Coffee compounds may help fight prostate cancer

In a first, scientists have identified compounds found in coffee which may inhibit the growth of prostate cancer.

The study, published in the journal The Prostate, was carried out on drug-resistant cancer cells in cell culture and in a mouse model.

Coffee is a complex mixture of compounds which has been shown to influence human health in both positive and negative ways.

There is increasing evidence that drinking certain types of coffee is associated with a reduction in incidence of some cancers, including prostate cancers.

Researchers from Kanazawa University in Japan have studied the effects of two compounds found in coffee, kahweol acetate and cafestol, on prostate cancer cells and in animals, where they were able to inhibit growth in cells which are resistant to common anti-cancer drugs such as Cabazitaxel.

The researchers initially tested six compounds, naturally found in coffee, on the proliferation of human prostate cancers cells in a petri-dish.

They found that cells treated with kahweol acetate and cafestol grew more slowly than controls.

They then tested these compounds on prostate cancer cells which had been transplanted to 16 mice.

Four mice were controls, four were treated with kahweol acetate, four with cafestol, with the remaining mice being treated with a combination of kahweol acetate and cafestol.

"We found that kahweol acetate and cafestol inhibited the growth of the cancer cells in mice, but the combination seemed to work synergistically, leading to a significantly slower tumour growth than in untreated mice," said Hiroaki Iwamoto from Kanazawa University.

"After 11 days, the untreated tumours had grown by around three and a half times the original volume, whereas the tumours in the mice treated with both compounds had grown by around just over one and a half times the original size," said Iwamoto.

This is a pilot study, so this work shows that the use of these compounds is scientifically feasible, but needs further investigation, researchers said. It does not mean that the findings can yet be applied to humans.

"What it does show is that these compounds appear to have an effect on drug resistant cells prostate cancer cells in the right circumstances, and that they too need further investigation," said Iwamoto.

"We are currently considering how we might test these findings in a larger sample, and then in humans," he said.

Kahweol acetate and cafestol are hydrocarbons, naturally found in Arabica coffee. The coffee-making process has been found to affect whether these compounds remain in coffee after brewing (as with espresso), or whether they are stripped out (as when filtered).

"These are promising findings, but they should not make people change their coffee consumption. However, if we can confirm these results, we may have candidates to treat drug-resistant prostate cancer," said Atsushi Mizokami, professor at Kanazawa University.