Discovery of aminothiazole inhibitors of cyclin-dependent kinase 2: synthesis, X-ray crystallographic analysis, and biological activities.
High throughput screening identified 2-acetamido-thiazolylthio acetic ester 1 as an inhibitor of cyclin-dependent kinase 2 (CDK2). Because this compound is inactive in cells and unstable in plasma, we have stabilized it to metabolic hydrolysis by replacing the ester moiety with a 5-ethyl-substituted oxazole as in compound 14. Combinatorial and parallel synthesis provided a rapid analysis of the structure-activity relationship (SAR) for these inhibitors of CDK2, and over 100 analogues with IC(50) values in the 1-10 nM range were rapidly prepared. The X-ray crystallographic data of the inhibitors bound to the active site of CDK2 protein provided insight into the binding modes of these inhibitors, and the SAR of this series of analogues was rationalized. Many of these analogues displayed potent and broad spectrum antiproliferative activity across a panel of tumor cell lines in vitro. In addition, A2780 ovarian carcinoma cells undergo rapid apoptosis following exposure to CDK2 inhibitors of this class. Mechanism of action studies have confirmed that the phosphorylation of CDK2 substrates such as RB, histone H1, and DNA polymerase alpha (p70 subunit) is reduced in the presence of compound 14. Further optimization led to compounds such as water soluble 45, which possesses a favorable pharmacokinetic profile in mice and demonstrates significant antitumor activity in vivo in several murine and human models, including an engineered murine mammary tumor that overexpresses cyclin E, the coactivator of CDK2.
Kim
Kyoung Soon
KS
Department of Oncology Chemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543-4000, USA. kyoung.kim@bms.com
Kimball
S David
SD
Misra
Raj N
RN
Rawlins
David B
DB
Hunt
John T
JT
Xiao
Hai-Yun
HY
Lu
Songfeng
S
Qian
Ligang
L
Han
Wen-Ching
WC
Shan
Weifang
W
Mitt
Toomas
T
Cai
Zhen-Wei
ZW
Poss
Michael A
MA
Zhu
Hong
H
Sack
John S
JS
Tokarski
John S
JS
Chang
Chieh Ying
CY
Pavletich
Nikola
N
Kamath
Amrita
A
Humphreys
William G
WG
Marathe
Punit
P
Bursuker
Isia
I
Kellar
Kristen A
KA
Roongta
Urvashi
U
Batorsky
Roberta
R
Mulheron
Janet G
JG
Bol
David
D
Fairchild
Craig R
CR
Lee
Francis Y
FY
Webster
Kevin R
KR
D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D044482:Benzeneacetamides; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000187:drug effects; D020650:Combinatorial Chemistry Techniques; D018360:Crystallography, X-Ray; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D004256:DNA Polymerase I / Q000378:metabolism; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D005260:Female; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D008958:Models, Molecular; D010080:Oxazoles / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D016160:Retinoblastoma Protein / Q000378:metabolism; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D044482:Benzeneacetamides; D019927:Cyclin E; D004791:Enzyme Inhibitors; D006657:Histones; C465460:N-(5-(((5-tert-butyl-2-oxazolyl)methyl)thio)-2-thiazolyl)-4-(((bis(hydroxymethyl)methyl)amino)methyl)benzeneacetamide; D010080:Oxazoles; D016160:Retinoblastoma Protein; D013844:Thiazoles; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D004256:DNA Polymerase I