Optimization of globomycin analogs as novel gram-negative antibiotics.

Discovery of novel classes of Gram-negative antibiotics with activity against multi-drug resistant infections is a critical unmet need. As an essential member of the lipoprotein biosynthetic pathway, lipoprotein signal peptidase II (LspA) is an attractive target for antibacterial drug discovery, with the natural product inhibitor globomycin offering a modestly-active starting point. Informed by structure-based design, the globomycin depsipeptide was optimized to improve activity against E. coli. Backbone modifications, together with adjustment of physicochemical properties, afforded potent compounds with good in vivo pharmacokinetic profiles. Optimized compounds such as 51 (E. coli MIC 3.1 µM) and 61 (E. coli MIC 0.78 µM) demonstrate broad spectrum activity against gram-negative pathogens and may provide opportunities for future antibiotic discovery.

Antibody-mediated delivery of chimeric protein degraders which target estrogen receptor alpha (ERα).

Chimeric molecules which effect intracellular degradation of target proteins via E3 ligase-mediated ubiquitination (e.g., PROTACs) are currently of high interest in medicinal chemistry. However, these entities are relatively large compounds that often possess molecular characteristics which may compromise oral bioavailability, solubility, and/or in vivo pharmacokinetic properties. Accordingly, we explored whether conjugation of chimeric degraders to monoclonal antibodies using technologies originally developed for cytotoxic payloads might provide alternate delivery options for these novel agents. In this report we describe the construction of several degrader-antibody conjugates comprised of two distinct ERα-targeting degrader entities and three independent ADC linker modalities. We subsequently demonstrate the antigen-dependent delivery to MCF7-neo/HER2 cells of the degrader payloads that are incorporated into these conjugates. We also provide evidence for efficient intracellular degrader release from one of the employed linkers. In addition, preliminary data are described which suggest that reasonably favorable in vivo stability properties are associated with the linkers utilized to construct the degrader conjugates.

Discovery of a class of highly potent Janus Kinase 1/2 (JAK1/2) inhibitors demonstrating effective cell-based blockade of IL-13 signaling.

Disruption of interleukin-13 (IL-13) signaling with large molecule antibody therapies has shown promise in diseases of allergic inflammation. Given that IL-13 recruits several members of the Janus Kinase family (JAK1, JAK2, and TYK2) to its receptor complex, JAK inhibition may offer an alternate small molecule approach to disrupting IL-13 signaling. Herein we demonstrate that JAK1 is likely the isoform most important to IL-13 signaling. Structure-based design was then used to improve the JAK1 potency of a series of previously reported JAK2 inhibitors. The ability to impede IL-13 signaling was thereby significantly improved, with the best compounds exhibiting single digit nM IC50's in cell-based assays dependent upon IL-13 signaling. Appropriate substitution was further found to influence inhibition of a key off-target, LRRK2. Finally, the most potent compounds were found to be metabolically labile, which makes them ideal scaffolds for further development as topical agents for IL-13 mediated diseases of the lungs and skin (for example asthma and atopic dermatitis, respectively).

PROTACs Targeting BRM (SMARCA2) Afford Selective In Vivo Degradation over BRG1 (SMARCA4) and Are Active in BRG1 Mutant Xenograft Tumor Models.

The identification of VHL-binding proteolysis targeting chimeras (PROTACs) that potently degrade the BRM protein (also known as SMARCA2) in SW1573 cell-based experiments is described. These molecules exhibit between 10- and 100-fold degradation selectivity for BRM over the closely related paralog protein BRG1 (SMARCA4). They also selectively impair the proliferation of the H1944 "BRG1-mutant" NSCLC cell line, which lacks functional BRG1 protein and is thus highly dependent on BRM for growth, relative to the wild-type Calu6 line. In vivo experiments performed with a subset of compounds identified PROTACs that potently and selectively degraded BRM in the Calu6 and/or the HCC2302 BRG1 mutant NSCLC xenograft models and also afforded antitumor efficacy in the latter system. Subsequent PK/PD analysis established a need to achieve strong BRM degradation (>95%) in order to trigger meaningful antitumor activity in vivo. Intratumor quantitation of mRNA associated with two genes whose transcription was controlled by BRM (PLAU and KRT80) also supported this conclusion.

γ-Carbolines: a novel class of cannabinoid agonists with high aqueous solubility and restricted CNS penetration.

An oral, peripherally restricted CB1/CB2 agonist could provide an interesting approach to treat chronic pain by harnessing the analgesic properties of cannabinoids but without the well-known central side effects. γ-Carbolines are a novel class of potent mixed CB1/CB2 agonists characterized by attractive physicochemical properties including high aqueous solubility. Optimization of the series has led to the discovery of 29, which has oral activity in a rat inflammatory pain model and limited brain exposure at analgesic doses, consistent with a lower risk of CNS-mediated tolerability issues.

Novel benzimidazole derivatives as selective CB2 agonists.

The preparation and evaluation of a novel class of CB2 agonists based on a benzimidazole moiety are reported. They showed binding affinities up to 1nM towards the CB2 receptor with partial to full agonist potencies. They also demonstrated good to excellent selectivity (>1000-fold) over the CB1 receptor.

Practical synthesis of quinoxalinones via palladium-catalyzed intramolecular N-arylations.

A practical and highly efficient route to the synthesis of pharmaceutically interesting quinoxalinone scaffolds is reported. The key step involves an intramolecular palladium-catalyzed N-arylation under microwave irradiation. The developed methodology tolerates a variety of bromoanilides to afford a diverse collection of bicyclic and polycyclic quinoxalinones in high yield.