Optimization of oxadiazole derivatives with a spirocyclic cyclohexane structure as novel GPR119 agonists.

We describe here a novel GPR119 agonist 24, which showed a potent and long-acting hypoglycemic effect in rats via oral dosing. For the discovery of 24, we chose compound 5, which possessed an oxadiazole linker, as a lead compound among our spirocyclic cyclohexane GPR119 agonist series, taking into account its lower plasma protein binding nature. 3,5-Difluoro and 4-methylsulfonylmethy groups on the left side phenyl group, and a gem-difluoro group on the right side of 24 are important for its agonist potency and metabolic stability, respectively.

Lead generation and optimization of novel GPR119 agonists with a spirocyclic cyclohexane structure.

We describe here the generation of a lead compound and its optimization studies that led to the identification of a novel GPR119 agonist. Based on a spirocyclic cyclohexane structure reported in our previous work, we identified compound 8 as a lead compound, being guided by ligand-lipophilicity efficiency (LLE), which linked potency and lipophilicity. Subsequent optimization studies of 8 for improvement of solubility afforded representative 21. Compound 21 had no inhibitory activity against six CYP isoforms and showed favorable pharmacokinetic properties and hypoglycemic activity in rats.

Optimization Efforts for Identification of Novel Highly Potent Keap1-Nrf2 Protein-Protein Interaction Inhibitors.

In research focused on protein-protein interaction (PPI) inhibitors, the optimization process to achieve both high inhibitory activity and favorable physicochemical properties remains challenging. Our previous study reported the discovery of novel and bioavailable Keap1-Nrf2 PPI inhibitor 8 which exhibited moderate in vivo activity in rats. In this work, we present our subsequent efforts to optimize this compound. Two distinct approaches were employed, targeting high energy water molecules and Ser602 as "hot spots" from the anchor with good aqueous solubility, metabolic stability, and membrane permeability. Through ligand efficiency (LE)-guided exploration, we identified two novel inhibitors 22 and 33 with good pharmacokinetics (PK) profiles and more potent in vivo activities, which appear to be promising chemical probes among the existing inhibitors.

Methyl and Fluorine Effects in Novel Orally Bioavailable Keap1-Nrf2 PPI Inhibitor.

Oxidative stress is one of the causes of progression of chronic kidney disease (CKD). Activation of the antioxidant protein regulator Nrf2 by inhibition of the Keap1-Nrf2 protein-protein interaction (PPI) is of interest as a potential treatment for CKD. We report the identification of the novel and weak PPI inhibitor 7 with good physical properties by a high throughput screening (HTS) campaign, followed by structural and computational analysis. The installation of only methyl and fluorine groups successfully provided the lead compound 25, which showed more than 400-fold stronger activity. Furthermore, these dramatic substituent effects can be explained by the analysis of using isothermal titration calorimetry (ITC). Thus, the resulting 25, which exhibited high oral absorption and durability, would be a CKD therapeutic agent because of the dose-dependent manner for up-regulation of the antioxidant protein heme oxigenase-1 (HO-1) in rat kidneys.

Broad antiretroviral activity and resistance profile of the novel human immunodeficiency virus integrase inhibitor elvitegravir (JTK-303/GS-9137).

Integrase (IN), an essential enzyme of human immunodeficiency virus (HIV), is an attractive antiretroviral drug target. The antiviral activity and resistance profile in vitro of a novel IN inhibitor, elvitegravir (EVG) (also known as JTK-303/GS-9137), currently being developed for the treatment of HIV-1 infection are described. EVG blocked the integration of HIV-1 cDNA through the inhibition of DNA strand transfer. EVG inhibited the replication of HIV-1, including various subtypes and multiple-drug-resistant clinical isolates, and HIV-2 strains with a 50% effective concentration in the subnanomolar to nanomolar range. EVG-resistant variants were selected in two independent inductions, and a total of 8 amino acid substitutions in the catalytic core domain of IN were observed. Among the observed IN mutations, T66I and E92Q substitutions mainly contributed to EVG resistance. These two primary resistance mutations are located in the active site, and other secondary mutations identified are proximal to these primary mutations. The EVG-selected IN mutations, some of which represent novel IN inhibitor resistance mutations, conferred reduced susceptibility to other IN inhibitors, suggesting that a common mechanism is involved in resistance and potential cross-resistance. The replication capacity of EVG-resistant variants was significantly reduced relative to both wild-type virus and other IN inhibitor-resistant variants selected by L-870,810. EVG and L-870,810 both inhibited the replication of murine leukemia virus and simian immunodeficiency virus, suggesting that IN inhibitors bind to a conformationally conserved region of various retroviral IN enzymes and are an ideal drug for a range of retroviral infections.

