title: MAGEB2 is activated by promoter demethylation in head and neck squamous cell carcinoma.
abstract: OBJECTIVE
  Although promoter hypermethylation has been an accepted means of tumor suppressor gene inactivation, activation of otherwise normally repressed proto-oncogenes by promoter demethylation has been infrequently documented.
  
  
  METHODS
  In this study we performed an integrative, whole-genome analysis for discovery of epigenetically activated proto-oncogenes in head and neck cancer tumors. We used the 47K GeneChip U133 Plus 2.0 Affymetrix expression microarray platform to obtain re-expression data from 5-aza treated normal cell line and expression data from primary head and neck squamous cell carcinoma (HNSCC) tumor tissues and normal mucosa tissues. We then investigated candidate genes by screening promoter regions for CpG islands and bisulfite sequencing followed by QUMSP and RT PCR for the best candidate genes. Finally, functional studies were performed on the top candidate gene.
  
  
  RESULTS
  From the top 178 screened candidates 96 had CpG islands in their promoter region. Seven candidate genes showed promoter region methylation in normal mucosa samples and promoter demethylation in a small cohort of primary HNSCC tissues. We then studied the demethylation of the top 3 candidate genes in an expanded cohort of 76 HNSCC tissue samples and 17 normal mucosa samples. We identified MAGEB2 as having significant promoter demethylation in primary head and neck squamous cell carcinoma tissues. We then found significantly higher expression of MAGEB2 in tumors in a separate cohort of 73 primary HNSCC tissues and 31 normal tissues. Finally, we found that MAGEB2 has growth promoting effects on minimally transformed oral keratinocyte cell lines but not a definite effect on HNSCC cell lines.
  
  
  CONCLUSIONS
  In conclusion, we identified MAGEB2 as activated by promoter demethylation in HNSCCand demonstrates growth promoting effects in a minimally transformed oral keratinocyte cell line. More studies are needed to evaluate MAGBE2's exact role in HNSCC.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Kavita M
authors.initials: KM
authors.lastname: Pattani
authors.forename: Ethan
authors.initials: E
authors.lastname: Soudry
authors.forename: Chad A
authors.initials: CA
authors.lastname: Glazer
authors.forename: Michael F
authors.initials: MF
authors.lastname: Ochs
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Juliana
authors.initials: J
authors.lastname: Schussel
authors.forename: Wenyue
authors.initials: W
authors.lastname: Sun
authors.forename: Patrick
authors.initials: P
authors.lastname: Hennessey
authors.forename: Wojciech
authors.initials: W
authors.lastname: Mydlarz
authors.forename: Myriam
authors.initials: M
authors.lastname: Loyo
authors.forename: Semra
authors.initials: S
authors.lastname: Demokan
authors.forename: Ian M
authors.initials: IM
authors.lastname: Smith
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Califano
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015203:Reproducibility of Results; D015533:Transcriptional Activation
chemical_list: D000951:Antigens, Neoplasm; D000964:Antimetabolites, Antineoplastic; C072012:MAGEB2 protein, human; D009363:Neoplasm Proteins; D001374:Azacitidine