Discovery of N,N'-diarylurea molecules with activity against multidrug-resistant Staphylococcus aureus.

The emergence and global spread of methicillin-resistant Staphylococcus aureus (MRSA) pose a serious threat to public health, underscoring the urgent need for novel antibacterial interventions. Here, we screened 18 newly synthesized N,N'-diarylurea derivatives to identify compounds with activity against MRSA. Our investigations led to the discovery of a small molecule, SCB-24, which exhibited promising antimicrobial activity against MRSA USA300. Notably, SCB-24 demonstrated high activity even in the presence of 10% fetal bovine serum and showed excellent selectivity for bacterial over mammalian cells. SCB-24 also showed potent activity against various MRSA strains, including those resistant to second- and third-line antibiotics. Importantly, the efficacy of SCB-24 was inferior to that of vancomycin in MRSA-infected Galleria mellonella larvae. Overall, our findings suggest that SCB-24 has great potential as a new therapeutic for multidrug-resistant S. aureus infections.

Synthesis and biological evaluation of novel N, N'-diarylurea derivatives as potent antibacterial agents against MRSA.

A series of new N, N'-diarylurea derivatives were designed and synthesized, some of which exhibited potent antibacterial activity against the drug-susceptible and drug-resistant Gram-positive strains. Especially, compounds 2c, 2g-2l showed broader antibacterial spectrum and more potent antibacterial activity (MIC = 0.30-2.72 µM) against MRSA and MRSE than the control levofloxacin (MIC = 0.69-22.14 µM). In addition, compounds 2c, 2g, 2h and 2l exhibited much better antibacterial activity (MIC = 1.29-2.86 µM) against VRE (E. faecium) than sorafenib (MIC = 275.37 µM), PK150 (MIC = 5.07-10.13 µM) and SC78 (MIC = 2.40-4.79 µM). More importantly, the low cytotoxicity of compounds on cell lines HeLa and HepG2 implied a relatively wide therapeutic window, which was of high importance for further study.

Amide-Assisted Rearrangement of Hydroxyarylformimidoyl Chloride to Diarylurea.

A novel amide-assisted rearrangement reaction of hydroxybenzimidoyl chloride has been established for the efficient synthesis of 1,3-diphenylurea derivatives. A variety of electronically and sterically different 1,3-diphenylurea derivatives can be obtained in good to excellent yields, and a proposed reaction mechanism is also presented.

Diarylurea derivatives comprising 2,4-diarylpyrimidines: Discovery of novel potential anticancer agents via combined failed-ligands repurposing and molecular hybridization approaches.

A series of diarylurea derivatives comprising 2,4-diarylpyrimidines were synthesized based on a combination of postulated molecular hybridization design and failed-ligands repurposing approaches, which enabled the discovery of novel potential antiproliferative agents. Towards credible biological evaluation, an in vitro anticancer activity assay was conducted employing a library of 60 cancer cell lines constituting nine panels representing blood, lung, colon, CNS, skin, ovary, renal, prostate, and breast cancers. The results revealed high effectiveness and broad-spectrum anticancer activity of compounds 4m and 4g. Five-dose assay of compounds 4m and 4g proved their high potency that surpassed that of four standard kinase inhibitors FDA-approved anticancer drugs against many cancer cells. Towards the identification of their molecular target, screening of kinase inhibitory profile employing a panel of 51 kinases involved in cancer revealed inhibition of several kinases from the platelet-derived growth factor/vascular endothelial growth factor receptor (PVR) kinase family, which might mediate, at least in part, the antiproliferative activity. Molecular docking of 4g into the crystal structure of the Feline McDonough Sarcoma (FMS) kinase predicted that it binds to a pocket formed by the juxtamembrane domain, the catalytic loop, and the αE helix, thus stabilizing the inhibited conformation of the kinase. Flow cytometric study of the cytotoxic effects of compound 4g in A549 cells showed it induces dose- and time-dependent apoptotic events leading to cell death. Collectively, this work presents compound 4g as a potential broad-spectrum anticancer agent against multiple cancer types.

Structural Optimization of the Diarylurea PSNCBAM-1, an Allosteric Modulator of Cannabinoid Receptor 1.

