Targeting host cell factors required for virus replication provides an alternative to targeting pathogen components and represents a promising approach to develop broad-spectrum antiviral therapeutics. High-throughput screening (HTS) identified two classes of inhibitors (2 and 3) with broad-spectrum antiviral activity against ortho- and paramyxoviruses including influenza A virus (IAV), measles virus (MeV), respiratory syncytial virus (RSV), and human parainfluenza virus type 3 (HPIV3). Hit-to-lead optimization delivered inhibitor 28a, with EC50 values of 0.88 and 0.81 μM against IAV strain WSN and MeV strain Edmonston, respectively. It was also found that compound 28a delivers good stability in human liver S9 fractions with a half-life of 165 min. These data establish 28a as a promising lead for antiviral therapy through a host-directed mechanism.Keywords: benzimidazole; host-directed; influenza A; metabolic stability; Myxovirus inhibitor; respiratory syncytial virus;

The measles virus (MeV), a member of the paramyxovirus family, is an important cause of pediatric morbidity and mortality worldwide. In an effort to provide therapeutic treatments for improved measles management, we previously identified a small, non-nucleoside organic inhibitor of the viral RNA-dependent RNA polymerase by means of high-throughput screening. Subsequent structure–activity relationship (SAR) studies around the corresponding pyrazole carboxamide scaffold led to the discovery of 2 (AS-136a), a first generation lead with low nanomolar potency against life MeV and attractive physical properties suitable for development. However, its poor water solubility and low oral bioavailability (F) in rat suggested that the lead could benefit from further SAR studies to improve the biophysical characteristics of the compound. Optimization of in vitro potency and aqueous solubility led to the discovery of 2o (ERDRP-00519), a potent inhibitor of MeV (EC50 = 60 nM) with an aqueous solubility of approximately 60 μg/mL. The agent shows a 10-fold exposure (AUC/Cmax) increase in the rat model relative to 2, displays near dose proportionality in the range of 10–50 mg/kg, and exhibits good oral bioavailability (F = 39%). The significant solubility increase appears linked to the improved oral bioavailability.

Drugs targeted to viral proteins are highly vulnerable to the development of viral resistance. One little explored approach to the treatment of viral diseases is the development of agents that target host factors required for virus replication. Myxoviruses are predominantly associated with acute disease and, thus, ideally suited for this approach since the necessary treatment time is anticipated to be limited. High-throughput screening previously identified benzimidazole 22407448 with broad antiviral activity against different influenza virus and paramyxovirus strains. Hit to lead chemistry has generated 6p (JMN3-003) with potent antiviral activity against a panel of myxovirus family members exhibiting EC50 values in the low nanomolar range.Keywords: benzimidazole; Host-directed; influenza virus; myxovirus; non-nucleoside; small molecule inhibitor

We previously reported a novel drug delivery system, drug-linker-Phe-Phe-Arg-methylketone (FFR-mk)-factor VIIa (fVIIa). The method utilizes tissue factor (TF), which is aberrantly and abundantly expressed on many cancer cells. The advantage of this delivery system is its ability to furnish a potent anticancer drug specifically to the tumor vasculature and cancer cells. In this paper, we describe the synthesis of paclitaxel (PTX)-Phe-Phe-Arg-chloromethyl ketone (FFR-ck), followed by coupling with fVIIa to form PTX-FFR-mk-fVIIa. FFRck was separately linked to the OH groups at the C2′ or C7 positions of PTX (C2′- or C7-PTX-FFRck), the C2′ analogue exhibiting better activity against human head and neck squamous KB 3-1 cells. The activity order against PTX-sensitive KB 3-1 cells is C2′-PTX-FFRmk-fVIIa > PTX > C2′-PTX-FFRck. The C2′ complex shows an IC50 of 12 nM against the PTX-sensitive cell line and 130 nM against PTX-resistant cells.

Activation of the Gαs-coupled EP2 receptor for prostaglandin E2 (PGE₂) promotes cell survival in several models of tissue damage. To advance understanding of EP2 functions, we designed experiments to develop allosteric potentiators of this key prostaglandin receptor. Screens of 292,000 compounds identified 93 that at 20 μM (i) potentiated the cAMP response to a low concentration of PGE₂ by > 50%; (ii) had no effect on EP4 or β2 adrenergic receptors, the cAMP assay itself, or the parent cell line; and (iii) increased the potency of PGE₂ on EP2 receptors at least 3-fold. In aqueous solution, the active compounds are largely present as nanoparticles that appear to serve as active reservoirs for bioactive monomer. From 94 compounds synthesized or purchased, based on the modification of one hit compound, the most active increased the potency of PGE₂ on EP2 receptors 4- to 5-fold at 10 to 20 μM and showed substantial neuroprotection in an excitotoxicity model. These small molecules represent previously undescribed allosteric modulators of a PGE₂ receptor. Our results strongly reinforce the notion that activation of EP2 receptors by endogenous PGE₂ released in a cell-injury setting is neuroprotective.

