Monday, July 30, 2007

Caffeine and apoptosis

This is not necessarily good ...
Coffee and plenty of exercise could cut risk of skin cancer | Science | The Guardian

...A combination of coffee drinking and regular exercise may help to lower the risk of developing skin cancer, according to scientists in the US.

The two are thought to work together to kill off precancerous cells whose DNA has been damaged by ultraviolet-B radiation from the sun....

... Previous studies have suggested that exercise and coffee may each play a small role in protecting against skin cancer, but the latest research shows for the first time that when combined, the two may offer far more protection.

Scientists led by Allan Conney at Rutgers University, New Jersey, examined the effect of ultraviolet light on mice bred to be hairless, and so particularly vulnerable to the effects of sunlight.

Four groups of mice were exposed to UV-B radiation, but were given different diets and exercise regimes. One group drank caffeinated water, giving them a caffeine intake equivalent to one to two cups of coffee a day. A second group was fed pure water but allowed to exercise on a running wheel. The third group was given caffeine and access to a running wheel, while the fourth did no exercise and had no caffeine.

The scientists later took samples and checked for signs of UV-induced genetic damage. They also looked for evidence of a natural survival mechanism called apoptosis, in which damaged and potentially cancerous cells are forced to commit suicide before they can form tumours.

The tests showed that caffeine alone led to a 95% increase in programmed cell death and there was a 120% increase from exercise alone. But when combined, exercise and caffeine led to a four-fold increase in cell death, suggesting the body was able to rid itself of pre-cancerous cells much more effectively....
A 400% increase in programmed cell death?! Omigod, that's a lot. It turns out there's a burgeoning literature on caffeine and apoptosis.

Yech. I have both an affection (heck, addiction) to caffeine and a family history of skin cancer, so one might think I'd find this lighthearted good news. Alas, biology doesn't work that way. If this effect occurs in humans we're looking at a significant impact of caffeine on the fundamental behavior of cells. It would be surprising if that effect were always benign. Apoptosis of pre-melanoma is fine, but apoptosis of dopaminergic neurons ... maybe not so fine.

No comments: