Original Article
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 21, 2014; 20(47): 17863-17876
Published online Dec 21, 2014. doi: 10.3748/wjg.v20.i47.17863
Claudin 1 mediates tumor necrosis factor alpha-induced cell migration in human gastric cancer cells
Atsushi Shiozaki, Hiroki Shimizu, Daisuke Ichikawa, Hirotaka Konishi, Shuhei Komatsu, Takeshi Kubota, Hitoshi Fujiwara, Kazuma Okamoto, Daisuke Iitaka, Shingo Nakashima, Yoshito Nako, Mingyao Liu, Eigo Otsuji
Atsushi Shiozaki, Hiroki Shimizu, Daisuke Ichikawa, Hirotaka Konishi, Shuhei Komatsu, Takeshi Kubota, Hitoshi Fujiwara, Kazuma Okamoto, Daisuke Iitaka, Shingo Nakashima, Yoshito Nako, Eigo Otsuji, Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
Mingyao Liu, Latner Thoracic Surgery Research Laboratories, University Health Network Toronto General Research Institute, Toronto M5G 1L7, Canada
Mingyao Liu, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto M5G 1L7, Canada
Author contributions: Shiozaki A and Shimizu H contributed equally to this work; Shiozaki A and Shimizu H designed the study, wrote the manuscript and performed the majority of the experiments; Ichikawa D, Konishi H, Komatsu S, Kubota T, Fujiwara H and Okamoto K analyzed the microarray data; Iitaka D, Nakashima S and Nako Y analyzed cell migration and invasion; Liu M and Otsuji E were involved in editing the manuscript.
Supported by Grants-in-Aid for Young Scientists (B); No. 22791295, No. 23791557 and No. 24791440; and Grant-in-Aid for Scientific Research (C) from the Japan Society for the Promotion of Science, No. 22591464 and No. 24591957
Correspondence to: Atsushi Shiozaki, Assistant Professor, Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto 602-8566, Japan. shiozaki@koto.kpu-m.ac.jp
Telephone: +81-75-2515527 Fax: +81-75-2515522
Received: January 17, 2014
Revised: May 2, 2014
Accepted: June 13, 2014
Published online: December 21, 2014
Processing time: 337 Days and 3.7 Hours
Abstract

AIM: To investigate the role of claudin 1 in the regulation of genes involved in cell migration and tumor necrosis factor alpha (TNF-α)-induced gene expression in human gastric adenocarcinoma cells.

METHODS: Knockdown experiments were conducted with claudin 1 small interfering RNA (siRNA), and the effects on the cell cycle, apoptosis, migration and invasion were analyzed in human gastric adenocarcinoma MKN28 cells. The gene expression profiles of cells were analyzed by microarray and bioinformatics.

RESULTS: The knockdown of claudin 1 significantly inhibited cell proliferation, migration and invasion, and increased apoptosis. Microarray analysis identified 245 genes whose expression levels were altered by the knockdown of claudin 1. Pathway analysis showed that the top-ranked molecular and cellular function was the cellular movement related pathway, which involved MMP7, TNF-SF10, TGFBR1, and CCL2. Furthermore, TNF- and nuclear frctor-κB were the top-ranked upstream regulators related to claudin 1. TNF-α treatment increased claudin 1 expression and cell migration in MKN28 cells. Microarray analysis indicated that the depletion of claudin 1 inhibited 80% of the TNF-α-induced mRNA expression changes. Further, TNF-α did not enhance cell migration in the claudin 1 siRNA transfected cells.

CONCLUSION: These results suggest that claudin 1 is an important messenger that regulates TNF-α-induced gene expression and migration in gastric cancer cells. A deeper understanding of these cellular processes may be helpful in establishing new therapeutic strategies for gastric cancer.

Keywords: Tumor necrosis factor alpha; Claudin 1; Cell migration; Microarray; Gene expression change

Core tip: The objectives of the present research were to investigate the role of claudin 1 in the regulation of genes involved in cell migration and tumor necrosis factor alpha (TNF-α)-induced gene expression in human gastric adenocarcinoma cells. Claudin 1 small interfering RNA transfection significantly inhibited cell migration and invasion in gastric cancer cells. Microarray analyses showed that down-regulation of claudin 1changed the expression levels of many genes related to cellular movement and TNF-α signal. We showed that TNF-α treatment induces the expression of claudin 1 in gastric carcinoma cells, and the latter controls gene expression and cell migration as the signal mediator.