title: Role of DNA methyltransferase 1 in pharyngeal cancer related to treatment resistance.
abstract: BACKGROUND
  The purpose of the present study was to highlight the role of DNA methyltransferase 1 (DNMT1) and its potential for improving treatment and informing prognosis for pharyngeal cancer.
  
  
  METHODS
  Human pharyngeal cancer cell lines FaDu and its derivative FaDu-C225-R were selected for cellular experiments. Furthermore, 95 pharyngeal cancer tissue specimens were analyzed by immunohistochemical staining.
  
  
  RESULTS
  DNMT1 was over-expressed in pharyngeal cancer specimens and cells with activated interleukin (IL)-6 signaling. When DNMT1 activity was blocked, accelerated tumor growth and treatment resistance were overcome as demonstrated by cell culture and animal experiments. The reduction in DNMT1 was associated with increased apoptosis, cell cycle arrest, and augmented irradiation-induced free radical levels and DNA damage. Furthermore, positive staining for DNMT1 in clinical cancer specimens was significantly linked to lower rates of response to treatments and shorter survival of patients with pharyngeal cancer.
  
  
  CONCLUSIONS
  DNMT1 may be a significant clinical predictor and a potential treatment strategy against head and neck cancer.
authors.affiliation: Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan.
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Chen
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Chen
authors.forename: Wen-Hung
authors.initials: WH
authors.lastname: Wang
authors.forename: Chang-Hsien
authors.initials: CH
authors.lastname: Lu
authors.forename: Paul-Yang
authors.initials: PY
authors.lastname: Lin
authors.forename: Kuan-Der
authors.initials: KD
authors.lastname: Lee
authors.forename: Miao-Fen
authors.initials: MF
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000818:Animals; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D016001:Confidence Intervals; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010610:Pharyngeal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D011237:Predictive Value of Tests; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D016019:Survival Analysis; D017211:Treatment Failure; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: C411744:DMAP1 protein, human; D005819:Genetic Markers; D012097:Repressor Proteins