Sindbis is different from these other cancer-killing viruses in that most of the others have to undergo some kind of genetic manipulation to target cancer cells, and they also have to be injected directly into tumors. The NYU School of Medicine team found that Sindbis requires no such manipulation to be effective, and it can apparently be injected anywhere into mice but still find its way through the bloodstream unscathed to the target area.
"Nature gave us a gift in Sindbis," says Dr Meruelo. "It has a natural ability to infect tumor cells almost exclusively, and naturally induces cell death in these tumor cells."
This relatively mild-mannered virus first came under scientific scrutiny as a potential vehicle for gene therapy, where modified viruses are used to ferry genetic treatments into cells. But the unmodified virus, without added genes, surprised Dr. Meruelo and his colleagues. They found that it was quite successful at killing tumor cells all on its own. "We realized the natural, unmodified Sindbis was working beautifully so we decided to examine that more carefully," says Dr. Meruelo.
Since Sindbis is a virus, the researchers were concerned that the immune system might attack it, thwarting any therapeutic effect. However, tests on genetically modified mice, which grow tumors but have fully working immune systems, were also successful.
To build upon Sindbis's natural cancer-killing skills, Dr. Meruelo and his colleagues also engineered the virus to carry a gene that makes a protein called IL-12. This protein has proven to be a good cancer killer but is also toxic to normal tissues. By putting the IL-12 gene into Sindbis, the gene w
Contact: Pam McDonnell
New York University Medical Center and School of Medicine