A virus that causes childhood coughs and colds could help in the fight against primary liver cancer, according to a study. Reovirus stimulates the body's own immune system to kill off the cancerous cells, the researchers at the University of Leeds found. In addition, reovirus is able to kill off the hepatitis C virus — a common cause of primary liver cancer — at the same time, the team discovered.
These early-stage findings are important because primary liver cancer is the third highest cause of cancer deaths worldwide and, if surgery is not an option, the prognosis is poor.
"Ultimately we hope that by simultaneously treating the tumor, and the hepatitis virus that is driving the growth of the tumor, we may provide a more effective therapy and improve the outcomes for patients," study co-leader Dr Stephen Griffin, associate professor of viral oncology at the University of Leeds, said. "Current treatments for liver cancer that can't be removed by surgery are mainly palliative — with chemotherapy only tending to prolong life, rather than cure — and it can have significant side effects."
Reovirus can cause respiratory illnesses and stomach upsets in children but by adulthood most people have been exposed to it and, therefore, it does not cause illness.
The University of Leeds team, whose study is published this week in the journal Gut, found that reovirus was successful in treating both liver cancer cells grown in the laboratory and those taken directly from patients undergoing surgery.
When introduced into the body, reovirus stimulates an immune system factor known as interferon, which in turn causes the activation of a specific white blood cell called a Natural Killer cell. These Natural Killer cells then kill both the tumor, and cells infected with the hepatitis C virus.
Stimulating the immune system to kill cancer cells is known as immunotherapy. It differs from chemotherapy, in which the actual drugs kill the cancer cells.
The researchers are now hoping to start the first in-human clinical trials.
"Our study establishes a completely new type of viral immunotherapy for the most common primary liver cancer type, hepatocellular carcinoma, which has a very poor prognosis in its advanced form," said study co-leader Professor Alan Melcher. "Using a mixture of experiments in human cancer samples and mice, our research showed that the reovirus therapy switches on the host immune system to attack cancer cells — as well as suppressing the replication of hepatitis C virus, which is linked to many hepatocellular cancers. We also showed that reovirus therapy could be used to treat a range of other cancer types associated with viral infection, including Epstein Barr Virus-associated lymphoma."