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Leading research in cancer prevention and food derivatives

If only we were all to eat enough of the right sort of fruit and vegetables every day we would almost certainly be less likely to suffer from certain cancers.

Simple as this sounds, it is difficult to persuade people to change to a healthier lifestyle, and researchers into cancer prevention at the University of Leicester are investigating pills derived from foods that are believed to prevent cancer. Work they have already done with laboratory models suggests the pills, too, could be effective.

Over the past decade, the University of Leicester Department of Cancer Studies and Molecular Medicine has become a world leader in research into chemoprevention (stopping cells becoming malignant), using substances derived from food to prevent or slow down breast, colon and prostate cancer.

Research led by Professors Andy Gescher and Will Steward (head of the University’s Department of Cancer Studies and Molecular Medicine) looks at how food-derived substances interfere with developing cancer cells, how they get into the circulation and reach the cancer tissue that is targeted, and how long they remain in the human organism. Their research results have been widely reported around the world.

Chemoprevention studies into diet-derived substances at Leicester began in 2000 with the study of the curry constituent curcumin. Since then, the research has attracted international interest and a succession of prestigious grants. Most recently, early in 2007, the University of Leicester and Leicester’s hospitals were awarded funding from Cancer Research UK and the Department of Health to set up the Leicester Experimental Cancer Medicine Centre. The Centre, the only group in the East Midlands to be awarded this funding, will receive approximately £1m over five years, which has given its research a significant boost.

Speaking of this award, Professor Steward said: “Our main aim will be to develop cancer preventative drugs. We will be recruiting normal healthy volunteers to a series of studies and take a variety of specimens to help find new ways to detect cancer early and follow its progress during treatment.

“This funding is vital to help us develop new approaches to preventing cancer and may help us to find new treatments for cancer once it has become established. We can bring together laboratory and clinical research and share knowledge and resources with other experimental cancer centres in the UK.”

Since their initial research into curcumin, Professors Will Steward and Andy Gescher have led research into resveratrol (from red berries and red wine), tricin (from brown rice), and polyphenols from tea. Their laboratory findings indicate that these food-derived substances not only appear to be effective on pre-cancerous cells, but also cancerous cells. Safe to use, they do not have the potential side effects of traditional anti-cancer drugs. The next challenge is to establish that they work effectively for humans.

If so, then derivatives from these foods could reduce the risk of some cancer in some people, and could offer alternatives to drugs currently used to treat advanced malignancy.

Speaking recently on Leicester’s research into chemoprevention at a National Cancer Research Institute Conference, Professor Steward said: “The compounds seem to work through a wide variety of mechanisms, including altering signals which reduce blood vessel formation, and by reducing DNA changes which can cause the cells to become malignant.

“We believe that this approach is a logical way to tackle the huge problem that societies face with the increasing incidence of cancer. It has to be much better to prevent or delay cancer than to treat it once it has occurred.

“If the research is successful we could prevent a huge amount of distress caused to patients and families – not just from the cancer itself, but also from the side effects of treatment.”

Bilberries

In one of several related research projects part-funded by Hope Against Cancer, Professor Andy Gescher is currently leading an investigation to carry out clinical trials with the commercially produced substance Mirtoselect (extracted from bilberries). The hope is to use these agents as drugs to stop colorectal and liver cancer from developing in apparently healthy people, and to prevent it recurring in patients who have been successfully treated. Ideally, there would be very few, or no, side effects, and so the substances could be taken daily for many years.

Tea

A research project involving Leicester Professor Kilian Mellon and Dr Bruno Morgan is investigating tea polyphenols as prostate cancer preventive agents, and has already progressed to clinical trials. In the laboratory, both green and black tea polyphenols have been shown to slow the growth of human prostate cancer cells and have inhibited prostate cancer in laboratory models.

Red Wine

This project tests the hypothesis that resveratrol (a polyphenol found in red wine and many fruits), when taken in large doses, generates agent levels in the human body which have been shown to engage cancer chemopreventive mechanisms in experiments in cells in test tubes. The research, carried out in collaboration with the University of Michigan, USA, received funding from the US National Cancer Institute (NCI), the major US government body to fund and co-ordinate cancer research, the first time that a group outside the US had been funded by the NCI for the early clinical development of a drug that may prevent cancer.

Rice Bran

Early in 2007, new laboratory research revealed for the first time that rice bran could reduce the risk of intestinal cancer. Published in the British Journal of Cancer, results from a controlled laboratory study in a preclinical model of gastrointestinal adenoma indicated that consumption of a high daily dose of stabilised rice bran caused an average 51% reduction in the number of precancerous adenomas in the intestinal tract.

Greens

Leicester scientists led by Professor Margaret Manson have found that a molecule in vegetables such as broccoli and cabbage (Indole-3-carbinol) can inhibit the growth of breast cancer cells and could be used in conjunction with drugs to help fight the cancer. Professor Manson commented: “Dietary agents are kind to normal cells at doses which can slow down or kill cancer cells, so combining them with drugs may enhance the drugs’ effectiveness and could allow reduced doses to be given to patients.”

This article originally appeared the Graduates' Review Spring 2008. To view this edition in PDF format, please click here.