NEW YORK (Reuters Health) - A component of green tea combined with a low dose of a COX-2 inhibitor may act in concert to slow the spread of human prostate cancer.
In the journal Clinical Cancer Research, they report that low doses of the COX-2 inhibitor celecoxib (sold as Celebrex), given along with a green tea polyphenol slowed the growth of prostate cancer in cell cultures and in a mouse model of the disease.
“Celecoxib and green tea have a synergistic effect, each triggering cellular pathways, that, combined, are more powerful than either agent alone,” Dr. Hasan Mukhtar from the University of Wisconsin, Madison, said in a statement.
Prior studies have linked the COX-2 enzyme to many cancer types, including prostate cancer. Mukhtar and colleagues previously found that COX-2 inhibitors like Celebrex suppress prostate cancer in animals. COX-2 inhibitors also have been shown to have adverse effects on the heart when taken at high doses for long periods of time.
Mukhtar’s team also previously found that the green tea polyphenol called EGCG has cancer-fighting abilities of its own; EGCG, they found, modulates key chemical pathways that fuel the death of human prostate cancer cells.
In their current studies, treatment of cultured human prostate cancer cells with either a COX-2 inhibitor or green tea extract significantly inhibited prostate cancer cell growth, but the combination was most effective, increasing cancer inhibition 15 percent to 28 percent more than the additive effects of the two therapies alone.
Similar results were obtained in a mouse model of human prostate cancer, with the Celebrex plus green tea combination inhibiting the growth of prostate tumors by 81 percent, compared with 42 percent with green tea extract alone and 57 percent with Celebrex alone.
This is the first time a synergism between these agents against prostate cancer cells has been demonstrated, the authors say.
“Prostate cancer typically arises from more than one defect in the cellular mechanics, which means that a single therapeutic might not work fighting a particular cancer long-term,” Mukhtar said. “If tests in human trials replicate these results, we could see a powerful combination therapy that is both simple to administer and relatively cost effective.”
It’s worth noting that the dose of Celebrex used in the studies translates into about 200 milligrams per day, which is much lower than the typical colon cancer prevention trials where doses of up to 800 milligrams per day were used.
SOURCE: Clinical Cancer Research March 1, 2007.