Indeed, further experimentation demonstrated that grape seed extract increased the level of Cip1/p21 protein, allowing it to bind to and shut down the CDKs driving the cell cycle. The investigators also found that the extract can do that even if a cancer cell is missing p53 function (which also helps controls the cell cycle).

"That is good news, because most cancers are missing p53," Agarwal said.

Finally, the researchers tested the extract in mice. They implanted the animals with advanced human colorectal cancer cells and at the same time, gave the mice grape seed extract through a feeding tube. They tested only one dose, which was larger than a human would comparatively use, Agarwal said, and after eight weeks, tumor volume in treated mice were reduced by 44 percent and tumor weight by percent, compared to control animals. No toxic side effects were observed in treated mice, despite the high doses.

Similar to the cell culture studies, Cip1/p21 protein levels increased in tumors in mice treated with grape seed extract, Agarwal said.

As a first step toward translating their findings into the clinic, the research team now plans to determine the lowest effective, as well as the highest non-toxic doses, by which grape seed extract can offer anticancer benefit in mice.

'"/>

Contact: Warren Froelich
froelich@aacr.org
215-440-9300
American Association for Cancer Research
18-Oct-2006