Discovery of a novel 6,7-disubstituted-4-(2-fluorophenoxy)quinolines bearing 1,2,3-triazole-4-carboxamide moiety as potent c-Met kinase inhibitors

Triazoles in Medicinal Chemistry: Physicochemical Properties, Bioisosterism, and Application

Triazole demonstrates distinctive physicochemical properties, characterized by weak basicity, various dipole moments, and significant dual hydrogen bond acceptor and donor capabilities. These features are poised to play a pivotal role in drug-target interactions. The inherent polarity of triazole contributes to its lower logP, suggesting the potential improvement in water solubility. The metabolic stability of triazole adds additional value to drug discovery. Moreover, the metal-binding capacity of the nitrogen atom lone pair electrons of triazole has broad applications in the development of metal chelators and antifungal agents. This Perspective aims to underscore the unique physicochemical attributes of triazole and its application. A comparative analysis involving triazole isomers and other heterocycles provides guiding insights for the subsequent design of triazoles, with the hope of offering valuable considerations for designing other heterocycles in medicinal chemistry.

Design and biological evaluation of 3-substituted quinazoline-2,4(1H,3H)-dione derivatives as dual c-Met/VEGFR-2-TK inhibitors

The dual c-Met/vascular endothelial growth factor receptor 2 (VEGFR-2) TK inhibition is a good strategy to overcome therapeutic resistance to small molecules VEGFR-2 inhibitors. In this study, we designed 3-substituted quinazoline-2,4(1H,3H)-dione derivatives as dual c-Met/VEGFR-2 TK inhibitors. We introduced new synthetic methods for reported derivatives of 3-substituted quinazoline-2,4(1H,3H)-dione 2a-g, in addition to the preparation of some new derivatives namely, 3 and 4a-j. Three compounds namely, 2c, 4b, and 4e showed substantial amount of inhibition for both c-Met and VEGFR-2 TK (IC₅₀ range 0.052-0.084 µM). Both compounds 4b, 4e showed HB with highly conserved residue Asp1222 in the HB region of c-Met TK. For VEGFR-2 TK, compound 4b showed HB with a highly conserved residue Asp1046 in the HB region. Compound 4e showed HB with Glu885 and Asp1046. Moreover, in silico prediction of pharmacokinetic and physicochemical parameters of target compounds was carried out using SwissADME website. The quinazoline-2,4(1H,3H)-dione derivatives are promising antiproliferative candidates that require further optimisation.HighlightsNew 3-substituted quinazoline-2,4(1H,3H)-dione derivatives were synthesised and characterised.Compounds 4b and 4e showed higher cytotoxic activity than cabozantinib against HCT-116 colorectal cell lines.Both compounds 4b and 4e showed less toxicity to WI38 normal cell line compared to HCT 116 colon cancer cell line.Compound 4b was superior to cabozantinib in VEGFR-2 inhibition while compound 2c was equipotent to cabozantinib.Compounds 4b and 4e showed remarkable c-Met inhibitory activity.Compounds 4b and 4e arrested cell cycle and induced significant levels of apoptosis.In silico ADME prediction revealed high oral bioavailability and enhanced water solubility of target compounds as compared to cabozantinib.Target compounds interacted with both c-Met and VEGFR-2 active site in similar way to cabozantinib.

Autofluorescent Artemisinin-Benzimidazole Hybrids via Organo-Click Reaction: Study of Antiviral Properties and Mode of Action in Living Cells

