Inhibition of Hsp90 acts synergistically with topoisomerase II poisons to increase the apoptotic killing of cells due to an increase in topoisomerase II mediated DNA damage

Barker, Catherine R, McNamara, Anne V, Rackstraw, Stephen A, Nelson, David E, White, Mike R, Watson, Alastair J M and Jenkins, John R (2006) Inhibition of Hsp90 acts synergistically with topoisomerase II poisons to increase the apoptotic killing of cells due to an increase in topoisomerase II mediated DNA damage. Nucleic Acids Research, 34 (4). pp. 1148-1157. ISSN 0305-1048

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Abstract

Topoisomerase II plays a crucial role during chromosome condensation and segregation in mitosis and meiosis and is a highly attractive target for chemotherapeutic agents. We have identified previously topoisomerase II and heat shock protein 90 (Hsp90) as part of a complex. In this paper we demonstrate that drug combinations targeting these two enzymes cause a synergistic increase in apoptosis. The objective of our study was to identify the mode of cell killing and the mechanism behind the increase in topoisomerase II mediated DNA damage. Importantly we demonstrate that Hsp90 inhibition results in an increased topoiosmerase II activity but not degradation of topoisomerase II and it is this, in the presence of a topoisomerase II poison that causes the increase in cell death. Our results suggest a novel mechanism of action where the inhibition of Hsp90 disrupts the Hsp90-topoisomerase II interaction leading to an increase in and activation of unbound topoisomerase II, which, in the presence of a topoisomerase II poison leads to the formation of an increased number of cleavable complexes ultimately resulting in rise in DNA damage and a subsequent increase cell death.

Item Type: Article
Uncontrolled Keywords: apoptosis,benzoquinones,cell line, tumor,dna,dna damage,dna topoisomerases, type ii,drug synergism,enzyme inhibitors,etoposide,hsp90 heat-shock proteins,humans,lactams, macrocyclic,protein kinases,quinones,topoisomerase ii inhibitors
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
University of East Anglia > Faculty of Medicine and Health Sciences > Research Groups > Gastroenterology and Gut Biology
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Depositing User: Rhiannon Harvey
Date Deposited: 14 Jul 2011 09:24
Last Modified: 25 Jul 2018 06:03
URI: https://ueaeprints.uea.ac.uk/id/eprint/33690
DOI: 10.1093/nar/gkj516

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