title: The selectivity of inhibitors of protein kinase CK2: an update.
abstract: CK2 (casein kinase 2) is a very pleiotropic serine/threonine protein kinase whose abnormally high constitutive activity has often been correlated to pathological conditions with special reference to neoplasia. The two most widely used cell permeable CK2 inhibitors, TBB (4,5,6,7-tetrabromo-1H-benzotriazole) and DMAT (2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole), are marketed as quite specific CK2 blockers. In the present study we show, by using a panel of approx. 80 protein kinases, that DMAT and its parent compound TBI (or TBBz; 4,5,6,7-tetrabromo-1H-benzimidazole) are potent inhibitors of several other kinases, with special reference to PIM (provirus integration site for Moloney murine leukaemia virus)1, PIM2, PIM3, PKD1 (protein kinase D1), HIPK2 (homeodomain-interacting protein kinase 2) and DYRK1a (dual-specificity tyrosine-phosphorylated and -regulated kinase 1a). In contrast, TBB is significantly more selective toward CK2, although it also inhibits PIM1 and PIM3. In an attempt to improve selectivity towards CK2 a library of 68 TBB/TBI-related compounds have been tested for their ability to discriminate between CK2, PIM1, HIPK2 and DYRK1a, ending up with seven compounds whose efficacy toward CK2 is markedly higher than that toward the second most inhibited kinase. Two of these, K64 (3,4,5,6,7-pentabromo-1H-indazole) and K66 (1-carboxymethyl-2-dimethylamino-4,5,6,7-tetrabromo-benzimidazole), display an overall selectivity much higher than TBB and DMAT when tested on a panel of 80 kinases and display similar efficacy as inducers of apoptosis.
authors.affiliation: Department of Biological Chemistry and CNR Institute of Neurosciences, University of Padova, viale G. Colombo 3, 35131 Padova, Italy.
authors.forename: Mario A
authors.initials: MA
authors.lastname: Pagano
authors.forename: Jenny
authors.initials: J
authors.lastname: Bain
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Kazimierczuk
authors.forename: Stefania
authors.initials: S
authors.lastname: Sarno
authors.forename: Maria
authors.initials: M
authors.lastname: Ruzzene
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Maira
authors.forename: Matthew
authors.initials: M
authors.lastname: Elliott
authors.forename: Andrzej
authors.initials: A
authors.lastname: Orzeszko
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cozza
authors.forename: Flavio
authors.initials: F
authors.lastname: Meggio
authors.forename: Lorenzo A
authors.initials: LA
authors.lastname: Pinna
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D047390:Casein Kinase II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D007191:Indazoles / Q000494:pharmacology; D019169:Jurkat Cells; D007700:Kinetics; D008958:Models, Molecular; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051381:Rats; D013329:Structure-Activity Relationship; D014230:Triazoles / Q000494:pharmacology
chemical_list: C533189:1-carboxymethyl-2-dimethylamino-4,5,6,7-tetrabromobenzimidazole; C492322:2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole; C533188:3,4,5,6,7-pentabromo-1H-indazole; C405354:4,5,6,7-tetrabromobenzotriazole; D001562:Benzimidazoles; D007191:Indazoles; D047428:Protein Kinase Inhibitors; D014230:Triazoles; C012771:benzotriazole; C031000:benzimidazole; D047390:Casein Kinase II