TFF-1 Functions to Suppress Multiple Phenotypes Associated with Lung Cancer Progression

Abstract

Kentaro Minegishi,1 Yoh Dobashi,2,3 Hiroyoshi Tsubochi,1 Koichi Hagiwara,4 Yuko Ishibashi,5,6 Sachiyo Nomura,7 Ritsuko Nakamura,8 Yasukazu Ohmoto,9 Shunsuke Endo1 1Department of Thoracic Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan; 2Department of Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan; 3Department of Pathology, School of Medicine, International University of Health and Welfare, Tochigi, Japan; 4Division of Pulmonary Medicine, Department of Medicine, Jichi Medical University, Tochigi, Japan; 5Department of Breast and Endocrine Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 6Division of Breast Surgery, Hospital of the National Center for the Global Health and Medicine, Tokyo, Japan; 7Department of Gastrointestinal Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 8Department of Molecular and Cellular Pathology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan; 9Tokushima University Industry-University R&D Startup Leading Institute, Tokushima, JapanCorrespondence: Yoh DobashiDepartment of Pathology, School of Medicine, International University of Health and Welfare, 537-3 Iguchi, Nasushiobara, Tochigi, 329-2763, JapanTel [phone]Fax [phone]Email [email protected]: Trefoil Factor (TFF) is a member of a protein family comprised of three isoforms, of which TFF-1 exhibits antithetical functions; promotion or suppression of cell proliferation, survival and invasion, depending on the cancer type. However, the pathobiological function of TFF-1 in lung carcinoma has been still unclear.Methods: We examined the expression and secretion of TFF-1 using cultured human lung carcinoma cells by immunoblotting, immunofluorescence, enzyme-linked immunosorbent assay and quantitative real-time PCR analyses. The effects of TFF-1 on various phenotypes were analyzed in two cell lines, including those transfected with cDNA encoding TFF-1. Cell proliferation and death were examined by hemocytometer cell counting and by colorimetric viability/cytotoxicity assay. Cell cycle profile, migration and invasion were also examined by flow cytometry, wound healing assay and Matrigel Transwell assay, respectively. The effect of TFF-1 overexpression was confirmed by additional transfection of TFF-1-specific siRNA.Results: Endogenous TFF-1 protein expression and secretion into the media were observed exclusively in adenocarcinoma-derived cell lines. Forced overexpression of TFF-1 drove cell cycle transition, while the proliferation decreased by 19% to 25% due to increased cell death. This cell death was predominantly caused by apoptosis, as assessed by the activation of caspase 3/7. Cell migration was also suppressed by 71% to 82% in TFF-1-transfected cells. The suppressive effect of TFF-1 on proliferation and migration was restored by transfection of TFF-1 siRNA. Moreover, invasion was also suppressed to 77% to 83% in TFF-1-transfected cells.Conclusion: These findings reveal that TFF-1 functions as a suppressor of cancer proliferation by induction of apoptosis, cell migration and invasion and thus may provide a synergistic target for potential treatment strategies for human lung carcinoma.Keywords: TFF-1, lung carcinoma cells, growth inhibition, apoptosis, migration, invasion

Keywords

• tff-1
• lung carcinoma cells
• growth inhibition
• apoptosis
• migration
• invasion