Drug modification by a fluorescent label is a common tool for studying its mechanism of action with fluorescence microscopy techniques. However, the attachment of a fluorescent label can significantly alter the polarity, solubility, and biological activity of the investigated drug, and, as a result, the studied mechanism of action can be misrepresented. Therefore, developing efficient drugs, which are inherently fluorescent and can be tracked directly in the cell is highly favorable. Here an easy formation of fluorescent hybrid drugs is presented, generated by a combination of two readily available non-fluorescent pharmacophores via a non-cleavable linker using a Ramachary-Bressy-Wang organocatalyzed azide-carbonyl [3+2] cycloaddition (organo-click) reaction. All newly prepared fluorescent compounds showed strong anti-HCMV activity (EC50 down to 0.07±0.00 μM), thus presenting a very promising drug developmental basis compared to the approved drug ganciclovir (EC50 2.60±0.50 μM). Remarkably, in vitro fluorescent imaging investigation of new compounds revealed induced changes in mitochondrial structures, which is a phenotypical hallmark of antiviral activity. This approach opens up new vistas for the easy formation of potent fluorescent drugs from readily available non-fluorescent parent compounds and might facilitate insight into their mode of action in living cells, avoiding the requirement of linkage to external fluorescent markers.

Design, Synthesis and Biological Evaluation of Multi-Target Anti-Cancer Agent PYR26

This study investigates the synthesis of a new compound, PYR26, and the multi-target mechanism of PYR26 inhibiting the proliferation of HepG2 human hepatocellular carcinoma cells. PYR26 significantly inhibits the growth of HepG2 cells (p < 0.0001) and this inhibition has a concentration effect. There was no significant change in ROS release from HepG2 cells after PYR26 treatment. The mRNA expressions of CDK4, c-Met and Bak genes in HepG2 cells were significantly inhibited (p < 0.05), while mRNA expression of pro-apoptotic factors such as caspase-3 and Cyt c was significantly increased (p < 0.01). The expression of PI3K, CDK4 and pERK proteins decreased. The expression level of caspase-3 protein was increased. PI3K is a kind of intracellular phosphatidylinositol kinase. PI3K signaling pathway is involved in signal transduction of a variety of growth factors, cytokines and extracellular matrix and plays an important role in preventing cell apoptosis, promoting cell survival and influencing cell glucose metabolism. CDK4 is a catalytic subunit of the protein kinase complex and is important for G1 phase progression of the cell cycle. PERK refers to phosphorylated activated ERK, which is translocated from cytoplasm to the nucleus after activation, and then participates in various biological reactions such as cell proliferation and differentiation, cell morphology maintenance, cytoskeleton construction, cell apoptosis and cell canceration. Compared with the model group and the positive control group, the tumor volume of the nude mice in the low-concentration PYR26 group, the medium-concentration group and the high-concentration group was smaller, and the organ volume was smaller than that in the model group and the positive control group. The tumor inhibition rates of low-concentration group PYR26, medium-concentration group and high-concentration group reached 50.46%, 80.66% and 74.59%, respectively. The results showed that PYR26 inhibited the proliferation of HepG2 cells and induced apoptosis of HepG2 cells by down-regulating c-Met, CDK4 and Bak, up-regulating the mRNA expression of caspase-3 and Cyt c genes, down-regulating PI3K, pERK and CDK4 proteins and up-regulating the protein level of caspase-3. In a certain range, with the increase in PYR26 concentration, the tumor growth was slower and the tumor volume was smaller. Preliminary results showed that PYR26 also had an inhibitory effect on the tumors of Hepa1-6 tumor-bearing mice. These results suggest that PYR26 has an inhibitory effect on the growth of liver cancer cells, therefore it has potential to be developed into a new anti-liver cancer drug.

Design and synthesis of new quinoline derivatives as selective C-RAF kinase inhibitors with potent anticancer activity

