotherapy
Background:
- Vesicular stomatitis virus (VSV) is a potential oncolytic agent.
- Engineering VSV to display tumor-targeting ligands could enhance its specificity and efficacy.
- Identifying suitable sites on the VSV glycoprotein (VSV-G) for ligand display is crucial.
Purpose of the Study:
- To demonstrate proof of principle for displaying tumor-targeting ligands on VSV.
- To investigate insertion sites on VSV-G for ligands like cyclic RGD (cRGD) and echistatin.
- To assess the impact of ligand display on viral replication, cell entry, and oncolytic efficacy.
Main Methods:
- Rational design and genetic engineering of VSV glycoprotein (VSV-G) to incorporate tumor-targeting ligands.
- Rescue and characterization of recombinant VSVs displaying cRGD and echistatin.
- In vitro binding assays to confirm ligand-receptor interactions (integrins).
- Assessment of viral entry mechanisms, including dependence on low-density lipoprotein receptor (LDLR).
- In vivo evaluation of oncolytic efficacy in a syngeneic mouse myeloma model.
Main Results:
- Successfully rescued VSVs displaying tumor vasculature-targeting ligands (cRGD and echistatin) on VSV-G.
- Identified seven insertion sites for cRGD and two for echistatin, with no impact on viral replication.
- VSV-echistatin viruses showed specific binding to target integrins in vitro.
- Engineered VSVs could enter cells independently of LDLR, unlike parental VSV.
- Ligand-displaying VSVs exhibited comparable oncolytic efficacy to parental VSV in vivo.
- Demonstrated successful insertion of single-chain antibody fragments against tumor antigens.
Conclusions:
- Functional tumor-targeting ligands can be displayed on replication-competent VSVs without compromising viral growth or oncolytic activity.
- This strategy provides a foundation for developing retargeted oncolytic VSVs for cancer therapy.
- VSV engineering offers a versatile platform for enhancing the specificity of oncolytic viruses.
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