Bone metastatic process of breast cancer involves methylation state affecting E-cadherin expression through TAZ and WWOX nuclear effectors.
We investigated the involvement of Hippo-related pathways in bone metastasis from breast cancer, by evaluating E-cadherin expression downstream of WWdomain-containing oxidoreductase (Wwox) and transcriptional co-activator with PDZ-binding motif (TAZ). These nuclear effectors functioned in a context-specific fashion on transcriptome, depending on breast-cancer aggressiveness and methylation state. Wwox and E-cadherin were found in human specimens of bone metastasis but not in primary-ductal breast carcinoma, while TAZ showed a characteristic localisation in metastasis nuclei. Wwox and E-cadherin were higher in 1833-metastatic clone with bone avidity than in parental-MDA-MB231 cells, while only metastatic cells presented TAZ. In 1833 cells, a complex interplay of transcriptional signalling controlled E-cadherin transactivation. Wwox and TAZ activated Hypoxia inducible factor-1 (HIF-1) binding to E-cadherin promoter, while Peroxisome proliferator-activated receptor γ (PPARγ) intervened in E-cadherin transactivation favouring and preventing Wwox and TAZ functions, respectively. Methylation impinged on Hippo-related pathways through Wwox and TAZ, modifying metastatic phenotype. The protract exposure to 5-azacytidine (Aza), by affecting methylation state modified the shape of 1833 cells, becoming mesenchymal as that of MDA-MB231 cells and reduced spontaneous-Matrigel invasion. The underlying-molecular mechanisms were diminutions of E-cadherin, Wwox, matrix metalloproteases 2 and 9, HIF-1- and PPARγ-activities, inversely correlated to Snail and nuclear-TAZ accumulations. Exogenous WWOX restored 1833-Aza invasion. Thus, 1833-Aza cells permitted to study the role played by methylation in metastasis plasticity, being E-cadherin loss part of an entire-gene reprogramming. Of note, bone-metastasis formation in 1833-Aza xenograft was partially impaired, prolonging mice survival. In conclusion, the methylation-heritable changes seemed important for cancer progression to establish bone metastasis engraftment/growth, by affecting steps requiring homotipic and/or heterotypic-adhesive properties and matrix degradation.
Dipartimento di Scienze Biomediche per Salute, Università degli Studi di Milano, Italy.
Emanuela
E
Matteucci
Paola
P
Maroni
Alessandro
A
Luzzati
Giuseppe
G
Perrucchini
Paola
P
Bendinelli
Maria Alfonsina
MA
Desiderio
D000818:Animals; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000096:biosynthesis* / Q000235:genetics; D019175:DNA Methylation; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000235:genetics* / Q000473:pathology; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators; D014157:Transcription Factors; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D059467:Transcriptome; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D000074584:WW Domain-Containing Oxidoreductase
D015820:Cadherins; D047908:Intracellular Signaling Peptides and Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D025521:Tumor Suppressor Proteins; C551991:WWTR1 protein, human; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human