How Zika Virus Could Help Fight Brain Cancer

The Zika virus can be a serious health threat, especially to unborn children, but now researchers say the virus itself could help treat another devastating illness — brain cancer.

A new study suggests that the same properties that make Zika a dangerous virus for unborn children could be useful in treating brain cancer in adults. The study was done in lab dishes and animals, and much more research is needed before it could be tested in humans.

It’s thought that the Zika virus naturally targets and kills brain stem cells, which are abundant in fetal brains during development. As a consequence, women infected with Zika virus during pregnancy are at increased risk of giving birth to children with neurological problems. But adults have fewer active stem cells in their brains, and as a result, the effect of Zika on adult brains is usually much less severe, the researchers said.

What’s more, the growth of certain brain cancers — including often-lethal glioblastomas — may be driven by cancer stem cells that divide and give rise to other tumor cells. These glioblastoma stem cells are typically resistant to therapies such as chemotherapy and radiation, and may fuel the return of the cancer after treatment. The researchers hypothesized that the Zika virus could target these cancer stem cells. [5 Facts About Brain Cancer]

“We wondered whether nature could provide a weapon to target the cells most likely responsible” for the return of glioblastoma after treatment, study co-author Milan Chheda of Washington University School of Medicine in St. Louis, said in a statement.

The researchers found that the Zika virus preferentially targeted and killed human glioblastoma stem cells in a lab dish, without having much of an effect on normal adult brain cells.

Next, the researchers tested the Zika therapy on mice with glioblastomas. To do this, they injected a mouse-adapted strain of Zika virus into the glioblastoma tumors. (The strain of Zika virus that infects humans does not infect mice.)

They found that mice treated with Zika showed slower tumor growth and lived longer than those that didn’t get the Zika treatment. All of the untreated mice died after about a month, but close to half of the treated mice were still alive after two months, the researchers said.

Still, much more research is needed to show that the therapy is safe and effective in humans. The researchers plan to genetically modify the Zika virus so that it is weaker and would not be expected to cause disease. A preliminary test of such an “attenuated” Zika strain showed that this virus was still capable of targeting and killing glioblastoma stem cells in a lab dish. [27 Devastating Infectious Diseases]

“Our study is a first step towards the development of safe and effective strains of Zika virus that could become important tools in neuro-oncology and the treatment of glioblastoma,” said study co-author Michael Diamond, also of Washington University.

But concerns over the safety of a Zika-based therapy will need to be addressed with further studies in animals before the therapy is tested in humans, Diamond said. Ultimately, the Zika therapy might be used along with other traditional brain cancer therapies to treat glioblastomas, the researchers said.

The new study is published today (Sept. 5) in The Journal of Experimental Medicine.

Zika is not the only virus being considered as a potential treatment for glioblastomas. Other research groups are testing measles, polio and herpes viruses as possible ways to target glioblastomas.