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 – cancer drugs – from reaching infected cells, limiting options for patients.

Nanoparticle expert Yu Seok Youn and his team have engineered gold particles so that they have the same rodlike shape and size as the virus. The nanoparticle’s shape gives it more surface area than spherical particles, improving the surface protein’s ability to bind with receptors on nerve cells that serve as a gateway to the nervous system. The particles don’t carry any drugs, but the tiny gold rods readily absorb laser light, which heats them up and kills surrounding tissue.