Design, synthesis, biological assessment, and in-Silico studies of 1,2,4-triazolo[1,5-a]pyrimidine derivatives as tubulin polymerization inhibitors

Organo NHC catalyzed aqueous synthesis of 4β-isoxazole-podophyllotoxins: in vitro anticancer, caspase activation, tubulin polymerization inhibition and molecular docking studies

We present, for the first time, the organo-N-heterocyclic carbene (NHC) catalyzed 1,3-dipolar cycloaddition of 4β-O-propargyl podophyllotoxin (1) with in situ aromatic nitrile oxides to afford regioselective 4β-isoxazolepodophyllotoxin hybrids (6a-n) in benign aqueous-organic media. Preliminary anticancer activity results showed that compound 6e displayed superior activity against MCF-7, HeLa and MIA PaCa2 human cell lines compared with podophyllotoxin. Compounds 6j and 6n showed greater activity against the MCF-7 cell line than the positive control. Caspase activation studies revealed that compound 6e at 20 μg ml-1 concentration had greater caspase 3/7 activation in MCF-7 and MIAPaCa2 cells than podophyllotoxin. Furthermore, in vitro tubulin polymerization inhibition studies revealed that compound 6e showed comparable activity with podophyllotoxin. Finally, in silico molecular docking studies of compounds 6e, 6j, 6n and podophyllotoxin on α,β-tubulin (pdb id 1SA0) revealed that compound 6n showed excellent binding energies and inhibition constants compared with podophyllotoxin.

Triazolopyrimidine Derivatives: An Updated Review on Recent Advances in Synthesis, Biological Activities and Drug Delivery Aspects

Molecules containing triazolopyrimidine core showed diverse biological activities, including anti-Alzheimer's, anti-diabetes, anti-cancer, anti-microbial, anti-tuberculosis, anti-viral, anti-malarial, anti-inflammatory, anti-parkinsonism, and anti-glaucoma activities. Triazolopyrimidines have 8 isomeric structures, including the most stable 1,2,4-triazolo[1,5- a] pyrimidine ones. Triazolopyrimidines were obtained by using various chemical reactions, including a) 1,2,4-triazole nucleus annulation to pyrimidine, b) pyrimidines annulation to 1,2,4-triazole structure, c) 1,2,4-triazolo[l,5-a] pyrimidines rearrangement, and d) pyrimidotetrazine rearrangement. This review discusses synthetic methods, recent pharmacological actions and drug delivery perspectives of triazolopyrimidines.

Discovery of novel tubulin CBSI from the indanone scaffold for the treatment of colorectal cancer

In view of the serious adverse reactions and clinical toxicity of first line therapy 5-fluorouracil and lack of small molecule therapeutics in colorectal cancer chemotherapy, a series of natural scaffold-based 3-arylindanone derivatives (9a-q) were designed, synthesized and evaluated as tubulin polymerization inhibitors targeting the colchicine site. The most potent colchicine binding site inhibitor (CBSI), (R)-9k, exhibited 14-38 times more dominant anti-proliferative activity against three colon cancer cell lines than 5-fluorouracil. Particularly, (R)-9k showed higher selectivity against human normal cells compared with 5-fluorouracil and colchicine, and displayed negligible cardiotoxicity through hERG assessment. Furthermore, the binding of (R)-9k to the colchicine site was strongly supported by EBI competition assay and (R)-9k inhibited more tubulin polymerization than colchicine. Besides, the mechanism of action and binding modes of (R)-9k were verified by molecular dynamics simulations and docking. Therefore, (R)-9k could be regarded as a promising CBSI for colorectal cancer therapy.

