THURSDAY, Oct. 16 (HealthDay News) -- Nicotine can spur human breast epithelial-like cells and cancer cells to proliferate and migrate, which may point to a role for nicotine in breast cancer due to secondhand smoke, according to research published in the Oct. 15 issue of Cancer Research.
Jinjin Guo, of the Beth Israel Deaconess Medical Center in Boston, and colleagues write that in vitro experimentation revealed that exposure to nicotine promotes cell cycle progression or proliferation in human mammary epithelial-like cells (MCF10A) and breast cancer cells (MCF7), which express four subunits of nicotine acetylcholine receptor.
The use of Boyden chamber and cell wound-healing assays indicated that nicotine promotes migration in breast cancer cells and functions through its receptor, governing multiple downstream pathways. In addition, mice injected with MCF7 cells followed by nicotine periodically for 28 days showed profuse tumor cells in their lungs, an effect not seen in mice that weren't treated with nicotine, the researchers report.
"Nicotine is originally thought to be mainly responsible for tobacco addiction. However, many studies now reveal that this tobacco component is able to modulate various key biological activities in non-neuronal tissues. In particular, nicotine has been shown to promote survival of many cell types, including keratinocytes and head or neck tumor cells," the authors write. "Overall, our study provides evidence to suggest that nicotine is a possible component for the initiation of breast cancer induced by secondhand smoking. The present investigation also warrants a caution for the clinical use of nicotine to relieve chronic pain or aid in the cessation of cigarette smoking."
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