Correction to Identification of Quinoline-Based RIP2 Kinase Inhibitors with an Improved Therapeutic Index to the hERG Ion Channel.

[This corrects the article DOI: 10.1021/acsmedchemlett.8b00344.].

Author Correction: Design of amidobenzimidazole STING receptor agonists with systemic activity.

Change history: In this Letter, author Ana Puhl was inadvertently omitted; this error has been corrected online.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Design of amidobenzimidazole STING receptor agonists with systemic activity.

Stimulator of interferon genes (STING) is a receptor in the endoplasmic reticulum that propagates innate immune sensing of cytosolic pathogen-derived and self DNA1. The development of compounds that modulate STING has recently been the focus of intense research for the treatment of cancer and infectious diseases and as vaccine adjuvants2. To our knowledge, current efforts are focused on the development of modified cyclic dinucleotides that mimic the endogenous STING ligand cGAMP; these have progressed into clinical trials in patients with solid accessible tumours amenable to intratumoral delivery3. Here we report the discovery of a small molecule STING agonist that is not a cyclic dinucleotide and is systemically efficacious for treating tumours in mice. We developed a linking strategy to synergize the effect of two symmetry-related amidobenzimidazole (ABZI)-based compounds to create linked ABZIs (diABZIs) with enhanced binding to STING and cellular function. Intravenous administration of a diABZI STING agonist to immunocompetent mice with established syngeneic colon tumours elicited strong anti-tumour activity, with complete and lasting regression of tumours. Our findings represent a milestone in the rapidly growing field of immune-modifying cancer therapies.

Identification of Quinoline-Based RIP2 Kinase Inhibitors with an Improved Therapeutic Index to the hERG Ion Channel.

RIP2 kinase was recently identified as a therapeutic target for a variety of autoimmune diseases. We have reported previously a selective 4-aminoquinoline-based RIP2 inhibitor GSK583 and demonstrated its effectiveness in blocking downstream NOD2 signaling in cellular models, rodent in vivo models, and human ex vivo disease models. While this tool compound was valuable in validating the biological pathway, it suffered from activity at the hERG ion channel and a poor PK/PD profile thereby limiting progression of this analog. Herein, we detail our efforts to improve both this off-target liability as well as the PK/PD profile of this series of inhibitors through modulation of lipophilicity and strengthening hinge binding ability. These efforts have led to inhibitor 7, which possesses high binding affinity for the ATP pocket of RIP2 (IC50 = 1 nM) and inhibition of downstream cytokine production in human whole blood (IC50 = 10 nM) with reduced hERG activity (14 µM).

Discovery of a First-in-Class Receptor Interacting Protein 1 (RIP1) Kinase Specific Clinical Candidate (GSK2982772) for the Treatment of Inflammatory Diseases.

RIP1 regulates necroptosis and inflammation and may play an important role in contributing to a variety of human pathologies, including immune-mediated inflammatory diseases. Small-molecule inhibitors of RIP1 kinase that are suitable for advancement into the clinic have yet to be described. Herein, we report our lead optimization of a benzoxazepinone hit from a DNA-encoded library and the discovery and profile of clinical candidate GSK2982772 (compound 5), currently in phase 2a clinical studies for psoriasis, rheumatoid arthritis, and ulcerative colitis. Compound 5 potently binds to RIP1 with exquisite kinase specificity and has excellent activity in blocking many TNF-dependent cellular responses. Highlighting its potential as a novel anti-inflammatory agent, the inhibitor was also able to reduce spontaneous production of cytokines from human ulcerative colitis explants. The highly favorable physicochemical and ADMET properties of 5, combined with high potency, led to a predicted low oral dose in humans.

The Identification and Pharmacological Characterization of 6-(tert-Butylsulfonyl)-N-(5-fluoro-1H-indazol-3-yl)quinolin-4-amine (GSK583), a Highly Potent and Selective Inhibitor of RIP2 Kinase.

RIP2 kinase is a central component of the innate immune system and enables downstream signaling following activation of the pattern recognition receptors NOD1 and NOD2, leading to the production of inflammatory cytokines. Recently, several inhibitors of RIP2 kinase have been disclosed that have contributed to the fundamental understanding of the role of RIP2 in this pathway. However, because they lack either broad kinase selectivity or strong affinity for RIP2, these tools have only limited utility to assess the role of RIP2 in complex environments. We present, herein, the discovery and pharmacological characterization of GSK583, a next-generation RIP2 inhibitor possessing exquisite selectivity and potency. Having demonstrated the pharmacological precision of this tool compound, we report its use in elucidating the role of RIP2 kinase in a variety of in vitro, in vivo, and ex vivo experiments, further clarifying our understanding of the role of RIP2 in NOD1 and NOD2 mediated disease pathogenesis.

