Investigators have identified compounds found in coffee that may inhibit the growth of prostate cancer, according to a study presented at the European Association of Urology congress in Barcelona. The pilot study, published in the peer-reviewed journal The Prostate, was carried out on drug-resistant cancer cells in cell culture and in a mouse model, however, it has not yet been tested in humans.
 
The effects of 2 compounds found in coffee, kahweol acetate and cafestol, were studied on prostate cancer cells and in animals, and scientists found that these compounds were able to inhibit growth in cells that were resistant to common anti-drugs, such as cabazitaxel, according to the press release.  
 
There was an initial test of 6 compounds naturally found in coffee on the proliferation of human prostate cancer cells in vitro. It was found that cells treated with kahweol acetate and cafetol grew more slowly than controls. They then tested these compounds on prostate cancer cells that had been transplanted to approximately 16 mice. Four mice were controls, 4 were treated with kahweol acetate, 4 with cafestol, and the remaining mice were 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 tumor growth than in untreated mice,” study leader Dr. Hiroaki Iwamoto said in a press release. “After 11 days, the untreated tumors had grown by around 3 and a half times the original volume (342%), whereas the tumors in the mice treated with both compounds had grown by around just over one and a half (167%) times the original size.”
 
He urged that the findings should be kept in perspective since it was a pilot study. According to Dr. Hiroaki, the use of these compounds is scientifically feasible, but it needs further investigation to determine whether or not the findings can be applied to humans.
 
We also found the growth reduction in transplanted tumor cells, rather than in native tumor cells,” Dr. Hiroaki said. “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. We are currently considering how we might test these findings in a larger sample, and then in humans."
 
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 (i.e. espresso) or whether they are stripped out (i.e. filtered).
 
"These are promising findings, but they should not make people change their coffee consumption,” said professor Atsushi Mizokami from Kanazawa University Graduate School of Medical Science, Japan. “Coffee can have both positive and negative effects (for example it can increase hypertension), so we need to find out more about the mechanisms behind these findings before we can think about clinical applications. However, if we can confirm these results, we may have candidates to treat drug-resistant prostate cancer."