Green tea and COX-2s slow prostate cancer

MADISON, Wis., March 2 (UPI) -- A combination of green tea and a COX-2 inhibitor effectively slows the growth of prostate cancer, say U.S. researchers.

Hasan Mukhtar and colleagues at the University of Wisconsin noted that COX-2 inhibitors such as Celebrex suppress prostate cancer in animals but have adverse cardiovascular effects when given at high doses over a long period of time.

They had previously shown that an element in green tea called pigallocatechin-3-gallate (ECGC) had the same effect and decided to try the two agents together in mice to see if the combination would let them use the COX-2 drugs at lower, safer doses.

One group of mice received no treatment, one received only NS-398 (a COX-2 inhibitor similar to Celebrex), one received ECGC alone, and one received a COX-2/ECGC combination.

The tumors of untreated mice averaged 1,300 cubic millimeters. The tumors of the ECGC group averaged 835 cubic millimeters, those given NS-398 alone averaged 650 cubic millimeters, and the combination-group tumors averaged 350 cubic millimeters.

Mice on the combination regimen also had lower levels of prostate specific antigen (PSA), a marker of prostate cancer growth.

"Prostate cancer typically arises from more than one defect in cellular mechanics, which means that a single therapeutic might not work ... long-term," Mukhtar said. "If ... human trials replicate these results, we could see a powerful combined therapy that is both simple to administer and relatively cost effective."

The research was published in the March 1 issue of Clinical Cancer Research.