Antitumor Compound Blocks Heat Shock Protein

Heat shock proteins are expressed in response to higher temperatures and help prevent disruptions in protein folding. Hsp90, in particular, is often overexpressed in cancer cells and maintains stability and function of several oncoproteins, known as client proteins.

Seung Hyun Oh, Ph.D., D.V.M., of the University of Texas M. D. Anderson Cancer Center in Houston, and colleagues investigated whether deguelin inhibits the function of Hsp90. Mice with transplanted human non--small-cell lung cancer, head and neck cancer, stomach cancer, or prostate cancer were treated with deguelin or placebo twice a day for 15-28 days.

The researchers showed that deguelin directly binds to Hsp90 and inhibits its functional activity, which results in a reduction in the expression of its client proteins. Additionally, deguelin reduced tumor growth in mice without any detectable toxic side effects.

"Extensive and complete chronic toxicity testing in clinical trials is warranted before the further development of deguelin as an anticancer therapeutic agent," the authors write.