title: Adhesion molecule periplakin is involved in cellular movement and attachment in pharyngeal squamous cancer cells.
abstract: BACKGROUND
  We previously reported that periplakin (PPL) is downregulated in human esophageal cancer tissues compared to the adjacent non-cancer epithelium. Thus PPL could be a useful marker for detection of early esophageal cancer and evaluation of tumor progression, but largely remains unknown in this field. To investigate PPL involvement in carcinogenesis, tumor progression, cellular movement or attachment activity, siRNAs against PPL were transfected into pharyngeal squamous cancer cell lines and their effects on cellular behaviours were examined.
  
  
  RESULTS
  PPL knockdown appeared to decrease tumor cell growth together with G2/M phase accumulation in cells attached to a culture dish. However, the extent of cell growth suppression, evaluated by the number of cells attached to the culture dish, was too distinctive to be explained only by cell cycle delay. Importantly, PPL knockdown suppressed cellular movement and attachment to the culture dish accompanied by decreased pAktSer473 phosphorylation. Additionally, LY294002, a PI3K inhibitor that dephosphorylates pAktSer473, significantly suppressed D562 cell migration. Thus PPL potentially engages in cellular movement al least partly via the PI3K/Akt axis.
  
  
  CONCLUSIONS
  PPL knockdown is related to reduced cellular movement and attachment activity in association with PI3K/Akt axis suppression, rather than malignant progression in pharyngeal cancer cells.
authors.affiliation: Department of Otorhinolaryngology, Chiba University Hospital, Chiba City, Japan.
authors.forename: Yurie
authors.initials: Y
authors.lastname: Tonoike
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Matsushita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tomonaga
authors.forename: Koji
authors.initials: K
authors.lastname: Katada
authors.forename: Nobuko
authors.initials: N
authors.lastname: Tanaka
authors.forename: Hideaki
authors.initials: H
authors.lastname: Shimada
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nakatani
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Fumio
authors.initials: F
authors.lastname: Nomura
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D002867:Chromones / Q000494:pharmacology; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D010610:Pharyngeal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D051179:Plakins / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D002867:Chromones; D009025:Morpholines; C491674:PPL protein, human; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051179:Plakins; D034741:RNA, Small Interfering; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C491754:AKT3 protein, human; D051057:Proto-Oncogene Proteins c-akt