Canadian researchers report a significant breakthrough in the use of viruses to target and destroy cancer cells, a field known as oncolytic virotherapy.

The research team, led by Dr. John Hiscott of McGill University’s Faculty of Medicine and the Lady Davis Institute and Dr. John C. Bell and colleagues at the University of Ottawa and Ottawa Health Research Institute have discovered a family of compounds — histone deacetylase inhibitors — may be the missing link that turns oncolytic viruses into a potent new weapon against cancer.

The researchers tested the combination histone deacetylase inhibitors/virotherapy approach in cell culture experiments in the lab, in animal models of cancer and also in human tissues from breast, prostate and colon cancer immediately after excision from patients.

“Treatment with these compounds dramatically increases the susceptibility of these cancers to killing by the oncolytic virus,” Hiscott said in a statement. “The combination dramatically and unexpectedly stimulates the ability of the viruses to target and kill cancer cells.”

Because human trials with similar viruses and with histone deacetylase inhibitors have already been approved, there is the possibility the results of these studies might be applied rapidly, the researchers said.

The findings are published in the Proceedings of the National Academy of Sciences.