BACKGROUND: Structure-activity relationship studies improve the pharmacological and pharmacokinetic properties of a lead compound such as PSNCBAM-1, an allosteric modulator of the cannabinoid receptor 1. OBJECTIVES: Here, several derivatives of PSNCBAM-1 were synthesized with the aim of reducing the number of rings within its structure and enhancing the solubility of the compounds. The derivatives studied contain substituents previously shown to enhance binding of agonists (ie, a cyano group and a pyrimidine ring), with a reduced number of rings compared with the parent compound, PSNCBAM-1. METHODS: The synthesized compounds were tested for the enhancement of the binding of orthosteric cannabinoid receptor 1 agonist CP55,940 in the presence of varying concentrations of each test compound. Select compounds were also tested for their effects on cannabinoid receptor 1 inverse agonist SR141716A binding. The compounds were also subjected to computational analysis of drug-like properties and solubility. RESULTS: Consistent with a positive allosteric modulator for orthosteric ligand binding, compounds LDK1317 (12a), LDK1320 (12b), LDK1321 (6a), LDK1323 (8a), and LDK1324 (6b) all enhanced the binding of agonist CP55,940 to some degree. Reduction in the number of rings did not abolish the activity. The new lead compounds LDK1317 (12a) and LDK1321 (6a) showed improved drug-like properties and enhanced solubility in silico. CONCLUSIONS: In contrast to PSNCBAM-1, the synthesized compounds are analogs with fewer rings. The compounds LDK1317 (12a) and LDK1321 (6a) contained only 2 or 3 rings, respectively, and showed the binding parameters (KB = 110 nM, α = 2.3, and KB = 85 nM, α = 5.9). Further, the computationally predicted drug-like properties and solubility suggest these compounds are acceptable new lead compounds for further development of cannabinoid receptor 1 allosteric modulators. (Curr Ther Res Clin Exp. 2020; 81:XXX-XXX).

Expanding the structural diversity of diarylureas as multi-target tyrosine kinase inhibitors.

Recently approved multi-target inhibitors of receptor tyrosine kinases (RTKs) have significantly improved the clinical treatment of cancers. A series of N,N'-diarylureas incorporated with aromatic heterocycle have been designed, synthesized and evaluated as novel multi-target RTK inhibitors. The preliminary biological evaluation indicated that several compounds exhibited comparable potency with Sorafenib. Among them, compound 6f was identified as the most potent multikinase inhibitor of EGFR, KDR and FGFR1 with IC50 values of 14.83nM, 21.57nM, and 28.23nM, respectively. These compounds expanded the structural diversity of diarylureas as RTK inhibitors. The results demonstrated that compound 6f could be served as novel lead compound for further development of multi-target RTK inhibitors.

Novel pentafluorosulfanyl-containing triclocarban analogs selectively kill Gram-positive bacteria.

Novel antimicrobial agents are needed to combat antimicrobial resistance. This study tested novel pentafluorosulfanyl-containing triclocarban analogs for their potential antibacterial efficacy. Standard procedures were used to produce pentafluorosulfanyl-containing triclocarban analogs. Twenty new compounds were tested against seven Gram-positive and Gram-negative indicator strains as well as 10 clinical isolates for their antibacterial and antibiofilm activity. Mechanistic investigations focused on damage to cell membrane, oxidizing reduced thiols, iron-sulfur clusters, and oxidative stress to explain the compounds' activity. Safety profiles were assessed using cytotoxicity experiments in eukaryotic cell lines. Following screening, selected components had significantly better antibacterial and antibiofilm activity against Gram-positive bacteria in lower concentrations in comparison to ciprofloxacin and gentamycin. For instance, one compound had a minimum inhibitory concentration of <0.0003 mM, but ciprofloxacin had 0.08 mM. Mechanistic studies show that these novel compounds do not affect reduced thiol content, iron-sulfur clusters, or hydrogen peroxide pathways. Their impact comes from Gram-positive bacterial cell membrane damage. Tests on cell culture toxicity and host component safety showed promise. Novel diarylurea compounds show promise as Gram-positive antimicrobials. These compounds offer prospects for study and optimization. IMPORTANCE: The rise of antibiotic resistance among bacterial pathogens poses a significant threat to global health, underscoring the urgent need for novel antimicrobial agents. This study presents research on a promising class of novel compounds with potent antibacterial properties against Gram-positive bacteria, notably Staphylococcus aureus and MRSA. What sets these novel analogs apart is their superior efficacy at substantially lower concentrations compared with commonly used antibiotics like ciprofloxacin and gentamycin. Importantly, these compounds act by disrupting the bacterial cell membrane, offering a unique mechanism that could potentially circumvent existing resistance mechanisms. Preliminary safety assessments also highlight their potential for therapeutic use. This study not only opens new avenues for combating antibiotic-resistant infections but also underscores the importance of innovative chemical approaches in addressing the global antimicrobial resistance crisis.

