‘Harmless’ soil bacteria can help kill tumours

London, Sep 5: Scientists are harnessing a harmless soil bug to kill tumours by using it as a drug delivery vehicle.

The therapy uses Clostridia sporogenes — a bug found abundantly in soil. Its spores are injected into patients and only grow in solid tumours, where a specific bacterial enzyme is produced.

An anti-cancer drug is injected separately into the patient. After reaching the tumour site, the bacterial enzyme activates the drug, allowing it to destroy only the tumour cells.

University of Nottimgham’s Nigel Minton, who led the research, 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-deficit environments, i.e. the centre of solid tumours, according to a Nottingham statement.

Researchers at the Universities of Nottingham (Britain) and Maastricht (the Netherlands) have now overcome the hurdles preventing this therapy from entering clinical trials.

They have introduced a gene for a much-improved version of the enzyme into the Clostridia sporogenes DNA.

This enzyme can now be produced in far greater quantities in the tumour than previous versions, and is more efficient at converting the pro-drug into its active form.

Any new cancer therapy is required to target cancer cells while excluding healthy cells. The research may ultimately lead to a simple and safe procedure for curing a wide range of solid tumours.

‘This therapy will kill all types of tumour cells. The treatment is superior to a surgical procedure, especially for patients at high risk or with difficult tumour locations,’ explained Minton.

The strain is expected to be tested in cancer patients in 2013, says a scientist at the Society for General Microbiology’s Autumn Conference at the University of York.