مقالات پذیرفته شده در هشتمین کنگره بین المللی زیست پزشکی
Oncolytic Viruses: The Rising Stars for Cancer Treatment
Oncolytic Viruses: The Rising Stars for Cancer Treatment
Niloofar GhanbariMofrad,1Shaghayegh Yazdani Neishaboori,2,*
1. Islamic Azad University, Tehran Medical Science Branch 2. Member of the faculty of the Department of Microbiology, Tehran Azad University of Medical Sciences
Introduction: Cancer is becoming a leading concern worldwide by the rate of global death. Not only, early detection and new methods of treatment increased remission expectancy but also, the cancer death rates have decreased by 33% from 1990s to the recent years due to many accepted therapies for cancer, such as chemotherapy, radiotherapy, targeted therapy, surgery, hormonal therapy and immunotherapy. However, they have limited efficacy for advanced cancer patients. During 1990s, patients with virus-infected cancer showed tumor remission for a short time which led to Oncolytic Viruses (OVs) have become the rising stars. This new innovative form of immunotherapy can infect and demolish cancer cells selectively, while saving normal cells from damage. Early case reports illustrate the effect of natural form of viruses on tumor cells. But by develop of genetic engineering and viral gene research, Oncolytic Viruses have become a promising approach for cancer treatment.
Methods: The infection mechanism of OVs depends on the type of virus infecting the tumor cells and the antiviral immune response of the host immune system will determine the success of oncolytic virotherapy. By adhering to the cancer cells, OVs use several lytic pathways to stimulate immune system. The virus uses the tumor cell’s protein translational machinery to block protein synthesis. The replication of viral nucleic acid and viral protein synthesis cause progeny virus particles which lyse tumor cells and release. The lysed cells release chemokines and cytokines that let the immune system to detects the lysed cells and provoke pathways to recognize other tumor cells. During the tumor cell apoptosis, the released tumor antigens, such as tumor-associated antigens (TAAs), damage-associated molecular patterns (DAMPs), and pathogen-associated molecular patterns (PAMPs), attract cytotoxic T lymphocytes, dendritic cells, natural killer cells, and macrophages to induce tumor-specific immune response. Furthermore, the release of cytokines can attract an immune response to nearby tumor cells without the apoptosis function. OVs can also decrease the oxygen and nutrients percentages by disrupting the blood vessels which connected to tumors.
Results: To date, many OVs have entered into early-phase clinical trials, such as adenoviruses, herpes viruses, measles viruses, coxsackie viruses, polioviruses, reoviruses, poxviruses, and Newcastle disease viruses, but OVs will exhibit a series of complicated and exact mechanisms of action when they are employed in cancer therapy. In some cases, the immune system can detect the OVs and defeat the viruses before they reach the target tumors. On the other hand, the virus can escape from the immune system, and causing inflammation elsewhere, which is also a cause of concern.
Conclusion: In conclusion, the OVs has the potential to be a highly effective way to treat cancer; however, there are still limitations and difficulties with virotherapy that can be solved by additional research and clinical trials. Further knowledge of the therapeutic activity mechanism, identification of biomarkers, and conducting clinical trials with combination therapies will enhance the therapeutic application of OV for various cancers. Immunotherapy aims for a sustainable full response or recovery; thus, we need to prioritize various OVs and develop methods to choose the most promising ones for cure.