Download MendeleyDesign of a brain-penetrant CDK4/6 inhibitor for glioblastoma.
Bronner, S.M., Merrick, K.A., Murray, J., Salphati, L., Moffat, J.G., Pang, J., Sneeringer, C.J., Dompe, N., Cyr, P., Purkey, H., Boenig, G.L., Li, J., Kolesnikov, A., Larouche-Gauthier, R., Lai, K.W., Shen, X., Aubert-Nicol, S., Chen, Y.C., Cheong, J., Crawford, J.J., Hafner, M., Haghshenas, P., Jakalian, A., Leclerc, J.P., Lim, N.K., O'Brien, T., Plise, E.G., Shalan, H., Sturino, C., Wai, J., Xiao, Y., Yin, J., Zhao, L., Gould, S., Olivero, A., Heffron, T.P.(2019) Bioorg Med Chem Lett 29: 2294-2301
- PubMed: 31307887
- DOI: https://doi.org/10.1016/j.bmcl.2019.06.021
- Primary Citation of Related Structures:
6OQI, 6OQL, 6OQO - PubMed Abstract:
CDK4 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 = 66 Å 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 (cpK a = 8.8) was identified that afforded acceptable selectivity over anti-target CDK1 while maintaining brain-penetration in vivo (mouse K p,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.
Organizational Affiliation:
Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, United States. Electronic address: sbronner@mazetx.com.
