title: Identification of the heterogeneous nuclear ribonucleoprotein A2/B1 as the antigen for the gastrointestinal cancer specific monoclonal antibody MG7.
abstract: MG7 is an early gastrointestinal cancer specific monoclonal antibody. It can detect gastric cancer with high sensitivity and specificity. However, the target antigen for MG7 has not been identified. Western blot analysis revealed that the MG7 antibody reproducibly recognized two approximately 35 kDa proteins in the total cell lysates of human gastric carcinoma cell lines KATO III and MKN-45. Using a proteomic approach, we identified these MG7 immunoreactive proteins as the human heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1). Western blot analysis of nuclear and cytosolic fraction of KATO III cells using either MG7 or hnRNP A2/B1 antibodies confirmed that the target antigen is located exclusively in the nucleus. With the use of archival samples, we also found that the level of hnRNP A2/B1 protein was increased in gastric cancer tissues (4 out of 5 patients), when compared to their corresponding matching normal stomach tissue.
authors.affiliation: The Proteomic Task Force, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Chi-ho
authors.initials: CH
authors.lastname: Lee
authors.forename: John Hon-kei
authors.initials: JH
authors.lastname: Lum
authors.forename: Belinda Pik-yuen
authors.initials: BP
authors.lastname: Cheung
authors.forename: Man-sau
authors.initials: MS
authors.lastname: Wong
authors.forename: Yoki Kwok-chu
authors.initials: YK
authors.lastname: Butt
authors.forename: Ming F
authors.initials: MF
authors.lastname: Tam
authors.forename: Wing Y
authors.initials: WY
authors.lastname: Chan
authors.forename: Chit
authors.initials: C
authors.lastname: Chow
authors.forename: Pak-kwan
authors.initials: PK
authors.lastname: Hui
authors.forename: Francis S L
authors.initials: FS
authors.lastname: Kwok
authors.forename: Samuel Chun-lap
authors.initials: SC
authors.lastname: Lo
authors.forename: D M
authors.initials: DM
authors.lastname: Fan
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000378:metabolism; D000912:Antibodies, Neoplasm / Q000737:chemistry*; D000951:Antigens, Neoplasm / Q000737:chemistry*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D030562:Databases, Protein; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005770:Gastrointestinal Neoplasms / Q000276:immunology / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000096:biosynthesis* / Q000737:chemistry*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D040901:Proteomics / Q000379:methods*; D012984:Software; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; C503210:MG7 monoclonal antibody; D010455:Peptides