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Updated: Sep 27, 2025

Paramyxoviruses for Tumor-targeted Immunomodulation: Design and Evaluation Ex Vivo
Published on: January 7, 2019
Virally programmed extracellular vesicles sensitize cancer cells to oncolytic virus and small molecule therapy
Marie-Eve Wedge1,2, Victoria A Jennings1,3,4, Mathieu J F Crupi1,5
1Centre for Innovative Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
Abstract:
Recent advances in cancer therapeutics clearly demonstrate the need for innovative multiplex therapies that attack the tumour on multiple fronts. Oncolytic or "cancer-killing" viruses (OVs) represent up-and-coming multi-mechanistic immunotherapeutic drugs for the treatment of cancer. In this study, we perform an in-vitro screen based on virus-encoded artificial microRNAs (amiRNAs) and find that a unique amiRNA, herein termed amiR-4, confers a replicative advantage to the VSVΔ51 OV platform. Target validation of amiR-4 reveals ARID1A, a protein involved in chromatin remodelling, as an important player in resistance to OV replication. Virus-directed targeting of ARID1A coupled with small-molecule inhibition of the methyltransferase EZH2 leads to the synthetic lethal killing of both infected and uninfected tumour cells. The bystander killing of uninfected cells is mediated by intercellular transfer of extracellular vesicles carrying amiR-4 cargo. Altogether, our findings establish that OVs can serve as replicating vehicles for amiRNA therapeutics with the potential for combination with small molecule and immune checkpoint inhibitor therapy.
Insights
Oncolytic viruses (OVs) engineered with artificial microRNAs (amiRNAs) show promise for cancer therapy. A novel amiRNA enhances OV replication and targets ARID1A, leading to synthetic lethality in tumor cells.
Area of Science:
- Oncology
- Virology
- Molecular Biology
Background:
- Cancer therapeutics require innovative multiplex strategies to combat tumors effectively.
- Oncolytic viruses (OVs) are emerging as multi-mechanistic immunotherapeutic agents for cancer treatment.
Purpose of the Study:
- To identify virus-encoded artificial microRNAs (amiRNAs) that enhance oncolytic virus replication.
- To investigate the mechanisms of OV resistance and develop combination therapies.
Main Methods:
- In vitro screening of virus-encoded amiRNAs to identify those conferring a replicative advantage to the VSVΔ51 OV platform.
- Target validation of identified amiRNAs, including ARID1A, and assessment of combination therapy with small-molecule inhibitors (EZH2).
- Evaluation of intercellular transfer of amiR-4 via extracellular vesicles for bystander killing effects.
Main Results:
- A unique amiRNA, amiR-4, was identified that enhances VSVΔ51 OV replication.
- ARID1A was validated as a key protein involved in resistance to OV replication.
- Combined targeting of ARID1A and EZH2 resulted in synthetic lethal killing of both infected and uninfected tumor cells.
- Extracellular vesicles mediated the intercellular transfer of amiR-4, leading to bystander killing.
Conclusions:
- Oncolytic viruses can serve as effective delivery vehicles for amiRNA therapeutics.
- Combination therapy involving OVs, amiRNAs, small molecules, and potentially immune checkpoint inhibitors offers a promising strategy for cancer treatment.
- The study highlights the potential of virus-directed amiRNA delivery for overcoming OV resistance and enhancing anti-tumor efficacy.
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