It’s all too easy to think of viruses as our sworn enemy, but they can also be awesome companions if we harness their power in the right way.
A new study by the University of Leeds in the UK has shown how a virus could be used to treat people with an incurable brain tumor. The virus is injected into the bloodstream, where it then crosses the blood-brain barrier and heads into the brain, replicates, and kills the cancer cells. Not only that, the virus also prompts the body's own immune system to ambush the tumor too.
“Our immune systems aren’t very good at ‘seeing’ cancers – partly because cancer cells look like our body’s own cells, and partly because cancers are good at telling immune cells to turn a blind eye. But the immune system is very good at seeing viruses," co-lead author Alan Melcher, Professor of Translational Immunotherapy at The Institute of Cancer Research, London, said in a statement.
"In our study, we were able to show that reovirus could infect cancer cells in the brain. And, importantly, brain tumors infected with reovirus became much more visible to the immune system,” he added.
As explained in the journal Science Translational Medicine, scientists used mammalian orthoreovirus type 3, a species of virus from the reovirus family. After infecting the body, the virus only attacked the cancer cells, leaving healthy human cells alone, so most of the patients only felt like they had come down with the common cold.
The study was only small, using just 9 patients, however, it holds some huge potential for people battling brain tumors, especially in combination with current cancer treatments. These 9 patients were all having their tumors removed surgically within a few days, but beforehand the surgeons infected them with the virus. After the tumor was removed, they found evidence that the virus had reached the cancer and begun to attack it. The tumor also indicated that the virus had been attacked by the immune system's “killer T-cell” white blood cells.
"This small-scale clinical trial allowed us to ask a crucial biological question about cancer immunotherapy and gain insights which can now be tested further, both in the laboratory and in the clinic,” added Professor Melcher.
"Now we know we can get reovirus across the blood-brain barrier, we have begun clinical studies to see just how effective this viral immunotherapy can be at extending and improving the lives of patients with brain tumours, who currently have very limited treatment options available to them."