Salmonella is a tumor killer

Neil Forbes from the University of Massachusetts has received a four-year grant of more than $1 million from the National Institutes of Health to improve the method developed under his leadership for turning bacteria into tiny terminator robots. Genetically modified salmonella (these bacteria are a common cause of intestinal infections) with the help of their flagella penetrate into the deep areas of the tumor inaccessible to modern methods of treatment, where they begin to synthesize compounds that trigger the self-destruction of tumor cells.

Attempts to use bacteria to fight cancer have been made for decades, however, without much success. The authors proposed a radical improvement of this approach, called "targeted intra-tumor therapeutic delivery". They modify bacteria in such a way as to be able to control the direction of their movement, the compounds synthesized by them and the moment of the beginning of the release of these compounds. The introduction of this technique into clinical practice will make it possible to select individual minimum doses of chemotherapy drugs and thus increase the specificity and effectiveness of therapy, as well as reduce patient mortality.

The main problem that the researchers tried to solve is that it is impossible to influence some regions of tumors with chemotherapy drugs, the penetration of which into the tissue is limited by the vascular network penetrating it. Each tumor is characterized by a special distribution of blood vessels, due to its nature and the genetic characteristics of the patient. In the intervals between the tumor vessels, slowly dividing, but living malignant cells are often preserved, causing the recurrence of tumors.

The concept developed by Forbes implies the use of modified salmonella, devoid of pathogenicity and loaded with chemotherapy drugs, which, with the help of their flagella, would move into hard-to-reach areas of the tumor and destroy the cells hiding there.

Usually salmonella move through the body in search of food with the help of sensors sensitive to ribose and other compounds released by dying cells. However, scientists are not interested in cells dying from the effects of chemotherapy drugs, so they deprive bacteria of sensitivity to ribose and endow them with the ability to move to areas of tumors that are difficult to access for modern methods of treatment.

The authors have already demonstrated the effectiveness of this approach in mice with malignant tumors. Usually, animals with such tumors die within 30 days, but all the mice of the experimental group, who were injected with modified salmonella and then irradiated with a dose of radioactive radiation, lived much longer. The authors argue that, translated into human terms, such an increase in survival is equivalent to many months or even years.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of the University of Massachusetts

04.03.2008