Studies strongly suggest that the nicotinic acetylcholine receptors for nicotine (nAChRs) play a significant role in lung cancer predisposition and natural history. The nAChR α7 subunit has been found to be pivotal in the control of nicotine-induced lung cancer development and in growth signal transduction induced by nicotine binding to nAChRs.Objectives:
To investigate the anticancer effects of α7-nAChR antagonists.Methods:
(1) To check the correlation between α7-nAChR presence and α-cobratoxin (α-CbT) sensitivity, binding experiments were performed in various normal human cells, lung cancer cell lines, and primary tumoral cells; (2) to demonstrate that α-CbT might be an efficient adjuvant therapy for non–small cell lung cancer (NSCLC) we expanded our previous observations to a panel of NSCLCs of various subtypes orthotopically grafted on nonobese diabetic/severe combined immunodeficient mice; (3) to gain insight into the mechanism of α-CbT–induced tumor reduction, the cells obtained after enzymatic digestion of tumors were analyzed for procaspase-9, Bax, Bad, and Bcl-XL protein; and (4) Snail/E-cadherin expression was evaluated to acquire information about the chemoresistance of cancer cells to α-CbT.Measurements and Main Results:
We report herein the results of an experimental strategy aimed at investigating the antitumor effects of a powerful α7-nAChR antagonist, α-CbT, in an in vivo setting set to mimic the clinical setting of lung cancer; in addition, a possible explanation for α-CbT selectivity toward cancer cells is presented.Conclusions:
We report the prolonged survival of α-CbT–treated animals in our mouse model of NSCLC, which is most likely the result of multiple mechanisms, including various antiproliferative and antiangiogenic effects.