Nicotine activates enzyme aiding cancer
WASHINGTON - 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 which inhibits cellular
suicide, says new research by scientists at the National Cancer
Institute.
Nicotine starts activating that enzyme, called Akt, within minutes,
while cancer-causing genetic damage takes hours to begin, institute
researchers report in the latest Journal of Clinical Investigation.
That suggests nicotine, along with other chemicals which block cell
suicide, may make cells more vulnerable to the
cancer-causers.
'Nicotine is not a carcinogen; we're not trying to make that
argument,' said study leader Phillip Dennis. But 'it may have a
permissive effect' on cancer formation.
Scientists first discovered nicotine may block cell suicide 10
years ago, said nicotine expert Neal Benowitz of the University of
California, San Francisco. But the new research uncovers the actual
enzyme involved.
The question now is whether the effect matters to smokers using
nicotine gum or patches in a bid to quit.
'It's clearly better for people to stop smoking and use a patch
than to continue smoking,' Dr Dennis said, adding that the study
reinforces that anti-smoking medicines are for short-term use
only.
But Dr Benowitz said the study had used cells in laboratory dishes,
while previous studies of snuff users - who do not absorb as many
carcinogens as smokers - suggest there is little cancer risk from
nicotine. --AP
Cells more vulnerable
Scientists at the National Cancer Institute say nicotine is not a
carcinogen. But it may pave the way for cancer formation.
It kick-starts an enzyme, called Akt, which inhibits suicide in
damaged cells. This means nicotine may make cells more vulnerable
to cancer-causing chemicals.
morale of the story? dont smoke! smoking
causes cancer! 
