title: Evidence for downregulation of the negative regulator SPRED2 in clinical prostate cancer.
abstract: BACKGROUND
  SPRED1 and 2 are key negative regulators of MAPK signalling in mammalian cells. Here, we investigate the expression and functional role of SPREDs in prostate cancer.
  
  
  METHODS
  A transcriptome bank of microdissected grade-specific primary cancers was constructed and interrogated for transcript expression of prostate cancer genes, known negative signalling regulators as well as SPRED1 and 2. The effect of SPRED2 manipulation was tested in in vitro assays.
  
  
  RESULTS
  In a panel of 5 benign glands and 15 tumours, we observed concomitant downregulation of the negative regulators SEF and DUSP1 in tumours with increasing Gleason grade. Profiling in the same cohorts revealed downregulation of SPRED2 mRNA in tumours compared with benign glands (P<0.05). By contrast, SPRED1 expression remained unchanged. This observation was further validated in two additional separate cohorts of microdissected tumours (total of n=10 benign and n=58 tumours) with specific downregulation of SPRED2 particularly in higher grade tumours. In functional assays, SPRED2 overexpression reduced ERK phosphorylation and inhibited prostate cancer cell proliferation and migration in response to different growth factors and full-media stimulation (P<0.001). Conversely, SPRED2 suppression by siRNA enhanced the mitogenic response to growth factors and full media (P<0.001).
  
  
  CONCLUSIONS
  These data suggest first evidence that SPRED2 is downregulated in prostate cancer and warrants further investigation as a potential tumour-suppressor gene.
authors.affiliation: Translational Prostate Cancer Group, Hutchison/MRC Research centre, University of Cambridge, Cambridge CB1 0XZ, UK.
authors.forename: N
authors.initials: N
authors.lastname: Kachroo
authors.forename: T
authors.initials: T
authors.lastname: Valencia
authors.forename: A Y
authors.initials: AY
authors.lastname: Warren
authors.forename: V J
authors.initials: VJ
authors.lastname: Gnanapragasam
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D015153:Blotting, Western; D002465:Cell Movement; D049109:Cell Proliferation; D015331:Cohort Studies; D015536:Down-Regulation; D054638:Dual Specificity Phosphatase 1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D060787:Neoplasm Grading; D011379:Prognosis; D011470:Prostatic Hyperplasia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018123:Receptors, Interleukin / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C477526:IL17RD protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018123:Receptors, Interleukin; D012097:Repressor Proteins; C504812:SPRED1 protein, human; C500760:SPRED2 protein, human; C517019:DUSP1 protein, human; D054638:Dual Specificity Phosphatase 1