A recent study, published September 5, 2017 by Jeremy Rich and colleagues at University of California announced a new potential treatment for brain cancer: Zika virus. Zika virus made headlines for its outbreak in 2015 but may prove useful in novel medical treatments. Zika virus is of the Flaviviridae family, the same as West Nile Virus and Yellow Fever. It is spread by mosquitoes, and although it is not deadly to most people in good health, it poses a problem for pregnant women, as it has been shown to cause birth defects. Cause for concern about birth defects is based on studies that show that Zika virus causes inhibited growth of cerebral organoids in embryonic stem cells. This means that expectant mothers who contract Zika virus are at risk for having babies with microcephaly, a condition in which babies are born with small heads and underdeveloped brains, often resulting in intellectual disability (2).
Interestingly, the very same properties of the Zika virus that harm fetal brain development can also slow the growth of brain tumors, such as those produced by Glioblastoma – an aggressive cancer in the brain or spinal cord. The tumors associated with Glioblastoma generally form from astrocytes, cells that support nerves (1). A mutation in the DNA of these astrocytes causes uncontrollable growth of the cells, leading to a brain or spinal cord tumor. Current Glioblastoma treatment can alleviate symptoms and slow progression, but the survival rate is low.
The study by Rich and his colleagues tested whether the tumor-suppressing qualities of Zika virus could be used to treat Glioblastoma. The researchers created tumors for testing from patient-derived germline stem cells (GSC). These tumors acted like human tumor cells in that they were able to grow, self-renew, and proliferate. Also, the GSC tumors they generated represented the three major Glioblastoma types: proneural, classical, and mesenchymal. The scientists used two strains of Zika, American and African, to infect the GSC tumors. Two days after virus administration, 60% of the GSCs were successfully infected with Zika. After 7 days of infection, the researchers found that the tumors that had been infected with Zika virus were destroyed, or their size was significantly reduced. Furthermore, the virus prevented tumor regrowth and slowed proliferation in the GSCs (3). The scientists also tested nonmalignant neural tissues, and found that the virus did not infect these cells, meaning the virus is specific to malignant tumor cells. The mechanism behind this specificity is unknown. However, RNA sequencing suggests that the GSCs lack a virus-blocking antibody that is found in normal cells (3). The scientists who conducted this experiment concluded that genetically modified Zika virus could be used to treat Glioblastoma in combination with other therapies such as chemotherapy (3). The purpose of the genetic modification would be to make the virus safer to use as cancer treatment. Such modification ensures the virus is completely specific to the tumors and will not infect other parts of the body as a result of treatment. This discovery holds exceptional promise in the treatment of these cancers and further research is anxiously awaited in the medical community.
- “Glioblastoma (GBM).” Glioblastoma (GBM) | American Brain Tumor Association. Web.
- Olagnier, David, Michela Muscolini, Carolyn B. Coyne, Michael S. Diamond, and John Hiscott. “Mechanisms of Zika Virus Infection and Neuropathogenesis.” DNA and Cell Biology. Mary Ann Liebert, Inc., 01 Aug. 2016. Web.
- Zhu, Zhe et al. “Zika Virus Has Oncolytic Activity against Glioblastoma Stem Cells.” Journal of Experimental Medicine. Rockefeller University Press, 05 Sept. 2017. Web.