title: Purification and characterization of 66-kDa glycoprotein from human breast carcinoma.
abstract: We extracted a 66-kDa glycoprotein (GP-1D8) from breast invasive ductal carcinoma tissues. The monoclonal antibody (mAb) against GP-1D8 was prepared in our laboratory. Western blotting with the purified protein using the mAb demonstrated a single band of 66 kDa. Immunocytochemical and immunohistochemical analysis revealed strong expression of GP-1D8 protein in the cytoplasm of MCF-7 cells and different types of breast carcinoma tissues, but GP-1D8 is absent in normal breast and benign breast tumor tissues. Glycosylation analysis showed GP-1D8 contained methylated salic acid. GP-1D8 was identified using mass-spectrometric techniques and N-terminal sequencing. These data were used to identify the protein through the SWISSPROT protein sequence database and BLAST homology search. These results showed GP-1D8 had some similarity to human albumin precursor. Co-immunoprecipitation assays of lysate from MCF-7 cells and mass spectrometric analysis revealed the interaction of GP-1D8 with beta-tubulin. This is the first time human breast carcinoma tissues and MCF-7 cells have been shown to express a 66-kDa glycoprotein similar to human albumin precursor. These results might be important in the detection of novel potential biomarkers and may provide insight into the molecular mechanisms of tumorigenesis.
authors.affiliation: Department of Biochemistry, College of Life Sciences, Peking University, Beijing 100871, China. rqfeng@pku.edu.cn
authors.forename: Renqing
authors.initials: R
authors.lastname: Feng
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.forename: Zhenquan
authors.initials: Z
authors.lastname: Guo
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor / Q000737:chemistry / Q000302:isolation & purification*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry* / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000737:chemistry; D011498:Protein Precursors / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry
chemical_list: D014408:Biomarkers, Tumor; D006023:Glycoproteins; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D011498:Protein Precursors; D012709:Serum Albumin