A Drug That Manipulates Retroviruses To Fight CancerS

A potential therapy for cancer already lurks in our own genes. Chunks of ancient viruses lie embedded in the human genome. Administer just one protein to cancer cells and these built-in viruses go hyperactive, eventually killing the cell.

The human genome is dotted with "endogenous retroviruses," the remains of viruses that infected humans tens of thousands of years ago, and eventually integrated themselves into our DNA. But these viruses can become active again, and a graduate student named Danny Leung at the University of British Columbia discovered how to turn them into cancer-fighting machines. He and a team of researchers published their work yesterday in Nature.

A release about their study explains how the cancer attack works:

A protein called ESET is crucial to preventing the activity of endogenous retroviruses in mouse embryonic stem cells. Distant relatives of such retroviruses are more active in the cells of testicular, breast and skin cancers in humans.

If ESET can be blocked, retroviruses would become dramatically more active, thus either killing the cancer cells hosting them or flagging them as targets for the immune system.

But wouldn't blocking ESET cause retroviruses to flare up all over the body, thus killing every cell instead of just cancer cells? Apparently not. A special characteristic of cancer cells is that they are very similar to stem cells, and ESET does its job best in undifferentiated stem cells rather than normal, differentiated cells. So the ESET treatment could switch on viruses in your cancer cells, but leave your healthy cells alone.

via Nature

Image of cancer cell death by Annie Cavanagh, Wellcome Images