Structure-guided design of purine-based probes for selective Nek2 inhibition.
Nek2 (NIMA-related kinase 2) is a cell cycle-dependent serine/threonine protein kinase that regulates centrosome separation at the onset of mitosis. Overexpression of Nek2 is common in human cancers and suppression can restrict tumor cell growth and promote apoptosis. Nek2 inhibition with small molecules, therefore, offers the prospect of a new therapy for cancer. To achieve this goal, a better understanding of the requirements for selective-inhibition of Nek2 is required. 6-Alkoxypurines were identified as ATP-competitive inhibitors of Nek2 and CDK2. Comparison with CDK2-inhibitor structures indicated that judicious modification of the 6-alkoxy and 2-arylamino substituents could achieve discrimination between Nek2 and CDK2. In this study, a library of 6-cyclohexylmethoxy-2-arylaminopurines bearing carboxamide, sulfonamide and urea substituents on the 2-arylamino ring was synthesized. Few of these compounds were selective for Nek2 over CDK2, with the best result being obtained for 3-((6-(cyclohexylmethoxy)-9H-purin-2-yl)amino)-N,N-dimethylbenzamide (CDK2 IC50 = 7.0 μM; Nek2 IC50 = 0.62 μM) with >10-fold selectivity. Deletion of the 6-substituent abrogated activity against both Nek2 and CDK2. Nine compounds containing an (E)-dialkylaminovinyl substituent at C-6, all showed selectivity for Nek2, e.g. (E)-6-(2-(azepan-1-yl)vinyl)-N-phenyl-9H-purin-2-amine (CDK2 IC50 = 2.70 μM; Nek2 IC50 = 0.27 μM). Structural biology of selected compounds enabled a partial rationalization of the observed structure activity relationships and mechanism of Nek2 activation. This showed that carboxamide 11 is the first reported inhibitor of Nek2 in the DFG-in conformation.
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Christopher R
CR
Coxon
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Christopher
C
Wong
Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
Richard
R
Bayliss
Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Surrey, UK.
Kathy
K
Boxall
Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
Katherine H
KH
Carr
Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
Andrew M
AM
Fry
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Ian R
IR
Hardcastle
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Christopher J
CJ
Matheson
Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK.
David R
DR
Newell
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Mangaleswaran
M
Sivaprakasam
Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK.
Huw
H
Thomas
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
David
D
Turner
Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
Sharon
S
Yeoh
Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK.
Lan Z
LZ
Wang
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Roger J
RJ
Griffin
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Bernard T
BT
Golding
Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
Céline
C
Cano
D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D015195:Drug Design; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D000072379:NIMA-Related Kinases / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship
D000970:Antineoplastic Agents; C089441:NEK2 protein, human; D000072379:NIMA-Related Kinases
Nek2; cancer; small molecule inhibitors; structure-guided design