Date of release: Friday, January 29, 2016

Anthrax toxin could help fight cancer, say Greenwich scientistsAnthrax, the lethal disease, could be an unexpected tool in the fight against cancer, according to research being led at the University of Greenwich.

While it is better known for being deadly rather than a treatment, the bacterium behind anthrax has been shown by scientists to be a possible solution for delivering drugs for a specific form of gene therapy.

A team led by Dr Simon Richardson, from the university's Faculty of Engineering & Science, has shown that by disarming the 'warhead' within anthrax, the toxin can be converted into a positive tool for delivering 'heavy' drugs, or those with a large mass, to where they are most needed within the cell. "This is the first time a disarmed toxin has been used to deliver gene-modulating drugs directly to a specific compartment within the cell, without any additional helper molecules," he says.

Anthrax is an acute disease caused by a bacterium that spreads via spores, which can become fatal when activated. Its ability to spread through the body so 'effectively' makes it attractive to scientists as a potential tool for drug delivery. By exploiting anthrax toxin's natural ability to navigate cells' defences, the toxin components can be used to access specific compartments within a cell.

Using genetic engineering, the Greenwich team has shown that the anthrax toxin's 'warhead' can be replaced with a gene therapy drug. The toxin's 'rocket motor' is left in place and can be used to transport the drug to the inside (the cytosol) of the cell, preventing it from being digested in the cell's stomach (or endolysosome). Rather than making a hole in the cell to get inside, which is harmful, this delivery system uses anthrax's natural ability to get to specific compartments within a cell through an "airlock" like system, leaving the cells membranes unharmed.

To test the delivery system, experiments were done on cancerous human cells that were grown in the laboratories at Greenwich. Scientists were able to deliver these drugs to their end destination with high efficiency and low toxicity, showing that their proposed method is effective thus far.

In their novel approach, team leader Dr Richardson and his laboratory team members looked to nature to see how other organisms' own delivery systems evolved. "Bacteria and plants produce toxins that access the same part of the cell that these new drugs need to reach, but rather than delivering a therapeutic, they deliver a warhead. We have replaced the warhead with a therapeutic," Dr Richardson adds.

Now that the team has demonstrated that anthrax can be used to deliver the gene therapy drug to the target cell, their focus turns to trying to find out exactly how the drug gets into the cell, and if this system can be used in a more complex environment that is more like a patient.

The research has been published in the Journal of Controlled Release. Dr Paul Dyer, Principal Lecturer in Biomedical Sciences at Greenwich, is first author of the paper.

Story by Public Relations

Picture: The delivery system (in red) is seen entering live cells grown in the university's laboratory.