Review on Application of Oncolytic Virotherapy of Cancer Cells in Veterinary Medicine

Abstract

Oncolytic virotherapy is using oncolytic viruses (OVs) which selectively infect and kill cancer cells. Oncolytic viruses represent a highly targeted approach to established cancer that brings a multimechanistics approach and an acceptable safety profile to patients with a variety of cancers. A variety number of viruses have been developed as oncolytic virotherapeutics, including Adenovirus, Vaccinia virus, Herpesvirus, Measles, Coxsackie A virus, Newcastle disease virus, and Reovirus. Anticancer viruses can now be engineered to selectively attack cancer cells, spare normal tissue, awaken the host immune system and reverse immunosuppression in the tumor microenvironment. But virotherapy is not a cure on its own. Research suggests that virotherapies will serve to supplement chemotherapy, radiation therapy or immunotherapy. Combinations of OV with cytotoxic agents are feasible and safe, with the potential of transient immune supperssion of the host in order to increase viral access to the tumor and provide time for viral oncolysis to exceed the tumor’s replicative  potential. Granulocyte macrophage colony stimulating factor as an immune-stimulatory cytokine boosts host immune activity through the infiltration of dendritic cells and CD4+ and CD8+ T cells at tumor sites. Concomitants to human, cancer is the leading cause of death in companion animals such as dogs and cats. The most important challenges for the successful clinical use of OVs in veterinary practice are reduction of viral toxicity, optimization of virus delivery to tumor, and enhancement of viral spread throughout the tumor mass. The multifactorial, interplay can be determined by the complex interactions between the tumor and its microenvironment, the virus, and the host immune response. Yet, there is promise that OVs will soon be a new, powerful treatment option for veterinary patients with cancer. Hence, sound understanding of the biology of OVs and its application in veterinary medicine require.

Keywords: Cancer, Combination-therapy, Oncolytic virotherapy, Virus.

DOI: 10.7176/ALST/79-04

Publication date:March 31^st 2020