Researchers here have learned how a derivative of vitamin E causes the death of cancer cells. The researchers then used that knowledge to make the agent an even more potent cancer killer.

The compound, called vitamin E succinate, or alpha tocopheryl succinate, is taken by some people as a nutritional supplement, mainly for its antioxidant properties. In addition, it has a weak ability to kill cancer cells, and it has been tested as a cancer chemopreventive agent. The substance kills cancer cells by causing them to undergo a natural process known as programmed cell death, or apoptosis. Until now, no one knew how the agent caused this to happen.

These findings answer that question and also indicate that the molecule's anti-tumour activity is separate from its antioxidant effect.

The study is led by researchers with The Ohio State University Comprehensive Cancer Centre - Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC-James).

"Our findings could lead to a potent chemopreventive agent that has both strong anticancer and antioxidant properties," says principal investigator Ching-Shih Chen, professor of pharmacy and of internal medicine and a researcher with the OSUCCC-James. "Such an agent might help reduce the risk of prostate, colon and other cancers," he added.

Chen and his collaborators found that vitamin E succinate works by blocking a protein called Bcl-xL. The protein, which is made by healthy cells, is often present at abnormally high levels in cancer cells and protects them from dying when they should. Using computer modelling, the researchers found that the vitamin E derivative works because it lodges in a groove in the structure of the Bcl-xL protein, disabling it.

Funding from the National Cancer Institute supported this research.