Characterization of tumor cell resistance to 4'-deoxy-4'-iododoxorubicin developed in Ehrlich ascites cells in vivo.
Reduced drug accumulation is the most common functional change accompanying development of P-glycoprotein-associated multidrug resistance. One of our laboratories showed earlier that the anthracycline analogue 4'-deoxy-4'-iododoxorubicin (DIDOX) was accumulated to identical levels in Ehrlich ascites tumor (EHR2) and daunorubicin (DNR)-resistant EHR2/DNR+ cells (E. Friche, P. B. Jensen, T. Skovsgaard, and N. I. Nissen, J. Cell. Pharmacol., 1:57-65, 1990). In this communication, we show that weekly treatment of EHR2-bearing mice with 4, 8, or 12 mg of DIDOX/kg/week led to the development of three DIDOX-resistant cell lines, EHR2/DIDOX-1, EHR2/DIDOX-2, and EHR2/DIDOX-3. The levels of DIDOX accumulation and retention and its outward transport were similar in the drug-sensitive and three drug-resistant cell lines. By contrast, the accumulation of the active DIDOX metabolite, 13-dihydro-DIDOX (13-OH-DIDOX), the parent compound doxorubicin, and daunorubicin were all decreased in proportion to the resistance of the cells. In EHR2/DIDOX-3 cells, the reduction in daunorubicin accumulation coincided with the development of P-glycoprotein as demonstrated by Western blot and flow cytometry with C219 antibody. DIDOX had no effect on the photolabeling of P-glycoprotein by [3H]azidopine, whereas 13-OH-DIDOX inhibited this labeling in a concentration-dependent manner. Subsequent analysis of topoisomerase II activities and amounts in EHR2/DIDOX-3 cells revealed decreased DNA topoisomerase II catalytic activity. The amounts of immunoreactive DNA topoisomerase II from EHR2/DIDOX-1, EHR2/DIDOX-2, and EHR2/DIDOX-3 cells were about 89%, 73%, and 52%, respectively, of that seen in the drug-sensitive cells. We also found that teniposide stabilized DNA-protein complexes in EHR2/DIDOX-3 but they never reached the level seen in EHR2 cells. Because it has been reported that DIDOX is rapidly metabolized to 13-OH-DIDOX, we postulate that the development of resistance to DIDOX in vivo is due in part to its metabolite, 13-OH-DIDOX, which is a substrate for plasma membrane glycoprotein, and in part to DIDOX, which is an inhibitor of topoisomerase II.
Department of Medicine and Hematology, Rigshospitalet-University Hospital, Copenhagen, Denmark.
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Friche
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Danks
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Beck
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000345:Affinity Labels; D000818:Animals; D001386:Azides / Q000378:metabolism; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy* / Q000378:metabolism; D002460:Cell Line; D004250:DNA Topoisomerases, Type II / Q000032:analysis / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000187:drug effects; D003630:Daunorubicin / Q000493:pharmacokinetics; D004095:Dihydropyridines / Q000378:metabolism; D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology; D004351:Drug Resistance; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000032:analysis; D051379:Mice; D009363:Neoplasm Proteins / Q000378:metabolism; D013713:Teniposide / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000345:Affinity Labels; D001386:Azides; D004268:DNA-Binding Proteins; D004095:Dihydropyridines; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C041130:azidopine; C053044:4'-deoxy-4'-iododoxorubicin; D004317:Doxorubicin; D013713:Teniposide; D004250:DNA Topoisomerases, Type II; D003630:Daunorubicin