title: Restoration of E-cadherin expression by selective Cox-2 inhibition and the clinical relevance of the epithelial-to-mesenchymal transition in head and neck squamous cell carcinoma.
abstract: BACKGROUND
  The epithelial-to-mesenchymal transition (EMT) accompanied by the downregulation of E-cadherin has been thought to promote metastasis. Cyclooxygenase-2 (Cox-2) is presumed to contribute to cancer progression through its multifaceted function, and recently its inverse relationship with E-cadherin was suggested. The aim of the present study was to investigate whether selective Cox-2 inhibitors restore the expression of E-cadherin in head and neck squamous cell carcinoma (HNSCC) cells, and to examine the possible correlations of the expression levels of EMT-related molecules with clinicopathological factors in HNSCC.
  
  
  METHODS
  We used quantitative real-time PCR to examine the effects of three selective Cox-2 inhibitors, i.e., celecoxib, NS-398, and SC-791 on the gene expressions of E-cadherin (CDH-1) and its transcriptional repressors (SIP1, Snail, Twist) in the human HNSCC cell lines HSC-2 and HSC-4. To evaluate the changes in E-cadherin expression on the cell surface, we used a flowcytometer and immunofluorescent staining in addition to Western blotting. We evaluated and statistically analyzed the clinicopathological factors and mRNA expressions of Cox-2, CDH-1 and its repressors in surgical specimens of 40 patients with tongue squamous cell carcinoma (TSCC).
  
  
  RESULTS
  The selective Cox-2 inhibitors upregulated the E-cadherin expression on the cell surface of the HNSCC cells through the downregulation of its transcriptional repressors. The extent of this effect depended on the baseline expression levels of both E-cadherin and Cox-2 in each cell line. A univariate analysis showed that higher Cox-2 mRNA expression (p = 0.037), lower CDH-1 mRNA expression (p = 0.020), and advanced T-classification (p = 0.036) were significantly correlated with lymph node metastasis in TSCC. A multivariate logistic regression revealed that lower CDH-1 mRNA expression was the independent risk factor affecting lymph node metastasis (p = 0.041).
  
  
  CONCLUSIONS
  These findings suggest that the appropriately selective administration of certain Cox-2 inhibitors may have an anti-metastatic effect through suppression of the EMT by restoring E-cadherin expression. In addition, the downregulation of CDH-1 resulting from the EMT may be closely involved in lymph node metastasis in TSCC.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Fujii
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan. yorihisa@ja2.so-net.ne.jp.
authors.forename: Yorihisa
authors.initials: Y
authors.lastname: Imanishi
authors.forename: Katsushi
authors.initials: K
authors.lastname: Shibata
authors.forename: Nobuya
authors.initials: N
authors.lastname: Sakai
authors.forename: Koji
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Seiji
authors.initials: S
authors.lastname: Shigetomi
authors.forename: Noboru
authors.initials: N
authors.lastname: Habu
authors.forename: Kuninori
authors.initials: K
authors.lastname: Otsuka
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Sato
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ozawa
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tomita
authors.forename: Kaori
authors.initials: K
authors.lastname: Kameyama
authors.forename: Masato
authors.initials: M
authors.lastname: Fujii
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D015703:Antigens, CD; D000970:Antineoplastic Agents / Q000494:pharmacology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000556:secondary; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology; D015999:Multivariate Analysis; D009578:Nitrobenzenes / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012307:Risk Factors; D013449:Sulfonamides / Q000494:pharmacology*; D014059:Tongue / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D000970:Antineoplastic Agents; C513384:CDH1 protein, human; D015820:Cadherins; D052246:Cyclooxygenase 2 Inhibitors; D009578:Nitrobenzenes; D012333:RNA, Messenger; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human