Nicotine promotes tumour growth says study
Researchers have discovered how nicotine, the addictive component of tobacco smoke, is able to stimulate the growth of normal and cancerous lung cells, despite not being itself a carcinogen, according to a paper published today in the Journal of Clinical Investigation.
The finding highlights how nicotine may encourage the growth of cells already damaged by the estimated seventy different carcinogens in tobacco smoke, thus fuelling the development of lung cancer.
A growing body of evidence has pointed to nicoine playing a role in promoting cell multiplication. Now researchers at the University of South Florida have unravelled the way in which it might do so.
The research focused on the effects of nicotine on a protein called the nicotinic acetylcholine receptor, nAChR, whose major role is to transmit signals between cells in the nervous system. However, recent research has found nAChRs in non-nerve cells, such as the cells of the lungs.
The team found that nicotine bound to the nAChRs on the surface of lung cancer cells, encouraging them to divide and grow. Nicotine’s effects on non-small cell lung cancer cells were shown to be particularly marked.
The researchers also found that the nAChR stimulated the cells using a well known method involving proteins called Raf-1 and Rb and a family of proteins called cyclin-dependent kinases.
Henry Scowcroft, science information officer at Cancer Research UK, said: "Aside from deadly carcinogens like benzene, formaldehyde and arsenic, there’s a growing body of evidence that nicotine - the major addictive component of cigarettes - can itself encourage cancer cells to divide.
"This study adds to that evidence, suggesting that cigarettes may be even more dangerous than was already known. "Giving up is the best thing a smoker can do to improve their health and reduce their risk of many cancers, including cancers of the lung, bladder, cervix, kidney, voice-box, mouth, oesophagus, pancreas and stomach, as well as heart disease, stroke and the many other smoking-related diseases."