title: CXC receptor-4 mRNA silencing abrogates CXCL12-induced migration of colorectal cancer cells.
abstract: BACKGROUND
  Interactions between CXCR4 and its ligand CXCL12 have been shown to be involved in cancer progression in colorectal cancer (CRC). We performed a comparative CXCL12/CXCR4 expression analysis and assessed the effect of external CXCL12 stimulation on migration of CRC cells without and with CXCR4 inhibition.
  
  
  METHODS
  Expression of CXCL12/CXCR4 was assessed by quantitative real-time PCR, ELISA and immunohistochemistry in resection specimens of 50 CRC patients as well as in the corresponding normal tissues and in three human CRC cell lines with different metastatic potential (Caco-2, SW480 and HT-29). Migration assays were performed after stimulation with CXCL12 and CXCR4 was inhibited by siRNA and neutralizing antibodies.
  
  
  RESULTS
  In CRC tissues CXCL12 was significantly down-regulated and CXCR4 was significantly up-regulated compared to the corresponding normal tissues. In cell lines CXCR4 was predominantly expressed in SW480 and less pronounced in HT-29 cells. CXCL12 was only detectable in Caco-2 cells. CXCL12 stimulation had no impact on Caco-2 cells but significantly increased migration of CXCR4 bearing SW480 and HT-29 cells. This effect was significantly abrogated by neutralizing anti-CXCR4 antibody as well as by CXCR4 siRNAs (P < 0.05).
  
  
  CONCLUSIONS
  CXCR4 expression was up-regulated in CRC and CXCL12 stimulation increased migration in CXCR4 bearing cell lines. Migration was inhibited by both neutralizing CXCR4 antibodies and CXCR4 siRNAs. Thus, the expression and functionality of CXCR4 might be associated with the metastatic potential of CRC cells and CXCL12/CXCR4 interactions might therefore constitute a promising target for specific treatment interventions.
authors.affiliation: Department of General -, Visceral-, Vascular - and Paediatric Surgery, University of the Saarland, 66421 Homburg/Saar, Germany. claudia.rubie@uks.eu
authors.forename: Claudia
authors.initials: C
authors.lastname: Rubie
authors.forename: Vilma O
authors.initials: VO
authors.lastname: Frick
authors.forename: Pirus
authors.initials: P
authors.lastname: Ghadjar
authors.forename: Mathias
authors.initials: M
authors.lastname: Wagner
authors.forename: Christoph
authors.initials: C
authors.lastname: Justinger
authors.forename: Sabrina K
authors.initials: SK
authors.lastname: Faust
authors.forename: Benjamin
authors.initials: B
authors.lastname: Vicinus
authors.forename: Stefan
authors.initials: S
authors.lastname: Gräber
authors.forename: Otto
authors.initials: O
authors.lastname: Kollmar
authors.forename: Martin K
authors.initials: MK
authors.lastname: Schilling
mesh_terms: D000368:Aged; D019138:Antibodies, Blocking / Q000494:pharmacology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000276:immunology / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000235:genetics* / Q000378:metabolism
chemical_list: D019138:Antibodies, Blocking; C515255:CXCL12 protein, human; C527276:CXCR4 protein, human; D054377:Chemokine CXCL12; D012333:RNA, Messenger; D019718:Receptors, CXCR4