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J Biol Chem. 2013 Nov 15;288(46):33049-59. doi: 10.1074/jbc.M113.501601. Epub 2013 Oct 2.

Nicotine induces the up-regulation of the α7-nicotinic receptor (α7-nAChR) in human squamous cell lung cancer cells via the Sp1/GATA protein pathway.

Author information

1
From the Department of Pharmacology, Physiology, and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia 25755.

Abstract

Nicotine, the addictive component of cigarettes, promotes lung cancer proliferation via the α7-nicotinic acetylcholine receptor (α7-nAChR) subtype. The present manuscript explores the effect of nicotine exposure on α7-nAChR levels in squamous cell carcinoma of the lung (SCC-L) in vitro and in vivo. Nicotine (at concentrations present in the plasma of average smokers) increased α7-nAChR levels in human SCC-L cell lines. Nicotine-induced up-regulation of α7-nAChR was confirmed in vivo by chicken chorioallantoic membrane models. We also observed that the levels of α7-nAChR in human SCC-L tumors (isolated from patients who are active smokers) correlated with their smoking history. Nicotine increased the levels of α7-nAChR mRNA and α7-nAChR transcription in human SCC-L cell lines and SCC-L tumors. Nicotine-induced up-regulation of α7-nAChR required GATA4 and GATA6. ChIP assays showed that nicotine induced the binding of GATA4 or GATA6 to Sp1 on the α7-nAChR promoter, thereby inducing its transcription and increasing its levels in human SCC-L. Our data are clinically relevant because SCC-L patients smoked for decades before being diagnosed with cancer. It may be envisaged that continuous exposure to nicotine (in such SCC-L patients) causes up-regulation of α7-nAChRs, which facilitates tumor growth and progression. Our results will also be relevant to many SCC-L patients exposed to nicotine via second-hand smoke, electronic cigarettes, and patches or gums to quit smoking.

KEYWORDS:

GATA; Lung Cancer; Nicotinic Acetylcholine Receptors; Proliferation; Sp1

PMID:
24089524
PMCID:
PMC3829154
DOI:
10.1074/jbc.M113.501601
[Indexed for MEDLINE]
Free PMC Article

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