title: Exocyst complex component Sec8: a presumed component in the progression of human oral squamous-cell carcinoma by secretion of matrix metalloproteinases.
abstract: OBJECTIVE
  Sec8, a component of the exocyst complex, has been implicated in tethering of secretory vesicles to specific regions on the plasma membrane. To investigate the involvement of Sec8 in oral squamous-cell carcinoma (OSCC), we evaluated the expression status and effect of Sec8 in OSCC cell lines.
  
  
  METHODS
  Sec8 mRNA and protein expressions in human OSCC cell lines were assessed by quantitative reverse transcriptase-polymerase chain reaction and immunoblotting. Functional analyses, proliferation assay, invasiveness assay, and gelatin zymography in Sec8 knockdown cells were performed. Also the correlation between Sec8 expression and the clinicopathological features in 98 primary OSCCs samples was evaluated by immunohistochemistry.
  
  
  RESULTS
  Sec8 mRNA and protein expression were significantly up-regulated in all cell lines (p < 0.05). Sec8 knockdown cells were characterized by reduced cellular proliferation, invasiveness, and secretion of matrix metalloproteinases (MMPs) (MMP-2, proMMP-2, and proMMP-9). Sec8 protein expression in primary OSCCs also was significantly (p < 0.05) greater than in normal counterparts, and higher Sec8 expression was correlated with tumor size (p = 0.03).
  
  
  CONCLUSIONS
  Our results suggested for the first time that Sec8 might play a specific role in OSCC progression by mediating MMP secretion.
authors.affiliation: Department of Clinical Molecular Biology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kasamatsu
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Ishige
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Koike
authors.forename: Kengo
authors.initials: K
authors.lastname: Saito
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Kouzu
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Koike
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: Katsunori
authors.initials: K
authors.lastname: Ogawara
authors.forename: Masashi
authors.initials: M
authors.lastname: Shiiba
authors.forename: Hideki
authors.initials: H
authors.lastname: Tanzawa
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Uzawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D018450:Disease Progression; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism*; D009062:Mouth Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D033921:Vesicular Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: C489607:EXOC4 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D033921:Vesicular Transport Proteins; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9