A new study shows that nicotine has more negative effects on the body than previously thought. The chemical found in tobacco appeared helping cancer cells spread from the lungs to the brain.
Estimates suggest that up to 40 percent of people with lung cancer are likely to develop metastatic brain tumors. That could cut the patient’s average survival time to less than six months.
However, scientists have yet to fully understand why the disease travels from the lungs to infect the brain. That led researchers at Wake Forest School of Medicine to look into the effects of nicotine exposure.
The new study, published in the Journal of Experimental Medicine, analyzed the health of 281 lung cancer patients. It found that cigarette smokers had higher incidence of brain cancer than other patients with the same lung condition.
Smoking contributed to brain cancer because of the effect of nicotine on the microglia, a type of immune cell in the brain. In a mouse model, researchers found that nicotine changes the microglial cells from their M1 form that destroys tumors to an alternate form called M2, which supports cancer growth.
“Based on our findings, we don’t think that nicotine replacement products are the safest way for people with lung cancer to stop smoking,” Kounosuke Watabe, lead study author and a professor of cancer biology at Wake Forest School of Medicine, said in a statement.
However, the team also found a way to reduce or block the effects of nicotine on cancer cells. Parthenolide, a compound in the herb feverfew, appeared helping prevent the brain metastasis caused by nicotine exposure.
Mice treated with parthenolide during the study did not develop brain tumors. Researchers said the treatment helped microglia retain its original form and prevented the immune cell from morphing into the M2 form.
“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.”
The researcher hopes to continue the study to test parthenolide and develop a new treatment that could prevent cancer from reaching the brain.