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BioMed Research International
Volume 2015, Article ID 734127, 9 pages
http://dx.doi.org/10.1155/2015/734127
Research Article

The Selectivity of CK2 Inhibitor Quinalizarin: A Reevaluation

Department of Biomedical Sciences, University of Padova and CNR Institute of Neurosciences, Via Ugo Bassi 58B, 35131 Padova, Italy

Received 29 May 2015; Accepted 14 July 2015

Academic Editor: Mariaelena Pierobon

Copyright © 2015 Giorgio Cozza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Many polyphenolic compounds have been reported to inhibit protein kinases, with special reference to CK2, a pleiotropic serine/threonine kinase, implicated in neoplasia, neurodegenerative disease, and viral infections. In general however these compounds are not endowed with stringent selectivity. Among them quinalizarin (1,2,5,8-tetrahydroxyanthraquinone) turned out to be particularly potent (Ki = 0.058 μM) and quite selective as judged by profiling it on a small panel of 70 protein kinases. Here, by profiling quinalizarin on a larger panel of 140 kinases we reach the conclusion that quinalizarin is one of the most selective inhibitors of CK2, superior to the first-in-class CK2 inhibitor, CX-4945, now in clinical trials for the treatment of cancer. Moreover here we show that quinalizarin is able to discriminate between the isolated CK2 catalytic subunit (CK2α) and CK2 holoenzyme (CK2α2β2), consistent with in silico and in vitro analyses.