Using Viruses to Engage and Destroy Cancer?
Can you use programmed viruses to target cancer cells and destroy them?
Kat - Well, this is certainly a really exciting area of therapy. It's called "oncolytic viruses", kind of meaning, cancer bursting viruses. There's a lot of different trials underway. There's lots of different types of viruses. Adenoviruses are one of the types of viruses that people are using because they infect a lot of cells. The idea is that because cancer cells, as Gerard said, are kind of genetically compromised, they've got things wrong with them, they're not working the right way. So, you send in a virus that basically takes advantage of that, that can only replicate in cancer cells, and then it replicates and it bursts the cancer cells and they produce more viruses as they burst and they infect more tumour cells. But the idea is, they wouldn't infect healthy cells so you'd only be killing the cancer. That sounds like an absolutely fantastic idea and in the lab, these work really well. The trouble is, when you try and put them into trials in patients and sort of scale up the system, they stop working so well and one of the big problems is that the immune system kicks in, recognises the virus and mops it all up. So, there's some interesting work going on about how you could maybe suppress the immune system so you could get the viral infection in and then kind of let the immune system go again. That's being investigated in terms of gene therapy, which works in a similar way - you're trying to infect specific cells to deliver a payload. So, it's a really exciting area of research, but not quite paying off yet.
Chris - I went to a conference recently where, actually, they were saying that that immune response can be quite valuable because if you get the virus going into the tumour, it then drives the immune system nuts because the immune system sees this cancer growing loads and loads of virus. So, it reacts to the virus, but in the process, also reacts to the cancer and then the same immune response goes elsewhere in the body and starts attacking any spread of the cancer elsewhere in the body. So, they think this may actually be quite constructive.