title: Apoptosis levels increase after castration in the CWR22 human prostate cancer xenograft.
abstract: BACKGROUND
  The role of apoptosis in the regression of human prostate cancer after androgen deprivation therapy remains controversial. Detection of caspase-3, an ubiquitous effector of apoptosis, is a highly specific technique for in vivo evaluation of apoptosis.
  
  
  METHODS
  Apoptotic rates were evaluated in the androgen-dependent CWR22 human prostate cancer xenograft in tumors that represented time points throughout the progression from androgen-stimulated to recurrent prostate cancer. Caspase-3 levels in formalin-fixed, paraffin-embedded specimens were quantified using immunohistochemical detection and video image analysis. Western blot analysis was used to confirm the results of immunodetection.
  
  
  RESULTS
  Expression of caspase-3 reached a maximum on day 2 after castration, decreased on day 6, and remained low until tumor recurrence. The percentage of tumor area expressing caspase-3 increased from 2.51 +/- 0.44% in tumors from intact mice to 20.84 +/- 1.75% on day 2 after castration. Among immunopositive cells, the intensity of caspase-3 expression measured using the mean optical density (MOD) increased 45% (0.3762 +/- 0.003 to 0.5461 +/- 0.001) on day 2 after castration compared to levels detected in tumors from intact mice.
  
  
  CONCLUSIONS
  Apoptosis contributes to tumor regression after castration in the CWR22 human prostate cancer xenograft model.
authors.affiliation: University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Smitherman
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Gregory
authors.forename: James L
authors.initials: JL
authors.lastname: Mohler
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008819:Mice, Nude; D018715:Microscopy, Video; D009368:Neoplasm Transplantation; D009919:Orchiectomy; D016612:Paraffin Embedding; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000473:pathology*; D014183:Transplantation, Heterologous
chemical_list: C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases