title: Effect of simvastatin on castration-resistant prostate cancer cells.
abstract: BACKGROUND
  In castration-resistant prostate cancer (CRPC), recent evidence has demonstrated the persistence of the intratumoral androgens. The multi-step androgen synthesis pathway originates from cholesterol, which can be obtained by cells from several major sources including intracellular synthesis through an enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR). The inhibition of this enzyme by the use of statins has been investigated in prostate cancer as a possible therapeutic target for blocking the de novo androgen synthesis resulting in decreased tumor growth. However, the effectiveness of statins in CRPC has not been investigated.
  
  
  METHODS
  Castration-resistant C4-2 and androgen-sensitive LNCaP cells were treated with Simvastatin for 48 hours. Dose-dependent responses to Simvastatin were analyzed using cell proliferation and cytotoxicity assays. Cellular growth curve was generated using haemocytometer. HMGCR activity was assessed using 14C-acetic acid detected by thin layer chromatography, and the protein expression was quantified using western blot analysis. Intracellular cholesterol and prostate specific antigen (PSA) levels were quantified using enzyme-linked immunosorbent assays (ELISA).
  
  
  RESULTS
  Significant decrease in cell viability and growth curve observed at 75 μM of Simvastatin compared to no treatment group in the castration-resistant C4-2 cells. HMGCR activity was significantly decreased up to 50% and 70% at 50 μM and 75 μM of Simvastatin respectively compared to the vehicle control in C4-2 cells. Simvastatin did not affect the protein expression. 80% decrease in the amount of total intracellular cholesterol levels was observed in 75 μM Simvastatin treatment group compared to vehicle control. PSA secretion levels were significantly reduced in the C4-2 cell line at 50 μM and 75 μM of Simvastatin compared to vehicle control.
  
  
  CONCLUSIONS
  The inhibition of HMGCR via Simvastatin lowered the viability of castration-resistant C4-2 cells. Simvastatin's ability to limit the endogenous supply of cholesterol contributes to the effects seen in cell viability.
authors.forename: Jenny Hanbi
authors.initials: JH
authors.lastname: Kim
authors.forename: Michael E
authors.initials: ME
authors.lastname: Cox
authors.affiliation: Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, British Columbia, Canada. kwasan@mail.ubc.ca.
authors.forename: Kishor M
authors.initials: KM
authors.lastname: Wasan
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000096:biosynthesis; D004354:Drug Screening Assays, Antitumor; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D007610:Kallikreins / Q000378:metabolism; D008297:Male; D017430:Prostate-Specific Antigen / Q000378:metabolism; D064129:Prostatic Neoplasms, Castration-Resistant; D019821:Simvastatin / Q000494:pharmacology*
chemical_list: D000964:Antimetabolites, Antineoplastic; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D002784:Cholesterol; D019821:Simvastatin; D006903:Hydroxymethylglutaryl CoA Reductases; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen