title: Pterostilbene, a bioactive component of blueberries, suppresses the generation of breast cancer stem cells within tumor microenvironment and metastasis via modulating NF-κB/microRNA 448 circuit.
abstract: METHODS
  Tumor-associated macrophages (TAMs) have been shown to promote metastasis and malignancy. Pterostilbene, a natural stilbene isolated from blueberries, has been suggested for anti-cancer effects. Here, we explored the potential cancer stem cells (CSCs)/TAM modulating effects of pterostilbene in breast cancer.
  
  
  RESULTS
  Using flowcytometric and Boyden chamber assay, we showed MCF7 and MDA-MB-231 cells cocultured with M2 TAMs exhibited increased percentage of CD44(+) /CD24(-) CSC population and migratory/invasive abilities. RT-PCR results showed that CD44(+) /CD24(-) cells expressed an increased level of HIF-1α, β-catenin, Twist1, and NF-κB and enhanced tumor sphere forming ability. Additionally, pterostilbene treatment dose dependently overcame M2 TAM-induced enrichment of CSCs and metastatic potential of breast cancer cells. Mechanistically, pterostilbene suppressed NFκB, Twist1, vimentin, and increased E-cadherin expression. Using siRNA technique, we demonstrated that pterostilbene-mediated NFκB downregulation was correlated to an increased amount of microRNA 448. Finally, pterostilbene-mediated suppression in tumorigenesis and metastasis was validated by noninvasive bioluminescence in mice bearing M2 TAM cocultured MDA-MB-231 tumor.
  
  
  CONCLUSIONS
  Pterostilbene effectively suppresses the generation of CSCs and metastatic potential under the influence of M2 TAMs via modulating EMT associated signaling pathways, specifically NF-κB/miR488 circuit. Thus, pterostilbene could be an ideal anti-CSC agent in clinical settings.
authors.affiliation: Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ka-Kit
authors.initials: KK
authors.lastname: Mak
authors.forename: Alexander T H
authors.initials: AT
authors.lastname: Wu
authors.forename: Wei-Hwa
authors.initials: WH
authors.lastname: Lee
authors.forename: Tung-Cheng
authors.initials: TC
authors.lastname: Chang
authors.forename: Jeng-Fong
authors.initials: JF
authors.lastname: Chiou
authors.forename: Liang-Shun
authors.initials: LS
authors.lastname: Wang
authors.forename: Chih-Hsiung
authors.initials: CH
authors.lastname: Wu
authors.forename: Chi-Ying F
authors.initials: CY
authors.lastname: Huang
authors.forename: Yi-Shing
authors.initials: YS
authors.lastname: Shieh
authors.forename: Tsu-Yi
authors.initials: TY
authors.lastname: Chao
authors.forename: Chi-Tang
authors.initials: CT
authors.lastname: Ho
authors.forename: Gow-Chin
authors.initials: GC
authors.lastname: Yen
authors.forename: Chi-Tai
authors.initials: CT
authors.lastname: Yeh
mesh_terms: D000818:Animals; D015703:Antigens, CD; D029798:Blueberry Plants / Q000737:chemistry*; D001943:Breast Neoplasms / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D063646:Carcinogenesis / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D020868:Gene Silencing; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D061986:MCF-7 Cells; D051379:Mice; D016513:Mice, SCID; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D013267:Stilbenes / Q000494:pharmacology*; D059016:Tumor Microenvironment / Q000187:drug effects*; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism; D014746:Vimentin / Q000235:genetics / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; C495270:CTNNB1 protein, human; D015820:Cadherins; C497442:HIF1A protein, human; D018960:Hyaluronan Receptors; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C557400:MIRN448 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; D009687:Nuclear Proteins; D013267:Stilbenes; C103173:TWIST1 protein, human; D051879:Twist-Related Protein 1; D014746:Vimentin; D051176:beta Catenin; C107773:pterostilbene
keywords: Breast cancer stem cells; Epithelial-to-mesenchymal transition; Pterostilbene; Tumor-associated macrophages; miR448