title: Association between Long Interspersed Nuclear Element-1 Methylation and Relative Telomere Length in Wilms Tumor.
abstract: BACKGROUND
  DNA hypomethylation of long interspersed nuclear elements-1 (LINEs-1) occurs during carcinogenesis, whereas information addressing LINE-1 methylation in Wilms tumor (WT) is limited. The main purpose of our study was to quantify LINE-1 methylation levels and evaluate their relationship with relative telomere length (TL) in WT.
  
  
  METHODS
  We investigated LINE-1 methylation and relative TL using bisulfite-polymerase chain reaction (PCR) pyrosequencing and quantitative PCR, respectively, in 20 WT tissues, 10 normal kidney tissues and a WT cell line. Significant changes were analyzed by t-tests.
  
  
  RESULTS
  LINE-1 methylation levels were significantly lower (P < 0.05) and relative TLs were significantly shorter (P < 0.05) in WT compared with normal kidney. There was a significant positive relationship between LINE-1 methylation and relative TL in WT (r = 0.671, P = 0.001). LINE-1 Methylation levels were significantly associated with global DNA methylation (r = 0.332, P < 0.01). In addition, relative TL was shortened and LINE-1 methylation was decreased in a WT cell line treated with the hypomethylating agent 5-aza-2'-deoxycytidine compared with untreated WT cell line.
  
  
  CONCLUSIONS
  These results suggest that LINE-1 hypomethylation is common and may be linked to telomere shortening in WT.
authors.forename: Hui-Bo
authors.initials: HB
authors.lastname: Chang
authors.forename: Ji-Zhen
authors.initials: JZ
authors.lastname: Zou
authors.forename: Cai
authors.initials: C
authors.lastname: He
authors.forename: Rui
authors.initials: R
authors.lastname: Zeng
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Li
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Ma
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Liu
authors.forename: Hui
authors.initials: H
authors.lastname: Ye
authors.affiliation: Department of Biochemistry, Capital Institute of Pediatrics, Beijing 100020, China.
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Wu
mesh_terms: D045744:Cell Line, Tumor; D002648:Child; D002675:Child, Preschool; D019175:DNA Methylation / Q000235:genetics; D005260:Female; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D016133:Polymerase Chain Reaction; D016615:Telomere / Q000235:genetics*; D009396:Wilms Tumor / Q000235:genetics*