Washington, Feb 20 : Researchers conducting a study on mice have discovered a specialised virus with the ability to reproduce its tumour-killing genes that selectively targets and eradicates cancers in the brain, leaving healthy brain-tissue virtually untouched.
These finding has the boffins excited as it could lead to a novel treatment for brain cancer in humans.
"Most importantly, this study finds that the virus can penetrate into the brain, where it even reaches cells that have migrated away from the main tumor. Assuming that the virus behaves similarly in humans, in the future, it may provide a novel and highly efficacious way to treat resistant tumors," said Harald Sontheimer, PhD, of the University of Alabama at Birmingham, who was not affiliated with the study.
The study was led by senior author Anthony van den Pol, PhD, and his team at Yale University School of Medicine, who spent 6 years of basic research into the fundamental processes of viruses and the cells they target. The team planned to test the vesicular stomatis virus, which was selected for its ability to attack brain tumors and leave healthy tissue largely uninfected.
They implanted tumor cells from brain cancers commonly found both in people and in mice, into immune-compromised mice, which later received an injection of the virus in the tail.
Van den Pol's team examined the fluorescent proteins embedded in both tumour and virus cells in the brains of living mice, and watched as the virus infected multiple sites in the brain, spreading across an entire tumour in just 3 days, and destroyed tumour cells that came in its way. However, it was found that the virus spared the normal mouse tissue or non-cancerous human brain cells transplanted into the mouse brain. In fact the team had speculated that, unlike those in healthy brain tissue, blood vessels within brain tumors may leak, allowing the virus to cross the usually impenetrable protective barrier around the brain.
This particular virus was equally effective in destroying tissue from cancers starting in the breast or lung and spread to the brain, the two cancers most likely to metastasize to the brain, and targeted tumors at different sites throughout the body.
The scientists will be conducting future research that will focus on understanding potential safety risks, like if the virus could eventually infect normal brain cells, as well exploring potential changes to the virus that could mitigate such risk.
"We have some ideas for making the virus safer in the human brain. This is important to prevent the virus from potentially infecting normal brain cells after it has targeted the brain tumor," said van den Pol.
The research is published in the recent issue of The Journal of Neuroscience.