Multidrug-resistant tumor cells remain sensitive to a recombinant interleukin-4-Pseudomonas exotoxin, except when overexpressing the multidrug resistance protein MRP1

M.C. de Jong, G.L. Scheffer, H.J. Broxterman, J.H. Hooijberg, J.W. Slootstra, R.H. Meloen, R.J. Kreitman, S.R. Husain, B.H. Joshi, R.K. Puri, R.J. Scheper

    Research output: Contribution to journalArticleAcademicpeer-review

    12 Citations (Scopus)

    Abstract

    Tumor cells may become resistant to conventional anticancer drugs through the occurrence of transmembrane transporter proteins such as P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2), or members of the multidrug resistance-associated protein family (MRP1¿MRP5; ABCC1¿ABCC5). In this report, we studied whether tumor cells that are cytostatic drug resistant because of overexpression of one of the above mentioned proteins are sensitive to a new anticancer agent, interleukin-4 toxin (IL-4 toxin). IL-4 toxin is a fusion protein composed of circularly permuted IL-4 and a truncated form of Pseudomonas exotoxin (PE) [IL-4(38¿37)-PE38KDEL]. Ninety-six-h cytotoxicity assays and 10-day clonogenic assays showed that drug-selected multidrug resistant (MDR) tumor cells that overexpress P-glycoprotein or breast cancer resistance proteins are still sensitive to IL-4 toxin. Also, tumor cells transfected with cDNA for MRP2¿5 showed no resistance, or marginal resistance, only to the toxin as compared with the parent cells. In contrast, MRP1-overexpressing cells, both drug selected and MRP1 transfected, are clearly resistant to IL-4 toxin with resistance factors of 4.3 to 8.4. MRP1-overexpressing cells were not resistant to PE itself. IL-4 toxin resistance in MRP1-overexpressing cells could be reversed by the MRP1 inhibitors probenecid or MK571 and were not affected by glutathione depletion by DL-buthionine-S,R-sulfoximine. In a transport assay using plasma membrane vesicles prepared from MRP1-overexpressing cells, IL-4 toxin and IL-4, but not PE, inhibited the translocation of the known MRP1 substrate 17ß-estradiol 17-(ß-D-glucuronide) (E217ßG). These data suggest that MRP1-overexpressing cells are resistant to IL-4 toxin because of extrusion of this agent by MRP1. Still, the results of this study demonstrate that IL-4 toxin effectively kills most MDR tumor cells and, therefore, represents a promising anticancer drug.
    Original languageEnglish
    Pages (from-to)5009-5017
    JournalClinical Cancer Research
    Volume9
    Issue number13
    Publication statusPublished - 2003

    Keywords

    • permuted interleukin 4-toxin
    • fibroblast-growth-factor
    • breast-carcinoma cells
    • p-glycoprotein
    • drug-resistance
    • cancer-cells
    • antitumor-activity
    • membrane-vesicles
    • atpase activity
    • il-4 receptors

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