More Evidence Green Tea Helps Combat Prostate Cancer
MADISON - Drinking a nice warm cup of green tea has long been touted for its healthful benefits, but now researchers have found that a component of green tea, combined with low doses of a common pain medication, could slow the spread of human prostate cancer.
In the March 1 issue of Clinical Cancer Research, scientists from University of Wisconsin Paul P. Carbone Comprehensive Cancer Center (UWCCC) demonstrate that a compound in green tea, taken with celecoxib, slows the growth of human prostate cancer in the lab. Their experiments were performed in cell cultures and in animal models.
Combining celecoxib, a drug designed to treat the pain and swelling of arthritis inflammation, with the green tea compound polyphenol, shows great promise, according to study leader Hasan Mukhtar, PhD, professor of dermatology at the University of Wisconsin-Madison and member of the UWCCC.
"Celecoxib and green tea have a synergistic effect - each triggering different cellular pathways that, when combined, are more powerful than either agent alone," says Mukhtar. "We hope that a clinical trial could lead to an effective preventive treatment for prostate cancer as simple as tea time."
He adds that there will need to be more study before recommending this combination as safe and effective for use in humans.
In 2004, Mukhtar and his colleagues demonstrated the cancer-fighting abilities of the green tea polyphenol EGCG. That study, also published in Cancer Research, showed that EGCG can modulate the insulin-like growth factor-1 (IGF-1)-driven molecular pathway, pushing human prostate cancer cells toward programmed cell death. The researchers had previously shown COX-2 inhibitors like celecoxib suppress prostate cancer in animal models.
"Our studies show that the additive effect of green tea enables us to use the cancer-fighting abilities of COX-2 inhibitors, but at lower, safer doses," Mukhtar says.
In this latest research, investigators looked at the effects of the two substances on cultured human prostate cancer cells. Alone, both compounds slowed cancer cell growth and limited the presence of known cancer-promoting proteins within the cells. Together, they suppressed cell growth by an additional 15 to 28 percent.
They repeated the experiment in mouse models of prostate cancer, using celecoxib and an oral suspension of the decaffeinated green tea polyphenol. By using pharmacy-grade celecoxib and actual tea, they hoped to replicate real-life conditions.
"The idea is that it would be easier to get people to drink green tea and take a safer dose of a common painkiller than it would be to take an additional dietary supplement," Mukhtar explains.
Again, when used alone, the celecoxib and green tea polyphenol each significantly reduced the size of prostate tumors. But when the two were used together, the decrease was even more dramatic. Also, the combined compounds reduced the prostate specific antigen (PSA), the protein commonly used as a marker to detect and assess the progression of prostate cancer.
These results, combined with a marked decrease in the presence of cancer-promoting proteins, offered clear indications that green tea and celecoxib, combined, could be useful in slowing prostate cancer growth, Mukhtar says.
"If tests in human trials replicate these results," suggests Mukhtar, "we could see a powerful therapy that is both simple to administer and relatively cost effective."
The study was funded by the National Cancer Institute.
Date Published: 06/06/2007