title: Tight junction protein claudin-1 enhances the invasive activity of oral squamous cell carcinoma cells by promoting cleavage of laminin-5 gamma2 chain via matrix metalloproteinase (MMP)-2 and membrane-type MMP-1.
abstract: Although adherent junctions have been extensively studied, the role of tight junctions in cancer cell invasion is not sufficiently explored. We investigated whether claudin-1, a component of tight junctions, regulated invasion activity in oral squamous cell carcinoma (OSC) cells. The expression of claudin-1, activity of matrix metalloproteinase (MMP)-2, and cleavage of laminin-5 gamma2 chains were assessed by Western blot analysis, immunohistochemistry, and zymography in OSC cell lines (OSC-4 and NOS-2, highly invasive; OSC-7, weakly invasive) and their xenografts in severe combined immunodeficient (SCID) mice. The influence of claudin-1 small interfering RNA (siRNA) on the invasion activity of the cell lines was also investigated. Compared with OSC-7, both OSC-4 and NOS-2 more strongly expressed claudin-1 and possessed high activities of MMP-2 and MMP-9. Tumors formed in the tongues of SCID mice xenografted with OSC-4, NOS-2, and OSC-7 immunohistochemically revealed strong, moderate, and weak expression of laminin-5 gamma2 chains, respectively, and laminin-5 gamma2 chains were secreted in the conditioned medium of the cancer cells in parallel with the in vivo results. Claudin-1 siRNA largely suppressed the invasion of OSC-4 and decreased the activation of MMP-2, the expression of membrane-type MMP-1 (MT1-MMP), and the cleavage of laminin-5 gamma2. In addition, not only antibodies against MT1-MMP and epidermal growth factor receptor (EGFR) but also MMP-2 and EGFR inhibitors strongly suppressed the invasion activity of OSC-4. These results suggest that claudin-1 up-regulates cancer cell invasion activity through activation of MT1-MMP and MMP-2, which results in enhanced cleavage of laminin-5 gamma2 chains.
authors.affiliation: Department of Oral Oncology, Kochi Medical School, Kochi University, Kohasu, Oko-cho, Nankoku-city, Kochi, Japan. nao_sachi228@yahoo.co.jp
authors.forename: Naohisa
authors.initials: N
authors.lastname: Oku
authors.forename: Eri
authors.initials: E
authors.lastname: Sasabe
authors.forename: Eisaku
authors.initials: E
authors.lastname: Ueta
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Tokio
authors.initials: T
authors.lastname: Osaki
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D062445:Claudin-1; D062506:Claudin-4; D006801:Humans; D007150:Immunohistochemistry; D007797:Laminin / Q000378:metabolism*; D008297:Male; D053511:Matrix Metalloproteinase 14; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D016513:Mice, SCID; D009062:Mouth Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D062793:Occludin; D034741:RNA, Small Interfering / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014062:Tongue Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D014183:Transplantation, Heterologous; D015854:Up-Regulation
chemical_list: C568108:CLDN1 protein, human; C568157:CLDN4 protein, human; D062445:Claudin-1; D062506:Claudin-4; C568113:Cldn1 protein, mouse; C568158:Cldn4 protein, mouse; C400567:LAMC2 protein, human; D007797:Laminin; D008565:Membrane Proteins; C507096:Mmp14 protein, mouse; C568985:OCLN protein, human; D062793:Occludin; C568986:Ocln protein, mouse; D034741:RNA, Small Interfering; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D020782:Matrix Metalloproteinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14