Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 28, 2015; 21(8): 2323-2335
Published online Feb 28, 2015. doi: 10.3748/wjg.v21.i8.2323
Silencing profilin-1 inhibits gastric cancer progression via integrin β1/focal adhesion kinase pathway modulation
Ya-Jun Cheng, Zhen-Xin Zhu, Jian-Sheng Zhou, Zun-Qi Hu, Jian-Peng Zhang, Qing-Ping Cai, Liang-Hua Wang
Ya-Jun Cheng, Zhen-Xin Zhu, Zun-Qi Hu, Qing-Ping Cai, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
Jian-Sheng Zhou, Jian-Peng Zhang, Liang-Hua Wang, Biochemistry and Molecular Biology Department, Second Military Medical University, Shanghai 200433, China
Author contributions: Cai QP and Wang LH designed the research; Cheng YJ and Hu ZQ performed the research; Zhang JP contributed new reagents or analytic tools; Zhu ZX analyzed the data; Cheng YJ and Zhou JS drafted the manuscript; Cheng YJ, Zhu ZX and Zhou JS contributed equally to this work.
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: Qing-Ping Cai, MD, Gastrointestinal Surgery Department, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003, China. wcwk2013@live.cn
Telephone: +86-21-63520020 Fax: +86-21-81885601
Received: April 25, 2014
Peer-review started: April 27, 2014
First decision: May 27, 2014
Revised: July 22, 2014
Accepted: October 15, 2014
Article in press: October 15, 2014
Published online: February 28, 2015
Processing time: 309 Days and 2.9 Hours
Abstract

AIM: To investigate the role of profilin-1 (PFN1) in gastric cancer and the underlying mechanisms.

METHODS: Immunohistochemical analysis, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect PFN1 expression in clinical gastric carcinoma and adjacent tissues, and the association of PFN1 expression with patient clinicopathological characteristics was analyzed. PFN1 was knocked down to investigate the role of this protein in cell proliferation and metastasis in the SGC-7901 cell line. To explore the underlying mechanisms, the expression of integrin β1 and the activity of focal adhesion kinase (FAK) and the downstream proteins extracellular-regulated kinase (ERK)1/2, P38 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), AKT and mammalian target of rapamycin (mTOR) were measured through Western blot or qRT-PCR analysis. Fibronectin (FN), a ligand of integrin β1, was used to verify the correlation between alterations in the integrin β1/FAK pathway and changes in tumor cell aggressiveness upon PFN1 perturbation.

RESULTS: Immunohistochemical, Western blot and qRT-PCR analyses revealed that PFN1 expression was higher at both the protein and mRNA levels in gastric carcinoma tissues compared with the adjacent tissues. In addition, high PFN1 expression (53/75, 70.4%) was correlated with tumor infiltration, lymph node metastasis and TNM stage in gastric cancer, but not with gender, age, location, tumor size, or histological differentiation. In vitro experiments showed that PFN1 knockdown inhibited the proliferation of SGC-7901 cells through the induction G0/G1 arrest. Silencing PFN1 inhibited cell migration and invasion and down-regulated the expression of matrix metalloproteinase (MMP)-2 and MMP9. Moreover, silencing PFN1 reduced the expression of integrin β1 at the protein level and inhibited the activity of FAK, and the downstream effectors ERK1/2, P38MAPK, PI3K, AKT and mTOR. FN-promoted cell proliferation and metastasis via the integrin β1/FAK pathway was ameliorated by PFN1 silencing.

CONCLUSION: These findings suggest that PFN1 plays a critical role in gastric carcinoma progression, and these effects are likely mediated through the integrin β1/FAK pathway.

Keywords: Gastric cancer; Profilin-1; Integrin β1; Focal adhesion kinase; Fibronectin

Core tip: The expression of profilin-1 (PFN1) has been detected in many types of human cancers and has also been associated with tumor malignancy. However, the role of PFN1 in gastric carcinoma is unclear. The results of the present study suggest an important role for PFN1 in gastric cancer. PFN1 is overexpressed in gastric cancer, associated with tumor infiltration, lymph node metastasis and TNM stage. Furthermore, we demonstrated that PFN1 silencing inhibits gastric cancer cell proliferation, migration and invasion through the integrin β1/focal adhesion kinase pathway.