Compounds derived from indirubin, a component of a Chinese herbal medicine, can cause human cancer cells to self-destruct, researchers have shown.

A traditional Chinese medicine, Danggui Longhui Wan, is used to treat Leukemia. In previous experiments, the active ingredient indirubin has seen to kill cells by blocking an enzyme called CDK and thus interrupting the normal cell cycle.

Now, Dr. Richard Jove, from the Moffitt Cancer Center and Research Institute in Tampa, Florida, and colleagues report in the Proceedings of the National Academy of Sciences on another way that derivatives of the indirubin kill cancer cells.

The researchers discovered that the compounds induce breast and Prostate cancer cells to shut down and die by inhibiting a signaling pathway, known as Src-Stat3.

“These findings provide evidence of another mechanism for indirubin’s antitumor activity,” Jove’s group writes.

One of the derivatives, designated E804, was particularly potent in destroying cancer cells and “has potential as an antitumor therapeutic agent in epithelial malignancies,” the team concludes.

SOURCE: Proceedings of the National Academy of Sciences, April 18, 2005.