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Topoisomerase II poisoning by ICRF-193.

Authors :
Huang, K C
Gao, H
Yamasaki, E F
Grabowski, D R
Liu, S
Shen, L L
Chan, K K
Ganapathi, R
Snapka, R M
Source :
Journal of Biological Chemistry; November 2001, Vol. 276 Issue: 48 p44488-94, 7p
Publication Year :
2001

Abstract

Antineoplastic bis(dioxopiperazine)s, such as meso-2,3-bis(2,6-dioxopiperazin-4-yl)butane (ICRF-193), are widely believed to be only catalytic inhibitors of topoisomerase II. However, topoisomerase inhibitors have little or no antineoplastic activity unless they are topoisomerase poisons, a special subclass of topoisomerase-targeting drugs that stabilize topoisomerase-DNA strand passing intermediates and thus cause the topoisomerase to become a cytotoxic DNA-damaging agent. Here we report that ICRF-193 is a very significant topoisomerase II poison. Detection of topoisomerase II poisoning by ICRF-193 required the use of a chaotropic protein denaturant in the topoisomerase poisoning assays. ICRF-193 caused dose-dependent cross-linking of human topoisomerase IIbeta to DNA and stimulated topoisomerase IIbeta-mediated DNA cleavage at specific sites on (32)P-end-labeled DNA. Human topoisomerase IIalpha-mediated DNA cleavage was stimulated to a lesser extent by ICRF-193. In vivo experiments with MCF-7 cells also showed the requirement of a chaotropic protein denaturant in the assays and selectivity for the beta-isozyme of human topoisomerase II. Studies with two topoisomerase IIbeta-negative cell model systems confirmed significant topoisomerase II poisoning by ICRF-193 in the wild type cells and were consistent with beta-isozyme selectivity. Common use of only the detergent, SDS, in assays may have led to failure to detect topoisomerase II poisoning by ICRF-193 in earlier studies.

Details

Language :
English
ISSN :
00219258 and 1083351X
Volume :
276
Issue :
48
Database :
Supplemental Index
Journal :
Journal of Biological Chemistry
Publication Type :
Periodical
Accession number :
ejs7174916
Full Text :
https://doi.org/10.1074/jbc.M104383200