Abstract
Jinn-Yuan Hsu1, Kwang-Yu Chang2, Shang-Hung Chen3, Chung-Ta Lee4, Sheng-Tsung Chang5, Hung-Chi Cheng6, Wen-Chang Chang7, Ben-Kuen Chen7,8,9
1Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, ROC
2National Institute of Cancer Research, National Health Research Institutes and Division of Hematology/Oncology, Department of Internal Medicine, National Cheng Kung University, Tainan 701, Taiwan, ROC
3Division of Hematology and Oncology, Department of Internal Medicine, Chi-Mei Medical Center, Liouying, Tainan 736, Taiwan, ROC
4Department of Pathology, National Cheng Kung University Hospital, Tainan 701, Taiwan, ROC
5Department of Pathology, Chi-Mei Medical Center, Tainan 710, Taiwan, ROC
6Institute of Biochemistry, National Cheng Kung University, Tainan 701, Taiwan, ROC
7Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan, ROC
8Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, ROC
9Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan, ROC
Correspondence to:
Ben-Kuen Chen, e-mail: bkchen58@mail.ncku.edu.tw
Wen-Chang Chang, e-mail: wcchang@tmu.edu.tw
Keywords: EGF, metastasis, COX-2, fibronectin
Received: August 28, 2014 Accepted: November 19, 2014 Published: December 22, 2014
ABSTRACT
Epidermal growth factor receptor (EGFR) activation is a major cause of metastasis in many cancers, such as head and neck squamous cell carcinoma (HNSCC). However, whether the induction of cyclooxygenase-2 (COX-2) mediates EGF-enhanced HNSCC metastasis remains unclear. Interestingly, we found that EGF induced COX-2 expression mainly in HNSCC. The tumor cell transformation induced by EGF was repressed by COX-2 knockdown, and this repression was reversed by simultaneously treating the cells with EGF and prostaglandin E2 (PGE2). The down-regulation of COX-2 expression or inhibition of COX-2 activity significantly blocked EGF enhancement of cell migration and invasion, but the addition of PGE2 compensated for this inhibitory effect in COX-2-knockdown cells. COX-2 depletion inhibited EGF-induced matrix metalloproteinase (MMP)-1, MMP-2, MMP-3, MMP-9, and fibronectin expression and Rac1/cdc42 activation. The inhibitory effect of COX-2 depletion on MMPs and the fibronectin/Rac1/cdc42 axis were reversed by co-treatment with PGE2. Furthermore, depletion of fibronectin impeded the COX-2-enhanced binding of HNSCC cells to endothelial cells and tumor cells metastatic seeding of the lungs. These results demonstrate that EGF-induced COX-2 expression enhances HNSCC metastasis via activation of the fibronectin signaling pathway. The inhibition of COX-2 expression and activation may be a potential strategy for the treatment of EGFR-mediated HNSCC metastasis.