title: Gel-based proteomics analysis of the heterogeneity of 20S proteasomes from four human pancreatic cancer cell lines.
abstract: OBJECTIVE
  The 20S proteasome is a multicatalytic protein complex, which plays a major role in intracellular protein degradation. In mammalian cells, it consists of 28 subunits arranged in four stacked rings (α1-7β1-7β1-7α1-7). The aim of this study is to characterize and compare subunit composition and heterogeneity (or subtypes) of the 20S proteasome from four human pancreatic cancer cell lines.
  
  
  METHODS
  To study subunit compositions and heterogeneity of 20S proteasome from human pancreatic cancer cell lines, in the present study, 20S proteasome from four different pancreatic cancer cell lines (SW1990, a human exocrine adenocarcinoma, derived from spleen metastasis; PANC-1, a human ductal carcinoma in situ; BxPC-3, a human ductal carcinoma in situ; and CFPAC-1, a human ductal adenocarcinoma, derived from liver metastasis) were subjected to a gel-based proteomics analysis, respectively.
  
  
  RESULTS
  It was found that the differences in the subunit compositions and subtypes of the 20S proteasomes among four pancreatic cancer cell lines exist. Gel-based proteomics analysis showed that more than 60 subunits spots were separated and identified by MS. Our study revealed the presence of various isoforms for each of the subunits and different subtypes of the 20S proteasome. The significant differences among four cell lines are the relative abundances of immunoproteasome subunits, β1i and β2i, indicating that different subtypes of immunoproteasome among four cell lines exist.
  
  
  CONCLUSIONS
  The 20S proteasome from four human pancreatic cancer cell lines was characterized. The different expression levels of immunoproteasome subunits, β1i and β2i, indicate that the 20S proteasome may have different subtypes among four cell lines, which may be related to cancer cell property and be useful for the establishment of personalized therapy using proteasome inhibitors in future.
authors.affiliation: Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, P. R. China.
authors.forename: Xinli
authors.initials: X
authors.lastname: Wang
authors.forename: Zhiyun
authors.initials: Z
authors.lastname: Zhao
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Luo
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Chen
authors.forename: Zhili
authors.initials: Z
authors.lastname: Li
mesh_terms: D045744:Cell Line, Tumor; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007525:Isoelectric Focusing; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D046988:Proteasome Endopeptidase Complex / Q000032:analysis* / Q000276:immunology; D021122:Protein Subunits / Q000032:analysis / Q000276:immunology; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D021122:Protein Subunits; D046988:Proteasome Endopeptidase Complex