title: Identification of a Novel Proto-oncogenic Network in Head and Neck Squamous Cell Carcinoma.
abstract: BACKGROUND
  The developmental transcription factor Grainyhead-like 3 (GRHL3) plays a critical tumor suppressor role in the mammalian epidermis through direct regulation of PTEN and the PI3K/AKT/mTOR signaling pathway. GRHL3 is highly expressed in all tissues derived from the surface ectoderm, including the oral cavity, raising a question about its potential role in suppression of head and neck squamous cell carcinoma (HNSCC).
  
  
  METHODS
  We explored the tumor suppressor role of Grhl3 in HNSCC using a conditional knockout (Grhl3 (∆/-) /K14Cre (+) ) mouse line (n = 26) exposed to an oral chemical carcinogen. We defined the proto-oncogenic pathway activated in the HNSCC derived from these mice and assessed it in primary human HNSCC samples, normal oral epithelial cell lines carrying shRNA to GRHL3, and human HNSCC cell lines. Data were analyzed with two-sided chi square and Student's t tests.
  
  
  RESULTS
  Deletion of Grhl3 in oral epithelium in mice did not perturb PTEN/PI3K/AKT/mTOR signaling, but instead evoked loss of GSK3B expression, resulting in stabilization and accumulation of c-MYC and aggressive HNSCC. This molecular signature was also evident in a subset of primary human HNSCC and HNSCC cell lines. Loss of Gsk3b in mice, independent of Grhl3, predisposed to chemical-induced HNSCC. Restoration of GSK3B expression blocked proliferation of normal oral epithelial cell lines carrying shRNA to GRHL3 (cell no., Day 8: Scramble ctl, 616±21.8 x 10(3) vs GRHL3-kd, 1194±44 X 10(3), P < .001; GRHL3-kd vs GRHL3-kd + GSK3B, 800±98.84 X 10(3), P = .003) and human HNSCC cells.
  
  
  CONCLUSIONS
  We defined a novel molecular signature in mammalian HNSCC, suggesting new treatment strategies targeting the GRHL3/GSK3B/c-MYC proto-oncogenic network.
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Smitha R
authors.initials: SR
authors.lastname: Georgy
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Michael
authors.initials: M
authors.lastname: Cangkrama
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Seema
authors.initials: S
authors.lastname: Srivastava
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Darren
authors.initials: D
authors.lastname: Partridge
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Alana
authors.initials: A
authors.lastname: Auden
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dworkin
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Catriona A
authors.initials: CA
authors.lastname: McLean
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ). stephen.jane@monash.edu.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Jane
authors.affiliation: Department of Medicine, Monash University Central Clinical School, Prahran, Victoria 3004, Australia (SRG, MC, SS, DP, AA, SD, SMJ, CD); Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria 3004, Australia (CAM); Department of Hematology, Alfred Hospital, Prahran VIC 3181, Australia (SMJ).
authors.forename: Charbel
authors.initials: C
authors.lastname: Darido
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006258:Head and Neck Neoplasms / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D015398:Signal Transduction; D000077195:Squamous Cell Carcinoma of Head and Neck; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D004268:DNA-Binding Proteins; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D016271:Proto-Oncogene Proteins c-myc; D058570:TOR Serine-Threonine Kinases; D014157:Transcription Factors; C473143:GRHL3 protein, human; C499942:Grhl3 protein, mouse; C489427:MYC protein, human; C489428:Myc protein, mouse; C546842:MTOR protein, human; C000605506:GSK3B protein, human; C000605507:Gsk3b protein, mouse; C494929:PTEN protein, human