Featured Research

from universities, journals, and other organizations

While On Trail Of Dioxin, Scientists Pinpoint Cancer Target Of Green Tea

Date:
May 20, 2005
Source:
University of Rochester Medical Center
Summary:
Green tea appears to protect against cancer by affecting a "promiscuous" protein that pharmaceutical experts are already targeting in an effort to develop a new drug to stop the disease, scientists have found.

Green tea appears to protect against cancer by affecting a "promiscuous" protein that pharmaceutical experts are already targeting in an effort to develop a new drug to stop the disease, scientists at the University of Rochester Medical Center have found. The research, which buttresses beliefs about the health benefits of green tea with solid scientific evidence, has been cited as part of the best doctoral thesis produced by a student at the university's School of Medicine and Dentistry this year.

Related Articles


The thesis by student Christine Palermo is part of a wider research project led by toxicologist Thomas A. Gasiewicz, Ph.D., whose decades-long studies of the harmful effects of dioxin ultimately led his group to explore the protective effects of green tea. While it's been reported that green tea protects people against some forms of cancer, such as breast and liver cancer, exactly how it does so has been difficult to pinpoint.

The latest results make more feasible the idea of harnessing green tea's protective power. Just as people with aches and pains no longer have to chew on willow bark to receive the benefits of the substance salicin -- they simply take an aspirin -- the current research opens the door to extending the health benefits first discovered in green tea to people who never touch the beverage. Isolating the chemicals that protect against cancer would also sidestep questions such as how to take into account different types of teas and different brewing processes, or how much tea one needs to drink.

"It's important to find out the source of green tea's protective effects," says Gasiewicz, professor and chair of Environmental Medicine and director of Rochester's Environmental Health Science Center. "What is exciting here is that a completely new mechanism has been found that very well could be responsible for its protective effects, and that could help us find a compound that is much more potent."

Palermo, Gasiewicz, and current undergraduate Claire Westlake discovered that a chaperone protein known as HSP90 is involved in conferring green tea's protective effects. Other researchers have shown that many cancer cells have an increase in the level of HSP90 compared to healthy cells, and that when HSP90 is blocked, levels of proteins that make cancer cells grow drop.

Drug makers are currently working on ways to block HSP90, which is known as a promiscuous chaperone protein because it binds to many different cells and receptors in the body. It turns out that those researchers are trying to duplicate what green tea does naturally. Gasiewicz says drug makers can learn from green tea, which might modulate HSP-90 in a way that researchers haven't seen before.

Gasiewicz is a world leader on dioxin, and it was by tracking the trail of dioxin's harmful effects on the body that his group made the green tea findings. His group has shown how dioxin and other substances like cigarette smoke manipulate a major cancer-causing molecule, the aryl hydrocarbon (AH) receptor, which frequently plays a role in turning on genes that are oftentimes harmful.

Two years ago the team discovered that AH activity is inhibited by a chemical found in white and green teas, epigallocatechingallate or EGCG, a cousin of flavonoids found in broccoli, cabbage, grapes and red wine that are known to help prevent cancer. The team had been working on other chemicals to try to stop AH activity.

"We initially hypothesized that EGCG would work in the same way as other AH antagonists, by binding directly to it. We were completely surprised that this isn't the case," says Gasiewicz, whose work was funded by the National Institute of Environmental Health Sciences and the American Institute for Cancer Research.

Instead, the team found that EGCG binds to HSP90, a protein that helps other proteins stay stable, serving the same role as a tail on a kite. When the two bind, HSP90 no longer turns on the AH receptor, stopping the cascade of events that would lead to the activation of several harmful genes.

This weekend Palermo is receiving the Wallace Fenn Award, named after a long-time physiology professor at the University of Rochester School of Medicine and Dentistry. The award is given at graduation each year to a student who has produced an outstanding thesis. The research also has earned Palermo awards from the Society of Toxicology in each of the last three years; the current research was published in the April 5 issue of the journal Biochemistry. She is now a post-doctoral associate at Tulane, where she is looking into the causes of childhood leukemia.


Story Source:

The above story is based on materials provided by University of Rochester Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

University of Rochester Medical Center. "While On Trail Of Dioxin, Scientists Pinpoint Cancer Target Of Green Tea." ScienceDaily. ScienceDaily, 20 May 2005. <www.sciencedaily.com/releases/2005/05/050519143007.htm>.
University of Rochester Medical Center. (2005, May 20). While On Trail Of Dioxin, Scientists Pinpoint Cancer Target Of Green Tea. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2005/05/050519143007.htm
University of Rochester Medical Center. "While On Trail Of Dioxin, Scientists Pinpoint Cancer Target Of Green Tea." ScienceDaily. www.sciencedaily.com/releases/2005/05/050519143007.htm (accessed October 30, 2014).

Share This



More Health & Medicine News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Reuters - Innovations Video Online (Oct. 29, 2014) A Swedish amputee who became the first person to ever receive a brain controlled prosthetic arm is able to manipulate and handle delicate objects with an unprecedented level of dexterity. The device is connected directly to his bone, nerves and muscles, giving him the ability to control it with his thoughts. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Google To Use Nanoparticles, Wearables To Detect Disease

Google To Use Nanoparticles, Wearables To Detect Disease

Newsy (Oct. 29, 2014) Google X wants to improve modern medicine with nanoparticles and a wearable device. It's all an attempt to tackle disease detection and prevention. Video provided by Newsy
Powered by NewsLook.com
Can Drinking Milk Lead To Early Death?

Can Drinking Milk Lead To Early Death?

Newsy (Oct. 29, 2014) Researchers in Sweden released a study showing heavy milk drinkers face an increased mortality risk from a variety of causes. Video provided by Newsy
Powered by NewsLook.com
Obama: The US Will Not 'run and Hide' From Ebola

Obama: The US Will Not 'run and Hide' From Ebola

AP (Oct. 29, 2014) Surrounded by health care workers in the White House East Room, President Barack Obama said the U.S. will likely see additional Ebola cases in the weeks ahead. But he said the nation can't seal itself off in the fight against the disease. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins