Today, cancer is being fought in many ways, including using viruses. For example, reoviruses, RNA viruses that can cause mild gastrointestinal illness, are known to kill cancer cells. Alan Melcher from the University of Leeds and his colleagues have found that the secreted products of reovirus infections can kill cancer cells even in the absence of the virus itself.
When reoviruses infect a cell, they induce that cell to secrete chemicals that both cause its own death and initiate the body’s immune response against that cell. Normal cells can protect themselves from this onslaught by secreting their own protective protein called PKR. However, many types of cancer cells inactivate PKR, leaving them vulnerable to reovirus attack.
In this study, the researchers took the growth media from dying reovirus-infected human melanoma cells and administered that extract to new tumor cells. Even in the absence of live virus, immune cells were recruited to attack the cancer cells.Although this line of attack is only in the preliminary stages, I wonder if eventually doctors will be able to brew up great vats of cancer-fighting reovirus media.