title: The promoter of miR-663 is hypermethylated in Chinese pediatric acute myeloid leukemia (AML).
abstract: BACKGROUND
  There is growing evidence supporting a role for microRNAs (miRNA) as targets in aberrant mechanisms of DNA hypermethylation. Epigenetic silencing of tumor suppressor miRNAs, including miR-663, which has recently been reported to be inactivated by hypermethylation in several cancers, may play important roles in pediatric acute myeloid leukemia (AML). However, expression of miR-663 and its promoter methylation remain status unclear in childhood leukemia.
  
  
  METHODS
  Promoter methylation status of miR-663 was investigated by methylation specific PCR (MSP) and bisulfate genomic sequencing (BGS). Transcriptional expression of miR-663 was evaluated by semi-quantitative and real-time PCR, and the relationship between expression of miR-663 and promoter methylation was confirmed using 5-aza-2'-deoxycytidine (5-Aza) demethylation reagent.
  
  
  RESULTS
  MiR-663 was aberrantly methylated in 45.5% (5/11) leukemia cell lines; BGS showed that the promoter was significantly methylated in three AML cell lines; methylation of miR-663 was significantly higher in Chinese pediatric AML patients [41.4% (29/70)] compared to normal bone marrow (NBM) control samples [10.0% (3/30)]. These results were confirmed by both BGS and 5-Aza demethylation analysis. In addition, miR-663 transcript expression was significantly lower in AML patients, both with and without miR-663 methylation, compared to controls; however, there were no significant differences in clinical features or French-American-British (FAB) classification between patients with and without miR-663 methylation.
  
  
  CONCLUSIONS
  Expression of miR-663 was significantly lower in pediatric AML cells compared to NBM controls; furthermore, a high frequency of miR-663 promoter hypermethylation was observed in both AML cell lines and pediatric AML samples. Inactivation of miR-663 by promoter hypermethylation could be affected by 5-Aza demethylation. These findings suggest that hypermethylation of the miR-663 promoter may be an early event in the development of pediatric AML.
authors.affiliation: Department of Hematology and Oncology, Children's Hospital of Soochow University, Suzhou, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yan-Fang
authors.forename: Ni
authors.initials: N
authors.lastname: Jian
authors.forename: Lu
authors.initials: L
authors.lastname: Jun
authors.forename: Wang
authors.initials: W
authors.lastname: Na
authors.forename: Xiao
authors.initials: X
authors.lastname: Pei-Fang
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wen-Li
authors.forename: Wu
authors.initials: W
authors.lastname: Dong
authors.forename: Pang
authors.initials: P
authors.lastname: Li
authors.forename: Wang
authors.initials: W
authors.lastname: Jian
authors.forename: Feng
authors.initials: F
authors.lastname: Xing
authors.forename: Pan
authors.initials: P
authors.lastname: Jian
mesh_terms: D000293:Adolescent; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001853:Bone Marrow; D045744:Cell Line, Tumor; D002648:Child; D002675:Child, Preschool; D002681:China; D019175:DNA Methylation; D000077209:Decitabine; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D007223:Infant; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: C552243:MIRN663 microRNA, human; D035683:MicroRNAs; D000077209:Decitabine; D001374:Azacitidine