title: Development and exploitation of CK2 inhibitors.
abstract: A number of quite specific and fairly potent inhibitors of protein kinase CK2, belonging to the classes of condensed polyphenolic compounds, tetrabromobenzimidazole/triazole derivatives and indoloquinazolines are available to date. The structural basis for their selectivity is provided by a hydrophobic pocket adjacent to the ATP/GTP binding site, which in CK2 is smaller than in the majority of other protein kinases due to the presence of a number of residues whose bulky side chains are generally replaced by smaller ones. Consequently a doubly substituted CK2 mutant V66A,I174A is much less sensitive than CK2 wild type to these classes of inhibitors. The most efficient inhibitors both in terms of potency and selectivity are 4,5,6,7-tetrabromo-1H-benzotriazole, TBB (Ki = 0.4 microM), the TBB derivative 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole, DMAT (Ki = 0.040 microM), the emodin related coumarinic compound 8-hydroxy-4-methyl-9-nitrobenzo[g]chromen-2-one, NBC (Ki = 0.22 microM) and the indoloquinazoline derivative ([5-oxo-5,6-dihydroindolo-(1,2a)quinazolin-7-yl]acetic acid), IQA (Ki = 0.17 microM). These inhibitors are cell permeable as judged from ability to block CK2 in living cells and they have been successfully employed, either alone or in combination with CK2 mutants refractory to inhibition, to dissect signaling pathways affected by CK2 and to identify the endogenous substrates of this pleitropic kinase. By blocking CK2 these inhibitors display a remarkable pro-apoptotic efficacy on a number of tumor derived cell lines, a property which can be exploited in perspective to develop antineoplastic drugs.
authors.affiliation: Dipartimento di Chimica Biologica, Universita' di Padova, Padova, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Sarno
authors.forename: Maria
authors.initials: M
authors.lastname: Ruzzene
authors.forename: Pietrogiulio
authors.initials: P
authors.lastname: Frascella
authors.forename: Mario A
authors.initials: MA
authors.lastname: Pagano
authors.forename: Flavio
authors.initials: F
authors.lastname: Meggio
authors.forename: Alfonso
authors.initials: A
authors.lastname: Zambon
authors.forename: Marco
authors.initials: M
authors.lastname: Mazzorana
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Maira
authors.forename: Vittorio
authors.initials: V
authors.lastname: Lucchini
authors.forename: Lorenzo A
authors.initials: LA
authors.lastname: Pinna
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D017209:Apoptosis; D001562:Benzimidazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D001665:Binding Sites; D047390:Casein Kinase II / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002463:Cell Membrane Permeability; D003374:Coumarins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D020035:Holoenzymes / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008024:Ligands; D009154:Mutation; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011799:Quinazolines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014230:Triazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D001562:Benzimidazoles; D003374:Coumarins; D020035:Holoenzymes; D008024:Ligands; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D014230:Triazoles; D000255:Adenosine Triphosphate; D047390:Casein Kinase II