title: RUNX3 has an oncogenic role in head and neck cancer.
abstract: BACKGROUND
  Runt-related transcription factor 3 (RUNX3) is a tumor suppressor of cancer and appears to be an important component of the transforming growth factor-beta (TGF-ss)-induced tumor suppression pathway. Surprisingly, we found that RUNX3 expression level in head and neck squamous cell carcinoma (HNSCC) tissues, which is one of the most common types of human cancer, was higher than that in normal tissues by a previously published microarray dataset in our preliminary study. Therefore, here we examined the oncogenic role of RUNX3 in HNSCC.
  
  
  RESULTS
  Frequent RUNX3 expression and its correlation with malignant behavior were observed in HNSCC. Ectopic RUNX3 overexpression promoted cell growth and inhibited serum starvation-induced apoptosis and chemotherapeutic drug induced apoptosis in HNSCC cells. These findings were confirmed by RUNX3 knockdown. Moreover, RUNX3 overexpression enhanced tumorsphere formation. RUNX3 expression level was well correlated with the methylation status in HNSCC cells. Moreover, RUNX3 expression was low due to the methylation of its promoter in normal oral epithelial cells.
  
  
  CONCLUSIONS
  Our findings suggest that i) RUNX3 has an oncogenic role in HNSCC, ii) RUNX3 expression observed in HNSCC may be caused in part by demethylation during cancer development, and iii) RUNX3 expression can be a useful marker for predicting malignant behavior and the effect of chemotherapeutic drugs in HNSCC.
authors.affiliation: Division of Frontier Medical Science, Department of Oral and Maxillofacial Pathobiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tsunematsu
authors.forename: Yasusei
authors.initials: Y
authors.lastname: Kudo
authors.forename: Shinji
authors.initials: S
authors.lastname: Iizuka
authors.forename: Ikuko
authors.initials: I
authors.lastname: Ogawa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Fujita
authors.forename: Hidemi
authors.initials: H
authors.lastname: Kurihara
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Abiko
authors.forename: Takashi
authors.initials: T
authors.lastname: Takata
mesh_terms: D017209:Apoptosis; D014408:Biomarkers, Tumor; D002294:Carcinoma, Squamous Cell; D045744:Cell Line, Tumor; D050677:Core Binding Factor Alpha 3 Subunit / Q000096:biosynthesis* / Q000502:physiology*; D019175:DNA Methylation; D004847:Epithelial Cells / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006258:Head and Neck Neoplasms / Q000378:metabolism*; D006801:Humans; D009062:Mouth Neoplasms / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D050677:Core Binding Factor Alpha 3 Subunit; D034741:RNA, Small Interfering; C493729:Runx3 protein, human; D016212:Transforming Growth Factor beta