Scientists have modified a common respiratory virus, specifically an adenovirus, to act like a Trojan horse and deliver genes for cancer therapies directly into tumor cells. Unlike chemotherapy or radiation therapy, this method does not harm normal healthy cells. Once inside tumor cells, the introduced genes serve as a blueprint for therapeutic antibodies, cytokines, and other signaling substances, which are produced by cancer cells themselves and act to kill tumors from within.
In other words, the technique tricks the tumor into killing itself by producing anticancer substances by its own cancer cells.
This method has been devised by a team that includes Andreas Plückthun and Sheena Smith, both from the University of Zurich in Switzerland.
The new technique builds on key advances previously made by Plückthun’s team, such as one that allows adenoviruses to be targeted at specific parts of the body to hide them from the immune system.
In an experiment using the new technique, the scientists made the breast tumor itself in a mouse model produce an antibody called trastuzumab, clinically approved against breast cancer. They found that, after a few days, the technique produced an amount of the antibody within the tumor that was greater than the amount that was achieved when the drug was injected directly in acceptable doses. In addition, the concentration in the bloodstream and other tissues where side effects can occur was significantly lower with this method.
Digital representation of a moment of the self-annihilation process that the new technique induced in a tumor. Red: blood vessels, turquoise: tumor cells, yellow: therapeutic antibody. (Image: Plückthun Lab)
Plückthun, Smith and their colleagues emphasize that the new technique is applicable not only to the fight against breast cancer. Since healthy tissues no longer come into contact with significant levels of the therapeutic agent, it is also applicable for the delivery of a wide range of potent protein-based drugs that would otherwise be too toxic. (Source: NCYT from Amazings)