Design, Synthesis, and Biological Activity of Substrate Competitive SMYD2 Inhibitors

Protein lysine methyltransferases (KMTs) have emerged as important regulators of epigenetic signaling. These enzymes catalyze the transfer of donor methyl groups from the cofactor <i>S</i>-adenosylmethionine to specific acceptor lysine residues on histones, leading to changes in chromatin structure and transcriptional regulation. These enzymes also methylate an array of nonhistone proteins, suggesting additional mechanisms by which they influence cellular physiology. SMYD2 is reported to be an oncogenic methyltransferase that represses the functional activity of the tumor suppressor proteins p53 and RB. HTS screening led to identification of five distinct substrate-competitive chemical series. Determination of liganded crystal structures of SMYD2 contributed significantly to “<i>hit-to-lead</i>” design efforts, culminating in the creation of potent and selective inhibitors that were used to understand the functional consequences of SMYD2 inhibition. Taken together, these results have broad implications for inhibitor design against KMTs and clearly demonstrate the potential for developing novel therapies against these enzymes

Design, Synthesis, and Biological Activity of Substrate Competitive SMYD2 Inhibitors

Protein lysine methyltransferases (KMTs) have emerged as important regulators of epigenetic signaling. These enzymes catalyze the transfer of donor methyl groups from the cofactor <i>S</i>-adenosylmethionine to specific acceptor lysine residues on histones, leading to changes in chromatin structure and transcriptional regulation. These enzymes also methylate an array of nonhistone proteins, suggesting additional mechanisms by which they influence cellular physiology. SMYD2 is reported to be an oncogenic methyltransferase that represses the functional activity of the tumor suppressor proteins p53 and RB. HTS screening led to identification of five distinct substrate-competitive chemical series. Determination of liganded crystal structures of SMYD2 contributed significantly to “<i>hit-to-lead</i>” design efforts, culminating in the creation of potent and selective inhibitors that were used to understand the functional consequences of SMYD2 inhibition. Taken together, these results have broad implications for inhibitor design against KMTs and clearly demonstrate the potential for developing novel therapies against these enzymes

Potent and Selective CK2 Kinase Inhibitors with Effects on Wnt Pathway Signaling <i>in Vivo</i>

The Wnt pathway is an evolutionarily conserved and tightly regulated signaling network with important roles in embryonic development and adult tissue regeneration. Impaired Wnt pathway regulation, arising from mutations in Wnt signaling components, such as Axin, APC, and β-catenin, results in uncontrolled cell growth and triggers oncogenesis. To explore the reported link between CK2 kinase activity and Wnt pathway signaling, we sought to identify a potent, selective inhibitor of CK2 suitable for proof of concept studies <i>in vivo</i>. Starting from a pyrazolo­[1,5-<i>a</i>]­pyrimidine lead (<b>2</b>), we identified compound <b>7h</b>, a potent CK2 inhibitor with picomolar affinity that is highly selectivity against other kinase family enzymes and inhibits Wnt pathway signaling (IC₅₀ = 50 nM) in DLD-1 cells. In addition, compound <b>7h</b> has physicochemical properties that are suitable for formulation as an intravenous solution, has demonstrated good pharmacokinetics in preclinical species, and exhibits a high level of activity as a monotherapy in HCT-116 and SW-620 xenografts

Structure and Property Based Design of Pyrazolo[1,5-a]pyrimidine Inhibitors of CK2 Kinase with Activity in Vivo

In this letter, we describe the design, synthesis, and structure–activity relationship of 5-anilinopyrazolo­[1,5-a]­pyrimidine inhibitors of CK2 kinase. Property-based optimization of early leads using the 7-oxetan-3-yl amino group led to a series of matched molecular pairs with lower lipophilicity, decreased affinity for human plasma proteins, and reduced binding to the hERG ion channel. Agents in this study were shown to modulate pAKT^S129, a direct substrate of CK2, in vitro and in vivo, and exhibited tumor growth inhibition when administered orally in a murine DLD-1 xenograft

Potent and Selective Inhibitors of CK2 Kinase Identified through Structure-Guided Hybridization

In this paper we describe a series of 3-cyano-5-aryl-7-aminopyrazolo­[1,5-<i>a</i>]­pyrimidine hits identified by kinase-focused subset screening as starting points for the structure-based design of conformationally constrained 6-acetamido-indole inhibitors of CK2. The synthesis, SAR, and effects of this novel series on Akt signaling and cell proliferation <i>in vitro</i> are described