Novel HIV-1 integrase inhibitors derived from quinolone antibiotics.

The viral enzyme integrase is essential for the replication of human immunodeficiency virus type 1 (HIV-1) and represents a remaining target for antiretroviral drugs. Here, we describe the modification of a quinolone antibiotic to produce the novel integrase inhibitor JTK-303 (GS 9137) that blocks strand transfer by the viral enzyme. It shares the core structure of quinolone antibiotics, exhibits an IC50 of 7.2 nM in the strand transfer assay, and shows an EC50 of 0.9 nM in an acute HIV-1 infection assay.

Quinolone carboxylic acids as a novel monoketo acid class of human immunodeficiency virus type 1 integrase inhibitors.

Human immunodeficiency virus type 1 (HIV-1) integrase is a crucial target for antiretroviral drugs, and several keto-enol acid class (often referred to as diketo acid class) inhibitors have clinically exhibited marked antiretroviral activity. Here, we show the synthesis and the detailed structure-activity relationship of the quinolone carboxylic acids as a novel monoketo acid class of integrase inhibitors. 6-(3-Chloro-2-fluorobenzyl)-1-((2S)-1-hydroxy-3,3-dimethylbutan-2-yl)-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid 51, which showed an IC50 of 5.8 nM in the strand transfer assay and an ED50 of 0.6 nM in the antiviral assay, and 6-(3-chloro-2-fluorobenzyl)-1-((2S)-1-hydroxy-3-methylbutan-2-yl)-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid 49, which had an IC50 of 7.2 nM and an ED50 of 0.9 nM, were the most potent compounds in this class. The monoketo acid 49 was much more potent at inhibiting integrase-catalyzed strand transfer processes than 3'-processing reactions, as is the case with the keto-enol acids. Elvitegravir 49 was chosen as a candidate for further studies and is currently in phase 3 clinical trials.

Comparative study of glucocorticoids, cyclosporine A, and JTE-607 [(-)-Ethyl-N[3,5-dichloro-2-hydroxy-4-[2-(4-methylpiperazin-1-yl)ethoxy]benzoyl]-L-phenylalaninate dihydrochloride] in a mouse septic shock model.

Actions of glucocorticoids, cyclosporine A, and JTE-607 [(-)-ethyl-N-[3,5-dichloro-2-hydroxy-4-[2-(4-methylpiperazin-1-yl)ethoxy]benzoyl]-L-phenylalaninate dihydrochloride], a proinflammatory cytokine inhibitor that does not inhibit interleukin (IL)-2 or interferon-gamma, were compared in a mouse septic shock model induced by cecal ligation and puncture (CLP). CLP caused elevation of macrophage inflammatory protein (MIP)-2 in lung, and MIP-2 and IL-6 in plasma and peritoneal fluid, reaching a peak 4 to 8 h after CLP. Myeloperoxidase (MPO) activity in lung increased and reached a peak 8 to 12 h after CLP. Acute treatment (subcutaneous injections 1 h before and 2 h after CLP) of mice with JTE-607 and methylprednisolone showed significant inhibition of elevated cytokine levels and MPO activity, plus increased survival rate. Similar treatment with cyclosporine A and prednisolone was ineffective. Chronic treatment (subcutaneous injection for seven consecutive days before CLP) of mice with JTE-607 also showed an inhibitory effect on cytokine production, MPO activity and mortality. In contrast, chronic treatment with cyclosporine A and prednisolone did not inhibit cytokine production or MPO activity, but rather exacerbated mortality. These results indicate that JTE-607 has protective effect on mouse mortality induced by CLP, correlating with inhibition of proinflammatory cytokines, whereas the immunosuppressants cyclosporine A and prednisolone do not. This suggests that JTE-607, a multiple cytokine inhibitor that does not cause adverse immunosuppression, is useful for treatment of septic shock.