title: Loss of reelin expression in breast cancer is epigenetically controlled and associated with poor prognosis.
abstract: Reelin is a secreted, signaling protein associated with neuronal cell positioning and migration. Recently, reelin was found to be epigenetically silenced in gastric and pancreatic cancers in which down-regulation was associated with increased migratory ability and reduced survival. Here we analyzed reelin expression by immunohistochemistry in 17 normal breast tissue samples from reduction mammoplasties and in two independent tissue microarrays of 136 and more than 2000 breast cancer biopsy samples, respectively. Results were analyzed with regard to clinical parameters, including BRE (Bloom, Richardson, Elston) grade, nodal status, estrogen receptor and HER2 status, and overall survival. Reelin was expressed in the luminal epithelium and myoepithelium of the normal human breast but not in cancerous breasts. Loss of reelin protein expression correlated significantly with decreased survival (P=0.01) and positive lymph node status (P<0.001). By measuring reelin expression and promoter methylation status in 39 primary breast tumors, as well as in breast cancer-derived cell lines before and after decitabine treatment, we established that reelin expression levels correlated inversely with promoter methylation status, whereas demethylation increased reelin mRNA expression in vitro. Reelin overexpression in MDA-MB231 cells, as well as incubation with recombinant reelin, suppressed cell migration, invadopodia formation, and invasiveness in vitro. We conclude that reelin may play an important role in controlling invasiveness and metastatic potential of breast cancer cells and that its expression is controlled by promoter methylation.
authors.affiliation: Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, Department of Pathology, Western Infirmary, University of Glasgow, Glasgow, G11 6NT, UK. torsten.stein@glasgow.ac.uk
authors.forename: Torsten
authors.initials: T
authors.lastname: Stein
authors.forename: Emilio
authors.initials: E
authors.lastname: Cosimo
authors.forename: Xinzi
authors.initials: X
authors.lastname: Yu
authors.forename: Paul R
authors.initials: PR
authors.lastname: Smith
authors.forename: Ronald
authors.initials: R
authors.lastname: Simon
authors.forename: Lorna
authors.initials: L
authors.lastname: Cottrell
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Pringle
authors.forename: Alexandra K
authors.initials: AK
authors.lastname: Bell
authors.forename: Laura
authors.initials: L
authors.lastname: Lattanzio
authors.forename: Guido
authors.initials: G
authors.lastname: Sauter
authors.forename: Cristiana
authors.initials: C
authors.lastname: Lo Nigro
authors.forename: Timothy
authors.initials: T
authors.lastname: Crook
authors.forename: Laura M
authors.initials: LM
authors.lastname: Machesky
authors.forename: Barry A
authors.initials: BA
authors.lastname: Gusterson
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D024042:Collagen Type I / Q000378:metabolism; D044127:Epigenesis, Genetic; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D009361:Neoplasm Invasiveness; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D011401:Promoter Regions, Genetic; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D024042:Collagen Type I; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D000091042:Reelin Protein; C000717127:RELN protein, human; D012697:Serine Endopeptidases