Discovery of novel FGF trap small molecules endowed with anti-myeloma activity.

Fibroblast growth factors (FGFs) act as proangiogenic and mitogenic cytokines in several cancers, including multiple myeloma (MM). Indeed, corrupted FGF autocrine and paracrine secretion induces an aberrant activation of the FGF receptor (FGFR) signaling sustaining cancer cell spreading and resistance to pharmacological treatments. Thus, FGF traps may represent a promising anti-cancer strategy to hamper the ligand-dependent activation of the FGF/FGFR system. We previously identified NSC12 as the first orally available small molecule FGF trap able to inhibit the growth and progression of several FGF-dependent tumor models. NSC12 is a pregnenolone derivative carrying a 1,1-bis-trifluoromethyl-1,3-propanediol chain in position 17 of the steroid nucleus. Investigation of structure-activity relationships (SARs) provided more potent and specific NSC12 steroid derivatives and highlighted that the C17-side chain is pivotal for the FGF trap activity. Here, a scaffold hopping approach allowed to obtain two FGF trap compounds (22 and 57) devoid of the steroid nucleus and able to efficiently bind FGF2 and to inhibit FGFR activation in MM cells. Accordingly, these compounds exert a potent anti-tumor activity on MM cell lines both in vitro and in vivo and on MM patient-derived primary cells, strongly affecting the survival of both proteasome-inhibitor sensitive and resistant MM cells. These results propose a new therapeutic option for relapsed/refractory MM patients and set the bases for the development of novel FGF traps prone to chemical diversification to be used in the clinic for the treatment of those tumors in which the FGF/FGFR system plays a pivotal role, including MM.

Molecular Determinants of EphA2 and EphB2 Antagonism Enable the Design of Ligands with Improved Selectivity.

With the aim of identifying novel antagonists selective for the EphA receptor family, a combined experimental and computational approach was taken to investigate the molecular basis of the recognition between a prototypical Eph-ephrin antagonist (UniPR1447) and two representative receptors of the EphA and EphB subfamilies, namely, EphA2 and EphB2 receptors. The conformational free-energy surface (FES) of the binding state of UniPR1447 within the ligand binding domain of EphA2 and EphB2, reconstructed from molecular dynamics (MD) simulations performed on the microsecond time scale, was exploited to drive the design and synthesis of a novel antagonist selective for EphA2 over the EphB2 receptor. The availability of compounds with this pharmacological profile will help discriminate the importance of these two receptors in the insurgence and progression of cancer.

Systematic Modification of the Substitution Pattern of the 7-Hydroxy-5-oxopyrazolo[4,3-b]pyridine-6-carboxamide Scaffold Enabled the Discovery of New Ligands with High Affinity and Selectivity for the Cannabinoid Type 2 Receptor.

Selective ligands of the CB2 receptor are receiving considerable attention due to their potential as therapeutic agents for a variety of diseases. Recently, 7-hydroxy-5-oxopyrazolo[4,3-b]pyridine-6-carboxamide derivatives were shown to act at the CB2 receptor either as agonists or as inverse agonists/antagonists in vitro and to have anti-osteoarthritic activity in vivo. In this article, we report the synthesis, pharmacological profile, and molecular modeling of a series of twenty-three new 7-hydroxy-5-oxopyrazolo[4,3-b]pyridine-6-carboxamides with the aim of further developing this new class of selective CB2 ligands. In addition to these compounds, seven other analogs that had been previously synthesized were included in this study to better define the structure-activity relationship (SAR). Ten of the new compounds studied were found to be potent and selective ligands of the CB2 receptor, with Ki values ranging from 48.46 to 0.45 nM and CB1/CB2 selectivity indices (SI) ranging from >206 to >4739. In particular, compounds 54 and 55 were found to be high-affinity CB2 inverse agonists that were not active at all at the CB1 receptor, whereas 57 acted as an agonist. The functional activity profile of the compounds within this structural class depends mainly on the substitution pattern of the pyrazole ring.

