POPPING PILLS made from natural plant toxins could become an effective way of preventing cancer, a leading Cancer Research UK scientist claimed last week at the charity's first annual conference in Warwickshire.
Citing broccoli as an example, Professor Roland Wolf said many plants produce chemicals that crank up the body's stress response - which also protects against cancer's development. Scientists have thought for some time that eating a diet rich in fruit and vegetables can help reduce the risk of cancer. But Prof Wolf - in collaboration with Prof John Hayes at the University of Dundee - is uncovering mechanisms that seem to be involved in the protective effect, in a bid to develop a new class of preventative anti-cancer drugs.
Prof Wolf, Honorary Director of the Cancer Research UK Molecular Pharmacology Unit in Dundee, said: "Plants are vulnerable to being eaten because, unlike animals, they can't run away, so they have evolved to produce a range of chemicals aimed at putting off the hungry herbivore. "But humans and other animals have in turn evolved stress response systems to help us cope with plant toxins - putting vegetables back on the menu. These systems are activated when we eat vegetables and seem not only to help us cope with plant chemicals, but also with the effects of carcinogens. So a pill containing a combination of some of the most potent plant chemicals could be an excellent way of keeping cancer at bay." Researchers have identified a number of systems in the body that help it to cope with plant toxins - one of which involves a group of molecules called the cytochrome p450s. These are important for breaking down alien chemicals, whether they be plant toxins or environmental carcinogens. His team, with others, has also shown that a number of separate components of broccoli and other plants can turn up the p450 system - like a volume control - to higher than normal levels, potentially giving the body extra strong protection against cancer.
Prof Wolf adds: "Some of the plant chemicals that have activity would not normally be thought of as potential medicines - like isothiocyanates and phenols, which at very high levels are poisonous. It may be a case of a little bit of what's bad for you being good for you." While preventing cancer with drugs - a strategy known as chemoprevention - may have great potential, Prof Wolf acknowledged there is still a great deal of work to be done. He said: "We need to know which agents work most effectively, what doses should be used and which combinations are most potent. The approach to developing these chemicals should be as rigorous and methodical as for any other drug. But I believe there's an excellent chance of producing powerful preventative agents." Scientists believe that changes to our diet, with increased intake of fruit and vegetables, could help prevent up to a third of cancers. Preventative drugs based on plant chemicals could also have a major impact in the future on incidence of the disease.
Sir Paul Nurse, Chief Executive of Cancer Research UK, said: "Prevention is extremely important and an area Cancer Research UK is particularly interested in. Prof Wolf's work opens up a new avenue of research and raises exciting possibilities. His work complements our research on diet, which we hope will also lead to more effective ways of preventing the disease."
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