Zika virus could treat deadly brain cancer

While Zika virus is notorious for causing devastating damage to the brains of unborn babies, it can also kill deadly brain cancer cells that are most resistant to standard treatments, scientists have found.
The findings may pave the way for an effective treatment for glioblastoma, a deadly form of brain cancer that is most often fatal within a year of diagnosis.
The research suggests that the lethal power of the virus - known for infecting and killing cells in the brains of foetuses, causing babies to be born with tiny, deformed heads - could be directed at malignant cells in the brain.

Doing so potentially could improve people's chances against glioblastoma.
"We showed that Zika virus can kill the kind of glioblastoma cells that tend to be resistant to current treatments and lead to death," said Michael S Diamond, professor at Washington University in the US.
The standard treatment against glioblastoma is aggressive - surgery, followed by chemotherapy and radiation - yet most tumours recur within six months.

A small population of cells, known as glioblastoma stem cells, often survives the onslaught and continues to divide, producing new tumour cells to replace the ones killed by the cancer drugs.
In their neurological origins and near-limitless ability to create new cells, glioblastoma stem cells appear similar to neuroprogenitor cells, which generate cells for the growing brain. Zika virus specifically targets and kills neuroprogenitor cells.

The findings suggest that Zika infection and chemotherapy-radiation treatment have complementary effects.
The standard treatment kills the bulk of the tumour cells but often leaves the stem cells intact to regenerate the tumour. Zika virus attacks the stem cells but bypasses the greater part of the tumour.
"We see Zika one day being used in combination with current therapies to eradicate the whole tumour," said Milan G Chheda of Washington University.
To find out whether the virus could help treat cancer in a living animal, the researchers injected either Zika virus or saltwater (a placebo) directly into the brain tumours of 18 and 15 mice, respectively.

Tumours were significantly smaller in the Zika-treated mice two weeks after injection, and those mice survived significantly longer than the ones given saltwater.
If Zika were used in people, it would have to be injected into the brain, most likely during surgery to remove the primary tumour.
If introduced through another part of the body, the person's immune system would sweep it away before it could reach the brain, researchers said.
The idea of injecting a virus notorious for causing brain damage into people's brains seems alarming, but Zika may be safer for use in adults because its primary targets - neuroprogenitor cells - are rare in the adult brain, researchers said.

The foetal brain, on the other hand, is loaded with such cells, which is part of the reason why Zika infection before birth produces widespread and severe brain damage, while natural infection in adulthood causes mild symptoms.
The researchers conducted additional studies of the virus using brain tissue from epilepsy patients and showed that the virus does not infect noncancerous brain cells.