title: Simvastatin induces apoptosis in castrate resistant prostate cancer cells by deregulating nuclear factor-κB pathway.
abstract: OBJECTIVE
  In castrate resistant prostate cancer cells we investigated the cytotoxic effect of simvastatin and the mechanism involved.
  
  
  METHODS
  After treating PC3 and DU-145 cells with simvastatin, cell viability and apoptosis were determined using tetrazolium salt based colorimetric assay and annexin-V-fluorescein isothiocyanate/propidium iodide double staining assay, respectively. To determine whether simvastatin affects the nuclear factor-κB pathway, we assessed IκBα and phosphorylated IκBα expression, and p65 and phosphorylated p65 subcellular localization by Western blot analysis. Also, changes in nuclear factor-κB transcriptional activity were assessed using a luciferase reporter assay.
  
  
  RESULTS
  After treating PC3 and DU-145 cells with 0, 20 or 40 μM simvastatin for 24, 48 or 72 hours, the proportion of viable cells decreased and the proportion of apoptotic cells increased in a dose and time dependent manner. Western blot analysis showed that simvastatin inhibited IκBα phosphorylation and degradation. It also demonstrated that simvastatin increased p65 protein levels in cytoplasmic fractions and decreased phosphorylated p65 protein levels in nuclear fractions but did not change p65 protein levels in cytoplasm. Luciferase reporter assay showed that simvastatin dose dependently reduced nuclear factor-κB activity. Reverse transcriptase-polymerase chain reaction and Western blot revealed that simvastatin inhibited nuclear factor-κB regulated cIAP-1 and 2, cFLIP-S and XIAP expression in dose and time dependent fashion.
  
  
  CONCLUSIONS
  Simvastatin inhibited castrate resistant prostate cancer cell growth by inducing apoptosis. These effects were probably mediated by the inhibition of IκBα phosphorylation and nuclear translocation of p50/p65 dimer in the nuclear factor-κB pathway.
authors.affiliation: Seoul National University Hospital, Seoul, Korea.
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Park
authors.forename: Su Yeon
authors.initials: SY
authors.lastname: Seo
authors.forename: Eunhye
authors.initials: E
authors.lastname: Lee
authors.forename: Ja Hyeon
authors.initials: JH
authors.lastname: Ku
authors.forename: Hyeon Hoe
authors.initials: HH
authors.lastname: Kim
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008297:Male; D016328:NF-kappa B / Q000187:drug effects* / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000473:pathology*; D015398:Signal Transduction / Q000187:drug effects*; D019821:Simvastatin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D016328:NF-kappa B; D019821:Simvastatin