Targeting tumours
Bacteria belonging to the genus Clostridium get a bad press because of 'superbugs' like Clostridium difficile, but according to researchers at Nottingham University 'cousins' of 'C.diff' can be used to target cancerous cells. Professor of Applied Molecular Microbiology, Nigel Minton and his colleagues are harnessing the ability of clostridium bacteria to thrive in oxygen-starved environments. They can deliver cancer-killing agents to the core of cancer tumours where traditional treatments such as radiotherapy and chemotherapy are ineffective.

How it works
Minton's team has developed the ground-breaking ClosTron technology. It can be used to identify the 'C. diff' genes responsible for causing disease, through their inactivation - leading ultimately to the development of more effective ways of treating the disease. However, it can also be used to introduce genes encoding anti-cancer agents into other harmless clostridia. Their aim is to develop a Clostridium that can deliver a harmless enzyme, and germinate only in the tumour. It then converts a non-toxic 'prodrug' into an anti-cancer drug, specifically targeting the cancerous cells of the patient.

Minton explains, 'all tumours have oxygen-free centres, the perfect environment for the spore to germinate. The only reason they can grow is because there is no oxygen and this makes it so brilliantly selective.'

Clostridium is notoriously difficult to eliminate due to its spore forming abilities, which can spread elsewhere. Their resistance to adversity makes them very problematic in the hospital environment, but their ability to proliferate selectively in certain areas of tumours make them ideal for overcoming a major obstacle in cancer gene therapy. They select only the cancerous cells.

Disease-free strain
Getting the go-ahead to test this process on humans means convincing funding agencies that injecting the genetically modified Clostridium strain in human bloodstreams will cause no undesirable side effects. Studies on mice have already demonstrated its effectiveness.  

Crucially, the introduced genes must be located in the bacterium's chromosome. This is where the ClosTron comes in, allowing genes to be rapidly and stably inserted into the bugs chromosome.

Professor Minton says, 'Clostridium is so fantastic. It can save the planet because it can also play an important role in generating biofuels. It can treat cancer. The bacteria are really important now in understanding infection so we need to get them under control.' Clostridium's potential brings a whole new meaning to the phrase 'my enemy's enemy is my friend'.