This article describes the design, synthesis, and biological screening of a new series of diarylurea and diarylamide derivatives including quinoline core armed with dimethylamino or morpholino side chain. Fifteen target compounds were selected by the National Cancer Institute (NCI, USA) for in vitro antiproliferative screening against a panel of 60 cancer cell lines of nine cancer types. Compounds 1j-l showed the highest mean inhibition percentage values over the 60-cell line panel at 10 μM with broad-spectrum antiproliferative activity. Subsequently, compounds 1j-l were subjected to a dose-response study to measure their GI₅₀ and total growth inhibition (TGI) values against the cell lines. Three of the tested molecules exerted higher potency against most of the cell lines than the reference drug, sorafenib. Compound 1l indicated a higher potency than sorafenib against 53 of tested cancer cell lines. Compounds 1j-l demonstrated promising selectivity against cancer cells than normal cells. Moreover, compound 1l induced apoptosis and necrosis in RPMI-8226 cell line in a dose-dependent manner. In addition, compounds 1j-l were tested against C-RAF kinase as a potential molecular target. The three compounds showed high potency, and the most potent C-RAF kinase inhibitor was compound 1j with an IC₅₀ value of 0.067 μM. In addition, Compounds 1j-l were further tested at 1 μM concentration against a panel of another twelve kinases and they showed a high selectivity for C-RAF kinase. Molecular modeling studies were performed to illuminate on the putative binding interactions of these motifs in the active site of C-RAF kinase. Additional studies were conducted to measure aqueous solubility, partition coefficient, and Caco-2 permeability of the most promising derivatives.

The Design and Synthesis of a New Series of 1,2,3-Triazole-Cored Structures Tethering Aryl Urea and Their Highly Selective Cytotoxicity toward HepG2

Target cancer drug therapy is an alternative treatment for advanced hepatocellular carcinoma (HCC) patients. However, the treatment using approved targeted drugs has encountered a number of limitations, including the poor pharmacological properties of drugs, therapy efficiency, adverse effects, and drug resistance. As a consequence, the discovery and development of anti-HCC drug structures are therefore still in high demand. Herein, we designed and synthesized a new series of 1,2,3-triazole-cored structures incorporating aryl urea as anti-HepG2 agents. Forty-nine analogs were prepared via nucleophilic addition and copper-catalyzed azide-alkyne cycloaddition (CuAAC) with excellent yields. Significantly, almost all triazole-cored analogs exhibited less cytotoxicity toward normal cells, human embryonal lung fibroblast cell MRC-5, compared to Sorafenib and Doxorubicin. Among them, 2m’ and 2e exhibited the highest selectivity indexes (SI = 14.7 and 12.2), which were ca. 4.4- and 3.7-fold superior to that of Sorafenib (SI = 3.30) and ca. 3.8- and 3.2-fold superior to that of Doxorubicin (SI = 3.83), respectively. Additionally, excellent inhibitory activity against hepatocellular carcinoma HepG2, comparable to Sorafenib, was still maintained. A cell-cycle analysis and apoptosis induction study suggested that 2m’ and 2e likely share a similar mechanism of action to Sorafenib. Furthermore, compounds 2m’ and 2e exhibit appropriate drug-likeness, analyzed by SwissADME. With their excellent anti-HepG2 activity, improved selectivity indexes, and appropriate druggability, the triazole-cored analogs 2m’ and 2e are suggested to be promising candidates for development as targeted cancer agents and drugs used in combination therapy for the treatment of HCC.

Amidine- and Amidoxime-Substituted Heterocycles: Synthesis, Antiproliferative Evaluations and DNA Binding

The novel 1,2,3-triazolyl-appended N- and O-heterocycles containing amidine 4–11 and amidoxime 12–22 moiety were prepared and evaluated for their antiproliferative activities in vitro. Among the series of amidine-substituted heterocycles, aromatic diamidine 5 and coumarine amidine 11 had the most potent growth-inhibitory effect on cervical carcinoma (HeLa), hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (SW620), with IC₅₀ values in the nM range. Although compound 5 was toxic to non-tumor HFF cells, compound 11 showed certain selectivity. From the amidoxime series, quinoline amidoximes 18 and 20 showed antiproliferative effects on lung adenocarcinoma (A549), HeLa and SW620 cells emphasizing compound 20 that exhibited no cytostatic effect on normal HFF fibroblasts. Results of CD titrations and thermal melting experiments indicated that compounds 5 and 10 most likely bind inside the minor groove of AT-DNA and intercalate into AU-RNA. Compounds 6, 9 and 11 bind to AT-DNA with mixed binding mode, most probably minor groove binding accompanied with aggregate binding along the DNA backbone.

