title: A possible role for microRNA-141 down-regulation in sunitinib resistant metastatic clear cell renal cell carcinoma through induction of epithelial-to-mesenchymal transition and hypoxia resistance.
abstract: OBJECTIVE
  We identified microRNA driven mechanisms in clear cell renal cell carcinoma associated with the tumor response to the multitargeted receptor tyrosine kinase inhibitor sunitinib.
  
  
  METHODS
  We performed screening genome-wide microRNA real-time quantitative polymerase chain reaction on 20 freshly frozen clear cell renal cell carcinoma tissue samples of patients who received sunitinib as first line targeted therapy. Nine patients with progressive disease within 6 months after initiating therapy were considered poor responders and 11 with at least 1-year progression-free survival were considered good responders. We studied microRNA-141 function in vitro by stable up-regulation of microRNA-141, quantification of target gene expression and cell viability in normoxic and hypoxic conditions. Relative expression in clinical and cell line samples was determined by real-time quantitative polymerase chain reaction. Localization of microRNA-141 and its targets was assessed by microRNA in situ hybridization and immunohistochemistry. Hypoxia induced cytotoxicity was assessed by a luminescence adenosine triphosphate detection assay.
  
  
  RESULTS
  Compared to good responders, microRNA-141 was significantly down-regulated in tumors of poor responders to sunitinib. This seemed spatially linked to epithelial-to-mesenchymal transition in vivo. Reintroduction of microRNA-141 in vitro reversed epithelial-to-mesenchymal transition and decreased cell viability in hypoxic conditions.
  
  
  CONCLUSIONS
  In our study microRNA-141 down-regulation driven epithelial-to-mesenchymal transition in clear cell renal cell carcinoma was linked to an unfavorable response to sunitinib therapy. Reintroduction of microRNA-141 in vitro led to epithelial-to-mesenchymal transition reversal and increased sensibility to a hypoxic environment. Future experiments should be done in vivo to see whether microRNA-141 driven reversal of epithelial-to-mesenchymal transition could affect the efficacy of sunitinib treatment.
authors.affiliation: Laboratory of Translational Cell and Tissue Research, Catholic University Leuven, Leuven, Belgium. johannes.berkers@uzleuven.be
authors.forename: Joost
authors.initials: J
authors.lastname: Berkers
authors.forename: Olivier
authors.initials: O
authors.lastname: Govaere
authors.forename: Pascal
authors.initials: P
authors.lastname: Wolter
authors.forename: Benoit
authors.initials: B
authors.lastname: Beuselinck
authors.forename: Patrick
authors.initials: P
authors.lastname: Schöffski
authors.forename: Léon C
authors.initials: LC
authors.lastname: van Kempen
authors.forename: Maarten
authors.initials: M
authors.lastname: Albersen
authors.forename: Joost
authors.initials: J
authors.lastname: Van den Oord
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.forename: Johan
authors.initials: J
authors.lastname: Swinnen
authors.forename: Steven
authors.initials: S
authors.lastname: Joniau
authors.forename: Hendrik
authors.initials: H
authors.lastname: Van Poppel
authors.forename: Evelyne
authors.initials: E
authors.lastname: Lerut
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002292:Carcinoma, Renal Cell / Q000188:drug therapy* / Q000235:genetics*; D015687:Cell Hypoxia / Q000235:genetics*; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D007680:Kidney Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D035683:MicroRNAs / Q000502:physiology*; D011758:Pyrroles / Q000627:therapeutic use*; D000077210:Sunitinib; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D007211:Indoles; C533895:MIRN141 microRNA, human; D035683:MicroRNAs; D011758:Pyrroles; D000077210:Sunitinib