Successful use of a plant gene in the treatment of cancer in vivo.

A new strategy for cancer gene therapy has been developed using a plant gene which encodes the enzyme, linamarase, that hydrolyzes the cyanogenic glucoside substrate, linamarin, into glucose, acetone and cyanide. Retroviral vectors that carry linamarase as a potential killer-suicide gene cause a marked sensitization to the innocuous substrate, linamarin, followed by cell death. We show that the system can eradicate very large intracerebral gliomas in vivo helped by a cyanide bystander effect. Animals showing a total regression of the tumor by magnetic resonance imaging (MRI), do not show other appreciable toxic effects.