Monash team in new prostate cancer find

A team at Monash Institute of Medical Research in Melbourne has grown a human prostate from embryonic stem cells, and hopes the discovery will lead to better understanding of what causes prostate cancer.

The prostate gland manufactures the seminal secretions that form part of ejaculation fluid. It takes up to 15 years to develop in men, but the MIMR team created mature tissue very similar to that found in the human prostate in 12 weeks. The tissue they created has the functions of normal, healthy prostate and produces PSA -- the protein used as a test for prostate cancer.

A study to be published in the March edition of Nature Methods describes how the team created the human prostate tissue by taking human embryonic stem cells (ES cells), then surrounding them with specialised prostate cells from mice and rats. The mixture of human ES cells and rodent cells was then placed in the kidney capsule of host male mice.

"The reason we achieved this when others didn't, is that [other scientists] took signals from the prostate itself," said team leader Prof Gail Risbridger. "We didn't use the prostate tissue to tell the embryonic stem cells to create prostate, which is totally counter-intuitive -- but in our hands this is what works best."

Dr Renea Taylor, one of the authors of the study, said the ES cells needed the signals from the specialised prostate cells to develop into prostate. "In close contact, the cells listen to the signals in the surrounding environment and become prostate. We created a tissue structure around the size of an M&M or a Smartie, from a cluster of cells that was the size of a full stop," said Taylor, who is based at the Monash Immunology and Stem Cell Laboratories.

The overall size of the tissue grown by the team is smaller than the walnut-sized human prostate. But "size doesn't matter -- it's what it looks like," Risbridger said. Taylor said the tissue created by the team had the same blood vessels and secreted the same fluids as the human prostate.

'Perfect model'

Because the prostate tissue was grown in mice in three months, researchers would not have to take it from humans, making it easier to study how a healthy prostate became diseased as it aged.

"The tissue we've grown behaves as a normal human prostate, so it's the perfect model for testing the different hormones and environmental factors we believe play a role in the onset of prostate disease," said co-author Prue Cowin.

Prostate cancer is the most common cancer in men, but the impact of benign prostate disease (BPH) is equally significant -- up to 90 per cent of men will have BPH by the time they reach 80 years of age. Although BPH is not usually life-threatening it can have a dramatic impact on quality of life.

From here, the scientists are aiming to isolate specific messenger cells from patients with prostate cancer or BPH and investigate the effect these cells have on ES cell growth and development.

Risbridger added that the researchers would now be able to use the platform technology they had created to develop tissue from other organs such as breast and bladder tissue.

The project was funded by the Australian financial services giant Perpetual Trustees and the US Department of Veteran Affairs, who together provided up to AUD$1.5 million.