title: The heterochromatin protein 1 family is regulated in prostate development and cancer.
abstract: OBJECTIVE
  The HP1 family of evolutionarily conserved proteins regulates heterochromatin packaging, in addition to a less defined role in the regulation of euchromatic genes. To examine the possible role of HP1 proteins in fetal prostate development and prostate cancer the protein expression of HP1alpha, beta and gamma was evaluated in human archival tissue.
  
  
  METHODS
  Tissue sections from human prostate cancer and fetal prostate were examined using antibodies against HP1 isoforms to evaluate HP1 modulation in cancer and development. Western blot analysis of HP1 proteins was also performed in extracts of cultured prostate cancer cells.
  
  
  RESULTS
  HP1alpha, beta and gamma are differentially regulated in various cellular compartments in prostate development. HP1alpha is not expressed at 14 or 24 weeks of prostate development but it is expressed in adult prostate tissue. HP1beta is highly expressed at 14 and 24 weeks, and it appears predominantly in epithelial cells compared to HP1gamma, which is expressed at equal levels in epithelial and stromal cells. All 3 HP1 isoforms show altered expression in prostate cancer compared to that in normal adult prostate tissue.
  
  
  CONCLUSIONS
  HP1 proteins are tightly regulated during prostate development. In the adult prostate HP1alpha, beta and gamma antibodies detect high levels of HP1 antigen in a contiguous layer of epithelial cells. However, the detection of HP1 in prostate cancer ranges from undetectable to inconsistent staining of noncontiguous epithelial cells.
authors.affiliation: Department of Urology, New York University School of Medicine, New York, New York, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Shapiro
authors.forename: Hongying
authors.initials: H
authors.lastname: Huang
authors.forename: Rachel
authors.initials: R
authors.lastname: Ruoff
authors.forename: Peng
authors.initials: P
authors.lastname: Lee
authors.forename: Naoko
authors.initials: N
authors.lastname: Tanese
authors.forename: Susan K
authors.initials: SK
authors.lastname: Logan
mesh_terms: D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis / Q000502:physiology*; D006801:Humans; D008297:Male; D011467:Prostate / Q000196:embryology*; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: C000715593:CBX1 protein, human; C000715594:CBX5 protein, human; D002868:Chromosomal Proteins, Non-Histone; D000090266:Chromobox Protein Homolog 5