Combining ligand- and structure-based approaches for the discovery of new inhibitors of the EPHA2-ephrin-A1 interaction.

The EPH receptor A2 (EPHA2) represents an attractive anticancer target. With the aim to identify novel EPHA2 receptor antagonists, a virtual screening campaign, combining shape-similarity and docking calculations, was conducted on a set of commercially available compounds. A combined score, taking into account both ligand- and structure-based results, was then used to identify the most promising candidates. Two compounds, selected among the best-ranked ones, were identified as EPHA2 receptor antagonists with micromolar affinity.

Analysis of illicit dietary supplements sold in the Italian market: identification of a sildenafil thioderivative as adulterant using UPLC-TOF/MS and GC/MS.

Identification of pharmaceutical active ingredients sildenafil and tadalafil and the characterization of a dimethylated thio-derivative of sildenafil, called thioaildenafil or thiodimethylsildenafil, in illicit dietary supplements were described. A multi-residual ultra-performance liquid chromatography-time of flight mass spectrometry (UPLC-TOF/MS) method was developed to screen for the presence of the phosphodiesterase-5 (PDE-5) inhibitors sildenafil, tadalafil, and vardenafil and their analogues thioaildenafil and thiohomosildenafil in powders and pharmaceutical dosage forms. The study was developed in connection with an operation supervised by the Italian Medicines Agency (A.I.F.A.), aimed to monitor dietary supplements in the Italian market. In two of the eleven specimens under investigation, high-resolution mass spectrometry (HR-MS) allowed the identification of the PDE-5 inhibitors sildenafil and tadalafil, while another specimen proved to contain a unapproved dimethylated thioderivative of sildenafil, thioaildenafil or thiodimethylsildenafil, identified for the first time in Italy as adulterant in food supplements.

Social stress-induced depressive-like symptoms and changes in gut microbial and lipidomic profiles are prevented by pharmacological inhibition of FAAH activity in male rats.

Pharmacological inhibition of fatty acid amide hydrolase (FAAH) activity has antidepressant-like effects in preclinical models of stress. In this study, we investigated whether the antidepressant-like effects of FAAH inhibition are associated with corresponding changes in gut microbial and lipidomic profiles, which are emerging as critical components in the pathophysiology of depression. Adult male Wistar rats experienced five weeks of repeated social defeat or control procedure and were treated with the FAAH inhibitor URB694 (0.3 mg/kg/day, i.p.) or vehicle starting from the third week. Repeated social defeat induced the emergence of depressive-like behavioral (sucrose preference reduction and passive coping behaviors in the forced swim test) and neuroendocrine (increased corticosterone levels) changes, which were prevented by URB694 treatment. Repeated social defeat also provoked a significant variation in gut microbiota (changes in the relative abundance of 14 bacterial taxa) and lipidic (e.g., glycerophospholipids) composition. These stress-induced changes were prevented by URB694 treatment. These findings indicate that inhibition of FAAH activity with URB694 blocks the co-occurrence of depressive-like behavioral and neuroendocrine changes and alterations in gut microbial and lipid composition in rats exposed to repeated social defeat. In conclusion, these results suggest that the gut microbiota-lipid crosstalk may represent a novel biological target for FAAH inhibitors to enhance stress resilience.

Targeting metabolic adaptive responses induced by glucose starvation inhibits cell proliferation and enhances cell death in osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines.

