title: Identification of differential proteins in colorectal cancer cells treated with caffeic acid phenethyl ester.
abstract: OBJECTIVE
  To investigate the molecular mechanisms of the anti-cancer activity of caffeic acid phenethyl ester (CAPE).
  
  
  METHODS
  Protein profiles of human colorectal cancer SW480 cells treated with or without CAPE were analysed using a two-dimensional (2D) electrophoresis gel-based proteomics approach. After electrophoresis, the gels were stained with Coomassie brilliant blue R-250. Digital images were taken with a GS-800 Calibrated Densitometer, and image analysis was performed using PDQuest 2-D Analysis software. The altered proteins following CAPE treatment were further identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry following a database search. The identified proteins were validated by Western blot and immunofluorescence assay.
  
  
  RESULTS
  CAPE induced human colorectal cancer cell apoptosis. Four up-regulated proteins and seven down-regulated proteins in colorectal cancer cells treated with CAPE were found. The identified down-regulated proteins in CAPE-treated colorectal cancer cells were Triosephosphate Isomerase (Tim), Proteasome subunit alpha 4 (PSMA4) protein, Guanine nucleotide binding protein beta, Phosphoserine aminotransferase 1 (PSAT1), PSMA1, Myosin XVIIIB and Tryptophanyl-tRNA synthetase. Notably, CAPE treatment led to the down-regulation of PSAT1 and PSMA1, two proteins that have been implicated in tumorigenesis. The identified up-regulated proteins were Annexin A4, glyceraldehyde-3-phosphate dehydrogenase, Glucosamine-6-phosphate deaminase 1 (GNPDA1), and Glutathione peroxidase (GPX-1). Based on high match scores and potential role in cell growth control, PSMA1, PSAT1, GNPDA1 and GPX-1 were further validated by Western blotting and immunofluorescence assay. PSMA1 and PSAT1 were down-regulated, while GNPDA1 and GPX-1 were up-regulated in CAPE-treated colorectal cancer cells.
  
  
  CONCLUSIONS
  These differentiated proteins in colorectal cancer cells following CAPE treatment, may be potential molecular targets of CAPE and involved in the anti-cancer effect of CAPE.
authors.affiliation: Yu-Jun He, Wan-Ling Li, Hui Dong, Zhi-Rong Mou, Yu-Zhang Wu, Institute of Immunology of PLA, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Yu-Jun
authors.initials: YJ
authors.lastname: He
authors.affiliation: Yu-Jun He, Wan-Ling Li, Hui Dong, Zhi-Rong Mou, Yu-Zhang Wu, Institute of Immunology of PLA, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Li
authors.affiliation: Yu-Jun He, Wan-Ling Li, Hui Dong, Zhi-Rong Mou, Yu-Zhang Wu, Institute of Immunology of PLA, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Bao-Hua
authors.initials: BH
authors.lastname: Liu
authors.affiliation: Yu-Jun He, Wan-Ling Li, Hui Dong, Zhi-Rong Mou, Yu-Zhang Wu, Institute of Immunology of PLA, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
authors.affiliation: Yu-Jun He, Wan-Ling Li, Hui Dong, Zhi-Rong Mou, Yu-Zhang Wu, Institute of Immunology of PLA, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Zhi-Rong
authors.initials: ZR
authors.lastname: Mou
authors.affiliation: Yu-Jun He, Wan-Ling Li, Hui Dong, Zhi-Rong Mou, Yu-Zhang Wu, Institute of Immunology of PLA, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Yu-Zhang
authors.initials: YZ
authors.lastname: Wu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D002109:Caffeic Acids / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D015180:Electrophoresis, Gel, Two-Dimensional; D005455:Fluorescent Antibody Technique; D006801:Humans; D018613:Microscopy, Confocal; D009363:Neoplasm Proteins / Q000378:metabolism*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000494:pharmacology; D040901:Proteomics / Q000379:methods; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D002109:Caffeic Acids; D009363:Neoplasm Proteins; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol
keywords: Caffeic acid phenethyl ester; Colorectal cancer; Mass spectrometry; Proteomics; Two-dimensional electrophoresis