Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Apr 15, 2019; 11(4): 281-294
Published online Apr 15, 2019. doi: 10.4251/wjgo.v11.i4.281
Up-regulation of tumor necrosis factor-α pathway survival genes and of the receptor TNFR2 in gastric cancer
Ana Flávia Teixeira Rossi, Júlia Cocenzo Contiero, Fernanda da Silva Manoel-Caetano, Fábio Eduardo Severino, Ana Elizabete Silva
Ana Flávia Teixeira Rossi, Júlia Cocenzo Contiero, Fernanda da Silva Manoel-Caetano, Ana Elizabete Silva, Department of Biology, São Paulo State University – UNESP, São José do Rio Preto, SP 15054-000, Brazil
Fábio Eduardo Severino, Department of Surgery and Orthopedics, Faculty of Medicine, São Paulo State University – UNESP, Botucatu, SP 18618-687, Brazil
Author contributions: Rossi AFT and Silva AE outlined the study; Rossi AFT, Contiero JC, Manoel-Caetano FS performed the experiments; Rossi AFT analyzed and interpreted the results; Severino FE built the interaction network; Rossi AFT and Silva AE drafted the manuscript and revised it; all authors approved the final version of the manuscript.
Supported by São Paulo Research Foundation-FAPESP, grants Nos. 2015/21464-0 and 2015/23392-7; and National Counsel of Technological and Scientific Development-CNPq, grant No. 310120/2015-2.
Institutional review board statement: This study was approved by local Research Ethics Committee (CEP – IBILCE/UNESP, number 1.336.892).
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
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: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ana Elizabete Silva, PhD, Adjunct Professor, Department of Biology, São Paulo State University - UNESP, Rua Cristóvão Colombo, 2265, São José do Rio Preto SP 15054-000, Brazil. ae.silva@unesp.br
Telephone: +55-17-32212384 Fax: +55-17-322212390
Received: January 11, 2019
Peer-review started: January 11, 2019
First decision: January 26, 2019
Revised: February 16, 2019
Accepted: February 27, 2019
Article in press: February 28, 2019
Published online: April 15, 2019
Processing time: 94 Days and 21.9 Hours
Abstract
BACKGROUND

Gastric carcinogenesis can be induced by chronic inflammation triggered by Helicobacter pylori (H. pylori) infection. Tumor necrosis factor (TNF)-α and its receptors (TNFR1 and TNFR2) regulate important cellular processes, such as apoptosis and cell survival, and the disruption of which can lead to cancer. This signaling pathway is also modulated by microRNAs (miRNAs), altering gene expression.

AIM

To evaluate the mRNA and miRNAs expression involved in the TNF-α signaling pathway in gastric cancer (GC) tissues and its relationship.

METHODS

Quantitative polymerase chain reaction (qPCR) by TaqMan® assay was used to quantify the RNA transcript levels of TNF-α signaling pathway (TNF, TNFR1, TNFR2, TRADD, TRAF2, CFLIP, NFKB1, NFKB2, CASP8, CASP3) and miRNAs that targets genes from this pathway (miR-19a, miR-34a, miR-103a, miR-130a, miR-181c) in 30 GC fresh tissue samples. Molecular diagnosis of H. pylori was performed by nested PCR for gene HSP60. A miRNA:mRNA interaction network was construct using Cytoscape v3.1.1 from the in silico analysis performed using public databases.

RESULTS

Up-regulation of cellular survival genes as TNF, TNFR2, TRADD, TRAF2, CFLIP, and NFKB2, besides CASP8 and miR-34a was observed in GC tissues, whereas mediators of apoptosis such as TNFR1 and CASP3 were down-regulated. When the samples were stratified by histological type, the expression of miR-103a and miR-130a was significantly increased in the diffuse-type of GC compared to the intestinal-type. However, no influence of H. pylori infection was observed on the expression levels of mRNA and miRNAs analyzed. Moreover, the miRNA:mRNA interaction network showed several interrelations between the miRNAs and their target genes, highlighting miR-19a and miR-103a, which has as predicted or validated target a large number of genes in the TNF-α pathway, including TNF, TNFR1, TNFR2, CFLIP, TRADD, CASP3 and CASP8.

CONCLUSION

Our findings show that cell survival genes mediated by TNF/TNFR2 binding is up-regulated in GC favoring its pro-tumoral effect, while pro-apoptotic genes as CASP3 and TNFR1 are down-regulated, indicating disbalance between apoptosis and cell proliferation processes in this neoplasm. This process can also be influenced by an intricate regulatory network of miRNA:mRNA.

Keywords: Gastric cancer; Tumor necrosis factor-α signaling; TNFR1; TNFR2; Cellular survival; MicroRNAs

Core tip: We evaluated the expression of mRNA and microRNAs (miRNAs) related to the tumor necrosis factor (TNF)-α signaling pathway in gastric cancer (GC) fresh tissues. Our study shows up-regulation of cell survival genes (TNF, TNFR2, TRADD, TRAF2, CFLIP, NFKB2, CASP8) of this signaling pathway in GC, stimulating cell growth possibly by TNFR2 and negatively controls TNFR1-mediated apoptosis by down-regulation of pro-apoptotic mediators (TNFR1 and CASP3). Furthermore, interaction network between miRNAs and mRNA investigated suggests that TNF-α signaling pathway can be regulated by the action of miRNAs, mainly miR-19a and miR-103a, which may influence tumor development. Ours findings suggest TNFR2 as a potential therapeutic target for GC.