Measles virus (MV) is one of the most infectious pathogens known. In spite of the existence of a vaccine, approximately 350000 deaths/year result from MV or associated complications. Antimeasles compounds could conceivably diminish these statistics and provide a therapy that complements vaccine treatment. We recently described a high-throughput screening hit compound 1 (16677) against MV-infected cells with the capacity to eliminate viral reproduction at 250 nM by inhibiting the action of the virus’s RNA-dependent RNA polymerase complex (RdRp). The compound, 1-methyl-3-(trifluoromethyl)-N-[4-sulfonylphenyl]-1H-pyrazole-5-carboxamide, 1 carries a critical CF3 moiety on the 1,2-pyrazole ring. Elaborating on the preliminary structure−activity (SAR) study, the present work presents the synthesis and SAR of a much broader range of low nanomolar nonpeptidic MV inhibitors and speculates on the role of the CF3 functionality.

The molecular chaperone Hsp90 plays important roles in maintaining malignant phenotypes. Recent studies suggest that Hsp90 exerts high-affinity interactions with multiple oncoproteins, which are essential for the growth of tumor cells. As a result, research has focused on finding Hsp90 probes as potential and selective anticancer agents. In a high-throughput screening exercise, we identified quinoline 7 as a moderate inhibitor of Hsp90. Further hit identification, SAR studies, and biological investigation revealed several synthetic analogs in this series with micromolar activities in both fluorescent polarization (FP) assay and a cell-based Western blot (WB) assay. These compounds represent a new class of Hsp90 inhibitors with simple chemical structures.

Nuclear factor kappa B (NF-κB) is a key signaling molecule in the elaboration of the inflammatory response. Data indicate that curcumin, a natural ingredient of the curry spice turmeric, acts as a NF-κB inhibitor and exhibits both anti-inflammatory and anti-cancer properties. Curcumin analogs with enhanced activity on NF-κB and other inflammatory signaling pathways have been developed including the synthetic monoketone compound 3,5-Bis(2-fluorobenzylidene)-4-piperidone (EF24). 3,5-Bis(2-pyridinylmethylidene)-4-piperidone (EF31) is a structurally-related curcumin analog whose potency for NF-κB inhibition has yet to be determined. To examine the activity of EF31 compared to EF24 and curcumin, mouse RAW264.7 macrophages were treated with EF31, EF24, curcumin (1–100 μM) or vehicle (DMSO 1%) for 1 h. NF-κB pathway activity was assessed following treatment with lipopolysaccharide (LPS) (1 μg/mL). EF31 (IC50 ~ 5 μM) exhibited significantly more potent inhibition of LPS-induced NF-κB DNA binding compared to both EF24 (IC50 ~ 35 μM) and curcumin (IC50 > 50 μM). In addition, EF31 exhibited greater inhibition of NF-κB nuclear translocation as well as the induction of downstream inflammatory mediators including pro-inflammatory cytokine mRNA and protein (tumor necrosis factor-α, interleukin-1β, and interleukin-6). Regarding the mechanism of these effects on NF-κB, EF31 (IC50 ~ 1.92 μM) exhibited significantly greater inhibition of IκB kinase β compared to EF24 (IC50 ~ 131 μM). Finally, EF31 demonstrated potent toxicity in NF-κB-dependent cancer cell lines while having minimal and reversible toxicity in RAW264.7 macrophages. These data indicate that EF31 is a more potent inhibitor of NF-κB activity than either EF24 or curcumin while exhibiting both anti-inflammatory and anticancer activities. Thus, EF31 represents a promising curcumin analog for further therapeutic development.Highlights► EF31 is a potent inhibitor of Iκβ kinase, NF-κB translocation, and NF-κB DNA-binding activity in RAW264.7 macrophages. ► EF31 blocks the expression of pro-inflammatory cytokine mRNA and protein. ► EF31 inhibits MAPK transcription factors. ► EF31 exhibits potent anti-cancer activity in various cancer cell lines.