title: Identification of proteins responsible for the multiple drug resistance in 5-fluorouracil-induced breast cancer cell using proteomics analysis.
abstract: OBJECTIVE
  This study aimed to explore the mechanism of multi-drug resistance (MDR) in 5-fluorouracil (5-FU)-induced breast cancer cell MCF-7.
  
  
  METHODS
  MCF-7 cells were exposed in stepwise escalating concentration of 5-FU to develop the resistant cell line, MCF-7/5-FU. Biological and molecular characteristics of the cells were studied through MTT, flow cytometry, real-time PCR, western-blot, and the global protein profiles between MCF-7/5-FU and parental MCF-7 were compared using proteomic approach. Then some of the differentially expressed proteins were validated by western-blot. In addition, the role of 14-3-3sigma was validated using gene transfection.
  
  
  RESULTS
  Drug resistance of MCF-7/5-FU cells to 5-FU, MX, cDDP, ADM, TAXOL all increased significantly compared with MCF-7 cells and that maybe related to BCRP, but not MDR1 and MRP1. Differentially expressed proteins between MCF-7/5-FU and MCF-7 cells were identified; 12 proteins were up-regulated and 18 proteins were down-regulated in MCF-7/5-FU cells. Expressive levels of some proteins in western-blot validation were consistent with the results in proteomic analysis. Enforced 14-3-3sigma expression can increase the sensitivity of MCF-7/5-FU cells to 5-FU and cDDP.
  
  
  CONCLUSIONS
  MDR of MCF-7/5-FU likely associated with differentially expressed proteins and 14-3-3sigma may play a positive role in chemotherapy. These findings may provide theoretical support for the prediction of chemotherapeutic response and reverse of MDR.
authors.affiliation: Cancer Research Institute, Xiangya School of Medicine, Central South University, Xiangya Road #110, Changsha 410078, Hunan, People's Republic of China.
authors.forename: Guopei
authors.initials: G
authors.lastname: Zheng
authors.forename: Fang
authors.initials: F
authors.lastname: Peng
authors.forename: Renkui
authors.initials: R
authors.lastname: Ding
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Yu
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Ouyang
authors.forename: Zhuchu
authors.initials: Z
authors.lastname: Chen
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Xiao
authors.forename: Zhimin
authors.initials: Z
authors.lastname: He
mesh_terms: D048948:14-3-3 Proteins / Q000502:physiology; D000595:Amino Acid Sequence; D014408:Biomarkers, Tumor / Q000502:physiology; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005092:Exonucleases / Q000502:physiology; D005095:Exoribonucleases; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology*; D050883:HSC70 Heat-Shock Proteins / Q000502:physiology; D006801:Humans; D053533:Keratin-8 / Q000502:physiology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000032:analysis* / Q000502:physiology; D010444:Peptide Elongation Factor Tu / Q000502:physiology; D040901:Proteomics / Q000379:methods*; D013482:Superoxide Dismutase / Q000502:physiology; D000099156:Superoxide Dismutase 2
chemical_list: D048948:14-3-3 Proteins; D014408:Biomarkers, Tumor; D005092:Exonucleases; D005095:Exoribonucleases; D005472:Fluorouracil; D050883:HSC70 Heat-Shock Proteins; D053533:Keratin-8; D009363:Neoplasm Proteins; D010444:Peptide Elongation Factor Tu; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C494371:HSPA8 protein, human; C413442:SFN protein, human