Recent Progress in Engineered Oncolytic Viruses

This review examines recent research in engineered oncolytic viruses and applies a thematic analysis to identify trends in the field. The major themes identified are tumor microenvironment remodeling, enhancing virus efficiency, treating slow-growing tumors, tumor targeting specificity, and combination with chimeric antigen receptor-T cell therapy. The tumor microenvironment plays a significant role in cancer progression through factors like immunosuppression and hypoxia. Engineered oncolytic viruses may be used to remodel aspects of the tumor microenvironment to favor and facilitate an immune response. Another major consideration in the development of oncolytic viruses is their efficiency in inducing antitumor effects. Viral vectors may be engineered with pro-apoptotic or pro-inflammatory signaling molecules to cause cancer cell death or mediate immune cell infiltration, respectively. Slow-growing tumors present a challenge to oncolytic virotherapy since many viruses infiltrate tumors through infected daughter cells arising from cancer cell division. This challenge may be overcome by engineering viruses to maintain a high viral load in infected cancer cells and drawing a sustained immune response. A concern in the development of oncolytic viruses is the issue of viral tropism and infection specificity. Although some viruses have limited tropism, oncolytic viruses may be engineered to specifically target tumors using cancer-specific receptor-ligand mechanisms. Oncolytic viruses may also be used in conjunction with chimeric antigen receptor-T cell therapy to reduce immunosuppression and enhance chimeric antigen receptor-T cell infiltration of tumors. This poses a promising approach in oncology research and treatment.