Retrospective Cohort Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 21, 2016; 22(31): 7146-7156
Published online Aug 21, 2016. doi: 10.3748/wjg.v22.i31.7146
Nicotinic cholinergic receptors in esophagus: Early alteration during carcinogenesis and prognostic value
Marina Chianello Nicolau, Luis Felipe Ribeiro Pinto, Pedro Nicolau-Neto, Paulo Roberto Alves de Pinho, Ana Rossini, Tatiana de Almeida Simão, Sheila Coelho Soares Lima
Marina Chianello Nicolau, Luis Felipe Ribeiro Pinto, Ana Rossini, Tatiana de Almeida Simão, Departamento de Bioquímica, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20551-013, Brazil
Marina Chianello Nicolau, Luis Felipe Ribeiro Pinto, Pedro Nicolau-Neto, Sheila Coelho Soares Lima, Programa de Carcinogênese Molecular, Instituto Nacional de Câncer, Coordenação de Pesquisa, Rio de Janeiro 20231-050, Brazil
Paulo Roberto Alves de Pinho, Gastroenterologia, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20551-013, Brazil
Author contributions: Chianello Nicolau M performed all experiments; Chianello Nicolau M, Nicolau-Neto P, de Pinho PRA and Rossini A collected materials and clinical data from patients and healthy individuals; de Almeida Simão T and Soares Lima SC designed and coordinated the research study; Chianello Nicolau M analyzed the data; Chianello Nicolau M, Pinto LFR, de Almeida Simão T and Soares Lima SC wrote the manuscript; Pinto LFR and Soares Lima SC provided financial support for the research.
Supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil), Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Ministério da Saúde (INCA) and Swiss Bridge Foundation.
Institutional review board statement: This research study was approved by the Ethics Committee in Research of Hospital Universitário Pedro Ernesto (CEP/HUPE, 416) and by the Ethics Committee in Research of Instituto Nacional de Câncer (CEP-INCA, 116/11).
Informed consent statement: Informed consent was obtained from all individuals included in the study.
Conflict-of-interest statement: The authors state no conflict of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Sheila Coelho Soares Lima, PhD, Researcher, Programa de Carcinogênese Molecular, Instituto Nacional de Câncer, Coordenação de Pesquisa, Rua André Cavalcanti, 37 - 6º andar, Bairro de Fátima, Rio de Janeiro 20231-050, Brazil.
Telephone: +55-21-32076596 Fax: +55-21-32076509
Received: February 12, 2016
Peer-review started: February 12, 2016
First decision: March 21, 2016
Revised: April 15, 2016
Accepted: May 4, 2016
Article in press: May 4, 2016
Published online: August 21, 2016

AIM: To compare expression of nicotinic cholinergic receptors (CHRNs) in healthy and squamous cell carcinoma-affected esophagus and determine the prognostic value.

METHODS: We performed RT-qPCR to measure the expression of CHRNs in 44 esophageal samples from healthy individuals and in matched normal surrounding mucosa, and in tumors from 28 patients diagnosed with esophageal squamous cell carcinoma (ESCC). Next, we performed correlation analysis for the detected expression of these receptors with the habits and clinico-pathological characteristics of all study participants. In order to investigate the possible correlations between the expression of the different CHRN subunits in both healthy esophagus and tissues from ESCC patients, correlation matrices were generated. Subsequently, we evaluated whether the detected alterations in expression of the various CHRNs could precede histopathological modifications during the esophageal carcinogenic processes by using receiver operating characteristic curve analysis. Finally, we evaluated the impact of CHRNA5 and CHRNA7 expression on overall survival by using multivariate analysis.

RESULTS: CHRNA3, CHRNA5, CHRNA7 and CHRNB4, but not CHRNA1, CHRNA4, CHRNA9 or CHRNA10, were found to be expressed in normal (healthy) esophageal mucosa. In ESCC, CHRNA5 and CHRNA7 were overexpressed as compared with patient-matched surrounding non-tumor mucosa (ESCC-adjacent mucosa; P < 0.0001 and P = 0.0091, respectively). Positive correlations were observed between CHRNA3 and CHRNB4 expression in all samples analyzed. Additionally, CHRNB4 was found to be differentially expressed in the healthy esophagus and the normal-appearing ESCC-adjacent mucosa, allowing for distinguishment between these tissues with a sensitivity of 75.86% and a specificity of 78.95% (P = 0.0002). Finally, CHRNA5 expression was identified as an independent prognostic factor in ESCC; patients with high CHRNA5 expression showed an increased overall survival, in comparison with those with low expression. The corresponding age- and tumor stage-adjusted hazard ratio was 0.2684 (95%CI: 0.075-0.97, P = 0.0448).

CONCLUSION: Expression of CHRNs is homogeneous along healthy esophagus and deregulated in ESCC, suggesting a pathogenic role for these receptors in ESCC development and progression.

Keywords: Nicotinic cholinergic receptors, Esophagus, Esophageal squamous cell carcinoma, Tobacco, Alcohol, Gene expression

Core tip: Esophageal squamous cell carcinoma (ESCC) is the main histological subtype of esophageal cancer, and is associated with alcohol and tobacco consumption. Tobacco components, such as nicotine and nitrosamines, are high-affinity agonists of nicotinic cholinergic receptors (CHRNs), the activation of which triggers cellular signaling pathways important for cancer progression. However, data regarding differential expression and regulation of CHRNs in healthy esophageal mucosa and ESCC are limited. This study shows homogeneous expression of CHRNs along healthy esophagus and deregulation in ESCC, CHRNB4 overexpression preceding the first histopathological alterations during ESCC development, and CHRNA5 expression as an independent predictor of prognosis.