Osimertinib, a tyrosine kinase inhibitor targeting mutant EGFR, has received approval for initial treatment in patients with Non-Small Cell Lung Cancer (NSCLC). While effective in both first- and second-line treatments, patients eventually develop acquired resistance. Metabolic reprogramming represents a strategy through which cancer cells may resist and adapt to the selective pressure exerted by the drug. In the current study, we investigated the metabolic adaptations associated with osimertinib-resistance in NSCLC cells under low glucose culture conditions. We demonstrated that, unlike osimertinib-sensitive cells, osimertinib-resistant cells were able to survive under low glucose conditions by increasing the rate of glucose and glutamine uptake and by shifting towards mitochondrial metabolism. Inhibiting glucose/pyruvate contribution to mitochondrial respiration, glutamine deamination to glutamate, and oxidative phosphorylation decreased the proliferation and survival abilities of osimertinib-resistant cells to glucose starvation. Our findings underscore the remarkable adaptability of osimertinib-resistant NSCLC cells in a low glucose environment and highlight the pivotal role of mitochondrial metabolism in mediating this adaptation. Targeting the metabolic adaptive responses triggered by glucose shortage emerges as a promising strategy, effectively inhibiting cell proliferation and promoting cell death in osimertinib-resistant cells.

Discovery of a new 1-(phenylsulfonyl)-1H-indole derivative targeting the EphA2 receptor with antiproliferative activity on U251 glioblastoma cell line.

In our continuing effort devoted at developing agents targeting the EphA2 receptor by means of protein-protein interaction (PPI) inhibitors, we report here the design and synthesis of a new class of l-ß-homotryptophan conjugates of 3-ß-hydroxy-Δ5-cholenic acid bearing a set of arylsulfonyl substituents at the indole nitrogen atom. An extensive structure-activity relationship (SAR) analysis indicates that the presence of a bulky lipophilic moiety at the indole nitrogen is fundamental for improving potency on the EphA2 receptor, while abrogating activity on the EphB1-EphB3 receptor subtypes. A rational exploration, guided by the combined application of an experimental design on σp and π physicochemical descriptors and docking simulations, led to the discovery of UniPR1454, a 1-(4-(trifluoromethyl)phenyl)sulfonyl derivative acting as potent and competitive EphA2 antagonist able to inhibit ephrin-A1 dependent signals and to reduce proliferation of glioblastoma (U251) cell line at micromolar concentration.

Targeting glucosylceramide synthase induces antiproliferative and proapoptotic effects in osimertinib-resistant NSCLC cell models.

The EGFR tyrosine kinase inhibitor osimertinib has been approved for the first-line treatment of EGFR-mutated Non-Small Cell Lung Cancer (NSCLC) patients. Despite its efficacy, patients develop resistance. Mechanisms of resistance are heterogeneous and not fully understood, and their characterization is essential to find new strategies to overcome resistance. Ceramides are well-known regulators of apoptosis and are converted into glucosylceramides (GlcCer) by glucosylceramide synthase (GCS). A higher content of GlcCers was observed in lung pleural effusions from NSCLC patients and their role in osimertinib-resistance has not been documented. The aim of this study was to determine the therapeutic potential of inhibiting GCS in NSCLC EGFR-mutant models resistant to osimertinib in vitro and in vivo. Lipidomic analysis showed a significant increase in the intracellular levels of glycosylceramides, including GlcCers in osimertinib resistant clones compared to sensitive cells. In resistant cells, the GCS inhibitor PDMP caused cell cycle arrest, inhibition of 2D and 3D cell proliferation, colony formation and migration capability, and apoptosis induction. The intratumoral injection of PDMP completely suppressed the growth of OR xenograft models. This study demonstrated that dysregulation of ceramide metabolism is involved in osimertinib-resistance and targeting GCS may be a promising therapeutic strategy for patients progressed to osimertinib.

Long-lasting inhibition of EGFR autophosphorylation in A549 tumor cells by intracellular accumulation of non-covalent inhibitors.

In the present study, a small set of reversible or irreversible 4-anilinoquinazoline EGFR inhibitors was tested in A549 cells at early (1h) and late (8h) time points after inhibitor removal from culture medium. A combination of assays was employed to explain the observed long-lasting inhibition of EGFR autophosphorylation. We found that EGFR inhibition at 8h can be due, besides to the covalent interaction of the inhibitor with Cys797, as for PD168393 (2) and its prodrug 4, to the intracellular accumulation of non-covalent inhibitors by means of an active cell uptake, as for 5 and 6. Compounds 5-6 showed similar potency and duration of inhibition of EGFR autophosphorylation as the covalent inhibitor 2, while being devoid of reactive groups forming covalent bonds with protein thiols.

