Yes, you read that right. We now can kill cancer! Glioblastoma to be exact, which is an aggressive type of cancer that can occur in the brain or spinal cord at any given age. This tumor originates from the star-shaped supporting (neuroglial) cells called astrocytes. According to scientists from Preston Robert Tisch Brain Tumor Center at Duke University, brain tumors can now be cured without the usage of radiation or chemotherapy which were the possible ways of reducing (but not curing) cancer back in the 19th and 20th century respectively. This team came up with a better and somewhat ingenious way of using microbes to help assist patients fight cancer. The idea of infecting cancer or tumor cells with microbes, such as viruses, has been around for about a hundred years. However, valid strategies for using (cancer-fighting) viruses emerged only recently. After a wide scaled research, a team of researchers re-engineered the poliovirus – which is responsible for causing Polio – to cure tumors by removing a key genetic sequence in the virus and replacing it with a piece of genetic code from the rhinovirus, a simple common cold-causing virus.
Dr. Matthias Gromeier, who has been working on the polio-virus project for 25 years, and his colleagues are currently injecting their genetically engineered poliovirus, dubbed PVS-RIPO, directly into brain tumors of human patients. Through clinical trials on both primate and human subjects, the research team discovered that the virus is capable of seeking and attaching itself to a receptor found on the surface of almost every solid tumor. Furthermore, they found that this new FDA “Breakthrough” labeled therapy was not only effective in releasing toxins that poison cancer cells, but was also incapable of reproducing in normal cells. This means that the therapy is essentially selective and does not harm normal cells. Due to the success of clinical trials, they hope to further their research by examining the effect PVS-RIPO has on other potentially fatal types of cancer, including breast, prostate, lung, colon, and pancreatic cancers.
So, why use microbes to kill the tumor cells? Well, cancer cells develop a shield or shroud of protective measures that make them invisible to the immune system. Hiding in plain sight, these cancerous cells eat away at the resources that should have been given to the healthy cells, effectively wasting the person away. Since the body’s immune system is essentially blind to these cells it can’t do anything to fight back. Here is where the microbe comes into effect. They somehow remove the protective shield and enable the immune system to kick in. These modified viruses are injected in the tumor cells where they reproduce and kill the cancerous host cells. But they don’t stop there. By killing these cells, the modified viruses cause the activation of the body’s immune system. Having had its blinds removed, the body’s immune system triggers an additional immune response, an anti-tumor immune response. This response essentially tracks down and kills the cancerous cells.
Although this therapy is still in clinical trials, it promises a huge success in the fight against cancer. Thanks to its remarkable achievements thus far, the FDA has given the “Breakthrough” status to this therapy. This means that the team at Duke can now work with the highest levels in the FDA to develop the most efficient clinical trial and pathway to fully evaluate the safety and efficacy of the genetically modified poliovirus for treating recurrent glioblastoma. Will this be the end of the war between man and cancer? We don’t know for sure, but it’s a very huge step towards that.