title: Depletion of the histone chaperone tNASP inhibits proliferation and induces apoptosis in prostate cancer PC-3 cells.
abstract: BACKGROUND
  NASP (Nuclear Autoantigenic Sperm Protein) is a histone chaperone that is present in all dividing cells. NASP has two splice variants: tNASP and sNASP. Only cancer, germ, transformed, and embryonic cells have a high level of expression of the tNASP splice variant. We examined the consequences of tNASP depletion for prostate cancer PC-3 cells.
  
  
  METHODS
  tNASP was depleted from prostate cancer PC-3 cells, cervical cancer HeLa cells, and prostate epithelial PWR-1E cells using lentivirus expression of tNASP shRNA. Cell cycle changes were studied by proliferation assay with CFSE labeling and double thymidine synchronization. Gene expression profiles were detected using RT(2)Profiler PCR Array, Western and Northern blotting.
  
  
  RESULTS
  PC-3 and HeLa cells showed inhibited proliferation, increased levels of cyclin-dependant kinase inhibitor p21 protein and apoptosis, whereas non-tumorigenic PWR-1E cells did not. All three cell types showed decreased levels of HSPA2. Supporting in vitro experiments demonstrated that tNASP, but not sNASP is required for activation of HSPA2.
  
  
  CONCLUSIONS
  Our results demonstrate that PC-3 and HeLa cancer cells require tNASP to maintain high levels of HSPA2 activity and therefore viability, while PWR-1E cells are unaffected by tNASP depletion. These different cellular responses most likely arise from changes in the interaction between tNASP and HSPA2 and disturbed tNASP chaperoning of linker histones. This study has demonstrated that tNASP is critical for the survival of prostate cancer cells and suggests that targeting tNASP expression can lead to a new approach for prostate cancer treatment.
authors.affiliation: Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC 27599, USA. oleg_alekseev@med.unc.edu
authors.forename: Oleg M
authors.initials: OM
authors.lastname: Alekseev
authors.forename: Richard T
authors.initials: RT
authors.lastname: Richardson
authors.forename: James K
authors.initials: JK
authors.lastname: Tsuruta
authors.forename: Michael G
authors.initials: MG
authors.lastname: O'Rand
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology*; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D001324:Autoantigens / Q000235:genetics* / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D056488:Histone Chaperones / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology; D011471:Prostatic Neoplasms / Q000235:genetics / Q000473:pathology*; D034741:RNA, Small Interfering / Q000494:pharmacology*
chemical_list: D001324:Autoantigens; D056488:Histone Chaperones; C489390:NASP protein, human; D009687:Nuclear Proteins; D034741:RNA, Small Interfering