Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 28, 2017; 23(36): 6639-6649
Published online Sep 28, 2017. doi: 10.3748/wjg.v23.i36.6639
Attenuation of MET-mediated migration and invasion in hepatocellular carcinoma cells by SOCS1
Yirui Gui, Md Gulam Musawwir Khan, Diwakar Bobbala, Claire Dubois, Sheela Ramanathan, Caroline Saucier, Subburaj Ilangumaran
Yirui Gui, Md Gulam Musawwir Khan, Diwakar Bobbala, Claire Dubois, Sheela Ramanathan, Subburaj Ilangumaran, Department of Pediatrics, Immunology Division, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
Caroline Saucier, Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
Author contributions: Gui Y, Bobbala D and Khan MGM performed experiments; Dubois C helped with the 3D-invasion assay and data analysis; Ramanathan S generated cell lines and provided mice; Saucier C helped with experiments, participated in data analysis and manuscript preparation; Gui Y, Saucier C and Ilangumaran S designed the study and wrote the manuscript; Saucier C and Ilangumaran S share senior authorship.
Supported by the Cancer Research Society, Montreal, Canada, No. 16195.
Institutional animal care and use committee statement: Tumor growth studies in mice were carried out under protocols approved by the Université de Sherbrooke ethics committee in accordance with Canadian Council on Animal Care guidelines (Protocol number 226-13B).
Conflict-of-interest statement: The authors do not have any conflicts of interest to disclose.
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: Subburaj Ilangumaran, PhD, Department of Pediatrics, Immunology Division, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 North 12th avenue, Sherbrooke, Québec J1H 5N4, Canada. subburaj.ilangumaran@Usherbrooke.ca
Telephone: +1-819-3461110-14834 Fax: +1-819-5645215
Received: March 1, 2017
Peer-review started: March 2, 2017
First decision: April 21, 2017
Revised: May 9, 2017
Accepted: July 4, 2017
Article in press: July 4, 2017
Published online: September 28, 2017
Abstract
AIM

To investigate the role of suppressor of cytokine signaling 1 (SOCS1) in regulating MET-mediated invasive potential of hepatocellular carcinoma (HCC) cells.

METHODS

Stable derivatives of mouse (Hepa1-6) and human (hep3B, HepG2) HCC cell lines expressing SOCS1 or control vector were evaluated for their ability to migrate towards hepatocyte growth factor (HGF) in the transwell migration assay, invade extracellular matrix in response to HGF stimulation in a 3-D invasion assay by confocal microscopy, and to undergo anchorage-independent proliferation in semisolid agar. Following intravenous and intrasplenic inoculation into NOD.scid.gamma mice, the ability of Hepa cells to form othotopic tumors was evaluated. Following HGF stimulation of Hepa and Hep3B cells, expression of proteins implicated in epithelial-to-mesenchymal transition was evaluated by western blot and qRT-PCR.

RESULTS

SOCS1 expression in mouse and human HCC cells inhibited HGF-induced migration through matrigel. In the 3-D invasion assay, HGF stimulation induced invasion of HCC cells across type-I collagen matrix, and SOCS1 expression significantly reduced the depth of invasion. SOCS1 expression also reduced the number and size of colonies formed by anchorage-independent growth in semisolid agar. Following intravenous inoculation, control Hepa cell formed large tumor nodules that obliterated the liver whereas the SOCS1-expressing Hepa cells formed significantly smaller nodules. Tumors formed by SOCS1-expressing cells showed reduced phosphorylation of STAT3 and ERK that was accompanied by reduced levels of MET protein expression. HGF stimulated Hepa cells expressing SOCS1 showed increased expression of E-cadherin and decreased expression of EGR1, SNAI1 and ZEB1. Comparable results were obtained with Hep3B cells. SOCS1 expressing HCC cells also showed reduced levels of EGR1 and SNAI1 transcripts.

CONCLUSION

Our findings indicate that loss of SOCS1-dependent control over epithelial-to-mesenchymal transition may contribute to MET-mediated migration, invasion and metastatic growth of HCC.

Keywords: Migration, Invasion, MET, Hepatocellular carcinoma, Suppressor of cytokine signaling 1

Core tip: The suppressor of cytokine signaling 1 (SOCS1) gene is frequently repressed in primary hepatocellular carcinoma (HCC) specimens, and mice lacking SOCS1 are highly susceptible to experimental HCC. The tumor suppressor functions of SOCS1 in HCC are not yet fully understood. We have shown that SOCS1 regulates hepatocyte growth factor signaling via the MET receptor in HCC cells and inhibits their growth. In this study, we characterize SOCS1 as a regulator of MET-mediated migration and invasion of HCC cells. We propose that SOCS1 gene expression status could be exploited as a selection marker for precision therapies targeting MET in HCC.