The prostate gland, the part of the male reproductive system that produces fluids found in semen, is also the site of a cancer that affects one in 10 men. PENNY FANNIN reports on the Monash research that aims to find new methods for treating prostate disease while identifying how the disease is caused.
The hawker markets that line streets throughout Asia are crowded with stalls offering all sorts of local fare. From miso soup to dishes with a liberal dose of tofu, the cuisine not only embodies the taste of Asia, it also appears to offer some protection from breast and prostate cancer.
Medical statistics show that the incidence of breast and prostate cancer in Asia is much lower than in Western countries. For some years, it has been suggested this is because parts of the Asian diet are rich in phytoestrogens, compounds that occur naturally in some plant foods and that are structurally similar to human oestrogen. Foods that contain phytoestrogens include soya, particularly tofu and miso, wheat, licorice, alfalfa, fennel and celery.
Scientists at Monash University's Institute of Reproduction and Devel-opment (IRD) are investigating the impact phytoestrogens have on the development of prostate cancer as
well as many other aspects of prostate disease.
Over the past few years, there has been a realisation that men and women both make the so-called sex hormones androgen and oestrogen but that the balance of these hormones differs between the sexes. Oestrogens are available to men in their diet as dietary oestrogens such as phytoestrogens, but men also make their own oestrogens.
Professor Gail Risbridger, director of the Centre for Urological Research at IRD, has been exploring what happens to the human prostate when there are imbalances between androgens and oestrogens.
"Oestrogens have a role to play in normal prostate function, but too little oestrogen or too much oestrogen will lead to diseases, albeit of different types," she says.
"If a man doesn't have enough oestrogen, he will end up with too much androgen in his system, which will cause the prostate to grow too quickly and become large. We actually think that one of the causes of benign prostate disease is too much androgen and too little oestrogen.
"On the other hand, too much oestrogen turns off androgens, causing the prostate to become smaller and develop pathological changes particularly in the epithelial cells - the cells that line the glands of the prostate. These changes can lead to malignant prostate tumours."
Professor Risbridger and her group have been working with pharmaceutical companies to find drugs that modulate the balance between androgens and oestrogens.
"We want to see what it is we need to do to get the hormonal balance right and prevent the prostate from growing too quickly or developing malignancies," she says.
"For example, in a situation where a prostate has become enlarged, we want to find a scenario where oestrogens reverse the growth or enlargement and restore the balance of hormones so the prostate shrinks to normal size."
The team is investigating synthetic oestrogens as well as dietary oestrogens such as those found in soy products or red clover.
"If oestrogens can restore the hormone balance in the prostate gland, it gives some credence to the belief that dietary oestrogen has beneficial health effects. It might explain why Asian men with high levels of soy in their diet have a lower incidence of prostate disease," Professor Risbridger says.
A recent study at IRD and the Department of Urology at Monash Medical Centre has provided further evidence of the potential health benefits of dietary oestrogen. The study looked at the effects of dietary oestrogen on men with prostate cancer before they underwent surgery.
It showed that when the men took dietary oestrogen, in the form of red clover, the malignant prostate cells were dying more quickly than in men with malignant prostate cancer who were not taking the oestrogen supplements. "These beneficial effects were obvious within a few weeks of the men taking the extra oestrogen," Professor Risbridger says.
The team is also working to identify adult stem cells in the prostate and determine which of these are the cells of origin for prostate cancer. Late last year the team was awarded an $800,000 grant by the US Department of Defense to carry out the investigation.
"Monash researchers, particularly Professor Alan Trounson, have made significant advances in stem cell technology, and this expertise has put us in a unique position for attempting this kind of project," Professor Risbridger says. "Stem cells are seen as the key culprits in the development of prostate disease.
"A lot of people think stem cell research is only about using stem cells to renew or grow new tissues or organs. We want to identify the adult stem cells in the prostate because we want to destroy the adult stem cells that lead to the development of prostate disease."
The prostate gland is lined with epithelial cells, and it is these cells that can become malignant or benign. "There is a variety of cells in the epithelial layer, but we have not been able to pinpoint which ones are the adult stem cells," Professor Risbridger says.
"We want to find these cells and then identify what makes them unique so we can find ways to stop them from growing or destroy them completely without damaging any of the other cells in the prostate."
The project, which began recently, has funding for three years. "We hope that by the end we will have new targets for drug development and be closer to effective treatments for prostate cancer," Professor Risbridger says.
Professor Gail Risbridger, with PhD researchers Ms Preetika Balanatham and Mr Stuart Ellem, has been exploring what happens to the human prostate when there are imbalances between androgens and oestrogens.