title: MicroRNA-223 is a novel negative regulator of HSP90B1 in CLL.
abstract: BACKGROUND
  MicroRNAs are known to inhibit gene expression by binding to the 3'UTR of the target transcript. Downregulation of miR-223 has been recently reported to have prognostic significance in CLL. However, there is no evidence of the pathogenetic mechanism of this miRNA in CLL patients.
  
  
  METHODS
  By applying next-generation sequencing techniques we have detected a common polymorphism (rs2307842), in 24% of CLL patients, which disrupts the binding site for miR-223 in HSP90B1 3'UTR. We investigated whether miR-223 directly targets HSP90B1 through luciferase assays and ectopic expression of miR-223. Quantitative real-time polymerase chain reaction and western blot were used to determine HSP90B1 expression in CLL patients. The relationship between rs2307842 status, HSP90B1 expression and clinico-biological data were assessed.
  
  
  RESULTS
  HSP90B1 is a direct target for miR-223 by interaction with the putative miR-223 binding site. The analysis in paired samples (CD19+ fraction cell and non-CD19+ fraction cell) showed that the presence of rs2307842 and IGHV unmutated genes determined HSP90B1 overexpression in B lymphocytes from CLL patients. These results were confirmed at the protein level by western blot. Of note, HSP90B1 overexpression was independently predictive of shorter time to the first therapy in CLL patients. By contrast, the presence of rs2307842 was not related to the outcome.
  
  
  CONCLUSIONS
  HSP90B1 is a direct target gene of miR-223. Our results provide a plausible explanation of why CLL patients harboring miR-223 downregulation are associated with a poor outcome, pointing out HSP90B1 as a new pathogenic mechanism in CLL and a promising therapeutic target.
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. anaerv@hotmail.com.
authors.forename: Ana E
authors.initials: AE
authors.lastname: Rodríguez-Vicente
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. dalia@usal.es.
authors.forename: Dalia
authors.initials: D
authors.lastname: Quwaider
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. beniroc@usal.es.
authors.forename: Rocío
authors.initials: R
authors.lastname: Benito
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. irenamk@usal.es.|National Medicines Institute, Warsaw, Poland. irenamk@usal.es.
authors.forename: Irena
authors.initials: I
authors.lastname: Misiewicz-Krzeminska
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. mahesa2504@hotmail.com.
authors.forename: María
authors.initials: M
authors.lastname: Hernández-Sánchez
authors.affiliation: Servicio de Hematología, Hospital Clínico Universitario, Valladolid, Spain. agarciadecoca@aehh.org.
authors.forename: Alfonso García
authors.initials: AG
authors.lastname: de Coca
authors.affiliation: Servicio de Hematología, Hospital General de Segovia, Segovia, Spain. rfisac@saludcastillayleon.es.
authors.forename: Rosa
authors.initials: R
authors.lastname: Fisac
authors.affiliation: Servicio de Hematología, Hospital Río Carrión, Palencia, Spain. hematologia.hrc@saludcastillayleon.es.
authors.forename: José-María
authors.initials: JM
authors.lastname: Alonso
authors.affiliation: Departamento de Informática y Automática, Universidad de Salamanca, Salamanca, Spain. carol_zato@usal.es.
authors.forename: Carolina
authors.initials: C
authors.lastname: Zato
authors.affiliation: Departamento de Informática y Automática, Universidad de Salamanca, Salamanca, Spain. fcofds@usal.es.
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: de Paz
authors.affiliation: Instituto de Estudios de Ciencias de la Salud de Castilla y León, (IECSCYL)-HUSAL, Castilla y León, Spain. jlgarcia@usal.es.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: García
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. sarasquete@hotmail.com.
authors.forename: Ma Eugenia
authors.initials: ME
authors.lastname: Sarasquete
authors.affiliation: Servicio de Hematología, Hospital Universitario Infanta Leonor, Universidad Complutense de Madrid, Madrid, Spain. jahr_jahr2006@yahoo.es.
authors.forename: José Ángel
authors.initials: JÁ
authors.lastname: Hernández
authors.affiliation: Departamento de Informática y Automática, Universidad de Salamanca, Salamanca, Spain. corchado@usal.es.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Corchado
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. margondi@usal.es.
authors.forename: Marcos
authors.initials: M
authors.lastname: González
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. normagu@usal.es.
authors.forename: Norma C
authors.initials: NC
authors.lastname: Gutiérrez
authors.affiliation: Servicio de Hematología, IBSAL, IBMCC, CIC, Universidad de Salamanca, CSIC, Hospital Universitario, Salamanca, Spain. jmhr@usal.es.
authors.forename: Jesús-María
authors.initials: JM
authors.lastname: Hernández-Rivas
mesh_terms: D020413:3' Untranslated Regions; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001665:Binding Sites; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011379:Prognosis; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D020413:3' Untranslated Regions; D008562:Membrane Glycoproteins; D035683:MicroRNAs; C525067:MIR223, human; C053387:endoplasmin