title: Links between the oncoprotein YB-1 and small non-coding RNAs in breast cancer.
abstract: BACKGROUND
  The nucleic acid-binding protein YB-1, a member of the cold-shock domain protein family, has been implicated in the progression of breast cancer and is associated with poor patient survival. YB-1 has sequence similarity to LIN28, another cold-shock protein family member, which has a role in the regulation of small noncoding RNAs (sncRNAs) including microRNAs (miRNAs). Therefore, to investigate whether there is an association between YB-1 and sncRNAs in breast cancer, we investigated whether sncRNAs were bound by YB-1 in two breast cancer cell lines (luminal A-like and basal cell-like), and whether the abundance of sncRNAs and mRNAs changed in response to experimental reduction of YB-1 expression.
  
  
  RESULTS
  RNA-immunoprecipitation with an anti-YB-1 antibody showed that several sncRNAs are bound by YB-1. Some of these were bound by YB-1 in both breast cancer cell lines; others were cell-line specific. The small RNAs bound by YB-1 were derived from various sncRNA families including miRNAs such as let-7 and miR-320, transfer RNAs, ribosomal RNAs and small nucleolar RNAs (snoRNA). Reducing YB-1 expression altered the abundance of a number of transcripts encoding miRNA biogenesis and processing proteins but did not alter the abundance of mature or precursor miRNAs.
  
  
  CONCLUSIONS
  YB-1 binds to specific miRNAs, snoRNAs and tRNA-derived fragments and appears to regulate the expression of miRNA biogenesis and processing machinery. We propose that some of the oncogenic effects of YB-1 in breast cancer may be mediated through its interactions with sncRNAs.
authors.affiliation: Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand ; Department of Surgery, University of Auckland, Auckland, New Zealand.
authors.forename: Cherie
authors.initials: C
authors.lastname: Blenkiron
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Hurley
authors.forename: Sandra
authors.initials: S
authors.lastname: Fitzgerald
authors.forename: Cristin G
authors.initials: CG
authors.lastname: Print
authors.forename: Annette
authors.initials: A
authors.lastname: Lasham
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D058727:RNA, Small Untranslated / Q000235:genetics / Q000378:metabolism*; D051840:Y-Box-Binding Protein 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D015513:Oncogene Proteins; D012333:RNA, Messenger; D058727:RNA, Small Untranslated; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human