Scientists at the University of Leeds announced the discovery of a virus that can kill liver cancer cells. The virus is part of a family of Reoviruses, known to cause childhood coughs and colds. By uncovering this mechanism, the researchers hope to exploit viral immunotherapy to treat intractable liver cancers.
The family of Reoviruses are so named because they affect the gastrointestinal and respiratory tract. That is, the suffix “Reo-” refers to respiratory enteric orphan viruses. Most of the time, the virus affects children, and adults grow up with an immunity and are unaffected.
In studying the virus, the research team found that natural killer cells – part of the body’s immune system – are activated in response to the pathogen. These activated cells are capable of killing both liver cancer cells as well as cells infected with the hepatitis C virus.
"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 Alan Melcher, professor of Translational Immunotherapy at the Institute of Cancer Research, London, and the study’s co-leader.
"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,” Melcher explained.
Immunotherapy is a hot field for cancer treatment, as it exploits the body’s own immune response to fight the cancer. And in some respect, some researchers think training the body to fight its own enemies could be more effective than any foreign drug that we can make. But the caveat is that the immune system has to be able to recognize what to kill and what to leave alone.
“As cancers are formed from our own cells, the immune system frequently struggles to identify the subtle differences that differentiate cancerous cells from normal cells, without help,” said Adel Samson, the study’s co-author. "Immunotherapy involves various strategies - such as a virus, as in our study - to kick-start our immune system to better identify and fight cancer.”
And new, effective treatments are in high demand for liver cancer. The American Cancer Society estimates that nearly 40,000 new cases of liver cancer will be diagnosed in the US in 2016. Of these, around 69% will die. Of note, most cases of primary liver cancer are associated with hepatitis B or C viral infection, while a smaller percentage is caused by excessive alcohol consumption.
"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,” said Stephen Griffin, Associate Professor of Viral Oncology at the University of Leeds, and the study’s co-leader. "Ultimately we hope that by simultaneously treating the tumour, and the hepatitis virus that is driving the growth of the tumour, we may provide a more effective therapy and improve the outcomes for patients."
Additional sources: MNT