title: Biomarkers of phenethyl isothiocyanate-mediated mammary cancer chemoprevention in a clinically relevant mouse model.
abstract: BACKGROUND
  Phenethyl isothiocyanate (PEITC) is a natural plant compound with chemopreventative potential against some cancers and the ability to induce apoptosis in breast cancer cells.
  
  
  METHODS
  Female mouse mammary tumor virus-neu mice were fed a control AIN-76A diet (n = 35) or the same diet supplemented with 3 µmol PEITC/g diet (n = 33) for 29 weeks, at which time they were killed. Breast tissue sections were stained with hematoxylin and eosin for histopathological assessments, and incidence and size of macroscopic mammary tumors were assessed. Cell proliferation (Ki-67 staining), apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick-labeling), and neoangiogenesis (CD31 staining) were determined in tumor sections. Plasma levels of transthyretin were measured in treated and control mice. Expression of proteins in mammary tumor sections was determined by immunohistochemistry. Proteomic profiling was performed by two-dimensional gel electrophoresis followed by mass spectrometry. All statistical tests were two-sided.
  
  
  RESULTS
  Administration of PEITC for 29 weeks was associated with 53.13% decreased incidence of macroscopic mammary tumors (mean tumor incidence, PEITC-supplemented diet vs control diet, 18.75% vs 40.00%, difference = -21.25%, 95% confidence interval [CI] = -43.19% to 0.69%, P = .07) and with a 56.25% reduction in microscopic mammary carcinoma lesions greater than 2 mm(2) (mean incidence, PEITC-supplemented diet vs control diet, 18.75% vs 42.86%, difference = -24.11%, 95% CI = -46.35% to -1.86%, P = .04). PEITC-mediated mammary cancer growth inhibition was not because of suppression of human epidermal growth factor receptor-2 expression but was associated with reduced cellular proliferation and neoangiogenesis, increased apoptosis, and altered expression of several proteins, including decreased ATP synthase in the tumor and increased plasma levels of transthyretin.
  
  
  CONCLUSIONS
  PEITC inhibits the growth of mammary cancers in a mouse model with similarities to human breast cancer progression. ATP synthase and transthyretin appear to be novel biomarkers associated with PEITC exposure.
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. singhs@upmc.edu
authors.forename: Shivendra V
authors.initials: SV
authors.lastname: Singh
authors.forename: Su-Hyeong
authors.initials: SH
authors.lastname: Kim
authors.forename: Anuradha
authors.initials: A
authors.lastname: Sehrawat
authors.forename: Julie A
authors.initials: JA
authors.lastname: Arlotti
authors.forename: Eun-Ryeong
authors.initials: ER
authors.lastname: Hahm
authors.forename: Kozue
authors.initials: K
authors.lastname: Sakao
authors.forename: Jan H
authors.initials: JH
authors.lastname: Beumer
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Jankowitz
authors.forename: Kumar
authors.initials: K
authors.lastname: Chandra-Kuntal
authors.forename: Joomin
authors.initials: J
authors.lastname: Lee
authors.forename: Anna A
authors.initials: AA
authors.lastname: Powolny
authors.forename: Rajiv
authors.initials: R
authors.lastname: Dhir
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D014408:Biomarkers, Tumor / Q000032:analysis*; D049109:Cell Proliferation / Q000187:drug effects*; D004195:Disease Models, Animal; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D020869:Gene Expression Profiling; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D017879:Isothiocyanates / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D019394:Ki-67 Antigen / Q000032:analysis; D008325:Mammary Neoplasms, Experimental / Q000737:chemistry / Q000473:pathology* / Q000517:prevention & control*; D008324:Mammary Tumor Virus, Mouse; D013058:Mass Spectrometry; D051379:Mice; D008822:Mice, Transgenic; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D011228:Prealbumin / Q000032:analysis
chemical_list: D016588:Anticarcinogenic Agents; D014408:Biomarkers, Tumor; D017879:Isothiocyanates; D019394:Ki-67 Antigen; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011228:Prealbumin; C058305:phenethyl isothiocyanate