Design, synthesis, and biological investigation of selective human carbonic anhydrase II, IX, and XII inhibitors using 7-aryl/heteroaryl triazolopyrimidines bearing a sulfanilamide scaffold

A novel library of human carbonic anhydrase (hCA) inhibitors based on the 2-sulfanilamido[1,2,4]triazolo[1,5-a]pyrimidine skeleton modified at its 7-position was prepared by an efficient convergent procedure. These derivatives were evaluated in vitro for their inhibition properties against a representative panel of hCA isoforms (hCA I, II, IV, IX, and XII). The target tumour-associated isoforms hCA IX and XII were potently inhibited with KIs in the low nanomolar range of 5-96 nM and 4-72 nM, respectively. Compounds 1d, 1j, 1v, and 1x were the most potent hCA IX inhibitors with KIs of 5.1, 8.6, 4.7, and 5.1 nM, respectively. Along with derivatives 1d and 1j, compounds 1r and 1ab potently inhibited hCA XII isoform with KIs in a single-digit nanomolar range of 8.8, 5.4, 4.3, and 9.0 nM, respectively. Compounds 1e, 1m, and 1p exhibited the best selectivity against hCA IX and hCA XII isoforms over off-target hCA II, with selectivity indexes ranging from 5 to 14.

Pyrrolizine/indolizine-bearing (un)substituted isoindole moiety: design, synthesis, antiproliferative and MDR reversal activities, and in silico studies

Two new series of pyrrolizine/indolizine derivative-bearing (un)substituted isoindole moiety were designed and synthesized. The anticancer potential of the new compounds was evaluated against hepatocellular carcinoma (HepG-2), colorectal carcinoma, colon cancer (HCT-116), and breast cancer (MCF-7) cell lines. Compounds 6d and 6o were the most potent derivatives with IC50 values ranging from 6.02 to 13.87 μM against HePG-2, HCT-116, and MCF-7 cell lines. Moreover, methyl analog of the fluoro-substituted indolizine derivative 6m revealed significant antiproliferative activity against HePG-2, HCT-116, and MCF-7 cancer cell lines with IC50 values of 11.97, 28.37, and 19.87 μM, respectively. The most active anticancer analogs, 6d, 6m, and 6o, were inspected for their putative mechanism of action by estimating their epidermal growth factor receptor (EGFR) and cyclin-dependent kinase (CDK 2) inhibitory activities. Thus, compound 6o displayed the most inhibitory activity against EGFR and CDK 2 with IC50 values of 62 and 118 nM, respectively. Additionally, the quantitative real-time PCR analysis for the P-glycoprotein effect of compounds 6d, 6m, and 6o was performed, in which compound 6o illustrated significant down-regulation of P-gp against the HepG-2 cell line by 0.2732 fold. Mechanistic studies for the most active compounds involving the reversal doxorubicin (DOX) effect of compounds 6d, 6m, and 6o were performed, which illustrated cytotoxic activity with IC50 22.27, 3.88, and 8.79 μM, respectively. Moreover, the apoptotic activity of the most active derivative 6o on HCT-116 cancer cells showed accumulation in the G1 and S phases of the cell cycle.

Discovery of novel 2-(trifluoromethyl)quinolin-4-amine derivatives as potent antitumor agents with microtubule polymerization inhibitory activity

In this work, a series of 2-(trifluoromethyl)quinolin-4-amine derivatives were designed and synthesized through structural optimization strategy as a microtubule-targeted agents (MTAs) and their cytotoxicity activity against PC3, K562 and HeLa cell lines were evaluated. The half maximal inhibitory concentration (IC50) of 5e, 5f, and 5o suggested that their potency of anti-proliferative activities against HeLa cell lines were better than the combretastatin A-4. Compound 5e showed the higher anti-proliferative activity against PC3, K562 and HeLa in vitro with IC50 values of 0.49 µM, 0.08 µM and 0.01 µM, respectively. Further mechanism study indicated that the representative compound 5e was new class of tubulin inhibitors by EBI competition assay and tubulin polymerization assays, it is similar to colchicine. Immunofluorescence staining revealed that compound 5e apparently disrupted tubulin network in HeLa cells, and compound 5e arrested HeLa cells at the G2/M phase and induced cells apoptosis in a dose-dependent manner. Molecular docking results illustrated that the hydrogen bonds of represented compounds reinforced the interactions in the pocket of colchicine binding site. Preliminary results suggested that 5e deserves further research as a promising tubulin inhibitor for the development of anticancer agents.

The Effects of Novel Triazolopyrimidine Derivatives on H2S Production in Lung and Vascular Tonus in Aorta

INTRODUCTION

Hydrogen sulfide (H2S), known as a third gasotransmitter, is a signaling molecule that plays a regulatory role in physiological and pathophysiological processes. Decreased H2S levels were reported in inflammatory respiratory diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary hypertension. H2S donors or drugs that increase H2S have emerged as novel treatments for inflammatory respiratory diseases. We previously showed that resveratrol (RVT) causes vascular relaxation and antioxidant effects by inducing H2S production. In the current study, we synthesized a new molecule Cpd2, as an RVT analog. We examined the effect of Cpd2 and its precursor chalcone compound (Cpd1) on H2S formation under both healthy and oxidative stress conditions in the lung, as well as vascular relaxation in the aorta.

METHODS

Cpd2 synthesized from Cpd1 with microwaved in basic conditions. H2S formation was measured by H2S biosensor in the mice lungs under both healthy and pyrogallol-induced oxidative stress conditions in the presence/absence of H2S synthesis inhibitor aminooxyacetic acid (AOAA). The effect of compounds on vascular tonus is investigated in mice aorta by DMT myograph.

RESULTS

RVT and Cpd2 significantly increased l-cysteine (l-cys) induced-H2S formation in the lung homogenates of healthy mice, but Cpd1 did not. Superoxide anion generator pyrogallol caused a decrease in H2S levels in mice lungs and Cpd2 restored it. Inhibition of Cpd2-induced H2S formation by AOAA confirmed that Cpd2 increases endogenous H2S formation in both healthy and oxidative stress conditions. Furthermore, we found that both Cpd1 and Cpd2 (10-8-10-4 M) caused vascular relaxation in mice aorta.

DISCUSSION AND CONCLUSION

We found that Cpd2, a newly synthesized RVT analog, is an H2S-inducing molecule and vasorelaxant similar to RVT. Since H2S has antioxidant and anti-inflammatory effects, Cpd2 has a potential for the treatment of respiratory diseases where oxidative stress and decreased H2S levels are present.

New Thiazole Carboxamide Derivatives as COX Inhibitors: Design, Synthesis, Anticancer Screening, In Silico Molecular Docking, and ADME Profile Studies

The goal of this work was to create and test a new series of thiazole carboxamide derivatives for their cyclooxygenase (COX) suppressor and anticancer effects. The compounds were characterized using 1H, 13C NMR, and HRMS spectrum analysis, and their selectivity toward COX-1 and COX-2 was assessed using an in vitro COX inhibition assay kit. Cytotoxicity was assessed using an MTS assay against a panel of cancer and normal cell lines. The docking studies were aided by the Prime MM-GBSA method for estimating binding affinities. The density functional theory (DFT) analysis was performed to assess compound chemical reactivity, which was calculated by computing the border orbital energy of both HOMO and LUMO orbitals, as well as the HOMO-LUMO energy gap. For ADME-T analysis, the QiKProp module was employed. Furthermore, using human X-ray crystal structures, molecular docking studies were carried out to discover the probable binding patterns of these drugs within both COX-1 and COX-2 isozymes. The results demonstrated that the most effective compound against the COX-1 enzyme was 2b with an IC50 of 0.239 μM. It also showed potent activity against COX-2 with an IC50 value of 0.191 μM and a selectivity ratio of 1.251. The highest selectivity ratio was 2.766 for compound 2a against COX-2 with an IC50 dose of 0.958 μM relating to the celecoxib ratio of 23.8 and its IC50 against COX-2 of 0.002 μM. Compound 2j also showed good selectivity toward COX-2 (1.507) with an IC50 value of 0.957 μM. All compounds showed negligible cytotoxic activity against the evaluated normal cell lines, and the IC50 values were more than 300 μM, except for compound 2b, whose IC50 values were 203.71 ± 1.89 and 116.96 ± 2.05 μM against LX-2 and Hek293t cell lines, respectively. Moreover, compound 2b showed moderate anticancer activity against COLO205 and B16F1 cancer cell lines with IC50 values of 30.79 and 74.15 μM, respectively.

