We all know of Zika as a horrible virus that causes deformities in unborn babies. But what if it could be used to do good? Well, researchers have now managed to use the disease to kill aggressive brain tumor cells, potentially paving the way for new effective treatments and maybe even a cure.
The research has so far only been done on human cells transplanted into mice, so we’re a long way from it being used to treat people clinically. Nevertheless, it’s exciting and opens doors to tackling a kind of cancer that’s infamously hard to beat.
The Zika virus is a mosquito-borne disease that made headlines in 2015 and 2016 due to a widespread epidemic in the Americas. It targets cells in the brain known as neural progenitor cells. Adults don’t have many of these cells, so the virus isn’t too dangerous, and symptoms include fever, headache, and a rash. It’s when it comes to unborn babies, who have many neural progenitor cells, that Zika is particularly nasty. If affected, babies can be born with an affliction called microencephaly, which causes an unusually small head and can lead to complications like seizures.
But now, scientists are employing this awful disease to tackle another. Publishing their findings in MBio, they report that they’ve successfully managed to use it to kill human glioblastoma cells transplanted into mice. Despite being very rare, glioblastoma is the most common form of malignant brain tumor. It is an incredibly aggressive type of cancer and is particularly tricky to treat. It often resurges and is usually lethal within two years.
Glioblastoma’s ability to return once removed is thought to be connected to glioblastoma stem cells (GSCs), which hide out in the brain.
"During the Zika epidemic, we learned that the virus preferentially infects neural progenitor cells in the fetus,” said study co-leader Pei-Yong Shi. “We made the connection that perhaps Zika virus could also specifically infect the GSCs.”
In previous research, the team showed that Zika could kill GSCs in both a dish and living mice. What’s more, it targeted these cells, and wasn't very efficient at attacking healthy brain cells. But that research used a typical strain of Zika.
Now, the researchers have gone a step further, creating a weakened version called ZIKV-LAV. When injected into mice bred to have no immune systems, it didn’t cause any negative side effects.
The team then combined their new vaccine with human glioblastoma cells and injected the mixture into mouse brains. As a control, they also injected some mice with only the GSCs. The mice that received ZIKV-LAV developed tumors much slower than the control group, and survived significantly longer (50 days as opposed to 30).
The team discovered that treated GSCs produced a strong anti-viral response, causing inflammation and ultimately the death of the tumor cells.
The treatment still needs tweaking, and has yet to be tested for both safety and efficacy in humans, but the results are promising. The researchers now plan on making their cancer-killing vaccine even more potent, and hope to work with clinicians to develop ways to test its safety in humans.