Scientists around the world are researching how anti-cancer drugs can most efficiently reach the tumors they target. One possibility is to use modified bacteria as „ferries“ to carry the drugs through the bloodstream to the tumors. Researchers at ETH Zurich have now succeeded in controlling certain bacteria so that they can effectively cross the blood vessel wall and infiltrate tumor tissue.
Scientists around the world are researching how anti-cancer drugs can most efficiently reach the tumors they target. One possibility is to use modified bacteria as „ferries“ to carry the drugs through the bloodstream to the tumors. Researchers at ETH Zurich have now succeeded in controlling certain bacteria so that they can effectively cross the blood vessel wall and infiltrate tumor tissue.
Led by Simone Schürle, Professor of Responsive Biomedical Systems, the ETH Zurich researchers chose to work with bacteria that are naturally magnetic due to iron oxide particles they contain. These bacteria of the genus Magnetospirillum respond to magnetic fields and can be controlled by magnets from outside the body.
Exploiting temporary gaps
In cell cultures and in mice, Schürle and her team have now shown that a rotating magnetic field applied at the tumor improves the bacteria’s ability to cross the vascular wall near the cancerous growth. At the vascular wall, the rotating magnetic field propels the bacteria forward in a circular motion.
To better understand how the mechanism to cross the vessel wall works, a detailed look is necessary: The blood vessel wall consists of a layer of cells and serves as a barrier between the bloodstream and the tumor tissue, which is permeated by many small blood vessels. Narrow spaces between these cells allow certain molecules from the to pass through the vessel wall. How large these intercellular spaces are is regulated by the cells of the vessel wall, and they can become temporarily wide enough to allow even bacteria to pass through the vessel wall.
