Identification and characterization of tumor antigens by using antibody phage display and intrabody strategies.
To generate a panel of antibodies binding human breast cancers, a human single chain Fv phage display library was selected for rapid internalization into the SK-BR-3 breast cancer cell line. Thirteen unique antibodies were identified within the 55 cell binding antibodies studied, all of them showing specific staining of tumor cells compare to normal epithelial cells. Two of the antibodies bound the ErbB2 oncogene while 6 bound the tumor marker transferrin receptor (TfR). By developing a scFv immunoprecipitation method, we were able to use LC-MS/MS to identify the antigen bound by one of the antibodies (3GA5) as FPRP (prostaglandin F2alpha receptor-regulatory protein)/EWI-F/CD9P-1 (CD9 partner 1) an Ig superfamily member that has been described to interact directly with CD9 and CD81 tetraspanins and to be overexpressed in adherent cancer cell lines. Although the 3GA5 scFv had no direct anti-proliferative effect, intracellular expression of the scFv was able to knockdown CD9P-1 expression and could be used to further define the role of the tetraspanin system in proliferation and metastasis. Moreover, the 3GA5 scFv was rapidly internalized into breast tumor cells and could have potential for the targeted delivery of cytotoxic agents to breast cancers. This study is the proof of principle that the direct selection of phage antibody libraries on tumor cells can effectively lead to the identification and functional characterization of relevant tumor markers.
Goenaga
Anne-Laure
AL
ENS Cachan Laboratoire de Biotechnologie et Pharmacologie Génétique Appliquée (LBPA), UMR CNRS 8113, 61 avenue du Président Wilson, 94235 Cachan Cedex, France.
Zhou
Yu
Y
Legay
Christine
C
Bougherara
Houcine
H
Huang
Lan
L
Liu
Bin
B
Drummond
Daryl C
DC
Kirpotin
Dmitri B
DB
Auclair
Christian
C
Marks
James D
JD
Poul
Marie-Alix
MA
D000595:Amino Acid Sequence; D000818:Animals; D000912:Antibodies, Neoplasm / Q000235:genetics / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification*; D016466:CHO Cells; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002853:Chromatography, Liquid; D006224:Cricetinae; D003412:Cricetulus; D015536:Down-Regulation; D004705:Endocytosis; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000276:immunology; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism; D019151:Peptide Library; D010641:Phenotype; D011485:Protein Binding
D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D000939:Epitopes; D007135:Immunoglobulin Variable Region; D009363:Neoplasm Proteins; D019151:Peptide Library