title: Proteomic analysis identifies translationally controlled tumor protein as a mediator of phosphatase of regenerating liver-3-promoted proliferation, migration and invasion in human colon cancer cells.
abstract: BACKGROUND
  Considerable evidence suggests that phosphatase of regenerating liver-3 (PRL-3) plays multiple roles in cancer metastasis; however, the molecular mechanisms remain largely unknown. The aim of this study was to identify proteins associated with PRL-3-promoted colon cancer metastasis, by comparative proteomic analysis.
  
  
  METHODS
  Proteomes of human colon cancer LoVo cells transfected with PRL-3 gene (LoVo-PRL-3) or empty vector PAcGFP-C3 (LoVo-control) were compared using 2D gel electrophoresis. Proteins that varied significantly in concentration were selected and identified using mass spectrometry. Expression of translationally controlled tumor protein (TCTP) mRNA and protein in LoVo-PRL-3 and LoVo-control cells was detected by real-time PCR and Western blotting. Small interfering RNA (siRNA) targeting TCTP was used for silencing TCTP expression in LoVo-PRL-3 cells. Functional significance of TCTP in PRL-3-promoted colon cancer cell proliferation, migration and invasion was investigated by Cell Counting Kit-8 assay and transwell chamber.
  
  
  RESULTS
  Seventeen proteins displaying significant and reproducible differences between LoVo-PRL-3 and LoVo-control cells were identified. Ten proteins were upregulated and seven were downregulated in LoVo-PRL-3 cells when compared with LoVo-control cells. Eight identified proteins are associated with distinct steps of tumor metastasis: ubiquitin-like protein ISG15, interleukin-18, TCTP, serpin B5, annexin A3, macrophage-capping protein, ATP-dependent RNA helicase DDX3X, and cathepsin D. Real-time PCR and Western blotting results showed that both TCTP mRNA and protein were significantly increased in LoVo-PRL-3 cells compared to LoVo-control cells. Transfection with TCTP siRNA significantly reduced the expression of both mRNA and protein levels of TCTP in LoVo-PRL-3 cells. Knockdown of TCTP by siRNA inhibited PRL-3-promoted proliferation, migration and invasion of LoVo-PRL-3 cells.
  
  
  CONCLUSIONS
  Our results imply that TCTP might be a mediator of PRL-3-promoted proliferation, migration and invasion of human colon cancer cells.
authors.affiliation: Department of Gastroenteropancreatic Surgery, the Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, China.
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Chu
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.forename: Chao-Xu
authors.initials: CX
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Lai
authors.forename: Shou-Feng
authors.initials: SF
authors.lastname: Li
authors.forename: Heng
authors.initials: H
authors.lastname: Wu
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Zeng
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Zhao
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Guan
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D003110:Colonic Neoplasms / Q000378:metabolism*; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction; D000090324:Tumor Protein, Translationally-Controlled 1
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; C000715647:TPT1 protein, human; D000090324:Tumor Protein, Translationally-Controlled 1; C484730:PTP4A3 protein, human; D017027:Protein Tyrosine Phosphatases