Green Tea Extract Has Potential As An Anti-Cancer Agents,

[Guest guest]

Many of the bioactive ingredients found in green tea, the polyphenols, are

also found in red grape juice (unpasteurized) and figs.

 

http://www.bio.com/newsfeatures/newsfeatures_research.jhtml?cid=7800134

 

Green Tea Extract Has Potential As An Anti-Cancer Agent

 

02/15/05 -- 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.

 

Source: University of California, Los Angeles