title: c-Jun N terminal kinase modulates NOX-4 derived ROS production and myofibroblasts differentiation in human breast stromal cells.
abstract: BACKGROUND
  Hard consistency, developed under the influence of tumor cell factors, is a characteristic feature of a breast tumor. Activation of resident fibroblasts leading to a myofibroblast phenotype is the principal feature that orchestrates this fibrotic process. The aim of this study was to assess the effects induced by TGF-β1, a growth factor abundantly present in tumor microenvironment, on the molecular mechanisms that mediate myofibroblastic differentiation of normal human mammary fibroblasts.
  
  
  METHODS
  We used an immortalized fibroblastic cell line derived from normal mammary tissue (RMF-EG cells) to study the effect of TGF-β1 in the expression of α-SMA and CTGF as markers of myofibroblastic differentiation. The influence of redox status and JNK activity on TGF-β1-induced transcriptional activity was measured by a luciferase reporter assay. We also used a shRNA approach to evaluate the influence of NOX4 in myofibroblastic differentiation.
  
  
  RESULTS
  TGF-β1 stimulates the expression of myofibroblast markers α-SMA and CTGF. Using a NOX inhibitor (DPI) and cells expressing a shRNA for NOX4, we demonstrated that TGF-β1 promotes an oxidative environment that favors myofibroblastic differentiation. We also found that activation of c-Jun N-terminal kinase is required for TGF-β1-dependent expression of CTGF, NOX4 and α-SMA.
  
  
  CONCLUSIONS
  Human mammary stromal fibrosis, evaluated by the expression of early and late markers as CTGF and α-SMA, depends on the activation of JNK signaling pathway. Our results show that JNK activation is an early event that precedes the increase in ROS levels leading to myofibroblastic differentiation and tumor fibrosis, suggesting that inhibition of JNK may be used a method to interrupt the development of tumor desmoplasia.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Tobar
authors.forename: Marcela
authors.initials: M
authors.lastname: Toyos
authors.forename: Carla
authors.initials: C
authors.lastname: Urra
authors.forename: Nicolás
authors.initials: N
authors.lastname: Méndez
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Arancibia
authors.forename: Patricio C
authors.initials: PC
authors.lastname: Smith
authors.affiliation: Laboratorio de Biología Celular y Molecular, INTA, Universidad de Chile, El Líbano 5524, Macul, Santiago, Chile. jmartine@inta.uchile.cl.
authors.forename: Jorge
authors.initials: J
authors.lastname: Martínez
mesh_terms: D000199:Actins / Q000378:metabolism; D001940:Breast / Q000166:cytology* / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D002460:Cell Line; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D058628:Myofibroblasts / Q000378:metabolism*; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; C526317:CCN2 protein, human; D017382:Reactive Oxygen Species; C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1; D055513:Connective Tissue Growth Factor; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; D048031:JNK Mitogen-Activated Protein Kinases