Oncolytic Viruses in Cancer Immunotherapy

Oncolytic viruses are novel and promising therapeutic regimens that promote antitumor efficacy through multimode mechanisms, including direct lysis of tumor cells, release of the tumor antigens and danger signals, induction of immunological cell death, activation of innate, and adaptive immune response. In addition, oncolytic viruses can be engineered to express virus-centered and immune-centered therapeutic transgenes, further transforming the "cold" tumor into "hot" and enhancing the oncolytic efficacy. Several oncolytic viruses are engineered and widely used as potential therapeutic agents for many cancers and the therapeutic strategies and effectiveness vary among different types of oncolytic viruses. Finally, oncolytic viruses-based combination immunotherapy is practiced in preclinical and clinical studies, and indicates that combination of oncolytic viruses with conventional therapy or immunomodulatory agents exerts favorable antitumor efficacy. Oncolytic viruses infect normal cells but are unable to replicate, so there is no viral replication, and healthy cells remain undamaged. However, when infecting cancer cells, oncolytic viruses replicate in them, releasing INF-gamma, TNF-alpha, TAA, and TSA. Viral replication activates immunological danger signaling through damage-associated molecular pattern and pathogen-associated molecular pattern receptors, leading to immunogenic cell death and tumor lysis. image