An international team of researchers has successfully "deployed" Zika virus vaccine so that it was possible to target and destroy the stem cells of brain cancer (glioblastoma) man transplanted into mice. In a study published this week in the «mBio®» journal, the researchers demonstrated that the live, weakened version of the virus Zika could be the basis for a new treatment of the deadly brain cancer.
Glioblastoma annually kills about 15,000 adults in the United States, at the moment it is an incurable disease. For patients there is a high recurrence rate even after standard therapies, radiotherapy and chemotherapy. Scientists suggest that the recurrence of the disease caused by glioblastoma cancer stem cells, which are "hidden" in the adjacent tissues of the brain.
"During an outbreak, Zeke, we learned that the virus preferentially infects the progenitor cells of fetal neurons and causes destructive microcephaly in infants born to infected mothers" - the researchers noted.
"We found that Zika virus can infect the stem cells of glioblastoma since these cells have similar properties of neural stem cells."
In previous work, scientists have demonstrated that Zika virus attacks and destroys the stem cells of glioblastoma, grown in the laboratory, as well as cells in mouse models of glioblastoma. In addition, the Zika virus was less effective when attacking healthy brain cells differentiated.
"If we could find a way to target the virus only in the cancer stem cells that cause relapse, we would be able to prevent the return of disease" - the researchers reported.
The original purpose of the team was to determine the safest way to use Zika virus in patients to attack stem tumor cells. Scientists have developed a potential candidate for a live vaccine, called Zika ZIKV-LAV, which turned out to be safe, non-virulent and effective in protecting against infection in mice and primates. In ZIKV-LAV has been little change in the viral genome, which prevented its efficient replication.
Once the team has introduced ZIKV-LAV in the brains of mice, revealed no health hazards of rodents, as well as weight loss, depression, and behavioral abnormalities: loss of appetite, lethargy, or self-harm. In addition, mice normally have passed tests for anxiety and motor function.
After team demonstrated that ZIKA-LAV can infect human stem cells to kill glioblastoma in mice models. For this purpose they are mixed glioblastoma stem cells obtained from two donors patients with ZIKA-LAV and the mixture was introduced into the brains of mice. In rodents that received only the injection of cancer stem cells, rapidly developed tumors, while mice injected with ZIKV-LAV, there was a delay of tumor development. The joint implant virus and stem cells of glioblastoma also extended the average survival time of the mice up to 50 days, when compared over time, rodent survival (30 days), have received only injections of stem tumor cells.
Scientists suggest that in the future patients will receive a vaccine Zeke simultaneously with surgery, and it will allow the virus to hunt down and destroy glioblastoma stem cells.
Scientists continue their research on the subject. They plan to work with clinicians to ensure the safety of ZIKV-LAV in the treatment of patients with glioblastoma. They may have modified the virus to make it even more powerful for the destruction of cancer cells. For example, researchers will add an immune modulator in the viral genome. When such a virus infects cancer cells and destroy it, releasing an immune modulator that activates the patient's immune system and direct it against the remaining cancer cells.