Zika virus used as weapon against cancer
Study findings seen as major progress in search for treatment
The Zika virus is showing promise fighting brain cancer, according to Galveston-led research in mice that attempts to harness therapeutic benefits from what’s been called “the infection from hell.”
The Zika virus is showing promise fighting the most lethal type of brain cancer, according to Galveston-led research in mice that attempts to harness therapeutic benefits from what’s been called “the infection from hell.”
A University of Texas Medical Branch at Galveston-led team of scientists reported this week successfully using a harmless version of Zika to target and kill glioblastoma, the common and aggressive cancer that last month killed U.S. Sen. John McCain. The version is a Zika vaccine developed at UTMB.
“More work needs to be done, but these findings represent major progress toward developing the Zika vaccine as a safe and effective treatment for human glioblastoma,” said Pei-Yong Shi, a UTMB professor of biochemistry and molecular biology and the study’s lead investigator. “This could be a great example of science’s ability to turn something bad into something useful.”
The results of the mouse study conducted by Shi and colleagues in Beijing were published Tuesday in the American Society for Microbiology’s journal mBIO.
Experts caution that therapeutic benefits in mice are considered a long way from human treatment. Research that shows great promise in the laboratory fails more often than it succeeds in people.
The research combines two dreaded diseases: glioblastoma, which kills more than 15,000 Americans annually and is considered incurable because it recurs
after the standard treatment of surgery, radiation and chemotherapy; and the mosquito-borne Zika virus, which became a major public health threat in recent years after it was shown to cause severe birth defects. Babies born to women infected during pregnancy often suffer from a condition known as microcephaly which is characterized by an abnormally small head and underdeveloped brain.
Shi’s team exploited Zika’s ability to infect developing brain cells to attack glioblastoma stem cells, considered a likely source of the cancer’s recurrence. Like fetal cells, glial stem cells are self-renewing and multiply quickly, properties that Zika targets.
UTMB researchers developed the Zika vaccine in 2017 as a preventative against the disease, still a major threat in much of Latin America. The team is negotiating with the government of Brazil to conduct vaccine trials with people at highest risk of contracting Zika. The vaccine has previously been shown to be effective in animal research.
Shi’s team found the vaccine, a weakened version of the virus, also works well against mice engineered to have a human version of glioblastoma. The study found glioblastomas developed significantly slower in mice whose brains received an injection of glioblastoma stem cells and the Zika vaccine than those that just received the stem cells.
Martyn Sharpe, head of research at Houston Methodist’s Brain & Pituitary Tumor Treatment Center, said Zika holds great potential because it targets stem cells, but added that the key question will be complications.
“The success of this research will depend on how good the vacc-cine is in humans at targeting the stem cells versus healthy tissue,” said Sharpe. “Research often works beautifully in animals, only to fail in humans. You just don’t know how the drug will interact with human tissue.”
Mice given the vaccine lived 50 days, compared to 30 days for those that received no therapy, reported the research team. They also reported the vaccine was much less efficient at attacking healthy brain cells than the glial stem cells.
Though the study only showed a benefit from Zika’s destruction of glioblastoma stem cells, the team of scientists hope it ultimately will enlist the immune system to attack the brain cancer. The idea, a new frontier of cancer therapy, is that Zika’s killing action will release tumor proteins that trigger an immune reaction, a strategy that doctors at MD Anderson Cancer Center, Houston Methodist Hospital and other institutions across the country are using with other viruses against brain cancer.
Shi said much more work need to be done to make Zika a safe and more potent weapon against glioblastoma. But he added that he hopes to soon work with UTMB clinicians to set up a clinical trial testing the vaccine in human patients.