Human immunodeficiency virus type-1 (HIV-1) integrase is one of the three virally encoded enzymes required for replication and therefore a rational target for chemotherapeutic intervention in the ...treatment of HIV-1 infection. We report here the discovery of Raltegravir, the first HIV-integrase inhibitor approved by FDA for the treatment of HIV infection. It derives from the evolution of 5,6-dihydroxypyrimidine-4-carboxamides and N-methyl-4-hydroxypyrimidinone-carboxamides, which exhibited potent inhibition of the HIV-integrase catalyzed strand transfer process. Structural modifications on these molecules were made in order to maximize potency as HIV-integrase inhibitors against the wild type virus, a selection of mutants, and optimize the selectivity, pharmacokinetic, and metabolic profiles in preclinical species. The good profile of Raltegravir has enabled its progression toward the end of phase III clinical trials for the treatment of HIV-1 infection and culminated with the FDA approval as the first HIV-integrase inhibitor for the treatment of HIV-1 infection.
The farnesoid X receptor (FXR) is expressed predominantly in tissues exposed to high levels of bile acids and controls bile acid and lipid homeostasis. FXR(-/-) mice develop hepatocellular carcinoma ...(HCC) and show an increased prevalence for intestinal malignancies, suggesting a role of FXR as a tumor suppressor in enterohepatic tissues. The N-myc downstream-regulated gene 2 (NDRG2) has been recognized as a tumor suppressor gene, which is downregulated in human hepatocellular carcinoma, colorectal carcinoma and many other malignancies.We show reduced NDRG2 mRNA in livers of FXR(-/-) mice compared to wild type mice and both, FXR and NDRG2 mRNAs, are reduced in human HCC compared to normal liver. Gene reporter assays and Chromatin Immunoprecipitation data support that FXR directly controls NDRG2 transcription via IR1-type element(s) identified in the first introns of the human, mouse and rat NDRG2 genes. NDRG2 mRNA was induced by non-steroidal FXR agonists in livers of mice and the magnitude of induction of NDRG2 mRNA in three different human hepatoma cell lines was increased when ectopically expressing human FXR. Growth and metastasis of SK-Hep-1 cells was strongly reduced by non-steroidal FXR agonists in an orthotopic liver xenograft tumor model. Ectopic expression of FXR in SK-Hep1 cells reduced tumor growth and metastasis potential of corresponding cells and increased the anti-tumor efficacy of FXR agonists, which may be partly mediated via increased NDRG2 expression. FXR agonists may show a potential in the prevention and/or treatment of human hepatocellular carcinoma, a devastating malignancy with increasing prevalence and limited therapeutic options.
The nuclear receptor retinoid-related orphan receptor gamma t (RORγt) plays a critical role in driving Th17 cell differentiation and expansion, as well as IL-17 production in innate and adaptive ...immune cells. The IL-23/IL-17 axis is implicated in several autoimmune and inflammatory diseases, and biologics targeting IL-23 and IL-17 have shown significant clinical efficacy in treating psoriasis and psoriatic arthritis. JNJ-61803534 is a potent RORγt inverse agonist, selectively inhibiting RORγt-driven transcription versus closely-related family members, RORα and RORβ. JNJ-61803534 inhibited IL-17A production in human CD4
T cells under Th17 differentiation conditions, but did not inhibit IFNγ production under Th1 differentiation conditions, and had no impact on in vitro differentiation of regulatory T cells (Treg), nor on the suppressive activity of natural Tregs. In the mouse collagen-induced arthritis model, JNJ-61803534 dose-dependently attenuated inflammation, achieving ~ 90% maximum inhibition of clinical score. JNJ-61803534 significantly inhibited disease score in the imiquimod-induced mouse skin inflammation model, and dose-dependently inhibited the expression of RORγt-regulated genes, including IL-17A, IL-17F, IL-22 and IL-23R. Preclinical 1-month toxicity studies in rats and dogs identified doses that were well tolerated supporting progression into first-in-human studies. An oral formulation of JNJ-61803534 was studied in a phase 1 randomized double-blind study in healthy human volunteers to assess safety, pharmacokinetics, and pharmacodynamics. The compound was well tolerated in single ascending doses (SAD) up to 200 mg, and exhibited dose-dependent increases in exposure upon oral dosing, with a plasma half-life of 164 to 170 h. In addition, dose-dependent inhibition of ex vivo stimulated IL-17A production in whole blood was observed, demonstrating in vivo target engagement. In conclusion, JNJ-61803534 is a potent and selective RORγt inhibitor that exhibited acceptable preclinical safety and efficacy, as well as an acceptable safety profile in a healthy volunteer SAD study, with clear evidence of a pharmacodynamic effect in humans.
Farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor, plays an important role in the regulation of cholesterol and more specifically high-density lipoprotein (HDL) homeostasis. ...Activation of FXR is reported to lead to both pro- and anti-atherosclerotic effects. In the present study we analyzed the impact of different FXR agonists on cholesterol homeostasis, plasma lipoprotein profiles, and transhepatic cholesterol efflux in C57BL/6J mice and cynomolgus monkeys and atherosclerosis development in cholesteryl ester transfer protein transgenic (CETPtg) low-density lipoprotein receptor (LDLR) (-/-) mice. In C57BL/6J mice on a high-fat diet the synthetic FXR agonists isopropyl 3-(3,4-difluorobenzoyl)-1,1-dimethyl-1,2,3,6-tetrahydroazepino4,5-bindole-5-carboxylate (FXR-450) and 4-2-2-chloro-4-5-cyclopropyl-3-(2,6-dichlorophenyl)-4-isoxazolylmethoxyphenylcyclopropylbenzoic acid (PX20606) demonstrated potent plasma cholesterol-lowering activity that affected all lipoprotein species, whereas 3-2-2-chloro-4-3-(2,6-dichlorophenyl)-5-(1-methylethyl)-4-isoxazolylmethoxyphenylethenylbenzoic acid (GW4064) and 6-ethyl chenodeoxycholic acid (6-ECDCA) showed only limited effects. In FXR wild-type mice, but not FXR(-/-) mice, the more efficacious FXR agonists increased fecal cholesterol excretion and reduced intestinal cholesterol (re)uptake. In CETPtg-LDLR(-/-) mice PX20606 potently lowered total cholesterol and, despite the observed HDL cholesterol (HDLc) reduction, caused a highly significant decrease in atherosclerotic plaque size. In normolipidemic cynomolgus monkeys PX20606 and 6-ECDCA both reduced total cholesterol, and PX20606 specifically lowered HDL(2c) but not HDL(3c) or apolipoprotein A1. That pharmacological FXR activation specifically affects this cholesterol-rich HDL(2) subclass is a new and highly interesting finding and sheds new light on FXR-dependent HDLc lowering, which has been perceived as a major limitation for the clinical development of FXR agonists.
The nuclear bile acid receptor Farnesoid X receptor (FXR) is strongly expressed in liver and intestine, controls bile acid and lipid homeostasis and exerts tumor‐protective functions in liver and ...intestine. Histidine‐rich glycoprotein (HRG) is an abundant plasma protein produced by the liver with the proposed function as a pattern recognition molecule involved in the clearance of immune complexes, necrotic cells and pathogens, the modulation of angiogenesis, the normalization of deranged endothelial vessel structure in tumors and tumor suppression. FXR recognition sequences were identified within a human HRG promoter fragment that mediated FXR/FXR‐agonist dependent reporter gene activity in vitro. We show that HRG is a novel transcriptional target gene of FXR in human hepatoma cells, human upcyte® primary hepatocytes and 3D human liver microtissues in vitro and in mouse liver in vivo. Prolonged administration of the potent nonsteroidal FXR agonist PX20606 increases HRG levels in mouse plasma. Finally, daily oral administration of this FXR agonist for seven days resulted in a significant increase of HRG levels in the plasma of healthy human male volunteers during a clinical Phase I safety study. HRG might serve as a surrogate marker indicative of liver‐specific FXR activation in future human clinical studies. Furthermore, potent FXR agonists might be beneficial in serious health conditions where HRG is reduced, for example, in hepatocellular carcinoma but also other solid cancers, liver failure, sepsis and pre‐eclampsia.
What's new?
The nuclear bile acid receptor FXR has been shown to exert tumor‐protective functions in the liver and intestine. This study provides evidence that the liver‐derived plasma protein and tumor suppressor histidine‐rich glycoprotein (HRG) is a novel and most likely direct transcriptional target gene of FXR. Plasma HRG levels in healthy male volunteers increased 1.6‐fold after daily administration of 0.5 mg/kg of the non‐steroidal FXR agonist PX20606 for seven days, raising the possibility that potent FXR agonists might be beneficial in serious health conditions with reduced HRG such as hepatocellular carcinoma but also other solid cancers, liver failure, sepsis, and preeclampsia.
SAR study on tetrazole thioacetanilides as NNRTIs led to potent compounds, with nanomolar activity on both WT HIV and on the clinically relevant K103N mutant, submicromolar activity in infected cells ...and orally bioavailable in rats.
A series of aryltetrazolylacetanilides was synthesized and evaluated as HIV-1 non-nucleoside reverse transcriptase inhibitors on wild-type virus and on the clinically relevant K103N mutant strain. Extensive SAR investigation led to potent compounds, with nanomolar activity on K103N, and orally bioavailable in rats.
The Hedgehog (Hh-) signaling pathway is a key developmental pathway which controls patterning, growth and cell migration in most tissues, but evidence has accumulated showing that many human tumors ...aberrantly reactivate this pathway. Smoothened antagonists offer opportunities for the treatment of malignancies dependent on the Hh pathway, and the most advanced clinical candidates are demonstrating encourage initial results. A novel series of 6,5-bicyclic tetrahydroimidazo1,5-apyrazine-1,3(2H,5H)-dione smoothened antagonists has been identified, and the series has been extensively explored to ascertain the key detriments for activity, demonstrating that the trans-2-phenylcyclopropyl and hydantoin ring systems are critical for potency, while a variety of urea substituents can be tolerated. The combination of these optimal groups gives smoothened antagonists with activity in the low nanomolar range.
The Hedgehog (Hh-) signaling pathway is a key developmental pathway which gets reactivated in many human tumors, and smoothened (Smo) antagonists are emerging as novel agents for the treatment of ...malignancies dependent on the Hh-pathway, with the most advanced compounds demonstrating encouraging results in initial clinical trials. A novel series of potent bicyclic hydantoin Smo antagonists was reported in the preceding article, these have been resolved, and optimized to identify potent homochiral derivatives with clean off-target profiles and good pharmacokinetic properties in preclinical species. While showing in vivo efficacy in mouse allograft models, unsubstituted bicyclic tetrahydroimidazo1,5-apyrazine-1,3(2H,5H)-diones were shown to epimerize in plasma. Alkylation of the C-8 position blocks this epimerization, resulting in the identification of MK-5710 (47) which was selected for further development.
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