Zika Virus Vaccine Kills Brain Cancer Cells, Slows Tumor Growth in New Study
Michelle Milliken
The Zika virus, which is primarily spread through mosquito bites, had people on edge with an outbreak in 2015 and 2016. Though it can make people quite ill, it may also be helping develop a new treatment for brain cancer.
Research recently published in the Journal of Translational Medicine investigated how a Zika vaccine could help battle glioblastoma multiforme (GBM), the most common form of primary brain cancer in adults. Though it is common, with more than 300,000 new cases diagnosed worldwide each year, its prognosis can be grim. The median survival time is just over a year. This is largely due to high recurrence rates, but it also boils down to insufficient treatment options. However, scientists have been investigating how engineered viruses may be able to fight cancers such as these, and that’s where the Zika virus comes in.
Researchers at Duke-NUS Medical School in Singapore used live-attenuated vaccine strains of Zika virus against human GBM cells in a lab. These strains are weakened and can’t infect people, but they can grow rapidly in a tumor, which is what they were found to do, as they targeted rapidly proliferating cells, like cancer, rather than mature cells.
Ann-Marie Chacko, the paper’s senior author and assistant professor at Duke-NUS’ Cancer & Stem Cell Biology Programme, explains, “Since the Zika virus outbreak in 2016, understandably, there has been fear about the nature of the virus and its devastating effects. Through our work, we hope to present the Zika virus in a new light by highlighting its potential to kill cancer cells. When a live virus is attenuated, such that it is safe and effective to fight infectious diseases, it can be beneficial to human health—not just as a vaccine but also as a potent tumor-eradicating agent.”
The vaccine strains were found to have strong tumor-eradicating abilities, as infection from these weakened strains killed 65-90% of tumor cells, while sparing healthy cells within blood vessels in the brain. When they managed to infect the healthy cells, they also had a hard time reproducing.
The researchers say this happened because the strains targeted rapidly proliferating cells, not mature cells, binding to proteins that are found in high levels in cancer cells but not in healthy cells. They then used the cell’s resources to reproduce, which could ultimately kill the cell. Once the cancer cell died and burst, it released components including virus progeny, which could then repeat the cycle. The team also found that this process may help induce an immune response that can fight back against tumor growth.
Dr. Carla Bianca Luena Victorio, the paper’s first author and Senior Research Fellow at the Cancer & Stem Cell Biology Programme at Duke-NUS, says, “We selected Zika virus because it naturally infects rapidly multiplying cells in the brain, allowing us to reach cancer cells that are traditionally difficult to target. Our ZIKV-LAV strains also replicate themselves in brain cancer cells, making this a living therapy that can spread and attack neighboring diseased cells.”
Going forward, the team hopes to investigate how this treatment could work for other cancers, including ovarian cancer, as well as how to make it safer for use in people.
