Natural agents targeting the α7-nicotinic-receptor in NSCLC: A promising prospective in anti-cancer drug development

Authors


  • Mice were maintained in accordance with the recommendations, regulations and standards approved by the Federation of European Laboratory Animal Science Association. The mice were used in accordance with institutional guidelines when they were 8-week-old and employed for both tumor maintenance and chemotherapy testing. All the procedures involving animal care and treatment were conducted as stipulated in Italian National Guidelines (D.L. No. 116 G.U., suppl. 40, 18.2.1992, circolare No. 8, G.U. luglio 1994) and in the appropriate European Directives (EEC Council Directive 86/609, 1.12.1987), adhering to the Guide for the Care and Use of Laboratory Animals (United States National Research Council, 1996) and according to an approved protocol reviewed by the National Cancer Research's Institutional Animal Care and Use Committee (Genova, 15 November 2004 n. of reference 149). For ethical reasons, each animal was submitted to euthanasia (in a CO2 atmosphere) when it had lost 20% of its weight as compared with its weight at the time of the tumor graft.

Abstract

Nicotinic acetylcholine receptors (nAChR) are expressed on normal bronchial epithelial and nonsmall cell lung cancer (NSCLC) cells and are involved in cell growth regulation. Nicotine induced cell proliferation. The purpose of this study was to determine if interruption of autocrine nicotinic cholinergic signaling might inhibit A549 NSCLC cell growth. For this purpose α-Cobratoxin (α-CbT), a high affinity α7-nAChR antagonist was studied. Cell growth decrease was evaluated by Clonogenic and MTT assays. Evidence of apoptosis was identified staining cell with Annexin-V/PI. Characterization of the basal NF-κB activity was done using the Trans-AM NF-κB assay colorimetric kit. “In vivo” antitumour activity was evaluated in orthotopically transplanted nude mice monitored by In vivo Imaging System technology. α-CbT caused concentration-dependent cell growth decrease, mitochondrial apoptosis caspases-9 and 3-dependent, but caspase-2 and p53-independent and down-regulation of basal high levels of activated NF-κB. α-CbT treatment determines a significant reduction of tumor growth in nude mice orthotopically engrafted with A549-luciferase cells (4.6% of living cells vs. 31% in untreated mice). No sign of toxicity was reported related to treatment. These findings suggest that α7-nAChR antagonists namely α-CbT may be useful adjuvant for treatment of NSCLC and potentially other cancers. © 2007 Wiley-Liss, Inc.

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