July 20, 2006 -- Nicotine directly speeds the growth of, University of South Florida researchers report.
Exactly how nicotine does this is now becoming clear: It plugs directly into lung cells, where it jump-starts the cells' growth machinery. If those cells are cancerous, nicotine makes them grow wildly.
"These events can be expected to contribute to the growth and progression of tumors exposed to nicotine through tobacco smoke or cigarette substitutes," suggest Piyali Dasgupta, PhD, and colleagues at H. Lee Moffitt Cancer Center, USF, Tampa, Fla.
Dasgupta and colleagues found that nicotine plugs into receptors called nicotinic acetylcholine receptors or nAChRs. These receptors are found throughout the body.
The finding may help explain why chemotherapy for is less effective in smokers and why cigarette smoke helps many different kinds of cancer grow.
The study appears in the August issue of the Journal of Clinical Investigation.