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 <<>> 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.
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.