Researchers have created something described as a cancer-fighting “stealth bomber” able to slip through the body’s defenses unseen to fight cancer. For decades, scientists have been testing oncolytic viruses that preferentially kill cancer cells. The FDA approved an oncolytic virus to fight melanoma in 2015.
The challenge for such treatments has always been the body’s immune system, which can quickly capture viruses injected in the blood and send them to the liver for excretion. Researchers at Emory and Case Western University have been able to circumvent the body’s immune system with a new adenovirus. Their adenovirus isn’t easily caught by the immune system making it possible to inject a virus into the blood without a massive inflammatory reaction.
Using a cryo-electron microscopy structure, the virus and its ability to eliminate disseminated tumors in mice has been reported in the new study. The researchers believe that it will be possible to deliver their modified virus systemically at doses high enough to suppress tumor growth without triggering systemic toxicities. In contrast, most oncolytic viruses are delivered directly into the tumor without being able to fight metastases.
The researchers say this is a new avenue for treating metastatic cancers. They can arm the adenovirus with genes and proteins that stimulate immunity to cancer. The shell of the virus, known as a capsid, can be assembled “like you’re putting in Lego blocks,” according to a researcher on the project.
The team of scientists notes that it is still possible for a slower-building adaptive immune response to develop in response to the modified virus, similar to what is observed with a vaccine. A panel of viruses could be used for sequential administration for cancer patients to extend the therapeutic benefits of treatment. The study is the first to show that researchers can modify the binding of natural IgM to an adenovirus.