title: Regulation of placenta growth factor by microRNA-125b in hepatocellular cancer.
abstract: OBJECTIVE
  microRNAs (miRNAs) are a class of small noncoding RNAs that can regulate gene expression by translation repression or mRNA degradation. Our aim was to evaluate the role of aberrantly expressed miRNAs in hepatocellular cancer (HCC).
  
  
  METHODS
  miRNA expression in HCC tissues and cells was evaluated by qPCR array and Taqman miRNA assay. Cell proliferation, motility, invasion, and the angiogenesis index were quantitated using commercial assays. DNA methylation status, matrix metalloproteinases (MMPs) mRNA expression was quantitated by real-time PCR analysis.
  
  
  RESULTS
  miRNA profiling identified a decrease in miR-125b expression in HCC tumor tissues and cell lines. The expression of miR-125b was significantly increased by the methylation inhibitor 5-aza-2'-deoxycytidine in HCC cells but not in normal controls, suggesting that the expression of miR-125b could be epigenetically modulated. Methylation-specific PCR revealed hypermethylation status of miR-125b in HCC cells compared to non-malignant controls. Cell proliferation, anchorage-independent growth, cell migration, invasion, and angiogenesis were significantly decreased by the introduction of miR-125b precursor in HCC cell lines. Placenta growth factor was identified as a target of miR-125b by bioinformatics analysis and experimentally verified using luciferase reporter constructs. Overexpression of miR-125b in HCC cells decreased PIGF expression, and altered the angiogenesis index. Furthermore, modulation of miR-125b also distorted expression of MMP-2 and -9, the mediators of enzymatic degradation of the extracellular matrix.
  
  
  CONCLUSIONS
  Our studies showing epigenetic silencing of miR-125b contributes to an invasive phenotype provide novel mechanistic insights and identify a potential target mechanism that could be manipulated for therapeutic benefit in HCC.
authors.affiliation: Department of Medicine and Scott & White Digestive Disease Research Center, Texas A&M HSC COM and Scott & White Hospital, Temple, TX 76504, USA. galpini@medicine.tamhsc.edu
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Alpini
authors.forename: Shannon S
authors.initials: SS
authors.lastname: Glaser
authors.forename: Jing-Ping
authors.initials: JP
authors.lastname: Zhang
authors.forename: Heather
authors.initials: H
authors.lastname: Francis
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Han
authors.forename: Jiao
authors.initials: J
authors.lastname: Gong
authors.forename: Allison
authors.initials: A
authors.lastname: Stokes
authors.forename: Taylor
authors.initials: T
authors.lastname: Francis
authors.forename: Nathan
authors.initials: N
authors.lastname: Hughart
authors.forename: Levi
authors.initials: L
authors.lastname: Hubble
authors.forename: Shi-Mei
authors.initials: SM
authors.lastname: Zhuang
authors.forename: Fanyin
authors.initials: F
authors.lastname: Meng
mesh_terms: D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D002465:Cell Movement; D042783:Endothelial Cells / Q000378:metabolism; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D020778:Matrix Metalloproteinase 2 / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics*; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: C531888:MIRN125 microRNA, human; D035683:MicroRNAs; C000608036:PGF protein, human; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D000072483:Placenta Growth Factor; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9