Thienopyrimidinone based sirtuin-2 (SIRT2)-selective inhibitors bind in the ligand induced 'selectivity pocket'.

Sirtuins (SIRTs) are NAD-dependent deacylases, known to be involved in a variety of pathophysiological processes and thus remain promising therapeutic targets for further validation. Previously, we reported a novel thienopyrimidinone SIRT2 inhibitor with good potency and excellent selectivity for SIRT2. Herein, we report an extensive SAR study of this chemical series and identify the key pharmacophoric elements and physiochemical properties that underpin the excellent activity observed. New analogues have been identified with submicromolar SIRT2 inhibtory activity and good to excellent SIRT2 subtype-selectivity. Importantly, we report a co-crystal structure of one of our compounds (29c) bound to SIRT2. This reveals our series to induce the formation of a previously reported 'selectivity pocket', but to bind in an inverted fashion to what might be intuitively expected. We believe these findings will contribute significantly to understanding of the mechanism of action of SIRT2 inhibitors and to the identification of refined, second generation inhibitors

Chroman-4-one- and Chromone-Based Sirtuin 2 Inhibitors with Antiproliferative Properties in Cancer Cells

Peer reviewe

Discovery of 5‑{4-[(7-Ethyl-6-oxo‑5,6-dihydro‑1,5-naphthyridin-3-yl)methyl]piperazin-1-yl}‑<i>N</i>‑methyl­pyridine-2-carboxamide (AZD5305): A PARP1–DNA Trapper with High Selectivity for PARP1 over PARP2 and Other PARPs

Poly-ADP-ribose-polymerase (PARP) inhibitors have achieved regulatory approval in oncology for homologous recombination repair deficient tumors including BRCA mutation. However, some have failed in combination with first-line chemotherapies, usually due to overlapping hematological toxicities. Currently approved PARP inhibitors lack selectivity for PARP1 over PARP2 and some other 16 PARP family members, and we hypothesized that this could contribute to toxicity. Recent literature has demonstrated that PARP1 inhibition and PARP1–DNA trapping are key for driving efficacy in a BRCA mutant background. Herein, we describe the structure- and property-based design of 25 (AZD5305), a potent and selective PARP1 inhibitor and PARP1–DNA trapper with excellent in vivo efficacy in a BRCA mutant HBCx-17 PDX model. Compound 25 is highly selective for PARP1 over other PARP family members, with good secondary pharmacology and physicochemical properties and excellent pharmacokinetics in preclinical species, with reduced effects on human bone marrow progenitor cells in vitro