Measles virus against brain cancer
According to the data published on May 21 in the preliminary on-line version of the journal Neuro-Oncology in the article "Treatment of medulloblastoma with a modified measles virus", the use of a modified measles virus is a promising new method of treating medulloblastoma – a malignant brain tumor that develops in childhood.
Medulloblastoma is the most common pediatric malignant disease of the central nervous system, accounting for about 20% of all childhood brain tumors. Medulloblastoma is localized in the cerebellum, a region of the brain that provides a sense of balance and other complex motor functions. Modern methods of treating this disease in almost 70% of cases provide patients with a 5-year survival rate, but they necessarily include surgery, chemo and radiotherapy.
Non-pathogenic strains of the measles virus used for the production of vaccines have already been used to destroy malignant cells of a number of tumors, including one of the types of adult brain cancer. For their research, scientists at the State Children's Hospital in Columbus (Ohio), working under the guidance of Dr. Corey Raffel, chose a special strain of the virus, called the Edmonston strain. This strain penetrates into target cells by interacting with the CD46 cell surface receptor, a high degree of expression of which is characteristic of many types of tumors.
The authors' analysis of the cell surface of five medulloblastoma lines and 13 biopsy samples in all cases revealed a high level of CD46 receptor expression. According to the authors' expectations based on the results obtained, treatment of the same five medulloblastoma cell lines with a modified measles virus within 72 hours resulted in the death of a significant number of cells of all lines.
The researchers also tested the effectiveness of a modified measles virus to treat mice with implanted human medulloblastoma. During a 10-day course of therapy, 11 animals were injected with a dose of therapeutic virus every other day. Such treatment significantly increased the life expectancy of the animals compared to the control group mice injected with the inactivated virus.
According to Dr. Raffel, the results obtained indicate that the modified measles virus has therapeutic potential for the treatment of medulloblastoma. He suggests that the virus can be injected into the tumor bed after its surgical removal to destroy microscopic residual cancer cells. This approach will soften the traditional rigid regimes of postoperative chemo- and radiotherapy.
Raffel also notes that his laboratory staff received preliminary results indicating the effectiveness of the modified measles virus in the treatment of a mouse model of disseminated (metastasized into the cerebrospinal fluid and subarachnoid space of the brain) medulloblastoma. Traditional methods of treatment in such cases are practically powerless.
In the near future, the researchers plan to develop the optimal dosage and administration scheme of the viral drug. They are also interested in testing various modifications of the virus that could potentially increase the effectiveness of medulloblastoma treatment.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru Based on Nationwide Children's Hospital: Modified Measures Virus Shows Potential for Treating Childhood Brain Tumors.
31.05.2010