6oql
From Proteopedia
CDK6 in complex with Cpd13 (R)-5-fluoro-4-(4-methyl-5,6,7,8-tetrahydro-4H-pyrazolo[1,5-a]azepin-3-yl)-N-(5-(4-methylpiperazin-1-yl)pyridin-2-yl)pyrimidin-2-amine
Structural highlights
FunctionCDK6_HUMAN Serine/threonine-protein kinase involved in the control of the cell cycle and differentiation; promotes G1/S transition. Phosphorylates pRB/RB1 and NPM1. Interacts with D-type G1 cyclins during interphase at G1 to form a pRB/RB1 kinase and controls the entrance into the cell cycle. Involved in initiation and maintenance of cell cycle exit during cell differentiation; prevents cell proliferation and regulates negatively cell differentiation, but is required for the proliferation of specific cell types (e.g. erythroid and hematopoietic cells). Essential for cell proliferation within the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricles. Required during thymocyte development. Promotes the production of newborn neurons, probably by modulating G1 length. Promotes, at least in astrocytes, changes in patterns of gene expression, changes in the actin cytoskeleton including loss of stress fibers, and enhanced motility during cell differentiation. Prevents myeloid differentiation by interfering with RUNX1 and reducing its transcription transactivation activity, but promotes proliferation of normal myeloid progenitors. Delays senescence. Promotes the proliferation of beta-cells in pancreatic islets of Langerhans.[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedCDK4 and CDK6 are kinases with similar sequences that regulate cell cycle progression and are validated targets in the treatment of cancer. Glioblastoma is characterized by a high frequency of CDKN2A/CCND2/CDK4/CDK6 pathway dysregulation, making dual inhibition of CDK4 and CDK6 an attractive therapeutic approach for this disease. Abemaciclib, ribociclib, and palbociclib are approved CDK4/6 inhibitors for the treatment of HR+/HER2- breast cancer, but these drugs are not expected to show strong activity in brain tumors due to poor blood brain barrier penetration. Herein, we report the identification of a brain-penetrant CDK4/6 inhibitor derived from a literature molecule with low molecular weight and topological polar surface area (MW=285 and TPSA=66A(2)), but lacking the CDK2/1 selectivity profile due to the absence of a basic amine. Removal of a hydrogen bond donor via cyclization of the pyrazole allowed for the introduction of basic and semi-basic amines, while maintaining in many cases efflux ratios reasonable for a CNS program. Ultimately, a basic spiroazetidine (cpKa=8.8) was identified that afforded acceptable selectivity over anti-target CDK1 while maintaining brain-penetration in vivo (mouse Kp,uu=0.20-0.59). To probe the potency and selectivity, our lead compound was evaluated in a panel of glioblastoma cell lines. Potency comparable to abemaciclib was observed in Rb-wild type lines U87MG, DBTRG-05MG, A172, and T98G, while Rb-deficient cell lines SF539 and M059J exhibited a lack of sensitivity. Design of a brain-penetrant CDK4/6 inhibitor for glioblastoma.,Bronner SM, Merrick KA, Murray J, Salphati L, Moffat JG, Pang J, Sneeringer CJ, Dompe N, Cyr P, Purkey H, Boenig GL, Li J, Kolesnikov A, Larouche-Gauthier R, Lai KW, Shen X, Aubert-Nicol S, Chen YC, Cheong J, Crawford JJ, Hafner M, Haghshenas P, Jakalian A, Leclerc JP, Lim NK, O'Brien T, Plise EG, Shalan H, Sturino C, Wai J, Xiao Y, Yin J, Zhao L, Gould S, Olivero A, Heffron TP Bioorg Med Chem Lett. 2019 Aug 15;29(16):2294-2301. doi:, 10.1016/j.bmcl.2019.06.021. Epub 2019 Jun 26. PMID:31307887[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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