French scientists have discovered how fat cells and cancer cells attract each other, causing aggressive tumours to spread beyond the prostate.
Despite numerous studies highlighting a link between obesity and aggressive prostate cancer, researchers have never been able to prove a cause and effect between the two or how it might happen – until now.
New research from the University of Toulouse, published in Nature Communications, has revealed clues about how obesity might cause prostate cancers to become more aggressive.
The researchers used experiments in cells and mice to show that fat cells in the area surrounding the prostate release a protein called CCL7, which spreads through the fatty tissue and migrates to the inside edge of the prostate. The prostate cancer cells display a second protein on their surface, called CCR3, which is attracted and binds to CCL7.
This attraction stimulates the cancer cells to start moving, a key step in the change between a localised prostate cancer cell and an aggressive one that can move and spread around the body. The cancer cells’ movement is driven by their CCR3 protein, which directs them along a 'gradient of attraction' from where there’s least CCL7 (inside the prostate) to where there’s more of it (in the fatty tissue outside the prostate).
The scientists went on to show that in conditions like obesity – where there are a lot of fat cells all secreting CCL7 at the same time – this effect was amplified, leading to more aggressive tumours.
Commenting on this research, Dr Iain Frame, our Director of Research, said: "There is a known link between obesity and developing aggressive prostate cancer, and this research starts to fill in some of the blanks as to why this link might exist.
"Prostate cancer is often symptomless in its early stages, when it is most treatable, so awareness of risk is crucial. We already know that men over 50, black men and men with a family history of prostate cancer face a greater danger of developing the disease. Being overweight is an important new warning sign to be aware of."
This is the first time we’ve had any clues about how obesity may encourage prostate cancer cells to spread. It’s important because this confirms a direct cause-and-effect relationship between obesity and prostate cancer progression. More importantly, though, understanding the nitty-gritty molecular details of exactly how and why prostate cancer starts to spread is a key step towards stopping this happening.
As part of their study, the researchers noted that blocking the effect of CCL7/CCR3 signalling stopped the enhanced tumour cell migration, suggesting that this could be worth exploring as a way to prevent prostate cancer progression in obese men. However, although drugs that block the CCL7/CCR3 interaction are currently being developed for other conditions, including asthma, it is by no means certain yet that these would work for prostate cancer and it could be many years before we have this information.
So although we may sound like a broken record, there’s a reason we keep repeating ourselves. The best way to look after yourself in the here and now is through a balanced diet and plenty of exercise.