In this latest research, Mukhtar and his colleagues looked at the effects of the two substances on cultured human prostate cancer cells. Alone, both EGCG and NS-398, a COX-2 inhibitor similar to celecoxib, demonstrated the ability to slow cancer cell growth and limit the presence of known cancer-promoting proteins within the cell samples. Together, EGCG and NS-398 suppressed cell growth by an additional 15 to 28 percent.

The researchers 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 had hoped to replicate real-life conditions. The idea is that it would be easier to get people to drink green tea than it would be to take an additional dietary supplement, Mukhtar said.

In mice that were not treated with either substance, the tumor volume averaged 1,300 cubic millimeters, whereas mice given either the tea or celecoxib had tumors averaging 835 cubic millimeters and 650 cubic millimeters, respectively. Tumors taken from mice given both agents, however, measured on average a volume of 350 cubic millimeters.

In parallel to tumor growth inhibition, mice that received a combination of green tea and celecoxib registered a greater decrease in prostate specific antigen (PSA) levels compared to that in celecoxib alone or green tea alone treated animals. PSA is a protein produced by the cells of the prostate and is used as a marker for detection and 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, Mukht
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Contact: Greg Lester
lester@aacr.org
267-646-0554
American Association for Cancer Research
1-Mar-2007