title: Will metformin postpone high-fat diet promotion of TRAMP mouse prostate cancer development and progression?
abstract: OBJECTIVE
  We aimed to examine the effect of high-fat diet (HFD) on prostate cancer (PCa) development and progression and to investigate whether metformin would postpone PCa development and progression promoted by HFD.
  
  
  METHODS
  TRAMP mice were randomly divided into three groups: normal diet group, HFD group and metformin-HFD (Met-HFD) group. Mortality rate and tumor formation rate were examined. TRAMP mice were sacrificed and sampled on the 20th, 24(th), and 28th week, respectively. Serum levels of insulin and IGF-1 were tested by ELISA. Prostate tissue of TRAMP mice was used for HE staining.
  
  
  RESULTS
  A total of 17 deaths of TRAMP mice were observed, including 3 (10 %) from the normal diet group, 10 (33.33 %) from the HFD group, and 4 (13.33 %) from Met-HFD group. The mortality rate of TRAMP mice from HFD group was significantly higher than that of normal diet group (P = 0.028), and metformin could moderately decrease the mortality rate by 60.01 % (P = 0.067). Tumor formation rates were not significantly different among the three groups. Levels of glucose, insulin, and IGF-1 tended to increase with TRAMP mice's age in HFD group. TRAMP mice from HFD group had higher serum insulin and IGF-1 levels. A moderate decrease in IGF-1 was also seen in Met-HFD group.
  
  
  CONCLUSIONS
  HFD could promote TRAMP mouse PCa development and progression and metformin had moderate effect of reducing PCa mortality rate with a decrease in serum IGF-1 level.
authors.affiliation: Department of Urology, Huashan Hospital, Fudan University, 12 WuLuMuQi Middle Road, Shanghai, 200040, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.forename: Meng-Bo
authors.initials: MB
authors.lastname: Hu
authors.forename: Pei-de
authors.initials: PD
authors.lastname: Bai
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Zhu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ding
authors.forename: Hao-Wen
authors.initials: HW
authors.lastname: Jiang
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D059305:Diet, High-Fat / Q000009:adverse effects*; D018450:Disease Progression; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008687:Metformin / Q000494:pharmacology*; D051379:Mice; D008822:Mice, Transgenic; D016133:Polymerase Chain Reaction; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D001786:Blood Glucose; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D008687:Metformin