Using viruses to kill cancer cells

Because of their great ability to enter and kill cells, viruses are an attractive potential cancer treatment.  

Importantly, any viruses used have to be able to enter and grow in cancer cells but not harm normal cells.

There are several candidate viruses currently under investigation.

Reoviruses do not normally cause problems for humans.

Interestingly, they are naturally better at infecting cancer cells due to the increased signaling from the Ras oncogene in these cells.

This difference means that reoviruses can infect and kill cancer cells and leave normal cells alone.

In this research, reovirus was used to treat prostate cancer in a mouse model system.

The researchers saw that the reovirus was able to infect and eliminate prostate cancer in this system.

The work is especially important for two reasons :
 

1. They were able to show that the death of the cancer cells caused the immune system of the animals to become extremely active against the cancer cells.

2. Immune cells from animals treated with the virus were able to protect other animals from a 'challenge' with prostate cancer cells.

They had 'learned' how to kill the cancer cells and were able to prevent the growth of cells even if no virus was around.

The activation of the immune system is a very welcome outcome of the treatment and could helpt o eliminate cancer cells at distant locations, where the virus might not be able to reach.

Clinical trials of a reovirus (Reolysin®) are underway for several cancer types.

The virus is a product of Oncolytics Biotech Inc.

Bottom line : Viruses that can selectively kill cancer cells have been identified.

One of these, reoviruses, were shown to be able to kill prostate cancer cells in a mouse model.

The infection and cancer cell death also induces a potent immune response that is able to protect animals from challenges with cancer cells.