title: SNPs at miR-155 binding sites of TYRP1 explain discrepancy between mRNA and protein and refine TYRP1 prognostic value in melanoma.
abstract: BACKGROUND
  We previously demonstrated an inverse correlation between tyrosinase-related protein 1 (TYRP1) mRNA expression in melanoma metastases and patient survival. However, TYRP1 protein was not detected in half of tissues expressing mRNA and did not correlate with survival. Based on a study reporting that 3' untranslated region (UTR) of TYRP1 mRNA contains two miR-155-5p (named miR-155) binding sites exhibiting single-nucleotide polymorphisms (SNPs) that promote (matched miRNA-mRNA interaction) mRNA decay or not (mismatched), we aimed to investigate the role of miR-155 in the regulation of TYRP1 mRNA expression and protein translation accounting for these SNPs.
  
  
  METHODS
  The effect of miR-155 on TYRP1 mRNA/protein expression was evaluated in two melanoma cell lines harbouring matched or mismatched miR-155-TYRP1 mRNA interaction after transfection with pre-miR-155. In parallel, 192 skin and lymph node melanoma metastases were examined for TYRP1 mRNA/protein, miR-155 and SNPs and correlated with patient survival. TYRP1 mRNA, SNPs at its 3'UTR and miR-155 were analysed by RT-qPCR, whereas TYRP1 protein was evaluated by western blot in cell lines and by immunohistochemistry in metastatic tissues.
  
  
  RESULTS
  The miR-155 induced a dose-dependent TYRP1 mRNA decay and hampered its translation into protein in the line with the 'match' genotype. In melanoma metastases, TYRP1 mRNA inversely correlated with miR-155 expression but not with TYRP1 protein in the 'match' group, whereas it positively correlated with protein but not with miR-155 in the 'mismatch' group. Consequently, in the latter group, TYRP1 protein inversely correlated with survival.
  
  
  CONCLUSIONS
  Polymorphisms in 3'UTR of TYRP1 mRNA can affect TYRP1 mRNA regulation by miR-155 and its subsequent translation into protein. These SNPs can render TYRP1 mRNA and protein expression nonsusceptible to miR-155 activity and disclose a prognostic value for TYRP1 protein in a subgroup of melanoma patients. These data support the interest in the prognostic value of melanogenic markers and propose TYRP1 to refine prognosis in patients with advanced disease.
authors.affiliation: Laboratory of Oncology and Experimental Surgery, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: El Hajj
authors.affiliation: CNRS UMR 6290, Université de Rennes 1, 2 Avenue du Pr. Léon Bernard, 35000 Rennes, France.
authors.forename: D
authors.initials: D
authors.lastname: Gilot
authors.affiliation: CNRS UMR 6290, Université de Rennes 1, 2 Avenue du Pr. Léon Bernard, 35000 Rennes, France.
authors.forename: M
authors.initials: M
authors.lastname: Migault
authors.affiliation: Department of Pathology, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Theunis
authors.affiliation: Department of Pathology, McGill University and Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Chemin de la Côte-Sainte-Catherine, H3T 1E2 Montreal, QC, Canada.
authors.forename: L C
authors.initials: LC
authors.lastname: van Kempen
authors.affiliation: Laboratory of Oncology and Experimental Surgery, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Salés
authors.affiliation: Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Fayyad-Kazan
authors.affiliation: Department of Biochemistry, Lebanese University, Rafic Campus, 1003 Hadath-Beirut, Lebanon.
authors.forename: B
authors.initials: B
authors.lastname: Badran
authors.affiliation: Department of Pathology, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Larsimont
authors.affiliation: Clinic of Medical Oncology, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Awada
authors.affiliation: CNRS UMR 6290, Université de Rennes 1, 2 Avenue du Pr. Léon Bernard, 35000 Rennes, France.
authors.forename: L
authors.initials: L
authors.lastname: Bachelot
authors.affiliation: CNRS UMR 6290, Université de Rennes 1, 2 Avenue du Pr. Léon Bernard, 35000 Rennes, France.
authors.forename: M-D
authors.initials: MD
authors.lastname: Galibert
authors.affiliation: Laboratory of Oncology and Experimental Surgery, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Ghanem
authors.affiliation: Laboratory of Oncology and Experimental Surgery, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Heger-Bordet, 1000 Brussels, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Journe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D045744:Cell Line, Tumor; D017931:DNA Primers; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics*; D055815:Young Adult
chemical_list: D017931:DNA Primers; C524942:MIRN155 microRNA, human; D008562:Membrane Glycoproteins; D035683:MicroRNAs; D012333:RNA, Messenger; D010088:Oxidoreductases; C489799:TYRP1 protein, human