Design, synthesis, biological evaluation and molecular docking study of novel urea-based benzamide derivatives as potent poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors.

Poly(ADP-ribose) polymerase-1 (PARP-1) is one of the key members of DNA repair enzymes that is responsible for the repair of DNA single-strand breaks. Inhibition of PARP-1 has been demonstrated to be a promising strategy to selectively kill tumor cells by targeting DNA repair pathway. Herein, a series of novel urea-based benzamide derivatives were designed and synthesized based on the structure-based drug design strategy. The anticancer activities against five human cancer cell lines including HCT116, MDA-MB-231, HeLa, A579 and A375 were evaluated and the preliminary structure-activity relationships were summarized. Among them, compounds 23f and 27f exhibited potent antiproliferative effects against HCT116 cells with IC50 values of 7.87 µM and 8.93 µM, respectively. Moreover, both compounds displayed excellent PARP-1 inhibitory activities with IC50 values of 5.17 nM and 6.06 nM, respectively. Mechanistic investigations showed that 23f and 27f could effectively inhibit colony formation and cell migration of HCT116 cells. Furthermore, 23f and 27f could cause cell cycle arrest at G2/M phase, and induce apoptosis by upregulating the expression of Bax and cleaved Caspase-3 and downregulating the expression of Caspase-3 and Bcl-2 in HCT116 cells. In addition, molecular docking studies provided the rational binding modes of these compounds in complex with PARP-1. Collectively, these results suggested that 23f and 27f could serve as promising drug candidates for further investigation.

Antibacterial and anti-biofilm activity of diarylureas against Enterococcus faecium by suppressing the gene expression of peptidoglycan hydrolases and adherence.

Enterococcus faecium (E. faecium) is a clinical multidrug-resistant pathogen causing life-threatening infection, which makes it important to discover antibacterial agents with novel scaffolds and unique mechanism. In this study, the diarylurea scaffold was found to have potent antibacterial effect on E. faecium. Diarylurea ZJ-2 with benign drug-like property exhibited potent antibacterial and anti-biofilm activity through inhibiting the genes expression of NlpC/p60 hydrolase-secreted antigen A (sagA) and autolysins (atlA), down-regulating the expression of biofilm adherence related genes aggregation substance (agg), enterococcal surface protein (esp) against E. faecium. Moreover, ZJ-2 can be docked into SagA to inhibit daughter cell separation. In a mouse model of abdominal infection, ZJ-2 decreased the bacterial load and the level of IL-6 and TNF-α in a time-dependent manner. Overall, these findings indicated that diarylurea ZJ-2 has the potential to be developed as a therapeutic agent to treat drug-resistant enterococci and biofilm-related infections.

Thidiazuron: New Trends and Future Perspectives to Fight Xylella fastidiosa in Olive Trees.

