Maureen Mckenna

Structure-Guided Design of EED Binders Allosterically Inhibiting the Epigenetic Polycomb Repressive Complex 2 (PRC2) Methyltransferase

PRC2 is a multisubunit methyltransferase involved in epigenetic regulation of early embryonic development and cell growth. The catalytic subunit EZH2 methylates primarily lysine 27 of histone H3, leading to chromatin compaction and repression of tumor suppressor genes. Inhibiting this activity by small molecules targeting EZH2 was shown to result in antitumor efficacy. Here, we describe the optimization of a chemical series representing a new class of PRC2 inhibitors which acts allosterically via the trimethyllysine pocket of the noncatalytic EED subunit. Deconstruction of a larger and complex screening hit to a simple fragment-sized molecule followed by structure-guided regrowth and careful property modulation were employed to yield compounds which achieve submicromolar inhibition in functional assays and cellular activity. The resulting molecules can serve as a simplified entry point for lead optimization and can be utilized to study this new mechanism of PRC2 inhibition and the associated biology in detail.

3D Pharmacophore Model-Assisted Discovery of Novel CDC7 Inhibitors

A ligand-based 3D pharmacophore model for serine/threonine kinase CDC7 inhibition was created and successfully applied in the discovery of novel 2-(heteroaryl)-6,7-dihydrothieno[3,2-c]pyridin-4(5H)-ones. The pharmacophore model provided a hypothesis for lead generation missed by docking to a homology model. Medicinal chemistry exploration of the series revealed clear structure-activity relationships consistent with the pharmacophore model and pointed to further optimization opportunities.

Discovery of RAF265: A Potent mut-B-RAF Inhibitor for the Treatment of Metastatic Melanoma.

Abrogation of errant signaling along the MAPK pathway through the inhibition of B-RAF kinase is a validated approach for the treatment of pathway-dependent cancers. We report the development of imidazo-benzimidazoles as potent B-RAF inhibitors. Robust in vivo efficacy coupled with correlating pharmacokinetic/pharmacodynamic (PKPD) and PD-efficacy relationships led to the identification of RAF265, 1, which has advanced into clinical trials.

Design, structure-activity relationship, and in vivo characterization of the development candidate NVP-HSP990.

Utilizing structure-based drug design, a novel dihydropyridopyrimidinone series which exhibited potent Hsp90 inhibition, good pharmacokinetics upon oral administration, and an excellent pharmacokinetic/pharmacodynamic relationship in vivo was developed from a commercial hit. The exploration of this series led to the selection of NVP-HSP990 as a development candidate.