Castilla, María ÁngelesDíaz-Martín, JuanSarrió, DavidRomero-Pérez, LauraLópez-García, María ÁngelesVieites, BegoñaBiscuola, MicheleRamiro-Fuentes, SusanaIsacke, Clare MPalacios, José2013-03-182013-03-182012-10-24Castilla MÁ, Díaz-Martín J, Sarrió D, Romero-Pérez L, López-García MÁ, Vieites B, et al. MicroRNA-200 family modulation in distinct breast cancer phenotypes. PLoS ONE; 7(10):e47709http://hdl.handle.net/10668/847Journal Article; Research Support, Non-U.S. Gov't;The epithelial to mesenchymal transition (EMT) contributes to tumor invasion and metastasis in a variety of cancer types. In human breast cancer, gene expression studies have determined that basal-B/claudin-low and metaplastic cancers exhibit EMT-related characteristics, but the molecular mechanisms underlying this observation are unknown. As the family of miR-200 microRNAs has been shown to regulate EMT in normal tissues and cancer, here we evaluated whether the expression of the miR-200 family (miR-200f) and their epigenetic state correlate with EMT features in human breast carcinomas. We analyzed by qRT-PCR the expression of miR-200f members and various EMT-transcriptional inducers in a series of 70 breast cancers comprising an array of phenotypic subtypes: estrogen receptor positive (ER+), HER2 positive (HER2+), and triple negative (TN), including a subset of metaplastic breast carcinomas (MBCs) with sarcomatous (homologous or heterologous) differentiation. No MBCs with squamous differentiation were included. The DNA methylation status of miR-200f loci in tumor samples were inspected using Sequenom MassArray® MALDI-TOF platform. We also used two non-tumorigenic breast basal cell lines that spontaneously undergo EMT to study the modulation of miR-200f expression during EMT in vitro. We demonstrate that miR-200f is strongly decreased in MBCs compared with other cancer types. TN and HER2+ breast cancers also exhibited lower miR-200f expression than ER+ tumors. Significantly, the decreased miR-200f expression found in MBCs is accompanied by an increase in the expression levels of EMT-transcriptional inducers, and hypermethylation of the miR-200c-141 locus. Similar to tumor samples, we demonstrated that downregulation of miR-200f and hypermethylation of the miR-200c-141 locus, together with upregulation of EMT-transcriptional inducers also occur in an in vitro cellular model of spontaneous EMT. Thus, the expression and methylation status of miR-200f could be used as hypothetical biomarkers to assess the occurrence of EMT in breast cancer.enNeoplasias de la MamaFenotipoTransición Epitelial-MesenquimalMedical Subject Headings::Diseases::Neoplasms::Neoplasms by Site::Breast NeoplasmsMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::PhenotypeMedical Subject Headings::Phenomena and Processes::Cell Physiological Phenomena::Cell Physiological Processes::Cell Transdifferentiation::Epithelial-Mesenchymal Transitionresearch article23112837open access10.1371/journal.pone.00477091932-6203PMC3480416