Synthesis, biological evaluation, and molecular modelling of new naphthalene-chalcone derivatives as potential anticancer agents on MCF-7 breast cancer cells by targeting tubulin colchicine binding site

A Novel 2-Methoxyestradiol Derivative: Disrupting Mitosis Inhibiting Cell Motility and Inducing Apoptosis in HeLa Cells In Vitro

The clinical application of 2-methoxyestradiol (2ME) in cancer therapy has been limited by its low solubility and rapid metabolism. Derivatives of 2ME have been synthesised to enhance bioavailability and decrease hepatic metabolism. Compound 4a, an analog of 2ME, has demonstrated exceptional pharmacological activity, in addition to promising pharmacokinetic profile. Our study, therefore, aimed at exploring the anticancer effects of 4a on the cervical cancer cell line, HeLa. Compound 4a exhibited a significant and dose-dependent antimetastatic and antiinvasive impact on HeLa cells, as determined by wound-healing and Boyden chamber assays, respectively. Hoechst/Propidium iodide (HOPI) double staining showcased a substantial induction of apoptosis via 4a, with minimal necrotic effect. Flow cytometry revealed a significant G2/M phase arrest, accompanied by a noteworthy rise in the sub-G1 cell population, indicating apoptosis, 18 h post-treatment. Moreover, a cell-independent tubulin polymerisation assay illustrated compound 4a's ability to stabilise microtubules by promoting tubulin polymerisation. Molecular modelling experiments depicted that 4a interacts with the colchicine-binding site, nestled between the α and β tubulin dimers. Furthermore, 4a displayed an affinity for binding to and activating ER-α, as demonstrated by the luciferase reporter assay. These findings underscore the potential of 4a in inhibiting HPV18+ cervical cancer proliferation and cellular motility.

Current scenario of chalcone hybrids with antibreast cancer therapeutic applications

Breast cancer, an epithelial malignant tumor that occurs in the terminal ducts of the breast, is the most common female malignancy. Currently, approximately 70%-80% of breast cancer with early-stage, nonmetastatic disorder is curable, but the emergency of drug resistance often leads to treatment failure. Moreover, advanced breast cancer with distant organ metastases is incurable with the available therapeutics, creating an urgent demand to explore novel antibreast cancer agents. Chalcones, the precursors for flavonoids and isoflavonoids, exhibit promising activity against various breast cancer hallmarks, inclusive of proliferation, angiogenesis, invasion, metastasis, inflammation, stemness, and regulation of cancer epigenetics, representing useful scaffolds for the discovery of novel antibreast cancer chemotherapeutic candidates. In particular, chalcone hybrids could act on two or more different biological targets simultaneously with more efficacy, lower toxicity, and less susceptibility to resistance. Accordingly, there is a huge scope for application of chalcone hybrids to tackle the present difficulties in breast cancer therapy. This review outlines the chalcone hybrids with antibreast cancer potential developed from 2018. The structure-activity relationships as well as mechanisms of action are also discussed to shed light on the development of more effective and multitargeted chalcone candidates.

Synthesis of chalcone derivatives by Claisen-Schmidt condensation and in vitro analyses of their antiprotozoal activities

Chalcone is a molecule with known biological activities. Based on this, a series of chalcone derivatives bearing methyl, phenyl or furanyl substituents at different positions of A and B rings were synthesised, characterised, and evaluated regarding antiprotozoal activity. Molecules were synthesised via base catalyzed Claisen-Schmidt condensation and characterised by IR and NMR spectral data. Antiprotozoal activity against Phytomonas serpens, Leishmania amazonensis and Acanthamoeba polyphaga was performed. All compounds inhibited more than 50% of the growth of P. serpens while five had this effect on L. amazonensis and all of them no more than 35% of inhibition on A. polyphaga. Remarkably interesting antiprotozoal effects were recorded with compound 5, with IC50 of 1.59 µM for P. serpens and 11.49 µM for L. amazonensis. The addition of a naphthyl group to the B ring can be postulated to be the cause of the 10 times increase observed in its trypanocidal activity.

Chitosan-sulfonic acid-catalyzed green synthesis of naphthalene-based azines as potential anticancer agents

Aim: This study focuses on advancing green chemistry in anticancer drug discovery, particularly through the synthesis of azine derivatives with a naphthalene core using CS-SO3H as a catalyst. Methods: Novel benzaldazine and ketazine derivatives were synthesized using (E)-(naphthalen-1-ylmethylene)hydrazine and various carbonyl compounds. The methods employed included thermal and grinding techniques, utilizing CS-SO3H as an eco-friendly and cost-effective catalyst. Results: The approach resulted in high yields, short reaction times and demonstrated catalyst reusability. Cytotoxicity tests highlighted compounds 3b, 11 and 13 as potent against the HEPG2-1. Conclusion: This study successfully aligns with the objectives of eco-conscious drug development in organic chemistry. Molecular docking and in silico studies further indicate the potential of these ligands as antitumor medicines, with favorable oral bioavailability properties.

An update on the development on tubulin inhibitors for the treatment of solid tumors

INTRODUCTION

Microtubules play a vital role in cancer therapeutics. They are implicated in tumorigenesis, thus inhibiting tubulin polymerization in cancer cells, and have now become a significant target for anticancer drug development. A plethora of drug molecules has been crafted to influence microtubule dynamics and presently, numerous tubulin inhibitors are being investigated. This review discusses the recently developed inhibitors including natural products, and also examines the preclinical and clinical data of some potential molecules.

AREA COVERED

The current review article summarizes the development of tubulin inhibitors while detailing their specific binding sites. It also discusses the newly designed inhibitors that may be useful in the treatment of solid tumors.

