title: 5-Hydroxymethylcytosine promotes proliferation of human uterine leiomyoma: a biological link to a new epigenetic modification in benign tumors.
abstract: BACKGROUND
  Uterine leiomyoma, or fibroids, represent the most common benign tumors of the female reproductive tract. A newly discovered epigenetic modification, 5-hydroxymethylation (5-hmC), and its regulators, the TET (Ten Eleven Translocation) enzymes, were implicated in the pathology of malignant tumors; however, their roles in benign tumors, including uterine fibroids, remain unknown.
  
  
  OBJECTIVE
  To determine the role of 5-hmC and TET proteins in the pathogenesis of leiomyoma using human uterine leiomyoma and normal matched myometrial tissues and primary cells.
  
  
  METHODS
  5-hmC levels were determined by ELISA and immunofluorescent staining in matched myometrial and leiomyoma tissues. TET expression was analyzed by quantitative RT-PCR and immunoblotting. TET1 or TET3 were silenced or inhibited by small interfering RNA or 2-hydroxyglutarate to study their effects on 5-hmC content and cell proliferation.
  
  
  RESULTS
  We demonstrated significantly higher 5-hmC levels in the genomic DNA of leiomyoma tissue compared to normal myometrial tissue. The increase in 5-hmC levels was associated with the up-regulation of TET1 or TET3 mRNA and protein expression in leiomyoma tissue. TET1 or TET3 knockdown significantly reduced 5-hmC levels in leiomyoma cells and decreased cell proliferation. Treatment with 2-hydroxyglutarate, a competitive TET enzyme inhibitor, significantly decreased both 5-hmC content and cell proliferation of leiomyoma cells.
  
  
  CONCLUSIONS
  An epigenetic imbalance in the 5-hmC content of leiomyoma tissue, caused by up-regulation of the TET1 and TET3 enzymes, might lead to discovery of new therapeutic targets in leiomyoma.
authors: Departments of Obstetrics and Gynecology (A.N., P.Y., M.O., D.M., M.B.M., J.S.C., M.T.D., J.-J.W., S.E.B.) and Pathology (J.-J.W.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
authors: Antonia
authors: A
authors: Navarro
authors: Ping
authors: P
authors: Yin
authors: Masanori
authors: M
authors: Ono
authors: Diana
authors: D
authors: Monsivais
authors: Molly B
authors: MB
authors: Moravek
authors: John S
authors: JS
authors: Coon
authors: Matthew T
authors: MT
authors: Dyson
authors: Jian-Jun
authors: JJ
authors: Wei
authors: Serdar E
authors: SE
authors: Bulun
mesh_terms: D044503:5-Methylcytosine / Q000031:analogs & derivatives; D000328:Adult; D049109:Cell Proliferation / Q000235:genetics*; D003596:Cytosine / Q000031:analogs & derivatives* / Q000378:metabolism; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D007889:Leiomyoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D014594:Uterine Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
chemical_list: C011865:5-hydroxymethylcytosine; D044503:5-Methylcytosine; D003596:Cytosine