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The Deubiquitinating Enzyme Inhibitor PR-619 is a Potent DNA Topoisomerase II Poison s

Lookup NU author(s): Dr Ian CowellORCiD, Elise Ling, Becky Swan, Professor Caroline AustinORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


2,6-Diaminopyridine-3,5-bis(thiocyanate) (PR-619) is a broad-spectrum deubiquitinating enzyme (DUB) inhibitor that has been employed in cell-based studies as a tool to investigate the role of ubiquitination in various cellular processes. Here, we demonstrate that in addition to its action as a DUB inhibitor, PR-619 is a potent DNA topoisomerase II (TOP2) poison, inducing both DNA topoisomerase IIα (TOP2A) and DNA topoisomerase IIβ (TOP2B) covalent DNA complexes with similar efficiency to the archetypal TOP2 poison etoposide. However, in contrast to etoposide, which induces TOP2-DNA complexes with a pan-nuclear distribution, PR-619 treatment results in nucleolar concentration of TOP2A and TOP2B. Notably, neither the induction of TOP2-DNA covalent complexes nor their nucleolar concentration are due to TOP2 hyperubiquitination since both occur even under conditions of depleted ubiquitin. Like etoposide, since PR-619 affected TOP2 enzyme activity in in vitro enzyme assays as well as in live cells, we conclude that PR-619 interacts directly with TOP2A and TOP2B. The concentration at which PR-619 exhibits robust cellular DUB inhibitor activity (5–20 μM) is similar to the lowest concentration at which TOP2 poison activity was detected (above 20 μM), which suggests that caution should be exercised when employing this DUB inhibitor in cell-based studies.

Publication metadata

Author(s): Cowell IG, Ling EM, Swan RL, Brooks MLW, Austin CA

Publication type: Article

Publication status: Published

Journal: Molecular Pharmacology

Year: 2019

Volume: 96

Issue: 5

Pages: 562–572

Print publication date: 01/11/2019

Online publication date: 30/09/2019

Acceptance date: 06/09/2019

Date deposited: 03/10/2019

ISSN (print): 0026-895X

ISSN (electronic): 1521-0111

Publisher: American Society for Pharmacology and Experimental Therapeutics


DOI: 10.1124/mol.119.117390


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