Green Tea Helps Fight Cancer
Green tea extract shows promise
as an anti-cancer agent, UCLA study finds
Jonsson Cancer Center researchers find green tea may
help fight bladder cancer
A study on bladder cancer cells lines showed that green tea extract
has potential as an anti-cancer agent, proving for the first time
that it is able to target cancer cells while leaving healthy cells
alone.
The study, published in the Feb. 15, 2005 issue of
the peer-reviewed journal Clinical Cancer Research, also uncovered
more about how green tea extract works to counteract the development
of cancer, said JianYu Rao, a Jonsson Cancer Center member, an associate
professor of pathology and laboratory medicine and the study's senior
author.
"Our study adds a new dimension in understanding
the mechanisms of green tea extract," Rao said. "If we knew
exactly how it works to inhibit the development of cancer, we could
figure out more precisely which bladder cancer patients might benefit
from taking it."
Numerous epidemiologic and animal studies have suggested
that green tea extract provides strong anti-cancer effects in several
human cancers, including bladder cancer. It has been shown to induce
death in cancer cells, as well as inhibiting the development of an
independent blood supply that cancers develop so they can grow and
spread.
In the UCLA study, which brought together researchers
from UCLA's Jonsson Cancer Center, School of Public Health, Center
for Human Nutrition and the departments of Pathology and Laboratory
Medicine, Surgery, Urology and Epidemiology, scientists were able
to show that green tea extract interrupts a process that is crucial
in allowing bladder cancer to become invasive and spread to other
areas of the body.
Green tea extract affects actin remodeling, an event
associated with cell movement. When a human moves, the muscles and
skeletal structure operate together to facilitate that movement.
For cancer to grow and spread, the malignant cells
must be able to move. The cell movement depends on actin remodeling,
which is carefully regulated by complex signaling pathways, including
the Rho pathway. When actin remodeling is activated, the cancer cells
can move and invade other healthy cells and eventually other organs.
By inducing Rho signaling, the green tea extract made
the cancer cells more mature and made them bind together more closely
- a process called cell adhesion. Both the maturity of the cells and
the adhesion inhibited the mobility of the cancer cells, Rao said.
"In effect, the green tea extract may keep the
cancer cells confined and localized, where they are easier to treat
and the prognosis is better," Rao said. "Cancer cells are
invasive and green tea extract interrupts the invasive process of
the cancer."
Bladder cancer is the fifth most common cancer in
the United States, with about 56,000 new cases diagnosed each year.
About half of all bladder cancers are believed to be related to cigarette
smoking. Without a reliable, non-invasive way to diagnose the disease,
bladder cancer can be difficult to detect in the early, most treatable
stages. When not found early, the tumors can be aggressive, and more
than half of patients with advanced cancers experience recurrences.
UCLA researchers currently are seeking hundreds of
former smokers who have had bladder cancer for a clinical trial studying
whether green tea extract prevents recurrence - one of the first studies
in the country to test the agent on cancer patients. The study is
part of a comprehensive program funded by the National Cancer Institute
and designed to prevent the recurrence and progression of smoking-related
bladder cancer. In addition to the trial, the program seeks to develop
new biomarker tests to help predict who will get bladder cancer, discover
the molecular profile of the disease to identify those most at risk
and create a tumor bank to aid research. Volunteers interested in
participating in the study should call (310) 825-4415.
Rao cautioned that his study was conducted in a carefully
controlled cell line environment and that more research needs to be
done to discover exactly how green tea extract functions as a cancer
fighter. The next phase of his research will analyze urine from bladder
cancer patients to determine which subset of patients would benefit
most from taking green tea extract. Researchers will be looking for
specific biomarkers associated with actin remodeling and activation
of the Rho signaling pathway.
"We're hoping the results from these studies
will tell us who will best benefit from the agent," Rao said,
adding that the basic research he is doing and the clinical trial
on bladder cancer patients will provide scientists with vital information
from both ends the research continuum, an example of bench-to-bedside-and-back-again
science.
"I think this publication further supports the
potential role of green tea in the prevention and treatment of bladder
cancer," said Dr. Robert Figlin, a UCLA professor of hematology/oncology
and urology and a principal investigator for the human studies. "In
the end, both studies will help us achieve our goal - to decrease
bladder cancer occurrence and develop molecular profiles that tell
us who is most at risk."
UCLA's
Jonsson Comprehensive Cancer Center is composed of more than 240
cancer researchers and clinicians engaged in cancer research, prevention,
detection, control and education. One of the nation's largest comprehensive
cancer centers, the JCCC is dedicated to promoting cancer research
and applying the results to clinical situations. In 2004, the Jonsson
Cancer Center was named the best cancer center in the western United
States by U.S. News & World Report, a ranking it has held for
five consecutive years.
Green
tea is a potent cancer-fighter. It is a known fact that people who
drink green tea are less likely to develop cancer. A new study indicates
green tea's ability to fight cancer is even more potent and varied
than scientists have suspected.
Researchers say they've discovered chemicals in green
tea that shut down one of the key molecules that tobacco relies upon
to cause cancer. The finding by scientists at the University of Rochester's
Environmental Health Science Center appears in the journal Chemical
Research in Toxicology, published by the American Chemical Society.
Pro Health's Green Tea Extract is a potent
formula containing 75% polyphenols - the substances that support healthy
cholesterol levels and efficient fat metabolism. Of further benefit,
polyphenols exert a strong antioxidant reaction, scavenging for free
radicals that can damage cells.
Evidence of green tea's health-promoting
benefits came from the Japanese culture. The Japanese have the lowest
level of heart disease and highest longevity rate of all industrialized
nations. Although many aspects contribute to the Japanese low-disease
rate, green tea is thought to be an important element.
- Top antioxidant in Asia.
- Equivalent to 12 cups of tea in convenient capsule
delivery
- Supports healthy cholesterol levels
- Fights free radicals
