Characterization of a Chinese hamster ovary cell line with acquired resistance to the bisdioxopiperazine dexrazoxane (ICRF-187) catalytic inhibitor of topoisomerase II

• Published in: Biochemical pharmacology Vol. 53; no. 12; pp. 1843 - 1853
• Main Authors: Hasinoff, Brian B., Kuschak, Theodore I., Creighton, Andrew M., Fattman, Cheryl L., Allan, William P., Thampatty, Padmakumari, Yalowich, Jack C.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.06.1997; Elsevier Science
• Subjects: Aclarubicin - pharmacology; Animal cells; Animals; Antineoplastic agents; Biological and medical sciences; Biotechnology; bisdioxopiperazine; CHO Cells - drug effects; Cricetinae; dexrazoxane; DNA Topoisomerases, Type II - genetics; Drug Resistance; Establishment of new cell lines, improvement of cultural methods, mass cultures; Ethylenediamines - toxicity; Etoposide - antagonists & inhibitors; Etoposide - pharmacology; Eukaryotic cell cultures; Fundamental and applied biological sciences. Psychology; General aspects; Glycine - analogs & derivatives; Glycine - toxicity; ICRF-187; ICRF-193; Medical sciences; Methods. Procedures. Technologies; Mutation; Pharmacology. Drug treatments; Razoxane - toxicity; resistant cell; Thiobarbiturates - pharmacology; topoisomerase II; Topoisomerase II Inhibitors; Verapamil - pharmacology; ICRF-193; dexrazoxane; topoisomerase II; bisdioxopiperazine; ICRF-187; resistant cell; Antineoplastic agent; Cell culture; DNA topoisomerase (ATP-hydrolysing); Enzyme; Dexrazoxane; Etoposide; Enzyme inhibitor; Cytotoxicity; In vitro; Characterization; Podophyllotoxine derivatives; Isomerases; Established cell line; Anthracyclins; Cross resistance; Piperazine derivatives
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(97)00013-0

A Chinese hamster ovary (CHO) cell line highly resistant to the non-cleavable complex-forming topoisomerase II inhibitor dexrazoxane (ICRF-187, Zinecard ®) was selected. The resistant cell line (DZR) was 1500-fold resistant (IC 50 = 2800 vs 1.8 μM) to continuous dexrazoxane exposure. DZR cells were also cross-resistant (8- to 500-fold) to other bisdioxopiperazines (ICRF-193, ICRF-154, and ICRF-186), and somewhat cross-resistant (4- to 14-fold) to anthracyclines (daunorubicin, doxorubicin, epirubicin, and idarubicin) and etoposide (8.5-fold), but not to the other non-cleavable complex-forming topoisomerase II inhibitors suramin and merbarone. The cytotoxicity of dexrazoxane to both cell lines was unchanged in the presence of the membrane-active agent verapamil. DZR cells were 9-fold resistant to dexrazoxane-mediated inhibition of topoisomerase II DNA decatenation activity compared with CHO cells (IC 50 = 400 vs 45 μM), but were only 1.4-fold (IC 50 = 110 vs 83 μM) resistant to etoposide. DZR cells contained one-half the level of topoisomerase II protein compared with parental CHO cells. However, the specific activity for decatenation using nuclear extract topoisomerase II was unchanged. Etoposide (100 μM)-induced topoisomerase II-DNA complexes in DZR cells and isolated nuclei were similarly one-half the level found in CHO cells and in isolated nuclei. However, the ability of 500 μM dexrazoxane to inhibit etoposide (100 μM)-induced topoisomerase II-DNA covalent complexes was reduced 4- to 6-fold in both DZR cells and nuclei compared with CHO cells and nuclei. In contrast, there was no differential ability of aclarubicin or merbarone to inhibit etoposide-induced topoisomerase II-DNA complexes in CHO compared with DZR cells and isolated nuclei. It was concluded that the DZR cell line acquired its resistance to dexrazoxane mainly through an alteration in the topoisomerase II target.