Soil bacteria used to target cancer

A DIRTY bug that targets tumours could soon be used to deliver frontline cancer treatment.

The bacterial strain, which lives in the soil, is set to be tested on cancer patients in 2013.

Because the Clostridium sprogenes microbe thrives in low-oxygen conditions, once it is injected into the bloodstream, it will only grow inside tumours.

The bug has been genetically engineered to release an enzyme that activates production of an anti-cancer drug.

Since this only occurs in tumours, no harm is caused to then surrounding healthy tissue.

Professor Nigel Minton, heading the University of Nottingham team of scientists, said: “Clostridia are an ancient group of bacteria that evolved on the planet before it had an oxygen-rich atmosphere and so they thrive in low-oxygen conditions.

“When Clostridia spores are injected into a cancer patient, they will only grow in oxygen-depleted environments, i.e., the centre of solid tumours. This is a totally natural phenomenon, which requires no fundamental alterations and is exquisitely specific. We can exploit this specificity to kill tumour cells, but leave healthy tissue unscathed.”

The researchers have overcome a key obstacle to the therapy by genetically creating a much-improved version of the all-important bacterial enzyme. It can now be produced in far greater quantities in the tumour than before. The bug is also more efficient at converting the dormant drug into its active form.

The latest progress in the research was announced to the autumn conference of the Society for General Microbiology at the University of York.

The trial, due to take place in the Netherlands, will be led by scientists at the University of Maastricht.