Using bacteria to battle cancer

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Gombert DAAD

Can diseases be cured by pathogens which thrive in food that has gone off? They certainly can if Professor Wolfgang Walther has anything to do with it.

Focusing on a bacterium in the gut

A biochemist conducting research into new cancer therapies at the Max Delbrück Center for Molecular Medicine in Berlin, Professor Walther is particularly interested in Clostridium perfringens. This is a bacterium which, if we eat food that has gone off, can provoke a case of food poisoning with severe diarrhoea. The bacterium produces a toxin in the gut of the infected person. The toxin attaches itself to cells in the intestinal mucosa and destroys them. And it is precisely this toxin that the cancer expert plans to use to attack tumours.

Professor Wolfgang Walther

Tailor-made bacterial weapon

This is because the cells that the toxin attacks in the gut are similar to some cancer cells in terms of their surface shape. In pancreatic cancer, for example, the tumour cells produce exactly the kinds of molecules which the toxic can dock onto. “They serve as a perfect target”, says Professor Walther. Once the toxin has attached itself to the tumour cells, it penetrates and destroys them – just as it does the intestinal cells.

The tumour destroys itself

Professor Walther and his team treated tumour cells with the bacterial toxin in the lab and observed how the diseased tissue died off almost entirely. The trick is that the cancer researchers did not inject the toxin itself, but only its genetic blueprint. “The tumour cells then produce the toxin themselves”, says Walther. “And they do so not only for a few hours, but over the course of several days”. As a result, the toxin spreads very quickly in all directions and has a much greater impact than would have been the case if it had been injected directly.

Hope for cancer sufferers

Further experiments will need to be carried out to show whether this idea will form the basis for novel cancer treatments. For people with pancreatic cancer, the toxin-producing bacteria could in any case offer a glimmer of hope in what otherwise still tends to be a fairly hopeless situation. Conventional cancer therapies rarely have the desired effect, and most people do not survive the aggressive cancer of the pancreas. If the new method was used to pre-treat the diseased tissue in future, the tumour could perhaps be effectively combated by radio- and chemotherapy after all.

More information

Max Delbrück Center for Molecular Medicine website: