Novel 1,2,4-triazole derivatives as potential anticancer agents: Design, synthesis, molecular docking and mechanistic studies

Combretastatin A-4 based compounds as potential anticancer agents: A review

The current review discusses the importance of combretastatin A-4 (CA-4) as a lead compound of microtubule targeting agents. CA-4 holds a unique place among naturally occurring compounds having cytotoxic activity. In this review an overall picture of design strategies, structure-activity relationship, synthesis, cytotoxic activity, and binding interactions of promising CA-4 analogues, are discussed and arranged chronologically from 2016 to early 2023. Also, this review emphasizes their biological activity as anticancer agents, within an overview of clinical application limitation and suggested strategies to overcome. Dual targeting tubulin inhibitors showed highpotentialto surpass medication resistance and provide synergistic efficacy. Linking platinum (IV), amino acids, and HDAC targeting moieties to active tubulin inhibitorsproduced potent active compounds. Analogues of CA-4 bridged with azetidin-2-one, pyrazole, sulfide, or carrying selenium atom exhibited cytotoxic action against a variety of malignant cell lines through different pathways.

Design, synthesis, and antiproliferative activity of new indole/1,2,4-triazole/chalcone hybrids as EGFR and/or c-MET inhibitors

A novel group of indolyl-1,2,4-triazole-chalcone hybrids was designed, synthesized, and assessed for their anticancer activity. The synthesized compounds exhibited significant antiproliferative activity. Compounds 9a and 9e exhibited significant cancer inhibition with GI50 ranging from 3.69 to 20.40 µM and from 0.29 to >100 µM, respectively. Both compounds displayed a broad spectrum of anticancer activity with selectivity ratios ranging between 0.50-2.78 and 0.25-2.81 at the GI50 level, respectively. The synthesized compounds were also screened for their cytotoxicity by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazol (MTT) assay and for inhibition of epidermal growth factor receptor (EGFR) and c-MET (mesenchymal-epithelial transition factor). Some of the tested compounds exhibited significant inhibition against EGFR and/or c-MET. Compound 9b showed the highest c-MET inhibition (IC50 = 4.70 nM) compared to foretinib (IC50 = 2.5 nM). Compound 9d showed equipotent activity compared with erlotinib against EGFR (IC50 = 0.052 µM) and displayed significant c-MET inhibition with an IC50 value of 4.90 nM.

An updated literature on BRAF inhibitors (2018-2023)

BRAF is the most common serine-threonine protein kinase and regulates signal transduction from RAS to MEK inside the cell. The BRAF is a highly active isoform of RAF kinase. BRAF has two domains such as regulatory and kinase domains. The BRAF inhibitors bind in the c-terminus of the kinase domain and inhibit the downstream pathways. The mutation occurs mainly in the A-loop of the kinase domain. The mutation occurs due to a conversion of valine to glutamate/lysine/arginine/aspartic acid at 600th position. Among the diverse mutations, BRAFV600E is the most common and responsible for numerous cancer such as melanoma, colorectal, ovarian, and thyroid cancer. Due to mutations in RAC1, loss of PTEN, NF1, CCND1, USP28-FBW7 complex, COT overexpression, and CCND1 amplification, the BRAF kinase enzyme developed resistance over the commercially available BRAF inhibitors. There is still unmute urgence for the development of BRAF inhibitors to overcome the persistent limitation such as resistance, mutation, and adverse effects of drugs. In the current study, we described the structure, activation, downstream signaling pathway, and mutation of BRAF. Our group also provided a detailed review of BRAF inhibitors from the last five years (2018-2023) highlighting the structure-activity relationship, mechanistic study, and molecular docking studies. We hope that the current analysis will be a useful resource for researchers and provide chemists a glimpse into the future as design and development of more effective and secure BRAF kinase inhibitors.

Synthesis, In vitro and In silico Studies of Novel Bis-triazolopyridopyrimidines from Curcumin Analogues as Potential Aromatase Agents

Breast cancer remains a major global health issue, particularly affecting women and contributing significantly to mortality rates. Current treatments for estrogen receptor-positive breast cancers, such as aromatase inhibitors, are effective but often come with side effects and resistance issues. This study addresses these gaps by targeting aromatase, an enzyme crucial for estrogen synthesis, which plays a pivotal role in breast cancer progression. The innovative approach involves synthesizing novel bis-triazolopyridopyrimidines, designed to leverage the combined pharmacological benefits of pyridopyrimidine and 1,2,4-triazole structures, known for their potent aromatase inhibition and anti-cancer properties. These compounds were synthesized and characterized using 1H-NMR, 13C-NMR, and MS spectral analyses, and their anticancer efficacy was evaluated through MTT assays against MCF-7 breast cancer cell lines in vitro. Molecular docking analyses revealed strong binding energies with aromatase, particularly for compounds 5 b, 5 c, 10 a, and 10 b, indicating their potential as effective aromatase inhibitors. The study highlights these compounds as promising candidates for further development as therapeutic agents against breast cancer.

A Metal-Free Cycloaddition of α-Diazoacetates with Amino Acid-Derived NHPI Esters for the Facile Synthesis of 1,2,4-Triazoles

1,2,4-Triazoles are privileged scaffolds for many pharmaceuticals, and methods for structurally diverse compound libraries are of current interest. Here we report an efficient coupling of α-diazoacetates with amino acid-derived alkyl N-hydroxy phthalimide esters, under metal-free conditions involving 1,8-diazabicyclo(5.4.0)undec-7-ene as the base, with which highly functionalized 1,2,4-triazoles can be obtained in excellent yields with remarkable functional group tolerance. Preliminary studies revealed that 1,2,4-triazole 3a exhibits potent inhibition of tyrosinase activities in melanoma B16F10 cell lines, demonstrating promising skin-whitening properties.

Significance of Triazole in Medicinal Chemistry: Advancement in Drug Design, Reward and Biological Activity

One of the triazole tautomers, 1,2,4-triazole derivatives, has a wide range of biological activities that suggest its potential therapeutic utility in medicinal chemistry. These actions include anti-inflammatory, anti-cancer, anti-bacterial, anti-tuberculosis, and anti-diabetic effects. Using computational simulations and models, we investigate the structure-activity relationships of 1,2,4-triazoles, showing how various modifications to the triazole core yield a variety of clinical therapeutic benefits. The review highlights the anti-inflammatory effect of 1,2,4-triazoles in relation to their ability to disrupt significant inflammatory mediators and pathways. We present in-silico data that illuminate the triazoles' capacity to inhibit cell division, encourage apoptosis, and stop metastasis in a range of cancer models. This review looks at the bactericidal and bacteriostatic properties of 1,2,4-triazole derivatives, with a focus on their potential efficacy against multi-drug resistant bacterial infections and their usage in tuberculosis therapy. In order to better understand these substances' potential anti-diabetic benefits, this review also looks at how they affect glucose metabolism regulation and insulin responsiveness. Coordinated efforts are required to translate the efficacy of 1,2,4-triazole compounds in preclinical models into practical therapeutic benefits. Based on the information provided, it can be concluded that 1,2,4-triazole derivatives are a promising class of diverse therapeutic agents with potential utility in a range of disorders. Their development and improvement might herald a new era of medical care that will be immensely advantageous to both patients and the medical community as a whole. This comprehensive research, which is further reinforced by in-silico investigations, highlights the great medicinal potential of 1,2,4-triazoles. Additionally, this study encourages more research into these substances and their enhancement for use in pharmaceutical development.

N-Heterocycles as Promising Antiviral Agents: A Comprehensive Overview

Viruses are a real threat to every organism at any stage of life leading to extensive infections and casualties. N-heterocycles can affect the viral life cycle at many points, including viral entrance into host cells, viral genome replication, and the production of novel viral species. Certain N-heterocycles can also stimulate the host's immune system, producing antiviral cytokines and chemokines that can stop the reproduction of viruses. This review focused on recent five- or six-membered synthetic N-heterocyclic molecules showing antiviral activity through SAR analyses. The review will assist in identifying robust scaffolds that might be utilized to create effective antiviral drugs with either no or few side effects.

Triazole derivatives as potential xanthine oxidase inhibitors: Design, enzyme inhibition potential, and docking studies

Considerable ingenuity has been shown in the recent years in the discovery of novel xanthine oxidase (XO) inhibitors that fall outside the purine scaffold. The triazole nucleus has been the cornerstone for the development of many enzyme inhibitors for the clinical management of several diseases, where hyperuricemia is one of them. Here, we give a critical overview of significant research on triazole-based XO inhibitors, with respect to their design, synthesis, inhibition potential, toxicity, and docking studies, done till now. Based on these literature findings, we can expect a burst of modifications on triazole-based scaffolds in the near future by targeting XO, which will treat hyperuricemics, that is, painful conditions like gout that at present are hard to deal with.

Biological evaluation of novel side chain containing CQTrICh-analogs as antimalarials and their development as PfCDPK1 kinase inhibitors

The rapid emergence of resistance to existing frontline antimalarial drugs emphasizes a need for the development of target-oriented molecules with novel modes of action. Given the importance of a plant-like Calcium-Dependent Protein Kinase 1 (PfCDPK1) as a stand-alone multistage signalling regulator of P. falciparum, we designed and synthesized 7-chloroquinoline-indole-chalcones tethered with a triazole (CQTrICh-analogs 7 (a-s) and 9) directed towards PfCDPK1. This was accomplished by reacting substituted 1-phenyl-3-(1-(prop-2-yn-1-yl)-1H-indol-3-yl) prop-2-en-1-one and 1-(prop-2-yn-1-yl)-1H-indole-3-carbaldehyde with 4-azido-7-chloroquinoline, respectively via a 'click' reaction. The selected CQTrICh-analogs: 7l and 7r inhibited the growth of chloroquine-sensitive 3D7 strain and -resistant RKL-9 isolate of Plasmodium falciparum, with IC50 values of 2.4 μM & 1.8 μM (7l), and 3.5 μM & 2.7 μM (7r), respectively, and showed no apparent hemolytic activity and cytotoxicity in mammalian cells. Intra-erythrocytic progression studies revealed that the active hybrids: 7l and 7r are effective against the mature stages of the parasite. 7l and 7r were found to stably interact with the catalytically active ATP-binding pocket of PfCDPK1 via energetically favourable H-bonds. The interaction was confirmed in vitro by microscale thermophoresis and kinase assays, which demonstrated that the active hybrids interact with PfCDPK1 and inhibit its kinase activity which is presumably responsible for the parasite growth inhibition. Interestingly, 7l and 7r showed no inhibitory effect on the human kinases, indicating their selectivity for the parasite kinase. We report the antiplasmodial potential of novel kinase-targeting bio-conjugates, a step towards developing pan-kinase inhibitors which is a prerequisite for multistage anti-malarial protection.

Natural-Product-Inspired Discovery of Trimethoxyphenyl-1,2,4-triazolosulfonamides as Potent Tubulin Polymerization Inhibitors

An approach of natural product-inspired strategy and incorporation of an NP-privileged motif has been investigated for the discovery of new tubulin polymerization inhibitors. Two series, N-Arylsulfonyl-3-arylamino-5-amino-1,2,4-triazole derivatives, and their isomers were considered. The compounds were synthesized by construction of the N-aryl-1,2,4-triazole-3,5-diamine motif and sulfonylation. Although the chemo- and regioselectivity in sulfonylation were challenging due to multiple ring-tautomerizable-NH and exocyclic NH2 functionalities present in the molecular motifs, the developed synthetic method enabled the preparation of designed molecular skeletons with biologically important motifs. The approach also led to explore interesting molecular regio- and stereochemical aspects valuable for activity. The X-ray crystallography study indicated that the hydrogen bonding between the arylamine-NH and the arylsulfonyl-"O" unit and appropriate molecular-functionality topology allowed the cis-locking of two aryls, which is important for tubulin-binding and antiproliferative properties. All synthesized compounds majorly showed characteristic antiproliferative effects in breast cancer cells (MCF-7), and four compounds exhibited potent antiproliferative activity. One compound potently bound to tubulin at the colchicine site and inhibited tubulin polymerization in vitro. The compound significantly depolymerized microtubules in MCF-7 cells, arrested the cells at the G2/M phase, and induced cell death. This study represents the importance of the design strategy in medicinal chemistry and the molecular structural features relevant to anticancer anti-tubulin properties. The explored molecules have the potential for further development.

Epidermal growth factor receptor dual-target inhibitors as a novel therapy for cancer: A review

Overexpression of the epidermal growth factor receptor (EGFR) has been linked to several human cancers, including esophageal cancer, pancreatic cancer, anal cancer, breast cancer, and lung cancer, particularly non-small cell lung cancer (NSCLC). Therefore, EGFR has emerged as a critical target for treating solid tumors. Many 1st-, 2nd-, 3rd-, and 4th-generation EGFR single-target inhibitors with clinical efficacy have been designed and synthesized in recent years. Drug resistance caused by EGFR mutations has posed a significant challenge to the large-scale clinical application of EGFR single-target inhibitors and the discovery of novel EGFR inhibitors. Therapeutic methods for overcoming multipoint EGFR mutations are still needed in medicine. EGFR dual-target inhibitors are more promising than single-target inhibitors as they have a lower risk of drug resistance, higher efficacy, lower dosage, and fewer adverse events. EGFR dual-target inhibitors have been developed sequentially to date, providing new options for remission in patients with previously untreatable malignancies and laying the groundwork for a future generation of compounds. This paper introduces the EGFR family proteins and their synergistic effects with other anticancer targets, and provides a comprehensive review of the development of EGFR dual-target inhibitors in cancer, as well as the opportunities and challenges associated with those fields.

Synthesis of tetrazoles through a domino reaction: A molecular electron density theory study of energetics, selectivities, and molecular mechanistic aspects

This study corresponds to a molecular electron density theory (MEDT) investigation to shed light on the energetics, selectivities, and molecular mechanistic aspects of an experimental domino reaction. Theoretical evidences at the M06-2X/6-31G(d) level indicates that this domino reaction includes three different successive steps and is initialized by a stepwise HCl elimination from precursor chlorohydrazone NPCH to yield nitrile imine NI-2. A subsequent stepwise and highly regioselective [3 + 2] cycloaddition (32CA) reaction of NI-2 toward tetramethylguanidine TMG-3 affords corresponding formal [3 + 2] cycloadduct CA-1 as the sole product. Finally, a stepwise HNMe2 elimination experienced by CA-1 leads to amino triazole ATA as an aromatic five-membered target product. Computed rate constants reveal that the HCl elimination step should be considered as the bottleneck of this domino reaction. However, a topological analysis of electron localization function (ELF) of NI-2 demonstrates a zwitterionic type (zw-type) 32 C A reaction is expected between NI-2 and TMG-3. This 32CA reaction also displays an almost noticeable polar character arising from moderate electrophilicity and strong nucleophilicity of NI-2 and TMG-3, respectively. The regioselectivity of 32CA reaction can be explained via analysis of Parr functions values calculated at the reactive sites of reagents. The molecular mechanism of the 32CA reaction was explored through portraying bond forming/breaking patterns involved in this polar, stepwise, and zw-type reaction by means of the ELF analysis. Indeed, formation of both C-N single bonds along the first and second steps takes place through coupling of the corresponding pseudoradical centers.

Investigation on CT-DNA and Protein Interaction of New Pd(II) Complexes Involving Ceftazidime and 3-Amino-1,2,3-triazole: Synthesis, Characterization, Biological Impact, Anticancer Evaluation, and Molecular Docking Approaches

Two new palladium (II) complexes, [Pd(CAZ)(OH2 )2 ]2+ (1) and [Pd(3-AT)(OH2 )2 ]2+ (2), (CAZ=ceftazidime, and 3-AT=amitrole) were synthesized and studied for their potential as anticancer drugs with low toxicity and high potency. To fully characterize these complexes, we conducted elemental analysis and FT-IR studies. Furthermore, we irradiated the complexes with Indian 60 Co gamma rays and thoroughly evaluated their antimicrobial properties. Our results demonstrate that the inhibitory activity of complexes was significantly enhanced against (G+) bacteria and fungi. Additionally, we probed the complexes' interaction with CT-DNA and BSA using various techniques, including UV-vis spectroscopy, thermal denaturation, viscometry, gel electrophoresis, and molecular docking studies. Our findings conclusively demonstrate that these complexes possess a strong binding interaction with CT-DNA via minor groove binding and/or electrostatic interactions, as well as excellent binding affinity to BSA. Finally, we conducted a cytotoxicity assay that clearly indicates these complexes hold immense promise as cell growth inhibitors against MCF-7 and HCT-116.

New Schiff bases derived from dimethylpyridine-1,2,4-triazole hybrid as cytotoxic agents targeting gastrointestinal cancers: Design, synthesis, biological evaluation and molecular docking studies

In this research, a series of novel hybrid structures of dimethylpyridine-1,2,4-triazole Schiff bases were designed, synthesized, and evaluated for their in vitro cytotoxic potency on several human gastrointestinal cancer cells (EPG, Caco-2, LoVo, LoVo/Dx, HT29) and normal colonic epithelial cells (CCD 841 CoN). Schiff base 4h was the most potent compound against gastric EPG cancer cells (CC50 = 12.10 ± 3.10 μM), being 9- and 21-fold more cytotoxic than 5-FU and cisplatin, respectively. Moreover, it was not toxic to normal cells. Regarding the cytotoxicity against colorectal cancer cells, compounds 4d and 4l exhibited good activity against HT29 cells (CC50 = 52.80 ± 2.80 μM and 61.40 ± 10.70 μM, respectively), and were comparable to or more potent than cisplatin and 5-FU. Also, they were less toxic to normal cells with a higher selectivity index (SI, CCD 841 CoN/HT29 = 4.20 and 2.85, respectively) than reference drugs (SI, CCD 841 CoN/HT29 < 1). Selected Schiff bases were subjected to the P-glycoprotein inhibition assay. Schiff bases 4d, 4e, and 4l influenced P-gp efflux function, significantly increasing the accumulation of rhodamine 123 in colon cancer cell lines. Further mechanistic studies showed that compound 4l induced apoptotic cell death through a caspase-dependent mechanism and by regulating the p53-MDM2 signaling pathway in HT29 cells. Also, physicochemical predictions of compounds 4d, 4e, 4h, and 4i were examined in silico. The results revealed that the compounds possessed promising drug-likeness profiles.

Coordination Complexes Built from a Ditopic Triazole-Pyrazole Ligand with Antibacterial and Antifungal Performances

Four mononuclear complexes (H3O){[NiL3](ClO4)3} (1), [CoL3](ClO4)2·2H2O (2), [CdL2Cl2] (3) and [CuL3](NO3)2 (4) have been prepared employing a newly synthesized 1,2,4-triazole ligand: 3-(3,5-dimethyl-1H-pyrazol-1-yl)-1H-1,2,4-triazole (L). The structures of the complexes, which crystallized in P63/m (1), P-1 (2), P1 (3), and P21/c (4), are reviewed within the context of the cooperative effect of the hydrogen bonding network and counter anions on the supramolecular formations. Moreover, within the framework of biological activity examination, these compounds showed favorable antibacterial performances compared to those of various species of bacteria, including both Gram-positive and Gram-negative strains. Significant antifungal inhibitory activity towards Fusarium oxysporum f. sp. albedinis fungi was recorded for 3 and 4 over the ligand L.

1,5-Diaryl-1,2,4-triazole Ureas as New SLC-0111 Analogues Endowed with Dual Carbonic Anhydrase and VEGFR-2 Inhibitory Activities

Presently, dual targeting by a single small molecule stands out as an effective cancer-fighting weapon. Carbonic anhydrase (CA) and vascular-endothelial growth factor (VEGF) are hypoxia-activatable genes that are implicated in tumorigenesis and progression of hypoxic tumors at different levels. Herein, we designed and synthesized 30 1,5-diaryl-1,2,4-triazole-tethered sulfonamides (11a-f, 12a-l, 13a-f, 15a-f) as novel SLC-0111 analogues with dual CA IX/XII and VEGFR-2 inhibitory activities. The 4-fluorophenyl SLC-0111 tail was replaced by substituted 1,5-diaryl-1,2,4-triazoles. Changing the sulfamoyl motif position provided regioisomers 11a-f and 12a-l. Elongation of the ureido linker yielded derivatives 15a-f. Inhibitory evaluations included a panel of hCAs (hCA I, II, IX, and XII) and screening against 60 cancer cell lines. Promising candidates were assessed for VEGFR-2 inhibition and selectivity and further evaluated on breast cancer cell lines (MCF-7 and T-47D) and the non-tumorigenic (MCF-10A) cells. Molecular docking studies explored the binding modes of the sulfonamides against hCA IX/XII and VEGFR-2 kinase.

Challenges and Opportunities in the Crusade of BRAF Inhibitors: From 2002 to 2022

Serine/threonine-protein kinase B-Raf (BRAF; RAF = rapidly accelerated fibrosarcoma) plays an important role in the mitogen-activated protein kinase (MAPK) signaling cascade. Somatic mutations in the BRAF gene were first discovered in 2002 by Davies et al., which was a major breakthrough in cancer research. Subsequently, three different classes of BRAF mutants have been discovered. This class includes class I monomeric mutants (BRAFV600), class II BRAF homodimer mutants (non-V600), and class III BRAF heterodimers (non-V600). Cancers caused by these include melanoma, thyroid cancer, ovarian cancer, colorectal cancer, nonsmall cell lung cancer, and others. In this study, we have highlighted the major binding pockets in BRAF protein, their active and inactive conformations with inhibitors, and BRAF dimerization and its importance in paradoxical activation and BRAF mutation. We have discussed the first-, second-, and third-generation drugs approved by the Food and Drug Administration and drugs under clinical trials with all four different binding approaches with DFG-IN/OUT and αC-IN/OUT for BRAF protein. We have investigated particular aspects and difficulties with all three generations of inhibitors. Finally, this study has also covered recent developments in synthetic BRAF inhibitors (from their discovery in 2002 to 2022), their unique properties, and importance in inhibiting BRAF mutants.

Benzoquinoline Derivatives: An Attractive Approach to Newly Small Molecules with Anticancer Activity

This study presents the synthesis, structural characterization, and in vitro evaluation of anticancer activity of some newly benzo[f]quinoline derivatives. The synthesis is facile and efficient, involving two steps: quaternization of nitrogen heterocycle followed by a [3+2] dipolar cycloaddition reaction. The synthesized compounds were characterized by FTIR, NMR, and X-ray diffraction on monocrystal in the case of compounds 6c and 7c. An in vitro single-dose anticancer assay of eighteen benzo[f]quinoline compounds, quaternary salts, and cycloadducts, was performed. The results showed that the most active compounds were quaternary salts 3d and 3f with aromatic R substituents. Quaternary salt 3d revealed non-selective activity against all types of cancer cells, while salt 3f exhibited a highly selective activity against leukemia cells. Compound 3d also presented remarkable cytotoxic efficiency against four distinct types of cancer cells-namely, non-small cell lung cancer HOP-92, melanoma LOX IMVI, melanoma SK-MEL-5, and breast cancer MDA-MB-468. Compound 3f was selected for five-dose screening. The study also includes SAR correlations.

Discovery of new 5-substituted-indole-2-carboxamides as dual epidermal growth factor receptor (EGFR)/cyclin dependent kinase-2 (CDK2) inhibitors with potent antiproliferative action

A new series of 5-substituted-3-ethylindole-2-carboxamides 5a-k and 6a-c was designed and synthesised in an attempt to develop a dual targeted antiproliferative agent. Various spectroscopic methods of analysis were used to confirm the structures of the new compounds. The antiproliferative effect of compounds 5a-k and 6a-c against four cancer cell lines was investigated. Compounds 5a-k and 6a-c had significant antiproliferative activity against the four cancer cell lines tested, with mean GI50 values ranging from 37 nM to 193 nM. The most powerful derivatives were compounds 5g, 5i, and 5j, with GI50 values of 55 nM, 49 nM, and 37 nM, respectively, in comparison to the reference erlotinib, which had a GI50 of 33 nM. The four most potent compounds, 5c, 5g, 5i, and 5j, were then investigated for their efficacy as EGFR inhibitors, and the findings showed that the tested compounds inhibited EGFR with IC50 values ranging from 85 nM to 124 nM when compared to the reference erlotinib (IC50 = 80 nM). Moreover, compounds 5c and 5g inhibited CDK2 with IC50 values of 46 ± 05 nM and 33 ± 04 nM, respectively. The EGFR and CDK2 assays revealed that compounds 5i and 5j displayed potent antiproliferative activity and can be considered as potential dual EGFR and CDK2 inhibitors.

Design, synthesis, and modelling study of new 1,2,3-triazole/chalcone hybrids with antiproliferative action as epidermal growth factor receptor inhibitors

A novel series of 1,2,3-triazole/chalcone hybrids 6a-n was designed and synthesized using a molecular hybridization approach to develop a new cytotoxic agent capable of targeting epidermal growth factor receptor (EGFR) and/or BRAF. The antiproliferative effect of the novel hybrids was investigated against four cancer cells using doxorubicin as a reference. Hybrids 6a, 6d, 6f-h, and 6n have the highest antiproliferative activity (IC₅₀ values 0.95-1.80 μM) compared to doxorubicin (IC₅₀ 1.14 μM). The most potent antiproliferative derivative, compound 6d, was also the most potent EGFR inhibitor with an IC₅₀ of 0.09 ± 0.05 μM, which is comparable to the reference Erlotinib (IC₅₀  = 0.05 ± 0.03 μM). 6d has modest BRAF inhibitory action with an IC₅₀ of 0.90 ± 0.10 μM. The findings were also related to molecular docking studies, which provided models of strong interactions with the EGFR-TK domain for the inhibitors. In cell cycle analysis, hybrid 6d caused a cell cycle arrest at the G1 transition phase.

New 1,3,4-oxadiazole-chalcone/benzimidazole hybrids as potent antiproliferative agents

A series of new 1,3,4-oxadiazole-chalcone/benzimidazole hybrids 9a-o and 10a-k were designed and synthesized as potential antiproliferative agents. Hybrids 9a-o exhibited remarkable antiproliferative activities on different NCI-60 cell lines in a single-dose assay. The antiproliferative activities of the newly synthesized compounds were evaluated against a panel of four human cancer cell lines (A-549, MCF-7, Panc-1, and HT-29). Compounds 9g-i and their oxygen isosteres, 10f-h, exhibited promising antiproliferative activities with IC₅₀ values ranging from 0.80 to 2.27 µM compared to doxorubicin (IC₅₀ ranging from 0.90 to 1.41 µM). Furthermore, the inhibitory potency of these compounds against the epidermal growth factor receptor (EGFR) and BRAF^V600E kinases was evaluated using erlotinib as a reference drug. Molecular modeling studies were done to investigate the binding mode of the most active hybrids in the ATP binding site of EGFR.

Design, Synthesis, and Antiproliferative Activity of New 5-Chloro-indole-2-carboxylate and Pyrrolo[3,4-b]indol-3-one Derivatives as Potent Inhibitors of EGFRT790M/BRAFV600E Pathways

Mutant EGFR/BRAF pathways are thought to be crucial targets for the development of anticancer drugs since they are over-activated in several malignancies. We present here the development of a novel series of 5-chloro-indole-2-carboxylate 3a-e, 4a-c and pyrrolo[3,4-b]indol-3-ones 5a-c derivatives as potent inhibitors of mutant EGFR/BRAF pathways with antiproliferative activity. The cell viability assay results of 3a-e, 4a-c, and 5a-c revealed that none of the compounds tested were cytotoxic, and that the majority of those tested at 50 µM had cell viability levels greater than 87%. Compounds 3a-e, 4a-c, and 5a-c had significant antiproliferative activity with GI50 values ranging from 29 nM to 78 nM, with 3a-e outperforming 4a-c and 5a-c in their inhibitory actions against the tested cancer cell lines. Compounds 3a-e were tested for EGFR inhibition, with IC50 values ranging from 68 nM to 89 nM. The most potent derivative was found to be the m-piperidinyl derivative 3e (R = m-piperidin-1-yl), with an IC50 value of 68 nM, which was 1.2-fold more potent than erlotinib (IC50 = 80 nM). Interestingly, all the tested compounds 3a-e had higher anti-BRAFV600E activity than the reference erlotinib but were less potent than vemurafenib, with compound 3e having the most potent activity. Moreover, compounds 3b and 3e showed an 8-fold selectivity index toward EGFRT790M protein over wild-type. Additionally, molecular docking of 3a and 3b against BRAFV600E and EGFRT790M enzymes revealed high binding affinity and active site interactions compared to the co-crystalized ligands. The pharmacokinetics properties (ADME) of 3a-e revealed safety and good pharmacokinetic profile.

Design and synthesis of new heterocyclic compounds containing 5-[(1H-1,2,4-triazol-1-yl)methyl]-3H-1,2,4-triazole-3-thione structure as potent hEGFR inhibitors

EGFR is one of the important mediators of the signaling cascade that determines key roles in various biological processes such as growth, differentiation, metabolism and apoptosis in the cell in response to external and internal stimuli. In recent years, it has been proven that although this enzyme activity is tightly regulated in normal cells, if the enzyme activity cannot be controlled, it can lead to malignancy. EGFR is also considered a prominent macromolecule in targeted cancer chemotherapy. For this purpose, a comprehensive modeling studies were conducted against EGFR protein and novel molecules containing 5-[(1H-1,2,4-triazol-1-yl)methyl]-3H-1,2,4-triazole-3-thione structure were suggested to be synthesized. Among the synthesized molecules, compounds 7c, 8c, 8f and 8g were determined to have significant IC50 values. Compound 8g was found to have the IC50 value closest to the very well-known EGFR inhibitor Gefitinib with its noncompetitive inhibition form. Ki value of compound 8g was calculated as 0.00232 µM.Communicated by Ramaswamy H. Sarma.

Discovery of new cyanopyridine/chalcone hybrids as dual inhibitors of EGFR/BRAF V600E with promising antiproliferative properties

As dual EGFR and BRAF^V600E inhibitors, 2-(3-cyano-4,6-bis(aryl)-2-oxo-1,2-dihydropyridine-1-yl)-N-(4-cinnamoylphenyl) acetamide derivatives 8-20 were developed. Compounds 8, 12, and 13 showed strong antiproliferative activity when the target compounds were synthesized and tested in vitro against four cancer cell lines. These hybrids have a dual inhibition activity on EGFR and BRAF^V600E , according to in vitro studies. The EGFR was inhibited by compounds 8, 12, and 13 with IC₅₀ values between 89 and 110 nM, which were equivalent to those of erlotinib (IC₅₀  = 80 nm). Compound 13 was found to be an effective inhibitor of the proliferation of cancer cells (GI₅₀  = 0.72 µM) and demonstrated hopeful inhibitory activity of BRAF^V600E (IC₅₀  = 58 nm), which is superior to erlotinib (IC₅₀  = 65 nm). Compound 13 caused apoptosis and showed cell cycle arrest in the G0/G1phase in a study on the MCF-7 cell line. The new compounds can fit tightly into the active sites of EGFR and BRAF^V600E kinases, according to molecular docking analyses.

Design and synthesis of new thiazolidinone/uracil derivatives as antiproliferative agents targeting EGFR and/or BRAFV600E

Thiourea derivatives of uracil were efficiently synthesized via the reaction of 5-aminouracil with isothiocyanates. Then, we prepared uracil-containing thiazoles via condensation of thioureas with diethyl/dimethyl acetylenedicarboxylates. The structures of the products were confirmed by a combination of spectral techniques including infra-red (IR), nuclear magnetic resonance (NMR), mass spectrometry (MS) and elemental analyses. A rationale for the formation of the products is presented. The newly synthesized compounds were evaluated for their in vitro antiproliferative activity against four cancer cell lines. The compounds tested showed promising antiproliferative activity, with GI₅₀ values ranging from 1.10 µM to 10.00 µM. Compounds 3c, 5b, 5c, 5h, 5i, and 5j were the most potent derivatives, with GI₅₀ values ranging from 1.10 µM to 1.80 µM. Compound 5b showed potent inhibitory activity against EGFR and BRAF^V600E with IC₅₀ of 91 ± 07 and 93 ± 08 nM, respectively, indicating that this compound could serve as a dual inhibitor of EGFR and BRAF^V600E with promising antiproliferative properties. Docking computations revealed the great potency of compounds 5b and 5j towards EGFR and BRAF^V600E with docking scores of -8.3 and -9.7 kcal/mol and -8.2 and -9.3 kcal/mol, respectively.

Synthesis, biological evaluation, and molecular modeling studies of acetophenones-tethered 1,2,4-triazoles and their oximes as epidermal growth factor receptor inhibitors

A series of 5-(4-pyridyl)-1,2,4-triazoles hybrids with acetophenones and their oxime derivatives was rationally designed and synthesized as epidermal growth factor receptor (EGFR) kinase inhibitors. Initially, drug Likeness and pharmacokinetics properties of the prepared compounds were evaluated. Afterward, the prepared compounds were in vitro screened for their ability to inhibit the growth of the NCI-60 human cancer cell lines where certain compounds showed moderate activity. Compounds 4e and 5b emerged as the most potent compounds in this series were further tested for their EGFR enzyme inhibition activity. They showed IC₅₀ values of 0.14 and 0.18 µM, respectively, in comparison with Gefitinib as a reference with an IC₅₀ value of 0.06 µM. Docking of compounds 4e and 5b into the binding site of EGFR tyrosine kinase was performed to explains their possible binding mode and to compare it with known inhibitors. Moreover, molecular dynamic simulations were estimated for deeper understanding of the binding mode of compounds 4e and 5b at the binding site of EGFR tyrosine kinase. The findings indicated that the novel ligands 4e and 5b were stable in the EGFR tyrosine kinase active site.

Design, synthesis and evaluation of novel 1,2,4-triazole derivatives as promising anticancer agents

Herein, we reported the synthesis of nineteen novel 1,2,4-triazole derivatives including 1,3-diphenyl-2-(1H-1,2,4-triazol-1-yl) propan-1-ones (7a-e), 1-(1,3-diphenylpropan-2-yl)-1H-1,2,4-triazole (8a-c) and 1,4-diphenyl-2-(1H-1,2,4-triazol-1-yl) butane-1,4-diones (10a-k). The structures of these derivatives were confirmed by spectroscopic techniques like IR, 1H-NMR, Mass spectroscopy and Elemental analysis. The cytotoxic activities of the synthesized compounds were evaluated against three human cancer cell lines including MCF-7, Hela and A549 using MTT assay. Compounds 7d, 7e, 10a and 10d showed a promising cytotoxic activity lower than 12 μM against Hela cell line. The safety of these compounds was also, evaluated on MRC-5 as a normal cell line and relieved that most of the synthesized compounds have proper selectivity against normal and cytotoxic cancerous cell lines. Finally, molecular docking studies were also, done to understand the mechanism and binding modes of these derivatives in the binding pocket of aromatase enzyme as a possible target.

New phthalimide-based derivatives as EGFR-TK inhibitors: Synthesis, biological evaluation, and molecular modeling study

A novel series of phthalimide derivatives was synthesized and evaluated for in vitro antitumor activity against six human cancer cell lines; HepG-2, HCT-116, MCF-7, Hep2, PC3 and Hela.The obtained results revealed that compound 32 was the most potent antitumor, while compounds 33, 22 and 24 showed strong activity against all tested cell lines. Further biological evaluation of the most active compounds was done and their in vitro EGFR-TK inhibition was tested, and the results came in accordance with the results of antitumor testing, where 32 displayed promising inhibitory activity (IC₅₀ = 0.065 µM) compared to the standard drug erlotinib (IC₅₀ = 0.067 µM). In addition, compounds 48, 22, 28 and 19 showed strong inhibitory activity (IC₅₀ = 0.089, 0.093, 0.147 and 0.152 µM respectively). Cell cycle analysis was conducted and the results revealed that 32 induced cell cycle arrest on Hela and MCF-7 at G0-G1 phase and Pre-G1 phase causing cell death mainly via apoptosis. Additionally, in vivo antitumor screening revealed that 32 reduced both body weight and tumor volume in solid tumor utilizing Ehrlich ascites carcinoma (EAC) animal model. Molecular modeling study showed that 32 and 48 have the highest affinity for binding with the active site of EGFR-TK with docking score comparable to erlotinib. Compounds 32 and 48 could be used as template models for further optimization.

Development of Dual Inhibitors Targeting Epidermal Growth Factor Receptor in Cancer Therapy

Epidermal growth factor receptor (EGFR) is of great significance in mediating cell signaling transduction and tumor behaviors. Currently, third-generation inhibitors of EGFR, especially osimertinib, are at the clinical frontier for the treatment of EGFR-mutant non-small-cell lung cancer (NSCLC). Regrettably, the rapidly developing drug resistance caused by EGFR mutations and the compensatory mechanism have largely limited their clinical efficacy. Given the synergistic effect between EGFR and other compensatory targets during tumorigenesis and tumor development, EGFR dual-target inhibitors are promising for their reduced risk of drug resistance, higher efficacy, lower dosage, and fewer adverse events than those of single-target inhibitors. Hence, we present the synergistic mechanism underlying the role of EGFR dual-target inhibitors against drug resistance, their structure-activity relationships, and their therapeutic potential. Most importantly, we emphasize the optimal target combinations and design strategies for EGFR dual-target inhibitors and provide some perspectives on new challenges and future directions in this field.

Biological Evaluation of 4-(1H-triazol-1-yl)benzoic Acid Hybrids as Antioxidant Agents: In Vitro Screening and DFT Study

Fourteen triazole benzoic acid hybrids were previously characterized. This work aimed to screen their in vitro antioxidant activity using different assays, i.e., DPPH (1,1-diphenyl-1-picrylhydrazyl), reducing the power capability, FRAP (ferric reducing antioxidants power) and ABTS (2,2′-azino-bis(3-ethylben zothiazoline-6-sulfonate) radical scavenging. The 14 compounds showed antioxidant properties in relation to standard BHA (butylated hydroxylanisole) and Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid). Higher antioxidant activity was observed by the parent (1) at a concentration of 100 µg/mL (89.95 ± 0.34 and 88.59 ± 0.13%) when tested by DPPH and ABTS methods in relation to BHA at 100 µg/mL (95.02 ± 0.74 and 96.18 ± 0.33%). The parent (2) demonstrated remarkable scavenging activity when tested by ABTS (62.00 ± 0.24%), however, 3 was less active (29.98 ± 0.13%). Compounds 5, 6, 9, and 11 exhibited good scavenging activity compared to 1. DFT studies were performed using the B3LYP/6-311++g (2d,2p) level of theory to evaluate different antioxidant descriptors for the targets. Three antioxidant mechanisms, i.e., hydrogen atom transfer (HAT), sequential electron transfer proton transfer (SETPT) and sequential proton loss electron transfer (SPLET) were suggested to describe the antioxidant properties of 1–14. Out of the 14 triazole benzoic acid hybrids, 5, 9, 6, and 11 showed some good theoretical results, which were in agreement with some experimental outcomes. Based on the computed (PA and ETE) and (BDE and IP) values in (SPLET) and (HAT and SETPT) mechanisms, respectively, compound 9 emerged has having good antioxidant activity.

Monoamine oxidase A and B inhibitory activities of 3,5-diphenyl-1,2,4-triazole substituted [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives

Monoamine oxidase (EC 1.4.3.4, MAO) is a flavin adenine dinucleotide-containing flavoenzyme located on the outer mitochondrial membrane and catalyzes the oxidative deamination of monoaminergic neurotransmitters and dietary amines. MAO exists in humans as two isoenzymes, hMAO-A and hMAO-B, which are distinguished by their tertiary structures, preferred substrates and inhibitors, and selective inhibition of these isoenzymes are used in the treatment of different diseases such as Alzheimer's, Parkinson's and depression. In the present study, we report the design, synthesis and characterization of 3,5-diphenyl-1,2,4-triazole substituted [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives as novel and selective inhibitors of hMAO-B. Twenty one compounds (38, 39a-h, 41a-d, 42a-h) were screened for their inhibitory activity against hMAO-A and hMAO-B by using in vitro Amplex Red® reagent based fluorometric method and all compounds were found to be as selective h-MAO-B inhibitors to a different degree. The compound 42e and 42h displayed the highest inhibitory activity against hMAO-B with IC₅₀ values of 2.51 and 2.81 µM, respectively, and more than 25-fold selectivity towards inhibition of hMAO-B. A further kinetic evaluation of the most potent derivative (42e) was also performed and a mixed mode of inhibition of hMAO-B by the compound 42e was determined (K_i = 0,26 µM). According to our findings the [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole emerged as a promising scaffold for the development of novel and selective hMAO-B inhibitors.

Structure-based design, synthesis, and biological evaluation of novel piperine-resveratrol hybrids as antiproliferative agents targeting SIRT-2

A series of novel piperine–resveratrol hybrids 5a–h was designed, synthesized, and structurally elucidated by IR, and ¹H, ¹³C, and ¹⁹F NMR. Antiproliferative activities of 5a–h were evaluated by NCI against sixty cancer cell lines. Compound 5b, possessing resveratrol pharmacophoric phenolic moieties, showed a complete cell death against leukemia HL-60 (TB) and Breast cancer MDA-MB-468 with growth inhibition percentage of −0.49 and −2.83, respectively. In addition, 5b recorded significant activity against the other cancer cell lines with growth inhibition percentage between 80 to 95. New 5a–h hybrids were evaluated for their inhibitory activities against Sirt-1 and Sirt-2 as molecular targets for their antiproliferative action. Results showed that compounds 5a–h were more potent inhibitors of Sirt-2 than Sirt-1 at 5 μm and 50 μm. Compound 5b showed the strongest inhibition of Sirt-2 (78 ± 3% and 26 ± 3% inhibition at 50 μM and 5 μM, respectively). Investigation of intermolecular interaction via Hirschfeld surface analysis indicates that these close contacts are mainly ascribed to the O–H⋯O hydrogen bonding. To get insights into the Sirt-2 inhibitory mechanism, a docking study was performed where 5b was found to fit nicely inside both extended C-pocket and selectivity pocket and could compete with the substrate acyl-Lys. Another possible binding pattern showed that 5b could act by partial occlusion of the NAD⁺ C-pocket. Collectively, these findings would contribute significantly to better understanding the Sirt-2 inhibitory mechanism in order to develop a new generation of refined and selective Sirt-2 inhibitors.

A series of novel piperine–resveratrol hybrids 5a–h was designed, synthesized, and structurally elucidated by IR, and ¹H, ¹³C, and ¹⁹F NMR.

Kravtsov V, Melnic E, Petrou A, Glamočlija J, Soković M, Carazo A, Mladěnka P, Poroikov V, Geronikaki A, Macaev FZ. Chromenol Derivatives as Novel Antifungal Agents: Synthesis, In Silico and In Vitro Evaluation

Herein we report the synthesis of some new 1H-1,2,4-triazole functionalized chromenols (3a-3n) via tandem reactions of 1-(alkyl/aryl)-2-(1H-1,2,4-triazole-1-yl) with salicylic aldehydes and the evaluation of their antifungal activity. In silico prediction of biological activity with computer program PASS indicate that the compounds have a high novelty compared to the known antifungal agents. We did not find any close analog among the over 580,000 pharmaceutical agents in the Cortellis Drug Discovery Intelligence database at the similarity cutoff of 70%. The evaluation of antifungal activity in vitro revealed that the highest activity was exhibited by compound 3k, followed by 3n. Their MIC values for different fungi were 22.1-184.2 and 71.3-199.8 µM, respectively. Twelve from fourteen tested compounds were more active than the reference drugs ketoconazole and bifonazole. The most sensitive fungus appeared to be Trichoderma viride, while Aspergillus fumigatus was the most resistant one. It was found that the presence of the 2-(tert-butyl)-2H-chromen-2-ol substituent on the 4th position of the triazole ring is very beneficial for antifungal activity. Molecular docking studies on C. albicans sterol 14α-demethylase (CYP51) and DNA topoisomerase IV were used to predict the mechanism of antifungal activities. According to the docking results, the inhibition of CYP51 is a putative mechanism of antifungal activity of the novel chromenol derivatives. We also showed that most active compounds have a low cytotoxicity, which allows us to consider them promising antifungal agents for the subsequent testing activity in in vivo assays.

Recent developments in mitogen activated protein kinase inhibitors as potential anticancer agents

The mitogen activated protein kinase (MAPK) belongs to group of kinase that links the extracellular stimuli to intracellular response. The MAPK signalling pathway (RAS-RAF-MEK-ERK) involved in different pathological conditions like cancer, caused due to genetic or any other factor such as physical or environmental. Many studies have been conducted on the pathological view of MAPK cascade and its associated element like RAS, RAF, MEK, ERK or its isoforms, and still the research is going on particularly with respect to its activation, regulation and inhibition. The MAPK signalling pathway has become the area of research to identify new target for the management of cancer. A number of heterocyclics are key to fight with the cancer associated with these enzymes thus give some hope in the management of cancer by inhibiting MAPK cascade. In the present article, we have focussed on MAPK signalling pathway and role of different heterocyclic scaffolds bearing nitrogen, sulphur and oxygen and about their potential to block MAPK signalling pathway. The heterocyclics are gaining importance due to high potency and selectivity with less off-target effects against different targets involved in the MAPK signalling pathway. We have tried to cover recent advancements in the MAPK signalling pathway inhibitors with an aim to get better understanding of the mechanism of action of the compounds. Several compounds in the preclinical and clinical studies have been thoroughly dealt with. In addition to the synthetic compounds, a significant number of natural products containing heterocyclic moieties as MAPK signalling pathway inhibitors have been put together. The structure activity relationship along with docking studies have been discussed to apprehend the mechanistic studies of various compounds that will ultimately help to design and develop more MAPK signalling pathway inhibitors.

Triazolo Based-Thiadiazole Derivatives. Synthesis, Biological Evaluation and Molecular Docking Studies

The goal of this research is to investigate the antimicrobial activity of nineteen previously synthesized 3,6-disubstituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole derivatives. The compounds were tested against a panel of three Gram-positive and three Gram-negative bacteria, three resistant strains, and six fungi. Minimal inhibitory, bactericidal, and fungicidal concentrations were determined by a microdilution method. All of the compounds showed antibacterial activity that was more potent than both reference drugs, ampicillin and streptomycin, against all bacteria tested. Similarly, they were also more active against resistant bacterial strains. The antifungal activity of the compounds was up to 80-fold higher than ketoconazole and from 3 to 40 times higher than bifonazole, both of which were used as reference drugs. The most active compounds (2, 3, 6, 7, and 19) were tested for their inhibition of P. aeruginosa biofilm formation. Among them, compound 3 showed significantly higher antibiofilm activity and appeared to be equipotent with ampicillin. The prediction of the probable mechanism by docking on antibacterial targets revealed that E. coli MurB is the most suitable enzyme, while docking studies on antifungal targets indicated a probable involvement of CYP51 in the mechanism of antifungal activity. Finally, the toxicity testing in human cells confirmed their low toxicity both in cancerous cell line MCF7 and non-cancerous cell line HK-2.

DeepBSP-a Machine Learning Method for Accurate Prediction of Protein-Ligand Docking Structures

In recent years, machine-learning-based scoring functions have significantly improved the scoring power. However, many of these methods do not perform well in distinguishing the native structure from docked decoy poses due to the lack of decoy structural information in their training data. Here, we developed a machine-learning model, named DeepBSP, that can directly predict the root mean square deviation (rmsd) of a ligand docking pose with reference to its native binding pose. Unlike the binding affinity, the rmsd between the docking poses with reference to their native structures can be straightforwardly determined. By training on a generated data set with 11,925 native complexes and more than 165,000 docked poses, our model shows excellent docking power on our test set and also on the CASF-2016 docking decoy set compared to other major scoring functions. Thus, by combining molecular dockings that generate many poses with the application of DeepBSP, one can more accurately predict the best binding pose that is closest to the native complex structure. This DeepBSP model shall be very useful in picking out poses close to their natives from many poses generated from a dock application.

Design, synthesis, and biological evaluation of novel EGFR inhibitors containing 5-chloro-3-hydroxymethyl-indole-2-carboxamide scaffold with apoptotic antiproliferative activity

New EGFR inhibitor series of fifteen 5-chloro-3-hydroxymethyl-indole-2-carboxamide derivatives has been designed, synthesized, and tested for antiproliferative activity against a panel of cancer cell lines. The results showed that p-substituted phenethyl derivatives 10, 11, 13, 15 and 17-19 showed superior antiproliferative activity compared to their m-substituted counterparts 12, 14, 16 and 20. Compounds 15, 16, 19 and 20 displayed promising EGFR inhibitory activity as well as an increase in caspase 3 levels. Compounds 15 and 19 increased caspase-8 and 9 levels, as well as inducing Bax and decreasing Bcl-2 protein levels. Compound 19 demonstrated cell cycle arrest at pre-G1 and G2/M phases. The results of the docking study into the active site of EGFR revealed strong fitting of the new compounds with higher binding affinities compared to erlotinib.