Anti-cancer effect of aspirin clarified

NEW YORK (Reuters) Previous research has shown a possible anti-cancer effect for aspirin. Now, new findings suggest that the drug achieves this by cutting off the tumor's blood supply, not just by blocking an enzyme called cyclooxygenase.

While aspirin may not represent a suitable treatment for cancer, since many of the effects are only seen at very high doses, understanding how the drug works may lead to new therapies.

''Our work,'' senior investigator Dr Helen M Arthur told Reuters Health, ''shows that the protective effects of aspirin against cancer may be partly due to the ability of aspirin to restrict the blood supply to a developing tumor, which limits tumor growth.'' To investigate underlying processes, Arthur, from the University of Newcastle in the UK, and colleagues exposed blood vessel cells to aspirin or to drugs like Celebrex (celecoxib), which block various forms of cyclooxygenase.

In the Federation of American Societies for Experimental Biology (FASEB) Journal, the researchers report that aspirin, at doses well above what is typically used for pain control, caused death of the blood vessel cells.

At standard doses, aspirin did not affect the cells, but seemed to disrupt the surrounding proteins that provide a support structure for blood vessels.

Celebrex and the other drugs, which largely target just cyclooxygenase, did not show these effects.

''The next stage in this research is to discover the mechanism by which aspirin can do this, which will also help us to identify new drug targets to treat cancer,'' Arthur concluded.

REUTERS AKJ KP0931