Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 7, 2018; 24(37): 4263-4271
Published online Oct 7, 2018. doi: 10.3748/wjg.v24.i37.4263
Potential involvement of heat shock proteins in pancreatic-duodenal homeobox-1-mediated effects on the genesis of gastric cancer: A 2D gel-based proteomic study
Juan Ma, Bei-Bei Wang, Xiao-Yan Ma, Wei-Ping Deng, Li-Shu Xu, Wei-Hong Sha
Juan Ma, Bei-Bei Wang, Wei-Ping Deng, Li-Shu Xu, Wei-Hong Sha, Department of Gastroenterology and Hepatology, Guangdong General Hospital (Guangdong Academy of Medical Sciences), Guangdong Geriatrics Institute, Guangzhou 510080, Guangdong Province, China
Xiao-Yan Ma, Forensic Identification Institute, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong Province, China
Author contributions: Ma J and Wang BB contributed equally to this work; Ma J and Sha WH conceived the study; Ma J and Ma XY performed the research; Wang BB and Deng WP analyzed the data; Ma J wrote this manuscript; Xu LS revised this manuscript; Sha WH supervised the report; all authors gave intellectual input to the study and approved the final version of the manuscript.
Supported by Guangdong Natural Science Fund, No. 2016A030313765; and Guangdong medical scientific research fund, No. A2017070 and No. A2017122.
Institutional review board statement: The institutional review board at the Guangdong General Hospital approved the study protocol. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Conflict-of-interest statement: The authors declare that they have 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: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Wei-Hong Sha, MD, PhD, Chief Doctor, Professor, Department of Gastroenterology and Hepatology, Guangdong General Hospital (Guangdong Academy of Medical Sciences), Guangdong Geriatrics Institute, 106 Zhongshan Er Road, Guangzhou 510080, Guangdong Province, China. shaweihong@gdghospital.com.cn
Telephone: +86-20-83827812 Fax: +86-20-83827812
Received: May 30, 2018
Peer-review started: May 30, 2018
First decision: July 18, 2018
Revised: August 9, 2018
Accepted: August 24, 2018
Article in press: August 24, 2018
Published online: October 7, 2018
Abstract
AIM

To identify functional proteins involved in pancreatic-duodenal homeobox-1 (PDX1)-mediated effects on gastric carcinogenesis.

METHODS

A PDX1-overexpressed model was established by transfecting gastric cancer cell line SGC7901 with pcDNA3.1(+)-PDX1 vector (SGC-PDX1). Transfection with empty pcDNA3.1 vector (SGC-pcDNA) served as control. Comparative protein profiles of the two groups were analyzed by two-dimensional electrophoresis based-proteomics (2DE gel-based proteomics). The differential proteins identified by 2DE were further validated by qRT-PCR and immunoblotting. Finally, co-immunoprecipitation was used to determine any direct interactions between PDX1 and the differential proteins.

RESULTS

2DE gel proteomics identified seven differential proteins in SGC-PDX1 when compared with those in SGC-pcDNA. These included four heat shock proteins (HSPs; HSP70p1B, HSP70p8, HSP60, HSP27) and three other proteins (ER60, laminin receptor 1, similar to epsilon isoform of 14-3-3 protein). Immunoblotting validated the expression of the HSPs (HSP70, HSP60, HSP27). Furthermore, their expressions were lowered to 80%, 20% and 24%, respectively, in SGC-PDX1, while PDX1 exhibited a 9-fold increase, compared to SGC-pcDNA. However, qRT-PCR analysis revealed that mRNA levels of the HSPs were increased in SGC-PDX1, suggesting that the expression of the HSPs was post-translationally regulated by the PDX1 protein. Finally, co-immunoprecipitation failed to identify any direct interaction between PDX1 and HSP70 proteins.

CONCLUSION

This study demonstrates the potential involvement of HSPs in PDX1-mediated effects on the genesis of gastric cancer.

Keywords: Pancreatic-duodenal homeobox-1, Heat shock proteins, Gastric cancer, Proteomics, Two-dimensional electrophoresis

Core tip: Using a pcDNA3.1(+)-pancreatic-duodenal homeobox-1 (PDX1) vector, a PDX1-overexpressed model was built. Seven differential proteins were identified in SGC-PDX1 by two-dimensional electrophoresis gel proteomics compared with those in SGC-pcDNA. Four heat shock proteins were identified and confirmed by immunoblotting. qRT-PCR analysis further revealed that the expression of the HSPs was post-translationally regulated by the PDX1 protein. This study suggests the potential involvement of HSPs in PDX1 mediated effects on gastric carcinogenesis.