SMOKING CESSATION PRODUCTS MAY INHIBIT LUNG CANCER TREATMENT

Use of a nicotine patch or nicotine gum may undermine the effectiveness of chemotherapy in treating lung cancer, according to a new study.

Specifically, chemotherapy drugs such as taxol are inhibited from killing lung cancer cells when exposed to nicotine, noted the study, which was presented recently at the annual meeting of the American Association for Cancer Research in Washington, D.C.

While nicotine is not a carcinogen, it can influence the biological pathways that promote tumor growth, said researchers at the H. Lee Moffitt Cancer Center and Research Institute. The research focused on human nonsmall cell lung cancer, which accounts for 80 percent of all lung cancer cases, and was published in Proceedings of the National Academy of Science.

According to the study, treatment with a concentration of nicotine, such as that used in a nicotine patch to stop smoking, inhibits apoptosis induced by the three standard chemotherapy drugs: gemcitabine, cisplatin and taxol. Apoptosis is a process whereby exposure to chemotherapy causes cancer cells to self-destruct.

"The siRNAs (small-interfering ribonucleic acid) for survivin and XIAP individually did not substantially reverse the anti-apoptotic effects of nicotine, but a combination of both the siRNAs totally ablated the protective effects of nicotine in drug-induced apoptosis," the study said.

The study also found that two genes -- survivin and XIAP -- play a key role in the antiapoptotic activity of nicotine. By "silencing" either gene, the authors were able to eliminate nicotine's protective effect on cancer cells. ()a href="http://www.fdanews.com/ddl/33_15/" target=_blank>