Alan Dove
 

Adding to the list of potential uses for neural stem cells, scientists at Harvard University (Boston, MA) and Layton Bioscience (Sunnyvale, CA) have found that stem cells can migrate throughout the brain and preferentially juxtapose themselves to metastasizing tumor cells. Experiments in rats demonstrated that these stem cells can be used to deliver therapeutic molecules to target tumor cells with impressive accuracy. A major barrier to the treatment of brain tumors has been tumor cells' tendency to migrate widely through the brain, making them inaccessible to traditional therapies. In the new work, reported in Proc. Natl. Acad. Sci. USA (97, 12846–12851, 2000;MEDLINE), researchers demonstrate that neural stem cells distribute themselves throughout experimentally induced gliomas in adult rats and also "chase down" migrating tumor cells elsewhere in the brain. When the stem cells are engineered to express cytosine deaminase, they can convert a nontoxic "prodrug" into an active chemotherapeutic agent, killing adjacent tumor cells. Evan Snyder, a senior author on the paper, asserts that this type of treatment "might be one of the first applications of neural stem cells for a true disease." He suggests that clinical trials using this approach could be as close as "two years away."