title: Identification of novel drug resistance-associated proteins by a panel of rat monoclonal antibodies.
abstract: Since some multidrug-resistant (MDR) tumor cell lines show drug accumulation defects but do not over-express Pgp or MDR protein (MRP), a search was made for novel MDR-related transporter proteins by immunizing rats with non-small cell lung cancer SW- 1573/2R120 cells to produce monoclonal antibodies (MAbs). Five rat MAbs (LMR-4, -12, -42, -44 and -94) were generated, showing strong membranous staining of non-Pgp MDR SW- 1573/2R120 tumor cells and minimal reactivity to the corresponding parental and revertant cell lines. In addition, a 6th MAb (LMR-5) was isolated, recognizing the MDR-related lung resistance protein (LRP), previously identified as the major vault protein. The first 5 LMR MAbs show predominantly membranous staining of several non-Pgp MDR tumor cell lines of different histogenetic origins, except for LMR-4, which recognizes only MDR sublines of the SW- 1573 cell line. Flow-cytometric analysis revealed that all MAbs, except LMR-4 and -5, detect outside epitopes. Functional studies showed that these MAbs did not restore the daunorubicin accumulation defect. All but one of the MAbs (LMR-42) showed staining of distinct normal human tissues, notably epithelial cells lining the airways and digestive tract. In addition, staining of vascular endothelial cells was found with all MAbs except LMR-4. Three MAbs (LMR-12, -44 and -94) showed remarkable immunoreactivity with vincristine-selected SW- 1573 sublines. By immunoblotting and precipitation, the LMR antigens were found to be in the 42-69 kDa range.
authors.affiliation: Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Flens
authors.forename: G L
authors.initials: GL
authors.lastname: Scheffer
authors.forename: P
authors.initials: P
authors.lastname: van der Valk
authors.forename: H J
authors.initials: HJ
authors.lastname: Broxterman
authors.forename: E W
authors.initials: EW
authors.lastname: Eijdems
authors.forename: A C
authors.initials: AC
authors.lastname: Huysmans
authors.forename: M A
authors.initials: MA
authors.lastname: Izquierdo
authors.forename: R J
authors.initials: RJ
authors.lastname: Scheper
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis* / Q000302:isolation & purification; D000951:Antigens, Neoplasm / Q000032:analysis / Q000276:immunology; D000970:Antineoplastic Agents / Q000494:pharmacology; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry* / Q000188:drug therapy; D002462:Cell Membrane / Q000737:chemistry; D018432:Drug Resistance, Multiple; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000737:chemistry* / Q000188:drug therapy; D009363:Neoplasm Proteins / Q000032:analysis* / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D000939:Epitopes; D009363:Neoplasm Proteins