Identification of novel drug resistance-associated proteins by a panel of rat monoclonal antibodies

MJ Flens, GL Scheffer, P vanderValk, HJ Broxterman, EWHM Eijdems, ACLM Huysmans, MA Izquierdo, RJ Scheper

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    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 nonsmall 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-I2, -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. (C) 1997 Wiley-Liss, Inc.

    Original languageEnglish
    Pages (from-to)249-257
    Number of pages9
    JournalInternational Journal of Cancer
    Volume73
    Issue number2
    Publication statusPublished - 9-Oct-1997

    Keywords

    • CANCER CELL-LINES
    • HUMAN TUMOR-CELLS
    • P-GLYCOPROTEIN
    • MULTIDRUG-RESISTANCE
    • EXPRESSION
    • OVEREXPRESSION
    • TRANSPORTER
    • MRP
    • ACCUMULATION
    • MEMBRANE

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