5,6-Dihydroxypyrimidine Scaffold to Target HIV-1 Nucleocapsid Protein.

The HIV-1 nucleocapsid (NC) protein is a small basic DNA and RNA binding protein that is absolutely necessary for viral replication and thus represents a target of great interest to develop new anti-HIV agents. Moreover, the highly conserved sequence offers the opportunity to escape the drug resistance (DR) that emerged following the highly active antiretroviral therapy (HAART) treatment. On the basis of our previous research, nordihydroguaiaretic acid 1 acts as a NC inhibitor showing moderate antiviral activity and suboptimal drug-like properties due to the presence of the catechol moieties. A bioisosteric catechol replacement approach led us to identify the 5-dihydroxypyrimidine-6-carboxamide substructure as a privileged scaffold of a new class of HIV-1 NC inhibitors. Hit validation efforts led to the identification of optimized analogs, as represented by compound 28, showing improved NC inhibition and antiviral activity as well as good ADME and PK properties.

Janus effect of glucocorticoids on differentiation of muscle fibro/adipogenic progenitors.

Muscle resident fibro-adipogenic progenitors (FAPs), support muscle regeneration by releasing cytokines that stimulate the differentiation of myogenic stem cells. However, in non-physiological contexts (myopathies, atrophy, aging) FAPs cause fibrotic and fat infiltrations that impair muscle function. We set out to perform a fluorescence microscopy-based screening to identify compounds that perturb the differentiation trajectories of these multipotent stem cells. From a primary screen of 1,120 FDA/EMA approved drugs, we identified 34 compounds as potential inhibitors of adipogenic differentiation of FAPs isolated from the murine model (mdx) of Duchenne muscular dystrophy (DMD). The hit list from this screen was surprisingly enriched with compounds from the glucocorticoid (GCs) chemical class, drugs that are known to promote adipogenesis in vitro and in vivo. To shed light on these data, three GCs identified in our screening efforts were characterized by different approaches. We found that like dexamethasone, budesonide inhibits adipogenesis induced by insulin in sub-confluent FAPs. However, both drugs have a pro-adipogenic impact when the adipogenic mix contains factors that increase the concentration of cAMP. Gene expression analysis demonstrated that treatment with glucocorticoids induces the transcription of Gilz/Tsc22d3, an inhibitor of the adipogenic master regulator PPARγ, only in anti-adipogenic conditions. Additionally, alongside their anti-adipogenic effect, GCs are shown to promote terminal differentiation of satellite cells. Both the anti-adipogenic and pro-myogenic effects are mediated by the glucocorticoid receptor and are not observed in the presence of receptor inhibitors. Steroid administration currently represents the standard treatment for DMD patients, the rationale being based on their anti-inflammatory effects. The findings presented here offer new insights on additional glucocorticoid effects on muscle stem cells that may affect muscle homeostasis and physiology.

Antifungal activity of azole compounds CPA18 and CPA109 against azole-susceptible and -resistant strains of Candida albicans.

OBJECTIVES: In this study we investigated the in vitro fungistatic and fungicidal activities of CPA18 and CPA109, two azole compounds with original structural features, alone and in combination with fluconazole against fluconazole-susceptible and -resistant Candida albicans strains. METHODS: Antifungal activities were measured by MIC evaluation and time-kill studies. Azole binding analysis was performed by UV-Vis spectroscopy. Hyphal growth inhibition and filipin and propidium iodide staining assays were used for morphological analysis. An analysis of membrane lipids was also performed to gauge alterations in membrane composition and integrity. Synergism was calculated using fractional inhibitory concentration indices (FICIs). Evaluation of cytotoxicity towards murine macrophages was performed to verify selective antifungal activity. RESULTS: Even though their binding affinity to C. albicans Erg11p is comparable to that of fluconazole, CPA compounds are active against resistant strains of C. albicans with a mutation in ERG11 sequences and/or overexpressing the ABC transporter genes CDR1 and CDR2, which encode ATP-dependent efflux pumps. Moreover, CPA18 is fungistatic, even against the two resistant strains, and was found to be synergistic with fluconazole. Differently from fluconazole and other related azoles, CPA compounds induced marked changes in membrane permeability and dramatic alterations in membrane lipid composition. CONCLUSIONS: Our outcomes suggest that CPA compounds are able to overcome major mechanisms of resistance in C. albicans. Also, they are promising candidates for combination treatment that could reduce the toxicity caused by high fluconazole doses, particularly in immunocompromised patients.

Modulation of cell differentiation, proliferation, and tumor growth by dihydrobenzyloxopyrimidine non-nucleoside reverse transcriptase inhibitors.

A series of 5-alkyl-2-(alkylthio)-6-(1-(2,6-difluorophenyl)propyl)-3,4-dihydropyrimidin-4(3H)-one derivatives (3a-h) belonging to the F(2)-DABOs class of non-nucleoside HIV-1 reverse transcriptase inhibitors (NNRTIs) are endowed with a strong antiproliferative effect and induce cytodifferentiation in A375 melanoma cells. Among tested compounds, the most potent is 3g (SPV122), which also induces apoptosis in a cell-density-dependent manner and antagonizes tumor growth in animal models. All these effects are similar or even more pronounced than those previously reported for other nucleoside or non-nucleoside inhibitors of reverse transcriptase or by functional knockout of the reverse-transcriptase-encoding long interspersed element 1 by RNA interference (RNAi). Taken together with our previously reported results, these data further confirm our idea that cellular alterations induced by NNRTIs are a consequence of the inhibition of the endogenous reverse transcriptase in A375 cells and support the potential of NNRTIs as valuable agents in cancer therapy.

Unprecedented synthesis of a novel amino quinone ring system via oxidative decarboxylation of quinone-based alpha,alpha-amino esters.

An unusual and efficient method for the synthesis of new quinone-based amine and its derivatives from the corresponding alpha,alpha-amino ester is described. The procedure involves the quinone-based system's oxidative decarboxylation via hydride transfer throughout basic hydrolysis. This synthetic method provides, with good yields, rapid access to new potentially cytotoxic quinones.

CYP19 (aromatase): exploring the scaffold flexibility for novel selective inhibitors.

Several derivatives out of a series of antifungal agents exhibited a good inhibitory potency against aromatase as well as a fairly good selectivity toward CYP17, even if lacking H-bond accepting substituents. Their common structural feature is a flexible backbone that did not fit into previously reported CYP19 models. Thus, a ligand-based approach was exploited to develop a novel statistically robust, self-consistent and predictive 3D-QSAR model herein proposed as a helpful tool to design new aromatase inhibitors.