title: Effect of isocaloric low fat diet on prostate cancer xenograft progression in a hormone deprivation model.
abstract: OBJECTIVE
  Previous mouse studies suggesting that low fat diets slow prostate cancer growth often used corn oil (omega-6), which enhances prostate cancer growth, as the primary fat. Using a saturated fat based diet we previously found no significant difference in tumor growth between low and high fat fed SCID mice (Taconic Farms, Hudson, New York) xenografted with LAPC-4 cells. Whether similar results would hold in a castration model is unclear.
  
  
  METHODS
  A total of 80 male SCID mice were fed a Western diet (40% fat and 44% carbohydrate) and injected with LAPC-4 human prostate cancer cells. When tumors were 200 mm(3), the mice were castrated and randomized to an isocaloric Western or a low fat diet (12% fat and 72% carbohydrate). Animals were sacrificed when tumors were 1,000 mm(3). Serum was collected and assayed for prostate specific antigen, insulin, insulin-like growth factor 1 and insulin-like growth factor binding protein 3. Tumors were assayed for total and phosphorylated Akt.
  
  
  RESULTS
  Mouse weight was equivalent in the 2 groups. Overall dietary group was not significantly associated with survival (log rank p = 0.32). There were no statistically significant differences in prostate specific antigen (p = 0.53), insulin-like growth factor axis parameters (each p >0.05) or p-Akt-to-t-Akt ratios (p = 0.22) between the groups at sacrifice.
  
  
  CONCLUSIONS
  In this xenograft model we found no difference in tumor growth or survival between low fat vs Western fed mice when the fat source was saturated fat. These results conflict with those of other studies in which corn oil was used to show that low fat diets delay prostate cancer growth, suggesting that fat type may be as important as fat amount in the prostate cancer setting.
authors.affiliation: Department of Surgery, Durham Veterans Affairs Medical Center, Duke University School of Medicine, Durham, North Carolina, USA.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Lloyd
authors.forename: Jodi A
authors.initials: JA
authors.lastname: Antonelli
authors.forename: Tameika E
authors.initials: TE
authors.lastname: Phillips
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Masko
authors.forename: Jean-Alfred
authors.initials: JA
authors.lastname: Thomas
authors.forename: Susan H M
authors.initials: SH
authors.lastname: Poulton
authors.forename: Michael
authors.initials: M
authors.lastname: Pollak
authors.forename: Michael
authors.initials: M
authors.lastname: Pollack
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Freedland
mesh_terms: D000818:Animals; D018752:Diet, Fat-Restricted; D018450:Disease Progression; D002149:Energy Intake; D008297:Male; D051379:Mice; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D009919:Orchiectomy; D011471:Prostatic Neoplasms / Q000178:diet therapy*; D014183:Transplantation, Heterologous