title: Expression of nicotinic acetylcholine receptor subunit genes in non-small-cell lung cancer reveals differences between smokers and nonsmokers.
abstract: Nicotine and its derivatives, by binding to nicotinic acetylcholine receptors (nAChR) on bronchial epithelial cells, can regulate cellular proliferation and apoptosis via activating the Akt pathway. Delineation of nAChR subtypes in non-small-cell lung cancers (NSCLC) may provide information for prevention or therapeutic targeting. Expression of nAChR subunit genes in 66 resected primary NSCLCs, 7 histologically non-involved lung tissues, 13 NSCLC cell lines, and 6 human bronchial epithelial cell lines (HBEC) was analyzed with quantitative PCR and microarray analysis. Five nonmalignant HBECs were exposed to nicotine in vitro to study the variation of nAChR subunit gene expression with nicotine exposure and removal. NSCLCs from nonsmokers showed higher expression of nAChR alpha6 (P < 0.001) and beta3 (P = 0.007) subunit genes than those from smokers, adjusted for gender. In addition, nAChR alpha4 (P < 0.001) and beta4 (P = 0.029) subunit gene expression showed significant difference between NSCLCs and normal lung. Using Affymetrix GeneChip U133 Sets, 65 differentially expressed genes associated with NSCLC nonsmoking nAChR alpha6beta3 phenotype were identified, which gave high sensitivity and specificity of prediction. nAChR alpha1, alpha5, and alpha7 showed significant reversible changes in expression levels in HBECs upon nicotine exposure. We conclude that between NSCLCs from smokers and nonsmokers, different nAChR subunit gene expression patterns were found, and a 65-gene expression signature was associated with nonsmoking nAChR alpha6beta3 expression. Finally, nicotine exposure in HBECs resulted in reversible differences in nAChR subunit gene expression. These results further implicate nicotine in bronchial carcinogenesis and suggest targeting nAChRs for prevention and therapy in lung cancer.
authors.affiliation: Department of Medicine, University of Hong Kong, HKSAR, China.
authors.forename: David Chi-Leung
authors.initials: DC
authors.lastname: Lam
authors.forename: Luc
authors.initials: L
authors.lastname: Girard
authors.forename: Ruben
authors.initials: R
authors.lastname: Ramirez
authors.forename: Wing-Shun
authors.initials: WS
authors.lastname: Chau
authors.forename: Wai-sing
authors.initials: WS
authors.lastname: Suen
authors.forename: Shelley
authors.initials: S
authors.lastname: Sheridan
authors.forename: Vicky P C
authors.initials: VP
authors.lastname: Tin
authors.forename: Lap-ping
authors.initials: LP
authors.lastname: Chung
authors.forename: Maria P
authors.initials: MP
authors.lastname: Wong
authors.forename: Jerry W
authors.initials: JW
authors.lastname: Shay
authors.forename: Adi F
authors.initials: AF
authors.lastname: Gazdar
authors.forename: Wah-kit
authors.initials: WK
authors.lastname: Lam
authors.forename: John D
authors.initials: JD
authors.lastname: Minna
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001980:Bronchi / Q000166:cytology; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D005260:Female; D015870:Gene Expression; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011978:Receptors, Nicotinic / Q000096:biosynthesis / Q000235:genetics*; D012907:Smoking / Q000009:adverse effects / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D011978:Receptors, Nicotinic; D009538:Nicotine