title: Genomic loss of miR-486 regulates tumor progression and the OLFM4 antiapoptotic factor in gastric cancer.
abstract: OBJECTIVE
  MicroRNAs (miRNA) play pivotal oncogenic and tumor-suppressor roles in several human cancers. We sought to discover novel tumor-suppressor miRNAs in gastric cancer (GC).
  
  
  METHODS
  Using Agilent miRNA microarrays, we compared miRNA expression profiles of 40 primary gastric tumors and 40 gastric normal tissues, identifying miRNAs significantly downregulated in gastric tumors.
  
  
  RESULTS
  Among the top 80 miRNAs differentially expressed between gastric tumors and normals (false discovery rate < 0.01), we identified hsa-miR-486 (miR-486) as a significantly downregulated miRNA in primary GCs and GC cell lines. Restoration of miR-486 expression in GC cell lines (YCC3, SCH and AGS) caused suppression of several pro-oncogenic traits, whereas conversely inhibiting miR-486 expression in YCC6 GC cells enhanced cellular proliferation. Array-CGH analysis of 106 primary GCs revealed genomic loss of the miR-486 locus in approximately 25% to 30% of GCs, including two tumors with focal genomic losses specifically deleting miR-486, consistent with miR-486 playing a tumor-suppressive role. Bioinformatic analysis identified the secreted antiapoptotic glycoprotein OLFM4 as a potential miR-486 target. Restoring miR-486 expression in GC cells decreased endogenous OLFM4 transcript and protein levels, and also inhibited expression of luciferase reporters containing an OLFM4 3' untranslated region with predicted miR-486 binding sites. Supporting the biological relevance of OLFM4 as a miR-486 target, proliferation in GC cells was also significantly reduced by OLFM4 silencing.
  
  
  CONCLUSIONS
  miR-486 may function as a novel tumor-suppressor miRNA in GC. Its antioncogenic activity may involve the direct targeting and inhibition of OLFM4.
authors.affiliation: Cellular and Molecular Research and Division of Medical Oncology, National Cancer Centre of Singapore, Singapore.
authors.forename: Hue-Kian
authors.initials: HK
authors.lastname: Oh
authors.forename: Angie Lay-Keng
authors.initials: AL
authors.lastname: Tan
authors.forename: Kakoli
authors.initials: K
authors.lastname: Das
authors.forename: Chia-Huey
authors.initials: CH
authors.lastname: Ooi
authors.forename: Nian-Tao
authors.initials: NT
authors.lastname: Deng
authors.forename: Iain Beehuat
authors.initials: IB
authors.lastname: Tan
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Beillard
authors.forename: Julian
authors.initials: J
authors.lastname: Lee
authors.forename: Kalpana
authors.initials: K
authors.lastname: Ramnarayanan
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Rha
authors.forename: Nallasivam
authors.initials: N
authors.lastname: Palanisamy
authors.forename: P Mathijs
authors.initials: PM
authors.lastname: Voorhoeve
authors.forename: Patrick
authors.initials: P
authors.lastname: Tan
mesh_terms: D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018450:Disease Progression; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D042822:Genomic Instability / Q000235:genetics / Q000502:physiology; D016179:Granulocyte Colony-Stimulating Factor / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000502:physiology*; D046228:Microarray Analysis; D009369:Neoplasms / Q000235:genetics / Q000473:pathology; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D051017:Apoptosis Regulatory Proteins; C560945:MIRN486 microRNA, human; D035683:MicroRNAs; C454127:OLFM4 protein, human; D016179:Granulocyte Colony-Stimulating Factor