Nicotine is proving to be a formidable carcinogen, say researchers who warn that nicotine-infused smoking cessation products may not be the safest way to help smokers quit.
Nicotine is one of 4,000 chemicals found in cigarette smoke. While many of these chemicals are recognised as carcinogens, nicotine has up until now only been considered addictive rather than carcinogenic.
It is heavily used in smoking cessation products in patches, gum, and now in the increasingly popular electronic cigarette, or e-cigarette.
Researchers at the Virginia Bioinformatics Institute found that nicotine excessively mutates a cell's DNA.
Geneticist Jasmin Bavarva and Harold Garner, a professor of biological science, computer science, and basic science affiliated with the College of Science, the College of Engineering, and the Virginia Tech Carilion School of Medicine, found that nicotine causes thousands of mutations called single nucleotide polymorphisms (SNPs) in exposed cells, compared with control cells that were not exposed.
These patterns are similar to those identified in cells experiencing oxidative stress, which is a known precursor to cancer, according to the study published in the journal Oncotarget.
A previous study in journal PLOS One by the researchers looked at gene expression patterns caused by nicotine.
"We now have a broad picture of genomic effects in nicotine," said Bavarva, lead author of both studies.
"These results are important because for the first time they directly measure large numbers of genetic variations caused only by nicotine, showing that nicotine alone can mutate the genome and initiate a cancer state," said Garner, director of the institute's Medical Informatics and Systems Division.
"This is particularly timely since nicotine is used as a smoking cessation therapeutic," Garner added.