Omega-6 fatty acids promote the growth of prostate tumor cells in the
laboratory
Medical Study NewsPublished: Tuesday, 2-Aug-2005  

 A study conducted at the San Francisco VA Medical Center (SFVAMC) has
demonstrated that omega-6 fatty acids such as the fat found in corn oil
promote the growth of prostate tumor cells in the laboratory. The study
also identifies a potential new molecular target for anti-tumor drugs:
an enzyme known as cPLA2, which plays a key role in the chain leading
from omega-6 fatty acids to prostate tumor cell growth.

The study was led by Millie Hughes-Fulford, PhD, director of the
Laboratory of Cell Growth at SFVAMC and scientific advisor to the U.S.
Undersecretary of Health for the Department of Veterans Affairs. It is
being published in the September 2005 issue of Carcinogenesis, and is
currently available online.

Working with human prostate cancer cells in tissue culture,
Hughes-Fulford and her fellow researchers identified for the first time
a direct chain of causation: When introduced into prostate tumor cells
in culture, omega-6 fatty acid causes the production of cPLA2, which
then causes the production of the enzyme COX2. In turn, COX2 stimulates
the release of PGE2, a hormone-like molecule that promotes cell growth.

"What's important about this is that omega-6 fatty acids are found in
corn oil and most of the oils used in bakery goods," says
Hughes-Fulford, who is also an adjunct professor of medicine at the
University of California, San Francisco (UCSF). "Which means that if
you're eating a diet high in omega-6 fatty acids, it's possible that
you're turning on this cancer cascade, which has been shown to be a
common denominator in the growth of prostate, colorectal, and some
breast cancers."

The study points out that 60 years ago in the United States, the dietary
ratio of omega-6 to omega-3, a beneficial fatty acid, was 1 to 2. Today,
the ratio is 25 to 1. Over that same 60 years, the incidence of prostate
cancer in the U.S. has increased steadily.

Hughes-Fulford also found that flurbiprofen, a non-steroidal
anti-inflammatory drug commonly prescribed for arthritis, blocked the
production of cPLA2 and broke the chain leading to cell growth. This
means, she says, that new drugs might be developed that could
specifically target cPLA2 and prevent COX2 from being released.

"COX2 has been implicated in the growth of many types of tumors," she
notes. "So if you can find a way to block that cascade in the tumor,
starting with cPLA2, you might have a new way of modifying or slowing
tumor growth."

Hughes-Fulford points out that cPLA2 inhibitors would avoid the problems
inherent in the class of drugs known as COX2 inhibitors. These drugs
have been shown to be effective against tumor growth as well as in
treating the pain associated with inflammatory conditions such as
arthritis, but have been implicated in increased risk of cardiovascular
problems in people who take them regularly. "COX2 inhibitors also
inhibit prostacyclins, which are enzymes that are beneficial to the
heart, and cPLA2 inhibitors would not affect those," she explains.

In future research, Hughes-Fulford will be looking at the overall effect
of different types of fatty acids on different tumor types in cell lines
as well as human biopsies. She plans a study that will correlate type of
fatty acid with tumor stage and grade in order to obtain a clearer
picture of specific effects of different fats on tumor progression.

Co-authors of the study were Raymond R. Tjandrawinata, PhD, of UCSF,
Chai-Fei Li, BA, of SFVAMC, and Sina Sayyah, BA, of SFVAMC and UCSF.
http://www.ucsf.edu/
 

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
http://community.webtv.net/PALMER_ENT/doc