title: HGF and TGFβ1 differently influenced Wwox regulatory function on Twist program for mesenchymal-epithelial transition in bone metastatic versus parental breast carcinoma cells.
abstract: BACKGROUND
  Much effort has been devoted to determining how metastatic cells and microenvironment reciprocally interact. However, the role of biological stimuli of microenvironment in controlling molecular events in bone metastasis from breast carcinoma for mesenchymal-epithelial transition (MET) is largely unknown. The purpose of the present paper was to clarify (1) the influence of hepatocyte-growth factor (HGF) and transforming growth factorβ1 (TGFβ1) on the phenotype of bone-metastatic 1833 and parental MDA-MB231 cells; (2) the hierarchic response of Twist and Snail controlled by Wwox co-factor, that might be critical for the control of 1833-adhesive properties via E-cadherin.
  
  
  METHODS
  We studied under HGF and TGFβ1 the gene profiles-responsible for epithelial-mesenchymal transition (EMT), versus the revertant MET phenotype-making the correspondence with 1833 morphology and the relation to HGF-dependent control of TGFβ1 signalling. In particular, the activation of Twist program and the underlying molecular mechanisms were investigated, considering the role of endogenous and exogenous Wwox with siRNAWWOX and the expression vector transfection, to clarify whether Twist affected E-cadherin transactivation through a network of transcription factors and regulators.
  
  
  RESULTS
  HGF and TGFβ1 oppositely affected the expression of Wwox in 1833 cells. Under HGF, endogenous Wwox decreased concomitant with Twist access to nuclei and its phosphorylation via PI3K/Akt pathway. Twist activated by HGF did not influence the gene profile through an E-box mechanism, but participated in the interplay of PPARγ/Ets1/NF-kB-transcription factors, triggering E-cadherin transactivation. Altogether, HGF conferred MET phenotype to 1833 cells, even if this was transient since followed by TGFβ1-signalling activation. TGFβ1 induced Snail in both the cell lines, with E-cadherin down-regulation only in 1833 cells because in MDA-MB231 cells E-cadherin was practically absent. Exogenous Wwox activated metastatic HIF-1, with Twist as co-factor.
  
  
  CONCLUSIONS
  HGF and TGFβ1 of bone-metastasis microenvironment acted co-ordinately, influencing non redundant pathways regulated by Twist program or Snail-transcription factor, with reversible MET switch. This process implicated different roles for Wwox in the various steps of the metastatic process including colonization, with microenvironmental/exogenous Wwox that activated HIF-1, important for E-cadherin expression. Interfering with the Twist program by targeting the pre-metastatic niche stimuli could be an effective anti-bone metastasis therapy.
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano, Italy. paola.bendinelli@unimi.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Bendinelli
authors.affiliation: Istituto Ortopedico Galeazzi, IRCCS, Milano, Italy. paola.maroni@grupposandonato.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Maroni
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano, Italy. emanuela.matteucci@unimi.it.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Matteucci
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano, Italy. a.desiderio@unimi.it.
authors.forename: Maria Alfonsina
authors.initials: MA
authors.lastname: Desiderio
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology / Q000556:secondary*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism; D015536:Down-Regulation; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D006801:Humans; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism; D008819:Mice, Nude; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D015398:Signal Transduction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D051879:Twist-Related Protein 1 / Q000378:metabolism*; D000074584:WW Domain-Containing Oxidoreductase
chemical_list: D015820:Cadherins; D004273:DNA, Neoplasm; C066855:HGF protein, human; D051793:Hypoxia-Inducible Factor 1; D009687:Nuclear Proteins; D000071250:Snail Family Transcription Factors; C508960:TGFB1 protein, human; C103173:TWIST1 protein, human; D014157:Transcription Factors; D053773:Transforming Growth Factor beta1; D025521:Tumor Suppressor Proteins; D051879:Twist-Related Protein 1; D017228:Hepatocyte Growth Factor; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human