Many cancer researchers can claim to have devised “smart bombs.” What has been missing is the stealth bomber – a delivery system that can slip through the body’s radar defenses.
Oncolytic viruses, or viruses that preferentially kill cancer cells, have been discussed and tested for decades. An oncolytic virus against melanoma was approved by the FDA in 2015. But against metastatic cancers, they’ve always faced an overwhelming barrier: the human immune system, which quickly captures viruses injected into the blood and sends them to the liver, the body’s garbage disposal.
Researchers at Emory and Case Western Reserve have now circumvented that barrier. They’ve re-engineered human adenovirus, so that the virus is not easily caught by parts of the innate immune system.
A cryo-electron microscopy structure of the virus and its ability to eliminate disseminated tumors in mice were reported on November 25 in Science Translational Medicine.
“The innate immune system is quite efficient at sending viruses to the liver when they are delivered intravenously,” says lead author Dmitry Shayakhmetov, PhD. “For this reason, most oncolytic viruses are delivered directly into the tumor, without affecting metastases. In contrast, we think it will be possible to deliver our modified virus systemically at doses high enough to suppress tumor growth — without triggering life-threatening systemic toxicities.”