title: Disrupted expression of CXCL5 in colorectal cancer is associated with rapid tumor formation in rats and poor prognosis in patients.
abstract: OBJECTIVE
  We isolated a subline (CC531M) from the CC531S rat colon carcinoma cell line, which grows and metastasizes much more rapidly than CC531S. We found, using RNA expression profiling, that one of the major changes in the CC531M cell line was a 5.8-fold reduction of the chemokine CXCL5. The purpose of this study was to determine the effect of CXCL5 expression on colorectal tumor growth and metastasis.
  
  
  METHODS
  CC531 clones were generated with either knockdown or restored expression of CXCL5. These clones were inoculated in the liver of rats. In addition, in two independent cohorts of colorectal cancer patients, the level of CXCL5 expression was determined and associated to clinical variables.
  
  
  RESULTS
  Knockdown of CXCL5 expression in CC531S resulted in rapid tumor growth and increased number of metastasis, whereas restored expression of CXCL5 in CC531M resulted in a return of the "mild" tumor growth pattern of the parental cell line CC531S. In vitro, no difference was found in proliferation rate between clones with either high or low expression of CXCL5, suggesting that environmental interactions directed by CXCL5 determine tumor outgrowth. Finally, the importance of our findings was established for patients with colorectal cancer. We found that low expression of CXCL5 was significantly associated with poor prognosis for colorectal cancer patients. CXCL5 showed a trend (P = 0.05) for a positive correlation with intratumoral CD8(+) T-cell infiltration, suggesting a possible explanation for the observed poorer prognosis.
  
  
  CONCLUSIONS
  Our results show that CXCL5 is important in growth and development of colorectal cancer, implicating a future role in both cancer therapy and diagnosis.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Speetjens
authors.forename: Peter J K
authors.initials: PJ
authors.lastname: Kuppen
authors.forename: Maro H
authors.initials: MH
authors.lastname: Sandel
authors.forename: Anand G
authors.initials: AG
authors.lastname: Menon
authors.forename: Danny
authors.initials: D
authors.lastname: Burg
authors.forename: Cornelis J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: Rob A E M
authors.initials: RA
authors.lastname: Tollenaar
authors.forename: Hans J G M
authors.initials: HJ
authors.lastname: de Bont
authors.forename: J Fred
authors.initials: JF
authors.lastname: Nagelkerke
mesh_terms: D000368:Aged; D000818:Animals; D045744:Cell Line, Tumor; D054365:Chemokine CXCL5 / Q000032:analysis / Q000502:physiology*; D015179:Colorectal Neoplasms / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D051381:Rats
chemical_list: C486263:CXCL5 protein, human; D054365:Chemokine CXCL5