Related Experiment Video

Updated: Oct 20, 2025

Paramyxoviruses for Tumor-targeted Immunomodulation: Design and Evaluation Ex Vivo
12:42

Paramyxoviruses for Tumor-targeted Immunomodulation: Design and Evaluation Ex Vivo

Published on: January 7, 2019

9.7K

Deletion of immunomodulatory genes as a novel approach to oncolytic vaccinia virus development

Tiffany Y Ho1, David Mealiea1,2, Lili Okamoto1

  • 1Toronto General Hospital Research Institute, University Health Network, 280 Elizabeth Street, Toronto, ON M5G 2C4, Canada.

Molecular Therapy Oncolytics
|September 13, 2021
PubMed

Insights

Oncolytic vaccinia virus (VV) mutants with deleted immune-evading genes show enhanced tumor selectivity and potency. These modified VVs offer a promising strategy for developing effective oncolytic virotherapy against cancer.

Area of Science:

  • Oncolytic virotherapy
  • Virology
  • Cancer biology

Background:

  • Vaccinia virus (VV) is a promising platform for oncolytic virotherapy.
  • Current VV candidates often rely on tumor cell proliferation rates for selectivity.
  • Tumor cells often have impaired innate immune responses, particularly interferon pathways.

Purpose of the Study:

  • To engineer and evaluate VV mutants with deletions in immunomodulatory genes for enhanced tumor selectivity and oncolytic potency.
  • To investigate if exploiting dampened tumor cell immune responses can create effective oncolytic viruses.
  • To compare the efficacy of these novel VV mutants against existing candidates like vvDD.

Main Methods:

  • Deletion of specific VV immunomodulatory genes (N1L, K1L, K3L, A46R, A52R).
  • In vitro assessment of viral replication, spread, and cytotoxicity in colon and ovarian cancer cells.
  • In vivo evaluation of tumor selectivity, anti-tumor potency, and survival improvement.

Main Results:

  • VV mutants with deletions in N1L, K1L, K3L, A46R, or A52R showed comparable or enhanced in vitro replication, spread, and cytotoxicity compared to vvDD.
  • Deletion mutants demonstrated tumor selectivity.
  • ΔK1L, ΔA46R, and ΔA52R VV mutants significantly improved survival and modulated the tumor immune environment.

Conclusions:

  • Deleting VV immunomodulatory genes is an effective strategy for generating tumor-selective oncolytic viruses.
  • Exploiting tumor cells' diminished antiviral responses enhances oncolytic virus potency.
  • These findings have significant implications for the future design of oncolytic viruses for cancer therapy.
Keywords:
cancer therapyimmunotherapyoncologyoncolytic virusvirologyvirotherapy

More Related Videos

A Simple and Efficient Approach to Construct Mutant Vaccinia Virus Vectors09:16

A Simple and Efficient Approach to Construct Mutant Vaccinia Virus Vectors

Published on: October 30, 2016

11.5K
Genome-wide RNAi Screening to Identify Host Factors That Modulate Oncolytic Virus Therapy08:51

Genome-wide RNAi Screening to Identify Host Factors That Modulate Oncolytic Virus Therapy

Published on: April 3, 2018

9.2K

Related Concept Videos

Cytotoxic T Cells-mediated Immune Response01:27

Cytotoxic T Cells-mediated Immune Response

Cytotoxic T cells are a vital component of the immune system. They have the remarkable ability to identify and target antigens on infected or abnormal cells. These antigens often originate from intracellular pathogens such as viruses or abnormal proteins cancer cells produce.
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
4.9K
Cancer Vaccines01:30

Cancer Vaccines

Cancer treatment vaccines are a rapidly evolving field that offers a promising approach to immunotherapy. Unlike traditional vaccines that prevent diseases, cancer treatment vaccines are designed to treat existing cancers by stimulating the immune system to recognize and attack cancer cells.
Cancer vaccines come in two categories: preventive (prophylactic) and treatment (active). Preventive vaccines, such as the Human Papillomavirus (HPV) vaccine, protect against viruses that cause certain...
569
Mechanisms of Retrovirus-induced Cancers01:51

Mechanisms of Retrovirus-induced Cancers

Retroviruses are RNA viruses that have been shown to cause cancers in diverse species, including chickens, mice, cats, and monkeys. The RNA genomes of these viruses are first reverse-transcribed into single and then double-stranded DNA (dsDNA) copies. This dsDNA called proviral DNA then integrates into the host genome. Subsequently, the host cell transcribes the proviral DNA in concert with the chromosomal DNA. This leads to the production of viral RNA and proteins that assemble at the host...
5.4K
Tumor Immunotherapy01:27

Tumor Immunotherapy

Immunotherapy is a treatment that boosts or manipulates the immune system to fight diseases, including cancer. For instance, by stimulating an immune response through vaccinations against viruses that cause cancers, like hepatitis B virus and human papillomavirus, these diseases can be prevented. Nonetheless, some cancer cells can avoid the immune system due to their rapid mutation and division. The immune response to many cancers involves three phases: elimination, equilibrium, and escape.
746
Immune Response Against Viral Pathogens01:29

Immune Response Against Viral Pathogens

The immune system's response to viral infections is a complex and coordinated process involving natural killer (NK) cells, T cell-mediated responses, and antibody-mediated responses.
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
1.1K
In-vitro Mutagenesis01:16

In-vitro Mutagenesis

To learn more about the function of a gene, researchers can observe what happens when the gene is inactivated or “knocked out,” by creating genetically engineered knockout animals. Knockout mice have been particularly useful as models for human diseases such as cancer, Parkinson’s disease, and diabetes.
15.4K