In early 2015, Zika outbreaks caused widespread panic in many parts of North and South America. However, now researchers are exploring the possibility of putting the virus to good use: fighting glioblastoma multiforme (GBM), the most deadly type of brain cancer.
Zika, which is mainly carried and transmitted through mosquitoes, causes major birth defects in babies whose mothers were infected. This is because the disease induces cell death and differentiation of neural precursor cells in fetuses. These are cells, such as stem cells, that have not yet been determined to become a certain body part. Glioblastoma stem cells (GSCs) are similar, and for that reason, researchers found that the Zika virus (ZIKV) targeted GSCs.
“Our results suggest that ZIKV is an oncolytic virus that can preferentially target GSCs. Thus, genetically modified strains that further optimize safety could have therapeutic efficacy for adult patients with gliobastoma,” the authors wrote in the study, which was published in the Journal of Experimental Medicine.
In mouse models, Zika-infected mice with GBM lived longer and had higher survival rates than mice without the virus. Further, it was shown that the glioblastoma cells were specifically targeted by ZIKV. These results were far more promising than those from nearly two decades ago, when the West Nile virus was tested to treat GBM. Not only did the West Nile virus have awful toxicities, but it also did not differentiate between killing tumor and non-tumor cells.
The researchers also took out-of-body glioma cells and injected some with the Brazil-strain of Zika and others with the Dakar-strain . After a day, both strains spread throughout the cells, and the disease typically would. Differentiated glioma cells (DGCs) – which do not act like stem cells – seemed to be safe, unlike GSCs.
“Whereas GSC proliferation was abolished by either ZIKV strain, DGCs were nearly unaffected,” the authors wrote.
Despite the promising outcomes, the researchers mentioned that they still have a long way to go before Zika is used to treat patients with GBM. Safety and side effects are still a concern.
“Our findings suggest that because of its tropism for neuroprogenitor cells, ZIKV may offer a tailored therapy that could be used in combination with conventional therapies that target bulk tumor cell populations,” the authors wrote, noting that perhaps one day it could be administered via injection through the tumor beds of the patients.
Zika is not the only virus being studied for the treatment of GBM. Others include measles, polio
“Our work serves as a foundation for further mechanistic studies and the genetic engineering of a safe and effective ZIKV, which could become an important tool in neuro-oncology,” the authors wrote.