Experimental Design of D-α-tocopherol polyethylene glycol 1000 succinate Stabilized Bile Salt Based Nano-vesicles for Improved Cytotoxicity and Bioavailability of Colchicine Binding Site Inhibitor Candidates: In Vitro, In silico, and Pharmacokinetic Studies

Nowadays, conventional anticancer therapy suffers many pitfalls, including drastic side effects and limited therapeutic efficacy resulting from diminished oral bioavailability. So, in an attempt to enhance their poor solubility and oral bioavailability along with the cytotoxic activity, the developed lead compounds (C1 and C2) were loaded in D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) modified vesicles adopting thin film hydration technique. The formulations of the aforementioned candidates (F1 and F2, respectively) were elected as the optimum formula with desirability values of 0.701 and 0.618, respectively. Furthermore, an outstanding enhancement in the drug's cytotoxic activity against different cancer cell lines (MCF-7, HepG-2, MDA-MB-321, A375, and MGC-803) after being included in the nano-TPGS-modified optimum formula was noticed relative to the unformulated compounds. The formula F1 showed the best cytotoxic activities against HepG-2 with an IC₅₀ = 3 µM. Furthermore, regarding MCF-7, F1 was shown to be the most potent and protective among all the tested formulations with an IC₅₀ = 6 µM. Besides, F1 exerted the best caspase 3/7 activity stimulation (around a 5-folds increase) compared to control in the MCF-7 cell line. Notably, it was disclosedthat both C1 and C2 induced cell cycle arrest at the resting S growth phase. Moreover, C1 and C2 decreased tubulin concentrations by approximately 2-folds and 6-folds, respectively. Meanwhile, the conducted molecular docking studies ensure the eligible binding affinities of the assessed compounds. Besides, MD simulations were performed for 1000 ns to confirm the docking results and study the exact behavior of the target candidates (C1 and C2) toward the CBS.

Triazole-fused pyrimidines in target-based anticancer drug discovery

In recent decades, the development of targeted drugs has featured prominently in the treatment of cancer, which is among the major causes of mortality globally. Triazole-fused pyrimidines, a widely-used class of heterocycles in medicinal chemistry, have attracted considerable interest as potential anticancer agents that target various cancer-associated targets in recent years, demonstrating them as valuable templates for discovering novel anticancer candidates. The current review concentrates on the latest advancements of triazole-pyrimidines as target-based anticancer agents, including works published between 2007 and the present (2007-2022). The structure-activity relationships (SARs) and multiple pathways are also reviewed to shed light on the development of more effective and biotargeted anticancer candidates.

An update on the recent advances and discovery of novel tubulin colchicine binding inhibitors

Microtubules, formed by α- and β-tubulin heterodimer, are considered as a major target to prevent the proliferation of tumor cells. Microtubule-targeted agents have become increasingly effective anticancer drugs. However, due to the relatively sophisticated chemical structure of taxane and vinblastine, their application has faced numerous obstacles. Conversely, the structure of colchicine binding site inhibitors (CBSIs) is much easier to be modified. Moreover, CBSIs have strong antiproliferative effect on multidrug-resistant tumor cells and have become the mainstream research orientation of microtubule-targeted agents. This review focuses mainly on the recent advances of CBSIs during 2017-2022, attempts to depict their biological activities to analyze the structure-activity relationships and offers new perspectives for designing next generation of novel CBSIs.