Enhancement of peripheral fatty acyl ethanolamide signaling prevents stress-induced social avoidance and anxiety-like behaviors in male rats.

RATIONALE: Exposure to traumatic events can lead to alterations in social and anxiety-related behaviors. Emerging evidence suggests that peripheral host-defense processes are implicated in the expression of stress-induced behavioral responses and may be targeted to mitigate the negative sequalae of stress exposure. OBJECTIVES: In this study, we used the peripherally restricted FAAH inhibitor URB937 to investigate the effects of the fatty acyl ethanolamide (FAE) family of lipid mediators - which include the endocannabinoid anandamide and the endogenous PPAR-α agonists, oleoylethanolamide and palmitoylethanolamide - on behavioral and peripheral biochemical responses to two ethologically distinct rat models of stress. METHODS: Male adult rats were exposed to acute social defeat, a model of psychological stress (Experiment 1), or to the predator odor 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a test of innate predator-evoked fear (Experiment 2), and subsequently treated with URB937 (1 or 3 mg/kg, intraperitoneal) or vehicle. Behavioral analyses were conducted 24 h (Experiment 1) or 7 days (Experiment 2) after exposure. RESULTS: URB937 administration prevented the emergence of both social avoidance behavior after social defeat stress and anxiety-related behaviors after TMT exposure. Further, URB937 administration blocked social defeat-induced transient increase in plasma concentrations of pro-inflammatory cytokines and the elevation in plasma corticosterone levels observed 24 h after social defeat CONCLUSIONS: Enhancement of peripheral FAAH-regulated lipid signaling prevents the emergence of stress-induced social avoidance and anxiety-like behaviors in male rats through mechanisms that may involve an attenuation of peripheral cytokine release induced by stress exposure.

Combined targeting of fatty acid amide hydrolase and melatonin receptors promotes neuroprotection and stimulates inflammation resolution in rats.

BACKGROUND AND PURPOSE: Devising novel strategies to therapeutically favour inflammation resolution and provide neuroprotection is an unmet clinical need. Enhancing endocannabinoid tone by inhibiting the catabolic enzyme fatty acid amide hydrolase (FAAH), or stimulating melatonin receptors has therapeutic potential to treat neuropathological states in which neuroinflammation plays a central role. EXPERIMENTAL APPROACH: A rodent hippocampal explant model of inflammatory injury was used to assess the effects of UCM1341, a dual-acting compound with FAAH inhibitory action and agonist activity at melatonin receptors, against neuroinflammatory damage. FAAH activity was measured by a radiometric assay, and N-acylethanolamine levels were assessed by HPLC-MS/MS methods. FAAH distribution, evolution of inflammation and the contribution of UCM1341 to the expression of proteins controlling macrophage behaviour were investigated by biochemical and confocal analyses. KEY RESULTS: UCM1341 exhibited greater neuroprotection against neuroinflammatory degeneration, compared with the reference compounds URB597 (FAAH inhibitor) and melatonin. During neuroinflammation, UCM1341 augmented the levels of anandamide and N-oleoylethanolamine, but not N-palmitoylethanolamine, up-regulated PPAR-α levels, attenuated demyelination and prevented the release of TNF-α. UCM1341 modulated inflammatory responses by contributing to microglia/macrophage polarization, stimulating formation of lipid-laden macrophages and regulating expression of proteins controlling cholesterol metabolism and efflux. The neuroprotective effects of UCM1341 were prevented by PPARα, TRPV1 and melatonin receptor antagonists. CONCLUSION AND IMPLICATIONS: UCM1341, by enhancing endocannabinoid and melatoninergic signalling, benefits neuroprotection and stimulates inflammation resolution pathways. Our findings provide an encouraging prospect of therapeutically targeting endocannabinoid and melatoninergic systems in inflammatory demyelinating states in the CNS.

