Safe delivery system finally found.

• Position: Cancer Drugs

An effective way to deliver staurosporine (STS)--a powerful anticancer compound that has vexed researchers for more than 30 years due to its instability in the blood and toxic nature in both healthy and cancerous cells--with no apparent side effects has been found by researchers at the University of California School of Medicine, San Diego.

"By itself, staurosporine shows potent activity against a number of cancer cell lines, including chemotherapy-resistant tumors. However, it also harms normal tissue," explains senior author Santosh Kesari, director of neuro ontology at the Moores Cancer Center. "With this study, we have been able to overcome the pharmacokinetic barriers to delivering staurosporine to tumors with the use of liposomes."

STS originally was isolated from the bacterium Streptomyces staurosporeus in 1977. The compound prompts a wide variety of cancer cell types to self-destruct, a process called apoptosis or programmed cell death. In its free form, STS quickly is metabolized and harmful to healthy cells. By trapping STS in tiny spheres called liposomes, researchers effectively have been able to deliver the compound, past healthy tissue, to the tumor, with potent results.

Liposomes are microscopic bubbles made from the same molecules as cell membranes. Researchers use these hollow spheres to deliver therapeutic agents. Anti-cancer drugs can be loaded inside, while disguising agents coat the external membrane surface to hide the cancer-killer from the immune system.

"Staurosporine is...