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Associated Press
Friday, January 3, 2003; Page A20

Nicotine makes smoking addictive and is bad for the heart, but 60 other cigarette chemicals are blamed for causing cancer. Now some biochemists say nicotine might help set the stage for those chemicals to do their dirty work.

Certain tobacco chemicals trigger cellular genetic damage.

Damaged cells are supposed to commit suicide; if they do not, the damage accumulates enough to turn cancerous. Nicotine activates an enzyme reaction that inhibits cellular suicide, according to new research by scientists at the National Cancer Institute.

Nicotine starts activating the enzyme, called Akt, within minutes, while cancer-causing genetic damage takes hours to begin, NCI researchers report in yesterday's Journal of Clinical Investigation. That suggests nicotine -- along with other chemicals that also block cell suicide -- may make cells more vulnerable to the cancer-causers.

"Nicotine is not a carcinogen, and we're not trying to make that argument," said Phillip Dennis, the study leader. But "it may have a permissive effect" for cancer formation.

Scientists discovered nicotine may block cell suicide 10 years ago, said nicotine expert Neal Benowitz of the University of California at San Francisco. But the new research uncovers the enzyme involved.