These days, most of our attention has been focused on the COVID-19 pandemic, and we have often neglected what is happening in the environment. For instance, the bacterium Xylella fastidiosa re-emerged as a plant pathogen of global importance in 2013 when it was first associated with an olive tree disease epidemic in Italy, called Olive Quick Decline Syndrome (OQDS), specifically caused by X. fastidiosa subspecies pauca ST53, which affects the Salento olive trees (Apulia, South-East Italy). This bacterium, transmitted by the insect Philaenus spumarius, is negatively reshaping the Salento landscape and has had a very high impact in the production of olives, leading to an increase of olive oil prices, thus new studies to curb this bacterium are urgently needed. Thidiazuron (TDZ), a diphenylurea (N-phenyl-1,2,3-thiadiazol-5-yl urea), has gained considerable attention in recent decades due to its efficient role in plant cell and tissue culture, being the most suitable growth regulator for rapid and effective plant production in vitro. Its biological activity against bacteria, fungi and biofilms has also been described, and the use of this low-cost compound to fight OQDS may be an intriguing idea.

Diaryl Ureas as an Antiprotozoal Chemotype.

We now describe the physicochemical profiling, in vitro ADME, and antiparasitic activity of eight N,N'-diarylureas to assess their potential as a broad-spectrum antiprotozoal chemotype. Chromatographic LogD7.4 values ranged from 2.5 to 4.5; kinetic aq. solubilities were ≤6.3 µg/mL, and plasma protein binding ranged from 95 to 99%. All of the compounds had low intrinsic clearance values in human, but not mouse, liver microsomes. Although no N,N'-diarylurea had submicromolar potency against Trypanosoma cruzi, two had submicromolar potencies against Toxoplasma gondii and Trypanosoma brucei rhodesiense, and five had submicromolar potencies against Leishmania donovani. Plasmodium falciparum appeared to be the most susceptible to growth inhibition by this compound series. Most of the N,N'-diarylureas had antiprotozoal selectivities ≥10. One N,N'-diarylurea had demonstrable activity in mouse models of malaria and toxoplasmosis.

Novel diarylamides and diarylureas with N-substitution dependent activity against medulloblastoma.

Medulloblastoma - highly aggressive and heterogeneous tumours of the cerebellum - account for 15-20% of all childhood brain tumours, and are the most common high-grade childhood embryonal tumour of the central nervous system. Herein, potent in vitro anticancer activity against two established medulloblastoma cell lines of the sonic hedgehog subgroup, namely DAOY (p53 mutant) and ONS-76 (p53 wild type), has been achieved. A number of first-generation diarylamides and diarylureas were evaluated and activity is likely to be, in-part, conformation-dependent. The most active compound from this first-generation set of compounds, 1-naphthyl derivative 4b, was selected and a second-generation of compounds were optimised and tested for activity against the medulloblastoma cell lines. This process resulted in drug-like compounds with up to sixty times the activity (sub-micromolar) of the first-generation - thus providing potent new leads for further study.

Diarylureas: Repositioning from Antitumor to Antimicrobials or Multi-Target Agents against New Pandemics.

Antimicrobials have allowed medical advancements over several decades. However, the continuous emergence of antimicrobial resistance restricts efficacy in treating infectious diseases. In this context, the drug repositioning of already known biological active compounds to antimicrobials could represent a useful strategy. In 2002 and 2003, the SARS-CoV pandemic immobilized the Far East regions. However, the drug discovery attempts to study the virus have stopped after the crisis declined. Today's COVID-19 pandemic could probably have been avoided if those efforts against SARS-CoV had continued. Recently, a new coronavirus variant was identified in the UK. Because of this, the search for safe and potent antimicrobials and antivirals is urgent. Apart from antiviral treatment for severe cases of COVID-19, many patients with mild disease without pneumonia or moderate disease with pneumonia have received different classes of antibiotics. Diarylureas are tyrosine kinase inhibitors well known in the art as anticancer agents, which might be useful tools for a reposition as antimicrobials. The first to come onto the market as anticancer was sorafenib, followed by some other active molecules. For this interesting class of organic compounds antimicrobial, antiviral, antithrombotic, antimalarial, and anti-inflammatory properties have been reported in the literature. These numerous properties make these compounds interesting for a new possible pandemic considering that, as well as for other viral infections also for CoVID-19, a multitarget therapeutic strategy could be favorable. This review is meant to be an overview on diarylureas, focusing on their biological activities, not dwelling on the already known antitumor activity. Quite a lot of papers present in the literature underline and highlight the importance of these molecules as versatile scaffolds for the development of new and promising antimicrobials and multitarget agents against new pandemic events.