A Review: Discovering 1,3,4-oxadiazole and chalcone nucleus for cytotoxicity/EGFR inhibitory anticancer activity

INTRODUCTION

Cancer is reported to be one of the most life-threatening diseases. Major limitations of currently used anticancer agents are drug resistance, very small therapeutic index, and severe, multiple side effects.

OBJECTIVE

The current scenario necessitates developing new anticancer agents, acting on novel targets for effectively controlling cancer. The epidermal growth factor receptor is one such target, which is being explored for 1,3,4-oxadiazole and chalcone nuclei.

METHOD

Findings of different researchers working on these scaffolds have been reviewed and analyzed, and the outcomes were summarized. This review focuses on Structure-Activity Relationship studies (SARs) and computational studies of various 1,3,4-oxadiazole and chalcone hybrids/derivatives reported as cytotoxic/EGFR-TK inhibitory anticancer activity.

RESULT AND CONCLUSION

1,3,4-oxadiazole and chalcone hybrids/derivatives with varied substitutions are found to be effective pharmacophores in obtaining potent anticancer activity. Having done a thorough literature survey, we conclude that this review will surely provide firm and better insights to the researchers to design and develop potent hybrids/derivatives that inhibit EGFR.

1,2,3-Triazole-Containing Compounds as Anti-Lung Cancer Agents: Current Developments, Mechanisms of Action, and Structure-Activity Relationship

Lung cancer is the most common malignancy and leads to around one-quarter of all cancer deaths. Great advances have been achieved in the treatment of lung cancer with novel anticancer agents and improved technology. However, morbidity and mortality rates remain extremely high, calling for an urgent need to develop novel anti-lung cancer agents. 1,2,3-Triazole could be readily interact with diverse enzymes and receptors in organisms through weak interaction. 1,2,3-Triazole can not only be acted as a linker to tether different pharmacophores but also serve as a pharmacophore. This review aims to summarize the recent advances in 1,2,3-triazole-containing compounds with anti-lung cancer potential, and their structure-activity relationship (SAR) together with mechanisms of action is also discussed to pave the way for the further rational development of novel anti-lung cancer candidates.

New Members of the Cinchona Alkaloids Family: Assembly of the Triazole Heterocycle at the 6' Position

The substance class of the well-known Cinchona alkaloids is widened by 6′-Amino-cinchonine and 6′-Amino-cinchonidine, novel compounds which incorporate a primary amino function in the quinolinic ring system. These key intermediates open the field for a range of fruitful chemistry. Here is described a short and direct pathway for the synthesis of triazole containing derivatives of the above-mentioned substances using the [3 + 2] Huisgen cycloaddition. For this purpose, the amines were first converted into the corresponding azides. Based on this, non-substituted and silyl-protected triazoles were synthesized as examples. Furthermore, didehydrated derivatives of quincorine and quincoridine were used as addition partners, resulting in compounds that carry the quinuclidine ring of the cinchona alkaloids at both ends. Some of these compounds were examined radiographically to investigate the position of the quinuclidine ring to the triazole. The solid-state structures of compounds 10, 11 and 28 were determined by X-ray diffraction analyses.

Determining Essential Requirements for Fluorophore Selection in Various Fluorescence Applications Taking Advantage of Diverse Structure-Fluorescence Information of Chromone Derivatives

Herein, we report our work exploring the essential requirements for fluorophore selection during the development of various fluorescence applications. We assembled a library of chromone-derived fluorophores with diverse structure-fluorescence properties, which allowed us to choose the fluorophore pairs with similar structures but differing fluorescence properties and compared the performance of the selected fluorophore pairs in three types of commonly used fluorescence applications. We found that the selection standard of a suitable fluorophore is variable depending on the application. (1) In fluorescence imaging, fluorophores with strong and constant fluorescence under various conditions, such as a large pH range, are preferred. Notably, (2) in the detection of bioactive species, fluorophores with relatively lower fluorescence quantum yield favor the detection sensitivity. Furthermore, (3) in enzymatic assays employing fluorescence, the key parameter is the binding affinity between the fluorophore and the enzyme.

Quinoline-Based Molecules Targeting c-Met, EGF, and VEGF Receptors and the Proteins Involved in Related Carcinogenic Pathways

The quinoline ring system has long been known as a versatile nucleus in the design and synthesis of biologically active compounds. Currently, more than one hundred quinoline compounds have been approved in therapy as antimicrobial, local anaesthetic, antipsychotic, and anticancer drugs. In drug discovery, indeed, over the last few years, an increase in the publication of papers and patents about quinoline derivatives possessing antiproliferative properties has been observed. This trend can be justified by the versatility and accessibility of the quinoline scaffold, from which new derivatives can be easily designed and synthesized. Within the numerous quinoline small molecules developed as antiproliferative drugs, this review is focused on compounds effective on c-Met, VEGF (vascular endothelial growth factor), and EGF (epidermal growth factor) receptors, pivotal targets for the activation of important carcinogenic pathways (Ras/Raf/MEK and PI3K/AkT/mTOR). These signalling cascades are closely connected and regulate the survival processes in the cell, such as proliferation, apoptosis, differentiation, and angiogenesis. The antiproliferative biological data of remarkable quinoline compounds have been analysed, confirming the pivotal importance of this ring system in the efficacy of several approved drugs. Furthermore, in view of an SAR (structure-activity relationship) study, the most recurrent ligand–protein interactions of the reviewed molecules are summarized.

Design, synthesis and biological evaluation of novel N-sulfonylamidine-based derivatives as c-Met inhibitors via Cu-catalyzed three-component reaction

In our continuing efforts to develop novel c-Met inhibitors as potential anticancer candidates, a series of new N-sulfonylamidine derivatives were designed, synthesized via Cu-catalyzed multicomponent reaction (MCR) as the key step, and evaluated for their in vitro biological activities against c-Met kinase and four cancer cell lines (A549, HT-29, MKN-45 and MDA-MB-231). Most of the target compounds showed moderate to significant potency at both the enzyme-based and cell-based assay and possessed selectivity for A549 and HT-29 cancer cell lines. The preliminary SAR studies demonstrated that compound 26af (c-Met IC₅₀ = 2.89 nM) was the most promising compound compared with the positive foretinib, which exhibited the remarkable antiproliferative activities, with IC₅₀ values ranging from 0.28 to 0.72 μM. Mechanistic studies of 26af showed the anticancer activity was closely related to the blocking phosphorylation of c-Met, leading to cell cycle arresting at G2/M phase and apoptosis of A549 cells by a concentration-dependent manner. The promising compound 26af was further identified as a relatively selective inhibitor of c-Met kinase, which also possessed an acceptable safety profile and favorable pharmacokinetic properties in BALB/c mouse. The favorable drug-likeness of 26af suggested that N-sulfonylamidines may be used as a promising scaffold for antitumor drug development. Additionally, the docking study and molecular dynamics simulations of 26af revealed a common mode of interaction with the binding site of c-Met. These positive results indicated that compound 26af is a potential anti-cancer candidate for clinical trials, and deserves further development as a selective c-Met inhibitor.

Design, synthesis and biological evaluation of new Axl kinase inhibitors containing 1,3,4-oxadiazole acetamide moiety as novel linker

Using the principle of bioisosteric replacement, we present a structure-based design approach to obtain new Axl kinase inhibitors with significant activity at the kinase and cellular levels. Through a stepwise structure-activity relationships exploration, a series of 6,7-disubstituted quinoline derivatives, which contain 1,3,4-oxadiazol acetamide moiety as novel Linker, were ultimately synthesized with Axl as the primary target. Most of them exhibited moderate to excellent activity, with IC₅₀ values ranging from 0.032 to 1.54 μM against the tested cell lines. Among them, the most promising compound 47e, as an Axl kinase inhibitor (IC₅₀ = 10 nM), shows remarkable cytotoxicity against A549, HT-29, PC-3, MCF-7, H1975 and MDA-MB-231 cell lines. More importantly, 47e also shows a significant inhibitory effect on EGFR-TKI resistant NSCLC cell lines H1975/gefitinib. Meanwhile, this study provides a novel type of linker for Axl kinase inhibitors, namely 1,3,4-oxadiazol acetamide moiety, which is out of the scope of the "5- atoms role ".

