Chemical in soy halts cancer
in mice
ANAHEIM, Calif.
June 5, 2001 (Cancer Digest) -- A chemical found in soy, slowed
prostate cancer growth in mice and caused prostate cancer cells
to die according to new research presented today at the American
Urological Association meeting.
A research team led
by Dr. Ralph deVere White, of the UC Davis Medical Center, showed
that a chemical found in soy called, genistein, reduced prostate
cancer tumor growth in mice and in laboratory experiments, triggered
programmed cell death in prostate cancer cells.
"We've identified
the mechanisms by which genistein may work in prostate cancer,
and it's consistent with other studies of soy," said deVere
White. "While we are encouraged by these results, we need
to test genistein in patients with prostate cancer to be certain
of its effectiveness."
Genistein is one of
two compounds in soy that belong to a family of chemicals known
as isoflavones, which are phytoestrogens, plant-based chemicals
that mimic the effects of estrogen in the body. Researchers theorize
that the prevalence of soy in Asian diets may be one reason men
in Asia have a lower rate of prostate cancer than men in the
United States.
In tissue culture,
genistein increased the production of a protein called, p21,
that regulates cell growth, and it reduced the production of
vascular endothelial growth factor (VEGF), a protein that helps
cancer grow. These factors caused cancer cells to die, a process
known as apoptosis.
The UC Davis researchers
are now evaluating the effects of genistein in men who have been
diagnosed with slow-growing prostate cancer. The cancer center
will ultimately enroll 70 men in the pilot study to see if genistein
lowers levels of prostate specific antigen (PSA), a tumor marker
for prostate cancer.
Men who have chosen
not to receive treatment for prostate cancer or who have undergone
treatment and whose PSA levels are rising slowly are eligible
to participate in the trial. Volunteers, depending on their body
weight, will take up to five grams of genistein daily for six
months. Results will be known in a year.
It is unlikely genistein
would become a stand-alone treatment for prostate cancer, said
deVere White. "But we hope it could be used in conjunction
with conventional therapy or as a preventive drug, if it indeed
lowers PSA."
Source: University Of California, Davis - Medical Center
|