title: UHRF1-mediated tumor suppressor gene inactivation in nonsmall cell lung cancer.
abstract: BACKGROUND
  The UHRF1 gene possesses an essential role in DNA methylation maintenance, but its contribution to tumor suppressor gene hypermethylation in primary human cancers currently remains unclear.
  
  
  METHODS
  mRNA expression levels of UHRF1, DNMT1, DNMT3A, DNMT3B, and E2F1 were evaluated in 105 primary nonsmall cell lung carcinomas by quantitative polymerase chain reaction. The methylation status of CDKN2A and RASSF1 promoters was examined by pyrosequencing. UHRF1 was knocked down by short hairpin RNA in A549 lung adenocarcinoma cells.
  
  
  RESULTS
  All 4 genes were overexpressed in a coordinated manner in the lung tumor tissues, and their expression correlated with that of E2F1. Higher UHRF1 expression in tumor tissues correlated with the hypermethylation of CDKN2A (P = .005) and RASSF1 promoters (P = .034), and the relationship with a combined epigenotype was even stronger (P = 2.3 × 10(-4) ). When UHRF1 was knocked down in A549 lung adenocarcinoma cells, lower methylation levels of RASSF1, CYGB, and CDH13 promoters were observed. Also, UHRF1 knockdown clones demonstrated reduced proliferation and decreased cell migration properties.
  
  
  CONCLUSIONS
  Our data demonstrate that UHRF1 is a key epigenetic switch, which controls cell cycle in nonsmall cell lung carcinoma through its ability to sustain the transcriptional silencing of tumor suppressor genes by maintaining their promoters in a hypermethylated status. Thus, UHRF1 should be considered, along with DNMTs, among the potential targets for cancer treatment and/or therapeutic stratification.
authors.affiliation: Roy Castle Lung Cancer Research Programme, University of Liverpool, Department of Clinical and Molecular Cancer Medicine, Liverpool, United Kingdom.
authors.forename: Alexandros
authors.initials: A
authors.lastname: Daskalos
authors.forename: Urszula
authors.initials: U
authors.lastname: Oleksiewicz
authors.forename: Anastasia
authors.initials: A
authors.lastname: Filia
authors.forename: George
authors.initials: G
authors.lastname: Nikolaidis
authors.forename: George
authors.initials: G
authors.lastname: Xinarianos
authors.forename: John R
authors.initials: JR
authors.lastname: Gosney
authors.forename: Angeliki
authors.initials: A
authors.lastname: Malliri
authors.forename: John K
authors.initials: JK
authors.lastname: Field
authors.forename: Triantafillos
authors.initials: T
authors.lastname: Liloglou
mesh_terms: D022762:CCAAT-Enhancer-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000473:pathology; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism; D000090205:DNA Methyltransferase 3A; D050687:E2F1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000502:physiology; D016147:Genes, Tumor Suppressor / Q000502:physiology; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D014162:Transfection; D014407:Tumor Cells, Cultured; D044767:Ubiquitin-Protein Ligases; D000097584:DNA Methyltransferase 3B
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D050687:E2F1 Transcription Factor; D044767:Ubiquitin-Protein Ligases; D000097584:DNA Methyltransferase 3B; C000717967:DNMT3A protein, human; C493753:E2F1 protein, human; C000619380:DNMT1 protein, human; C406364:UHRF1 protein, human