How to increase the effectiveness of antitumor therapy with oncolytic viruses?
Currently, doctors are already using genetically modified viruses to treat patients with lethal fast-growing malignant tumors. Clinical studies have shown that such therapeutic viruses are safe, but less effective than expected.
The results of a new study conducted by scientists at Ohio State University, working under the leadership of Professor Antonio Chiocca, showed that this is partly due to the activity of the patients' own immune system, which destroys particles of the therapeutic virus within a few hours.
The authors found that natural killers attack therapeutic viruses expressing NKp30 and NKp46 molecules on their surface. Experiments have shown that blocking receptors to these molecules on the surface of natural killers prolongs the circulation time of the therapeutic virus in the body and, accordingly, increases the life expectancy of mice with a brain tumor glioblastoma. The next stage of the work will be blocking these receptors on the surface of natural killers of patients with glioblastoma and monitoring their condition after therapy with oncolytic viruses.
The results of earlier studies have shown that the therapy of brain tumors with oncolytic viruses is safe. According to the data obtained by the authors, the replication of the virus inside tumor cells attracts natural killers to the tumor zone, which, in turn, activate other immune cells, such as macrophages and microglial cells, which have both antiviral and anticancer properties. On the one hand, deactivation of virus-recognizing natural killer receptors improves the survival of mice with glioblastoma treated with oncolytic virus. However, natural killers expressing virus-recognizing receptors for NKp30 and NKp46 molecules destroy tumor cells infected with the virus.
A detailed study of these mechanisms will help specialists optimize the approach to the treatment of tumors with the help of oncolytic viruses. With regard to glioblastoma, this is of exceptional importance, since the average life expectancy of patients with such a diagnosis does not exceed 12 months on average.
Article by Christopher A Alvarez-Breckenridge et al. NK cells impede glioblastoma virotherapy through NKp30 and NKp46 natural cytotoxicity receptors is published in the journal Nature Medicine.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of The Ohio State University:
Patient’s Own Immune Cells May Blunt Viral Therapy For Brain Cancer.
28.11.2012