title: Targeting an extracellular epitope of the human multidrug resistance protein 1 (MRP1) in malignant cells with a novel recombinant single chain Fv antibody.
abstract: Inherent and acquired multidrug resistance (MDR) is characterized by a simultaneous resistance to diverse anticancer drugs and is a major impediment towards curative chemotherapy of cancer. Hence one important goal is to develop strategies aimed at specific targeting of major anticancer drug efflux transporters of the ATP-binding cassette (ABC) superfamily including multidrug resistance protein 1 -MRP1 (ABCC1). To date, no monoclonal antibody has been isolated that can target an extracellular MRP1 epitope. Using a phage display approach, we have isolated a recombinant single-chain Fv (scFv) antibody that specifically reacts with the extracellular N-terminus of the human MRP1. Flow cytometric analysis revealed that this scFv fragment binds specifically to various viable human tumor cells that display variable MRP1 expression levels but not to MRP1 null cells. Furthermore, this scFv antibody failed to react with tumor cells that overexpress other members of the MRP family that have an extracellular N-terminus (MRP2 and MRP3) as well as with MRP4, MRP5, and breast cancer resistance protein. Flow cytometric analysis also showed a good correlation between the fluorescence intensity of the anti-MRP1 scFv antibody and MRP1 levels in viable tumor cells. These findings constitute the first successful isolation of a small recombinant scFv antibody directed to an extracellular epitope of the MRP1 in viable malignant cells. These novel small Fv-based recombinant antibodies that possess superior tumor penetration capabilities may possibly be used to selectively target drugs or tumor cells that express MRP-1.
authors.affiliation: Department of Biology, Technion-Israel Institute of Technology, Technion City, Room 333, Haifa 32000, Israel.
authors.forename: Liat
authors.initials: L
authors.lastname: Binyamin
authors.forename: Yehuda G
authors.initials: YG
authors.lastname: Assaraf
authors.forename: Maya
authors.initials: M
authors.lastname: Haus-Cohen
authors.forename: Michal
authors.initials: M
authors.lastname: Stark
authors.forename: Yoram
authors.initials: Y
authors.lastname: Reiter
mesh_terms: D000595:Amino Acid Sequence; D000915:Antibody Affinity; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007128:Immunoglobulin Fragments / Q000276:immunology*; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000276:immunology* / Q000473:pathology; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D000939:Epitopes; D007128:Immunoglobulin Fragments; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; C055966:immunoglobulin Fv; C421109:multidrug resistance-associated protein 1