jm049354h_si_001.pdf (52.84 kB)
Discovery of a Potent and Selective Inhibitor of Cyclin-Dependent Kinase 4/6
journal contribution
posted on 2005-04-07, 00:00 authored by Peter L. Toogood, Patricia J. Harvey, Joseph T. Repine, Derek J. Sheehan, Scott N. VanderWel, Hairong Zhou, Paul R. Keller, Dennis J. McNamara, Debra Sherry, Tong Zhu, Joanne Brodfuehrer, Chung Choi, Mark R. Barvian, David W. FryA pharmacological approach to inhibition of cyclin-dependent kinases 4 and 6 (Cdk4/6) using
highly selective small molecule inhibitors has the potential to provide novel cancer therapies
for clinical use. Achieving high levels of selectivity for Cdk4/6, versus other ATP-dependent
kinases, presents a significant challenge. The pyrido[2,3-d]pyrimidin-7-one template provides
an effective platform for the inhibition of a broad cross-section of kinases, including Cdks. It
is now demonstrated that the modification of pyrido[2,3-d]pyrimidin-7-ones to include a
2-aminopyridine side chain at the C2-position provides inhibitors with exquisite selectivity for
Cdk4/6 in vitro. This selectivity profile is recapitulated in cells where the most selective
inhibitors create a G1 block at concentrations up to 100-fold the IC50 for cell proliferation. On
the basis of its selectivity profile and pharmacokinetic profile, compound 43 (PD 0332991) was
identified as a drug candidate for the treatment of cancer.