A promising new treatment approach for advanced prostate cancer are cancer-killing viruses. They specifically infect and kill cancer cells, while leaving healthy cells untouched.
One of these viruses, reovirus, has already been used to shrink tumours in cancer patients. It does this by not only directly killing the cancer cells, but also by kick-starting the body’s immune system to recognise and kill the cancer itself, providing patients with long-term protection from relapse.
Immune-boosting drugs to increase viral power
Although reovirus has been used against some cancers, it has never been used for prostate cancer. In this project, Professor Pandha set out to do just that, by testing the ability of reovirus to kill prostate cancer cells in the lab.
The team also wanted to test the virus in mice with prostate cancer, and try investigating whether boosting their immune systems with drugs called ‘checkpoint inhibitors’ could make the virus more powerful.
Success seen in animal models of prostate cancer
The team found that reovirus can infect and kill prostate cancer cells grown in the lab, and tested multiple doses in mice to find the amount that kills the most cancer cells with the fewest side effects. As they’d hoped, boosting the immune system with checkpoint inhibitor drugs increased the killing of prostate cancer cells by the virus.
Excitingly, when they tried to implant mice that had already been infected with the virus with more prostate cancer cells, they found the mice were protected, suggesting the treatment could be used to prevent men’s prostate cancer from relapsing.
We were able to demonstrate that Reovirus is able to infect and kill prostate cancer cells. This, combined with the immunotherapy approach, offers a novel treatment that has the potential to give men long-term immune control of prostate cancer.
Potential for long-term protection from prostate cancer
Although this is early research, it provides promising evidence for using a combination of the reovirus and checkpoint inhibitors to treat men with prostate cancer. Importantly, the combination therapy could also offer men a long-term treatment plan that would help prevent relapse of the disease.