Expanding the knowledge around antitubercular 5-(2-aminothiazol-4-yl)isoxazole-3-carboxamides: Hit-to-lead optimization and release of a novel antitubercular chemotype via scaffold derivatization.

Tuberculosis is one of the deadliest infectious diseases in the world, and the increased number of multidrug-resistant and extensively drug-resistant strains is a reason for concern. We have previously reported a series of substituted 5-(2-aminothiazol-4-yl)isoxazole-3-carboxamides with growth inhibitory activity against Mycobacterium tuberculosis strains and low propensity to be substrate of efflux pumps. Encouraged by these preliminary results, we have undertaken a medicinal chemistry campaign to determine the metabolic fate of these compounds and to delineate a reliable body of Structure-Activity Relationships. Keeping intact the (thiazol-4-yl)isoxazole-3-carboxamide core, as it is deemed to be the pharmacophore of the molecule, we have extensively explored the structural modifications able to confer good activity and avoid rapid clearance. Also, a small set of analogues based on isostere manipulation of the 2-aminothiazole were prepared and tested, with the aim to disclose novel antitubercular chemotypes. These studies, combined, were instrumental in designing improved compounds such as 42g and 42l, escaping metabolic degradation by human liver microsomes and, at the same time, maintaining good antitubercular activity against both drug-susceptible and drug-resistant strains.

Disentangling the interactions between nasopharyngeal and gut microbiome and their involvement in the modulation of COVID-19 infection.

The human organism is inhabited by trillions of microorganisms, known as microbiota, which are considered to exploit a pivotal role in the regulation of host health and immunity. Recent investigations have suggested a relationship between the composition of the human microbiota and COVID-19 infection, highlighting a possible role of bacterial communities in the modulation of the disease severity. In this study, we performed a shotgun metagenomics analysis to explore and compare the nasopharyngeal microbiota of 38 hospitalized Italian patients with and without COVID-19 infection during the third and fourth pandemic waves. In detail, the metagenomic analysis combined with specific correlation analyses suggested a positive association of several microbial species, such as S. parasanguinis and P. melaninogenica, with the severity of COVID-19 infection. Furthermore, the comparison of the microbiota composition between the nasopharyngeal and their respective fecal samples highlighted an association between these different compartments represented by a sharing of several bacterial species. Additionally, lipidomic and deep-shotgun functional analyses of the fecal samples suggested a metabolic impact of the microbiome on the host's immune response, indicating the presence of key metabolic compounds in COVID-19 patients, such as lipid oxidation end products, potentially related to the inflammatory state. Conversely, the patients without COVID-19 displayed enzymatic patterns associated with the biosynthesis and degradation of specific compounds like lysine (synthesis) and phenylalanine (degradation) that could positively impact disease severity and contribute to modulating COVID-19 infection. IMPORTANCE The human microbiota is reported to play a major role in the regulation of host health and immunity, suggesting a possible impact on the severity of COVID-19 disease. This preliminary study investigated the possible correlation between nasopharyngeal microbiota and COVID-19 infection. In detail, the analysis of the nasopharyngeal microbiota of hospitalized Italian patients with and without COVID-19 infection suggested a positive association of several microbial species with the severity of the disease and highlighted a sharing of several bacteria species with the respective fecal samples. Moreover, the metabolic analyses suggested a possible impact of the microbiome on the host's immune response and the disease severity.

Brain pharmacokinetics of non-imidazole biphenyl H3 receptor antagonists: a liquid chromatography/electrospray-mass spectrometry and ex vivo binding study in rats.