Diarylureas Containing 5-Membered Heterocycles as CB1 Receptor Allosteric Modulators: Design, Synthesis, and Pharmacological Evaluation.

Allosteric modulators have attracted significant interest as an alternate strategy to modulate CB1 receptor signaling for therapeutic benefits that may avoid the adverse effects associated with orthosteric ligands. Here we extended our previous structure-activity relationship studies on the diarylurea-based CB1 negative allosteric modulators (NAMs) by introducing five-membered heterocycles to replace the 5-pyrrolidinylpyridinyl group in PSNCBAM-1 (1), one of the first generation CB1 allosteric modulators. Many of these compounds had comparable potency to 1 in blocking the CB1 agonist CP55,940 stimulated calcium mobilization and [35S]GTP-γ-S binding. Similar to 1, most compounds showed positive cooperativity by increasing [3H]CP55,940 binding, consistent with the positive allosteric modulator (PAM)-antagonist mechanism. Interestingly, these compounds exhibited differences in ability to increase specific binding of [3H]CP55,940 and decrease binding of the antagonist [3H]SR141716. In saturation binding studies, only increases in [3H]CP55,940 Bmax, but not Kd, were observed, suggesting that these compounds stabilize low affinity receptors into a high affinity state. Among the series, the 2-pyrrolyl analogue (13) exhibited greater potency than 1 in the [35S]GTP-γ-S binding assay and significantly enhanced the maximum binding level in the [3H]CP5,5940 binding assay, indicating greater CB1 receptor affinity and/or cooperativity.

Design and synthesis of new RAF kinase-inhibiting antiproliferative quinoline derivatives. Part 2: Diarylurea derivatives.

This article describes the design, synthesis, and biological screening of a new series of diarylurea derivatives possessing quinoline nucleus. Nine target compounds were selected by the National Cancer Institute (NCI, Bethesda, Maryland, USA) for in vitro antiproliferative screening against a panel of 58 cancer cell lines of nine cancer types. Following one-dose initial screening, compounds 1d-g and 2b were selected for 5-dose screening in order to calculate their IC50 and total growth inhibition (TGI) values against the cell lines. Compounds 1e and 1g were the most promising analogues. Both compounds showed strong potency and broad-spectrum antiproliferative activity against the different tested cancer types. Their IC50 and TGI values were less than those of the reference drug, sorafenib, against most of the tested cell lines of the nine different cancer types. Furthermore, the most potent compounds 1d-g were tested against C-RAF kinase as a potential molecular target of this series of compounds. All of them showed high potency, and the most potent derivative was compound 1e (IC50 = 0.10 µM). It was further tested against a panel of another twelve kinases, and it showed selectivity against C-RAF kinase. This could be, at least in part, the possible mechanism of antiproliferative action of this series of compounds at molecular level. The binding modes of compounds 1e and 1g were studied by docking studies, which highlighted the importance of the urea linker compared with the amide linker.

Rational drug design of indazole-based diarylurea derivatives as anticancer agents.

A series of novel indazole-based diarylurea derivatives targeting c-kit were designed by structure-based drug design. The derivatives were prepared, and their antiproliferative activities were evaluated against human colon cancer HCT-116 cell line and hepatocellular carcinoma PLC/PRF/5 cell line. The antiproliferative activities demonstrated that six of nine compounds exhibited comparable activities with sorafenib against HCT-116. The structure-activity relationship (SAR) analysis indicated that the indazole ring part tolerated different kinds of substituents, and the N position of the central pyridine ring played key roles in antiproliferative activity. The SAR and interaction mechanisms were further explored using molecular docking method. Compound 1i with N-(2-(pyrrolidin-1-yl)ethyl)-carboxamide possessed improved solubility, 596.1 ng/ml and best activities, IC50 at 1.0 µm against HCT-116, and 3.48 µm against PLC/PRF/5. It is a promising anticancer agent for further development.

Design and synthesis of new imidazo[1,2-a]pyridine and imidazo[1,2-a]pyrazine derivatives with antiproliferative activity against melanoma cells.

