Nearly 40% of patients who suffer from non-small cell lung cancer also develop metastatic brain tumors with an average survival time of six months or less. Until now, scientists did not understand why non-small cell lung cancer spreads to the brain. Researchers at Wake Forest School of Medicine have found that nicotine promotes metastasis of lung cancer cells into the brain.
"Based on our findings, we don't think that nicotine replacement products are the safest way for people with lung cancer to stop smoking," said Kounosuke Watabe, Ph.D., professor of cancer biology at Wake Forest School of Medicine and lead author of the study. The study, published in the June 4th edition of the Journal of Experimental Medicine, Watabe and team examined 281 lung cancer patients. They found that those who smoked cigarettes had a much higher incidence of brain cancer.
In the next phase of the study, the scientists used mice to discover that nicotine enhanced the metastatic process because it’s able to cross the blood-brain-barrier and change microglia from being a protective immune cell into one that supports tumor growth.
Then the team looked for drugs that could reverse the effects that nicotine has, and they discovered parthenolide, which occurs in nature as the medicinal herb, feverfew, could block metastasis that was the result of nicotine. Feverfew is not a new drug; it has been used for years and is considered safe, so Watabe thinks that parthenolide might be a useful therapy, especially for lung cancer patients who smoke.
"Currently, the only treatment for this devastating illness is radiation therapy," Watabe said. "Traditional chemotherapy drugs can't cross the blood-brain barrier, but parthenolide can, and thus holds promise as a treatment or possibly even a way to prevent brain metastasis."