title: Interaction between human-breast cancer metastasis and bone microenvironment through activated hepatocyte growth factor/Met and beta-catenin/Wnt pathways.
abstract: To clarify the reciprocal interaction between human-breast cancer metastatic cells and bone microenvironment, we studied the influence of HGF/Met system on a proposed-prognostic marker of aggressiveness, the beta-catenin/Wnt pathway. For in vitro and in vivo experiments we used 1833-bone metastatic clone, derived from human-MDA-MB231 cells. In osteolytic bone metastases and in metastatic cells, Met was expressed in nuclei and at plasma membrane, and abnormally co-localised at nuclear level with beta-catenin and the tyrosine phosphorylated c-Src kinase. Thus, in 1833 cells nuclear-Met COOH-terminal fragment and beta-catenin-TCF were constitutively activated, possibly by receptor and non-receptor tyrosine kinases. The activity of the gene reporter TOPFLASH (containing multiple TCF/LEF-consensus sites) was measured, as index of beta-catenin functionality. In 1833 cells, human and mouse HGF increased Met and beta-catenin tyrosine phosphorylation and expression in nuclear and perinuclear compartments, beta-catenin nuclear translocation via Kank and TOPFLASH transactivation. Human HGF was autocrine/intracrine in bone metastasis, and mouse HGF originating from the adjacent host-bone marrow, was found inside the metastatic nuclei. Parental MDA-MB231 cell nuclei did not show functional beta-catenin, for TCF-transactivating activity, and the regulation by HGF. Our study highlighted the importance of the metastasis-stroma interaction in human-breast cancer metastatisation and first identified the HGF/nuclear Met/phospho-c-Src/beta-catenin-TCF/Wnt pathway as a potential-therapeutic target to delay establishment/progression of bone metastases by affecting the aggressive phenotype.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Previdi
authors.forename: Paola
authors.initials: P
authors.lastname: Maroni
authors.forename: Emanuela
authors.initials: E
authors.lastname: Matteucci
authors.forename: Massimo
authors.initials: M
authors.lastname: Broggini
authors.forename: Paola
authors.initials: P
authors.lastname: Bendinelli
authors.forename: Maria Alfonsina
authors.initials: MA
authors.lastname: Desiderio
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000556:secondary*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D005260:Female; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000378:metabolism; D010766:Phosphorylation; D011379:Prognosis; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays / Q000379:methods; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D051153:Wnt Proteins; D051176:beta Catenin; D014443:Tyrosine; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met