Recent Advances of Tubulin Inhibitors Targeting the Colchicine Binding Site for Cancer Therapy

Cancer accounts for numerous deaths each year, and it is one of the most common causes of death worldwide, despite many breakthroughs in the discovery of novel anticancer candidates. Each new year the FDA approves the use of new drugs for cancer treatments. In the last years, the biological targets of anticancer agents have started to be clearer and one of these main targets is tubulin protein; this protein plays an essential role in cell division, as well as in intracellular transportation. The inhibition of microtubule formation by targeting tubulin protein induces cell death by apoptosis. In the last years, numerous novel structures were designed and synthesized to target tubulin, and this can be achieved by inhibiting the polymerization or depolymerization of the microtubules. In this review article, recent novel compounds that have antiproliferation activities against a panel of cancer cell lines that target tubulin are explored in detail. This review article emphasizes the recent developments of tubulin inhibitors, with insights into their antiproliferative and anti-tubulin activities. A full literature review shows that tubulin inhibitors are associated with properties in the inhibition of cancer cell line viability, inducing apoptosis, and good binding interaction with the colchicine binding site of tubulin. Furthermore, some drugs, such as cabazitaxel and fosbretabulin, have been approved by FDA in the last three years as tubulin inhibitors. The design and development of efficient tubulin inhibitors is progressively becoming a credible solution in treating many species of cancers.

Design, Synthesis and Biological Investigation of 2-Anilino Triazolopyrimidines as Tubulin Polymerization Inhibitors with Anticancer Activities

A further investigation aiming to generate new potential antitumor agents led us to synthesize a new series of twenty-two compounds characterized by the presence of the 7-(3',4',5'-trimethoxyphenyl)-[1,2,4]triazolo[1,5-a]pyrimidine pharmacophore modified at its 2-position. Among the synthesized compounds, three were significantly more active than the others. These bore the substituents p-toluidino (3d), p-ethylanilino (3h) and 3',4'-dimethylanilino (3f), and these compounds had IC50 values of 30-43, 160-240 and 67-160 nM, respectively, on HeLa, A549 and HT-29 cancer cells. The p-toluidino derivative 3d was the most potent inhibitor of tubulin polymerization (IC50: 0.45 µM) and strongly inhibited the binding of colchicine to tubulin (72% inhibition), with antiproliferative activity superior to CA-4 against A549 and HeLa cancer cell lines. In vitro investigation showed that compound 3d was able to block treated cells in the G2/M phase of the cell cycle and to induce apoptosis following the intrinsic pathway, further confirmed by mitochondrial depolarization and caspase-9 activation. In vivo experiments conducted on the zebrafish model showed good activity of 3d in reducing the mass of a HeLa cell xenograft. These effects occurred at nontoxic concentrations to the animal, indicating that 3d merits further developmental studies.

Design, Synthesis and Biological Evaluation of [1,2,4]Triazolo[1,5-a]pyrimidine Indole Derivatives against Gastric Cancer Cells MGC-803 via the Suppression of ERK Signaling Pathway

[1,2,4]Triazolo[1,5-a]pyrimidine and indole skeletons are widely used to design anticancer agents. Therefore, in this work, a series of [1,2,4]triazolo[1,5-a]pyrimidine indole derivatives were designed and synthesized by the molecular hybridization strategy. The antiproliferative activities of the target compounds H1-H18 against three human cancer cell lines, MGC-803, HCT-116 and MCF-7, were tested. Among them, compound H12 exhibited the most active antiproliferative activities against MGC-803, HCT-116 and MCF-7 cells, with IC₅₀ values of 9.47, 9.58 and 13.1 μM, respectively, which were more potent than that of the positive drug 5-Fu. In addition, compound H12 could dose-dependently inhibit the growth and colony formation of MGC-803 cells. Compound H12 exhibited significant inhibitory effects on the ERK signaling pathway, resulting in the decreased phosphorylation levels of ERK1/2, c-Raf, MEK1/2 and AKT. Furthermore, compound 12 induced cell apoptosis and G2/M phase arrest, and regulated cell cycle-related and apoptosis-related proteins in MGC-803 cells. Taken together, we report here that [1,2,4]triazolo[1,5-a]pyrimidine indole derivatives, used as anticancer agents via the suppression of ERK signaling pathway and the most active compound, H12, might be a valuable hit compound for the development of anticancer agents.