Melanoma is an aggressive form of skin cancer and it is generally associated with poor prognosis in patients with late-stage disease. Due to the increasing occurrence of melanoma, there is a need for the development of novel therapies. A new series of diarylamide and diarylurea derivatives containing imidazo[1,2-a]pyridine or imidazo[1,2-a]pyrazine scaffold was designed and synthesized to investigate their in vitro efficacy against the A375P human melanoma cell line. We found several compounds expressing submicromolar IC50 values against the A375P cells, from which 15d, 17e, 18c, 18h, 18i demonstrated the highest potencies with IC50 below 0.06 µM.

A novel anticancer diarylurea derivative HL-40 as a multi-kinases inhibitor with good pharmacokinetics in Wistar rats.

HL-40, N-(4-(1-(4-chlorine indazole)) phenyl)-N-(4-chloro-3-three fluorine methyl phenyl) urea, is a novel diarylurea derivative. In this study, we investigated the kinases activities and binding constants, pharmacokinetics of HL-40, and then evaluated its anticancer efficacy by both in vitro and in vivo methods. Enzyme activities assays in vitro were employed to identify eight candidate kinase targets. The competition binding assays against eight candidate kinases suggested that HL-40 showed strong affinity to c-Kit, PDGFRß and FLT3. The pharmacokinetic studies in Wistar rats showed that HL-40 could maintain high compound concentration and long residence time in the blood circulation. HL-40 possessed strong inhibition activities against 12 human cancer cells. Meanwhile, HL-40 effectively delayed the growth of cancer xenografts without significant toxicity to mice. Based on these in vitro and in vivo results, we suggested that HL-40 might be developed as a potential multi-kinases inhibitor for cancer treatment.

1082-39, an analogue of sorafenib, inhibited human cancer cell growth more potently than sorafenib.

PURPOSE: 1082-39, an analogue of sorafenib, is a derivative of indazole diarylurea. We evaluated the activity of 1082-39 against human cancer cell growth. Its effects and mechanisms of action were then compared with those of sorafenib. The experiments were performed in human melanoma M21 cells. METHODS: Cell viability was estimated by using the colorimetric assay. Annexin V-FITC/PI staining assay was used to recognize the apoptotic cells. Further analysis of the mitochondria membrane potential (MMP) was performed by the JC-1 fluorescence probe staining. The levels of apoptotic proteins and kinases related to cancer proliferation were determined by western blotting assay. RESULTS: 1082-39 possessed the activity against cancer cell proliferation with time- and dose-dependent manner. 1082-39 induced M21 cell to apoptosis, showing the increase of annexin V-FITC/PI staining cells, the MMP collapse and releasing cytochrome c from mitochondria. Western blotting analysis showed the activation of the mitochondria-mediated intrinsic pathway, showing the increase of cleaved caspase-9, cleaved caspase-3 and cleaved PARP. Statistical analysis suggested that 1082-39 possessed greater activities than sorafenib in the inhibition of M21 proliferation and induction of apoptosis. These effects of 1082-39 might arise from its activity of regulation the PI3K/Akt and Wnt/ß-catenin signaling pathways. CONCLUSIONS: 1082-39 is a promising candidate compound which could develop as a potent anticancer agent.

New diarylamides and diarylureas possessing 8-amino(acetamido)quinoline scaffold: synthesis, antiproliferative activities against melanoma cell lines, kinase inhibition, and in silico studies.

Synthesis of a new series of diarylureas and diarylamides possessing 4-aryl-8-amino(acetamido)quinoline scaffold is described. Their in vitro antiproliferative activities against ten melanoma cell lines were tested. Compounds 1l, 2l, 3c, and 4c showed the highest potency against A375P cell line with IC50 values in sub-micromolar scale. Compound 4c was equipotent to Vemurafenib against A375P. In addition, compounds 1l, 2a, and 2l showed high potency over the NCI-9 tested melanoma cell line panel. The IC50 values of compounds 1l and 2l were in 2-digit nanomolar scale over four and five cell lines, respectively. Compound 2l showed high, dose-dependent inhibition of ERK kinase. ADME profiling showed that compounds 1l, 2l, 3c, 4c, and 5b are estimated to be orally bioavailable.