4-(3-Aryloxyaryl)quinoline sulfones are potent liver X receptor agonists.

A series of 4-(3-aryloxyaryl)quinolines with sulfone substituents on the terminal aryl ring (7) was prepared as LXR agonists. High affinity LXR ligands with excellent agonist potency and efficacy in functional assays of LXR activity were identified. In general, these sulfone agonists were equal to or superior to previously described alcohol and amide analogs in terms of affinity, functional potency, and microsomal stability. Many of the sulfones had LXRbeta binding IC(50) values <10nM while the most potent compounds in an ABCA1 mRNA induction assay in J774 mouse cells had EC(50) values <10nM and were as efficacious as T0901317.

3-(3-Aryloxyaryl)imidazo[1,2-a]pyridine sulfones as liver X receptor agonists.

Replacement of a quinoline with an imidazo[1,2-a]pyridine in a series of liver X receptor (LXR) agonists incorporating a [3-(sulfonyl)aryloxyphenyl] side chain provided high affinity LXR ligands 7. In functional assays of LXR activity, good agonist potency and efficacy were found for several analogs.

4-(3-aryloxyaryl)quinoline alcohols are liver X receptor agonists.

A series of 4-(3-aryloxyaryl)quinolines with alcohol substituents on the terminal aryl ring was prepared as potential LXR agonists, in which an alcohol group replaced an amide in previously reported amide analogs. High affinity LXR ligands with excellent agonist potency and efficacy in a functional model of LXR activity were identified, demonstrating that alcohols can substitute for amides while retaining LXR activity. The most potent compound was 5b which had an IC(50)=3.3 nM for LXRbeta binding and EC(50)=12 nM (122% efficacy relative to T0901317) in an ABCA1 mRNA induction assay in J774 mouse cells.

Biarylether amide quinolines as liver X receptor agonists.

A series of 4-(amido-biarylether)-quinolines was prepared as potential LXR agonists. Appropriate substitution with amide groups provided high affinity LXR ligands, some with excellent potency and efficacy in functional assays of LXR activity. Novel amide 4g had a binding IC(50)=1.9 nM for LXRbeta and EC(50)=34 nM (96% efficacy relative to T0901317) in an ABCA1 gene expression assay in mouse J774 cells, demonstrating that 4-(biarylether)-quinolines with appropriate amide substitution are potent LXR agonists.

Further modification on phenyl acetic acid based quinolines as liver X receptor modulators.

A series of phenyl acetic acid based quinolines was prepared as LXR modulators. An SAR study in which the C-3 and C-8 positions of the quinoline core were varied led to the identification of two potent LXR agonists 23 and 27. Both compounds displayed good binding affinity for LXRbeta and LXRalpha, and increased expression of ABCA1 in THP-1 cells. These two compounds also had desirable pharmacokinetic profiles in mice and displayed in vivo efficacy in a 12-week Apo E knockout mouse lesion model.

Estrogen receptor beta ligands: design and synthesis of new 2-phenyl-isoindole-1,3-diones.

The design, synthesis, and biological evaluation of the 2-phenyl-isoindole-1,3-diones will be discussed. Detailed modeling studies with X-ray support were used to understand the ligand binding orientation and observed selectivity.

Discovery of phenyl acetic acid substituted quinolines as novel liver X receptor agonists for the treatment of atherosclerosis.

A structure-based approach was used to optimize our new class of quinoline LXR modulators leading to phenyl acetic acid substituted quinolines 15 and 16. Both compounds displayed good binding affinity for LXRbeta and LXRalpha and were potent activators in LBD transactivation assays. The compounds also increased expression of ABCA1 and stimulated cholesterol efflux in THP-1 cells. Quinoline 16 showed good oral bioavailability and in vivo efficacy in a LDLr knockout mouse model for lesions.

Synthesis of 1-Amino-3-[2-(1,7-dicarba-closo-dodecaboran(12)-1-yl)ethyl]cyclobutanecarboxylic Acid: A Potential BNCT Agent.

The synthesis of an unnatural amino acid, 1-amino-3-[2-(1,7-dicarba-closo-dodecaboran(12)-1-yl)ethyl]cyclobutanecarboxylic acid, was achieved. This new potential BNCT agent was prepared via the monoalkylation of m-carborane with 4-bromobutene to produce 4-m-carboranyl-1-butene, which was then subjected to a 2 + 2 cycloaddition using dichloroketene. The resultant boronated cyclobutanone was reductively dechlorinated prior to the formation of the corresponding hydantoin, which was hydrolized to the title compound in excellent yield.