An enzyme leads the dance of immortality and death

Regular readers of SmartPlanet may recall Christina Hernandez' July piece on Weihang Chai of Washington State University, who found a way to kill cancer cells by deactivating the enzyme telomerase, and thus causing them to age and die like normal cells.

Telomerase acts on the ends of DNA strands, which are called telomeres. The 2009 Nobel Prize in Medicine was given for research showing how this works, the telomerase building the equivalent of caps at the end of DNA shoelaces.

If the enzyme keeps building new caps, a DNA strand can replicate indefinitely. It's immortal. But that's what differentiates cancer cells from "normal" ones -- they have the enzyme, they have the secret to immortality. An immortality which kills its host, namely you.

Now Harvard scientists have opened this door, using telomerase to reverse the aging process in mice. Writing in the journal Nature, a group under Ronald DePinho (above, from Harvard) say they "engineered a knock-in allele" that turned the cap-making process back on, making old mice young again.

Here's the problem. Mice make telomerase throughout their lives. People stop making it once we're grown.

It may be possible to add telomerase to the human body and halt the aging process, in other words. But the word for that may well be cancer.

This may be the most bittersweet irony I have ever covered for SmartPlanet. Cancer is caused by the same chemical that can make cells immortal.

Immortality and cancer, two trains running on one line. One train's me and the other's a friend of mine.

This post was originally published on Smartplanet.com