In the present article, we report on the kinetics of brain penetration in rats of the H3R antagonist 1,1'-[1,1'-biphenyl-4,4'-diylbis(methylene)]bis-[piperidine] (1), which had shown a favorable in vitro pharmacological profile and in vivo potency in preventing scopolamine-induced amnesia. Two different approaches were employed: high-performance liquid chromatography/electrospray-mass spectrometry (HPLC/ESI-MS) and ex vivo binding against the labeled agonist [(3)H]-(R)-α-methylhistamine ([(3)H]RAMHA). Starting from the structure of 1, the rigid piperidine ring was replaced by a flexible dipropylamino group (see 2) or by a morpholino ring (see 3), endowed with lower basicity. The effect of replacement on rat plasma and brain disposition in the 24 h after administration was analyzed. High (µM) and persistent concentrations of 1 were found in rat plasma, while plasma levels were significantly lower (range: 0-200 nM) for the other two derivatives. This could be explained, among other factors, by the higher stability, observed for 1, to liver metabolic cleavage. The applied chemical modulation had an important effect on in vivo brain disposition, as, despite the comparable physico-chemical properties, 2 did not show the tendency to accumulate within the brain, as stated by its brain vs. plasma concentration ratios, if compared to 1. These structureproperty relationships should be taken into account in the pharmacokinetic optimization of new series of H3 receptor antagonists.

Liquid chromatography-mass spectrometric method for determination of the non-imidazole H3-receptor antagonist UPR1056 in rat plasma.

The non-imidazole H3 receptor antagonist UPR1056 was dosed in plasma samples from rats individually administered with a single i.p. dose of 1.25 mg/kg by means of a newly validated HPLC-MS method. UPR1056 was extracted from rat plasma by protein precipitation with acetonitrile and was separated by linear gradient elution, employing water and methanol both additioned with 0.05% trifluoroacetic acid as mobile phases. UPR1056 was detected in MS using an electrospray ion source operating in positive ion mode. Acquisition was performed in single ion monitoring mode at m/z=349.3. The method was validated over the concentration range of 17.43-1743 ng/mL (50-5000 pmol/mL). Within- and between-run precision for the low, mid and high quality controls (QC) levels were 6.75% or less and accuracy ranged from 95.8 to 107.6%. The lower limit of quantification was 17.43 ng/mL. The analysis of the time course of UPR1056 concentrations over the 24-h period revealed a C(max) of 1147 ng/mL after 2 h from peripheral administration of the non-imidazole H(3)-receptor antagonist, with a prolonged elimination half-life of over 9 h.

Metabolic Soft Spot and Pharmacokinetics: Functionalization of C-3 Position of an Eph-Ephrin Antagonist Featuring a Bile Acid Core as an Effective Strategy to Obtain Oral Bioavailability in Mice.

UniPR129, an L-ß-homotryptophan conjugate of the secondary bile acid lithocholic acid (LCA), acts as an effective protein-protein interaction (PPI) inhibitor of the Eph-ephrin system but suffers from a poor oral bioavailability in mice. To improve UniPR129 bioavailability, a metabolic soft spot, i.e., the 3α-hydroxyl group on the LCA steroidal ring, was functionalized to 3-hydroxyimine. In vitro metabolism of UniPR129 and 3-hydroxyimine derivative UniPR500 was compared in mouse liver subcellular fractions, and main metabolites were profiled by high resolution (HR-MS) and tandem (MS/MS) mass spectrometry. In mouse liver microsomes (MLM), UniPR129 was converted into several metabolites: M1 derived from the oxidation of the 3-hydroxy group to 3-oxo, M2-M7, mono-hydroxylated metabolites, M8-M10, di-hydroxylated metabolites, and M11, a mono-hydroxylated metabolite of M1. Phase II reactions were only minor routes of in vitro biotransformation. UniPR500 shared several metabolic pathways with parent UniPR129, but it showed higher stability in MLM, with a half-life (t1/2) of 60.4 min, if compared to a t1/2 = 16.8 min for UniPR129. When orally administered to mice at the same dose, UniPR500 showed an increased systemic exposure, maintaining an in vitro valuable pharmacological profile as an EphA2 receptor antagonist and an overall improvement in its physico-chemical profile (solubility, lipophilicity), if compared to UniPR129. The present work highlights an effective strategy for the pharmacokinetic optimization of aminoacid conjugates of bile acids as small molecule Eph-ephrin antagonists.