1,2,3-Triazole-containing hybrids as potential anticancer agents: Current developments, action mechanisms and structure-activity relationships

Anticancer agents are critical for the cancer treatment, but side effects and the drug resistance associated with the currently used anticancer agents create an urgent need to explore novel drugs with low side effects and high efficacy. 1,2,3-Triazole is privileged building block in the discovery of new anticancer agents, and some of its derivatives have already been applied in clinics or under clinical trials for fighting against cancers. Hybrid molecules occupy an important position in cancer control, and hybridization of 1,2,3-triazole framework with other anticancer pharmacophores may provide valuable therapeutic intervention for the treatment of cancer, especially drug-resistant cancer. This review emphasizes the recent advances in 1,2,3-triazole-containing hybrids with anticancer potential, covering articles published between 2015 and 2019, and the structure-activity relationships, together with mechanisms of action are also discussed.

Design, synthesis, and biological evaluation of 4-((6,7-dimethoxyquinoline-4-yl)oxy)aniline derivatives as FLT3 inhibitors for the treatment of acute myeloid leukemia

FMS-like tyrosine kinase 3 (FLT3) was an important therapeutic target in acute myeloid leukemia (AML). We synthesized two series of 4-((6,7-dimethoxyquinoline-4-yl)oxy)aniline derivatives possessing the semicarbazide moiety and 2,2,2-trifluoro-N,N'-dimethylacetamide moiety as the linker. The cell proliferation assay in vitro against HL-60 and MV4-11 cell lines demonstrated that most series I compounds containing semicarbazide moiety had more potent than Cabozantinib. Furthermore, the enzyme assay showed that compound 12c and 12g were potent FLT3 inhibitors with IC₅₀ values of 312 nM and 384 nM, respectively. Following that, molecular docking analysis was also performed to determine possible binding mode between FLT3 and the target compound.

Design, synthesis and biological evaluation of novel benzimidazole amidines as potent multi-target inhibitors for the treatment of non-small cell lung cancer

A series of novel amidino 2-substituted benzimidazoles linked to 1,4-disubstituted 1,2,3-triazoles were synthesized by implementation of microwave and ultrasound irradiation in click reaction and subsequent condensation of thus obtained 4-(1,2,3-triazol-1-yl)benzaldehyde with o-phenylenediamines. In vitro antiproliferative screening of compounds performed on human cancer cell lines revealed that p-chlorophenyl-substituted 1,2,3-triazolyl N-isopropylamidine 10c and benzyl-substituted 1,2,3-triazolyl imidazoline 11f benzimidazoles had selective and potent cytostatic activities in the low nM range against non-small cell lung cancer cell line A549, which could be attributed to induction of apoptosis and primary necrosis. Additional Western blot analyses showed different mechanisms of cytostatic activity between compounds 10c and 11f that could be associated with the nature of aromatic substituent at 1-(1,2,3-triazolyl) and amidino moiety at C-5 position of benzimidazole ring. Specifically, compound 11f abrogated the activity of several protein kinases including TGM2, CDK9, SK1 and p38 MAPK, whereas compound 10c did not have profound effect on the activities of CDK9 and TGM2, but instead showed moderate downregulation of SK1 activity concomitant with a significant reduction in p38 MAPK. Further in silico structural analysis demonstrated that compound 11f bound slightly better to the ATP binding site of p38 MAPK compared to 10c, which correlated well with observed stronger decrement in the expression level of phospho-p38 MAPK elicited by 11f in comparison with 10c.