A disease caused by Zika virus can lead to microcephaly, which causes abnormally small heads and undeveloped brains in unborn babies.
In early 2015, a widespread epidemic of Zika fever, caused by the Zika virus in Brazil, spread to other parts of South and North America as well as affected several islands in the Pacific and Southeast Asia, forcing World Health Organization to declare Zika a global emergency.
But researchers from the Washington University School of Medicine in St. Louis and the University of California San Diego School of Medicine have shown Zika could be used as a weapon against glioblastoma, the most aggressive type of brain cancer. Their study, published in The Journal of Experimental Medicine, shows the virus can selectively infect and kill hard-to-treat cancerous cells in adult brains.
“It looks like there’s a silver lining to Zika. This virus that targets cells that are very important for brain growth in babies, we could use that now to target growing tumors,” Dr Michael Diamond, the study’s co-senior author, told BBC News.
“The virus kills the stem cells of glioblastoma tumors, which radiotherapy, chemotherapy, and surgery often fail to target. After treatment, these cells can keep on growing and dividing, forming new cancers and allowing tumors to regrow. This is where Zika comes in. Because Zika targets stem cells, it can be used to specifically attack these cancer-causing stem cells in the brain.”
The researchers infected human brain tumor tissue with Zika in the laboratory and found that it successfully killed tumor stem cells. Live mice with tumors were also injected with either Zika or a placebo. Those with Zika developed smaller tumors and lived considerably longer than their placebo counterparts.
When the same experiment was done using healthy brain tissue, Zika did not infect normal brain cells. The researchers say the virus targets tumor stem cells over both non-stem cancer cells and healthy cells.
In combination with chemotherapy, the researchers believe, Zika could be used to create a unique treatment for glioblastoma sufferers. Chemotherapy radiation is good at targeting already formed tumor cells but not so good at killing stem cells, but Zika’s affinity for stem cells solves this problem.
Since Zika is dangerous to humans, the researchers are modifying the virus to make it safe for humans. They have weakened the ability of the Zika virus to tackle the human body’s immune defenses, which means the virus would not grow in healthy cells. Cancer cells already have weak defenses so Zika could attack them.