title: Klf4 transcription factor is expressed in the cytoplasm of prostate cancer cells.
abstract: BACKGROUND
  Cancer initiation and progression might be driven by small populations of cells endowed with stem cell-like properties. Here we comparatively addressed the expression of genes encoding putative stemness regulators including c-Myc, Klf4, Nanog, Oct4A and Sox2 genes in benign prostatic hyperplasia (BPH) and prostate cancer (PCA).
  
  
  METHODS
  Fifty-eight PCA and thirty-nine BPH tissues samples were used for gene expression analysis, as evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of specific Klf4 isoforms was tested by conventional PCR. Klf4 specific antibodies were used for protein detection in a tissue microarray including 404 prostate samples.
  
  
  RESULTS
  Nanog, Oct4A and Sox2 genes were comparably expressed in BPH and PCA samples, whereas c-Myc and Klf4 genes were expressed to significantly higher extents in PCA than in BPH specimens. Immunohistochemical studies revealed that Klf4 protein is detectable in a large majority of epithelial prostatic cells, irrespective of malignant transformation. However, in PCA, a predominantly cytoplasmic location was observed, consistent with the expression of a differentially spliced Klf4α isoform.
  
  
  CONCLUSIONS
  Klf4 is highly expressed at gene and protein level in BPH and PCA tissues but a cytoplasmic location of the specific gene product is predominantly detectable in malignant cells. Klf4 location might be of critical relevance to steer its functions during oncogenesis.
authors.affiliation: Institute for Surgical Research and Hospital Management, Department of Biomedicine, Basel University Hospital, Basel, Switzerland. lemagnenc@uhbs.ch
authors.forename: Clémentine
authors.initials: C
authors.lastname: Le Magnen
authors.forename: Lukas
authors.initials: L
authors.lastname: Bubendorf
authors.forename: Christian
authors.initials: C
authors.lastname: Ruiz
authors.forename: Inti
authors.initials: I
authors.lastname: Zlobec
authors.forename: Alexander
authors.initials: A
authors.lastname: Bachmann
authors.forename: Michael
authors.initials: M
authors.lastname: Heberer
authors.forename: Giulio C
authors.initials: GC
authors.lastname: Spagnoli
authors.forename: Stephen
authors.initials: S
authors.lastname: Wyler
authors.forename: Chantal
authors.initials: C
authors.lastname: Mengus
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D003593:Cytoplasm / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D000071317:Nanog Homeobox Protein; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009367:Neoplasm Staging; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D011379:Prognosis; D011470:Prostatic Hyperplasia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019048:Prostatic Intraepithelial Neoplasia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D046888:Tissue Array Analysis; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D018398:Homeodomain Proteins; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; C489427:MYC protein, human; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors