How to stop brain cancer—with rabies.

A ruthless killer may soon help brain cancer patients. The rabies virus, which kills tens of thousands of people a year, has a rare ability to enter nerve cells and use them as a conduit to infect brain tissue. Now, scientists are trying to mimic this strategy to ferry tumor-killing nanoparticles into brain tumors. So far the approach has been shown to work only in mice. 

If successful in people, these nanoparticles could one day help doctors send treatment directly to tumors without harming healthy cells. The rabies virus, transmitted largely through the bites of infected animals, has evolved over thousands of years to hijack nerve cells, which it uses to climb from infected muscle tissue into the brain. 

That allows it to bypass a major hurdle: the blood-brain barrier, a selective membrane that keeps out most pathogens that travel through the bloodstream. But the barrier also prevents treatments—like cancer drugs—from reaching infected cells, limiting options for patients. To get around this problem, scientists are looking to the virus for inspiration. Already, researchers have packaged cancer-fighting drugs into nanoparticles coated with part of a rabies surface protein that lets the virus slip into the central nervous system. continue