Palladium Catalyst Recycling for Heck-Cassar-Sonogashira Cross-Coupling Reactions in Green Solvent/Base Blend.

The identification of a green, versatile, user-friendly, and efficient methodology is necessary to facilitate the use of Heck-Cassar-Sonogashira (HCS) cross-coupling reaction in drug discovery and industrial production in the pharmaceutical segment. The Heck-Cassar and Sonogashira protocols, using N-hydroxyethylpyrrolidone (HEP)/water/N,N,N',N'-tetramethyl guanidine (TMG) as green solvent/base mixture and sulfonated phosphine ligands, allowed to recycle the catalyst, always guaranteeing high yields and fast conversion under mild conditions, with aryl iodides, bromides, and triflates. No catalyst leakage or metal contamination of the final product were observed during the HCS recycling. To our knowledge, a turnover number (TON) up to 2375, a turnover frequency (TOF) of 158 h-1 , and a process mass intensity (PMI) around 7 that decreased around 3 after solvent, base, and palladium recovery, represent one of the best results to date using a sustainable protocol. The Heck-Cassar protocol using sSPhos was successfully applied to the telescoped synthesis of Erlotinib (TON: 1380; TOF: 46 h-1 ).

A sulfonyl fluoride derivative inhibits EGFRL858R/T790M/C797S by covalent modification of the catalytic lysine.

The emergence of the C797S mutation in EGFR is a frequent mechanism of resistance to osimertinib in the treatment of non-small cell lung cancer (NSCLC). In the present work, we report the design, synthesis and biochemical characterization of UPR1444 (compound 11), a new sulfonyl fluoride derivative which potently and irreversibly inhibits EGFRL858R/T790M/C797S through the formation of a sulfonamide bond with the catalytic residue Lys745. Enzymatic assays show that compound 11 displayed an inhibitory activity on EGFRWT comparable to that of osimertinib, and it resulted more selective than the sulfonyl fluoride probe XO44, recently reported to inhibit a significant part of the kinome. Neither compound 11 nor XO44 inhibited EGFRdel19/T790M/C797S triple mutant. When tested in Ba/F3 cells expressing EGFRL858R/T790M/C797S, compound 11 resulted significantly more potent than osimertinib at inhibiting both EGFR autophosphorylation and proliferation, even if the inhibition of EGFR autophosphorylation by compound 11 in Ba/F3 cells was not long lasting.

N-(Anilinoethyl)amide Melatonergic Ligands with Improved Water Solubility and Metabolic Stability.

The MT2 -selective melatonin receptor ligand UCM765 (N-(2-((3-methoxyphenyl)(phenyl)amino)ethyl)acetamide), showed interesting sleep inducing, analgesic and anxiolytic properties in rodents, but suffers from low water solubility and modest metabolic stability. To overcome these limitations, different strategies were investigated, including modification of metabolically liable sites, introduction of hydrophilic substituents and design of more basic derivatives. Thermodynamic solubility, microsomal stability and lipophilicity of new compounds were experimentally evaluated, together with their MT1 and MT2 binding affinities. Introduction of a m-hydroxymethyl substituent on the phenyl ring of UCM765 and replacement of the replacement of the N,N-diphenyl-amino scaffold with a N-methyl-N-phenyl-amino one led to highly soluble compounds with good microsomal stability and receptor binding affinity. Docking studies into the receptor crystal structure provided a rationale for their binding affinity. Pharmacokinetic characterization in rats highlighted higher plasma concentrations for the N-methyl-N-phenyl-amino derivative, consistent with its improved microsomal stability and makes this compound worthy of consideration for further pharmacological investigation.