EXPERT OPINION

Microtubules play a crucial role in cellular processes, especially in cancer therapy where inhibiting tubulin polymerization holds promise. Ongoing trials signify a commitment to revolutionizing cancer treatment and exploring targeted therapies. Challenges in microtubule modulation, like resistance and off-target effects, demand focused efforts, emphasizing combination therapies and personalized treatments. Beyond microtubules, promising avenues in cancer research include immunotherapy, genomic medicine, CRISPR gene editing, liquid biopsies, AI diagnostics, and stem cell therapy, showcasing a holistic approach for future advancements.

Tubulin inhibitors. Selected scaffolds and main trends in the design of novel anticancer and antiparasitic agents

Design of tubulin inhibitors as anticancer drugs dynamically developed over the past 20 years. The modern arsenal of potential tubulin-targeting anticancer agents is represented by small molecules, monoclonal antibodies, and antibody-drug conjugates. Moreover, targeting tubulin has been a successful strategy in the development of antiparasitic drugs. In the present review, an overall picture of the research and development of potential tubulin-targeting agents using small molecules between 2018 and 2023 is provided. The data about some most often used and prospective chemotypes of small molecules (privileged heterocycles, moieties of natural molecules) and synthetic methodologies (analogue-based, fragment-based drug design, molecular hybridization) applied for the design of novel agents with an impact on the tubulin system are summarized. The design and prospects of multi-target agents with an impact on the tubulin system were also highlighted. Reported in the review data contribute to the "structure-activity" profile of tubulin-targeting small molecules as anticancer and antiparasitic agents and will be useful for the application by medicinal chemists in further exploration, design, improvement, and optimization of this class of molecules.

Synthesis and Anti-Breast Cancer Potency of Mono- and Bis-(pyrazolyl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine) Derivatives as EGFR/CDK-2 Target Inhibitors

The target mono- and bis-(6-pyrazolyltriazolo-thiadiazine) derivatives 4a-c and 6a-d were synthesized using a straightforward protocol via reaction of 3-bromoacetylpyrazole 2 with 4-amino-s-triazole-3-thiols 3a-c and bis(4-amino-5-mercapto-s-triazol-3-yl)alkanes 5a-d, respectively. The bis(6-pyrazolyl-s-triazolo[3,4-b][1,3,4]thiadiazine) derivatives 8a,b and 10 were also constructed by reaction of the triazolo[3,4-b][1,3,4]thiadiazine-3-thiol 4c with the proper dibromo compounds 7a,b and 9, respectively. Structures of the new substances were determined by spectroscopic and analytical data. Compounds 4b, 4c, and 6a showed potent cytotoxicity against MCF-7 (IC50 = 3.16, 2.74, and 0.39 μM, respectively) and were safe against the MCF-10A cells. Compounds 4b, 4c, and 6a also showed promising dual EGFR and CDK-2 inhibition activities, particularly 6a was the most effective (IC50 = 19.6 and 87.9 nM, respectively), better than Erlotinib and Roscovitine. Compound 6a treatment induced EGFR and CDK-2 enzyme inhibition by 97.18% and 94.11%, respectively, at 10 μM (the highest concentration). Compound 6a notably induced cell apoptosis in MCF-7 cells, increasing the cell population by total apoptosis 43.3% compared to 1.29% for the untreated control group, increasing the cell population at the S-phase by 39.2% compared to 18.6% (control).

In silico, in vitro VEGFR-2 inhibition, and anticancer activity of a 3-(hydrazonomethyl)naphthalene-2-ol derivative

In agreement with the general features of VEGFR-2 inhibitors, a new naphthalene analog (compound 7) has been designed and synthesized. The inhibitory potential of compound 7 was indicated by the proper binding and the perfect energy of -21.10 kcal/mol compared to sorafenib (-21.22) in the molecular docking studies. Next, six MD simulation studies over 100 ns (RMSD, RMSF, SASA, RoG, hydrogen bonding, and distance between the center of mass) confirmed the accurate interaction of compound 7 with the catalytic pocket of VEGFR-2. Similarly, an MM-GBSA established proper binding showing an exact total binding energy of -36.95 ± 3.03 kcal/Mol. Additionally, the MM-GBSA experiment indicated the vital amino acids in the binding process. Types and number of interactions of compound 7 with catalytic pocket of VEGFR-2 were determined through Protein-Ligand Interaction Profiler (PLIP). As a new compound, the DFT was employed to optimize the molecular structure of compound 7. The DFT experiments also verified the interaction features of compound 7 with the VEGFR-2 active site. In silico ADMET experiments revealed the general drug-likeness of compound 7. Fascinatingly, the in vitro examinations were consistent with the in silico experiments as compound 7 inhibited the VEGFR-2 enzyme with an IC50 value of 37 nM. Captivatingly, compound 7 inhibited both MCF-7 and HCT 116 cancer cells exhibiting IC50 values of 10.56 and 7.07 µM exhibiting excellent selectivity indexes of 9.04 and 13.50, respectively.Communicated by Ramaswamy H. Sarma.

Synthesis of novel mono- and bis-pyrazolylthiazole derivatives as anti-liver cancer agents through EGFR/HER2 target inhibition

3-Bromoacetyl-4-(2-naphthoyl)-1-phenyl-1H-pyrazole (6) was synthesized from 2-acetylnaphthalene and was used as a new key building block for constructing the title targets. Thus, the reaction of 6 with the thiosemicarbazones 7a-d and 9-11 afforded the corresponding simple naphthoyl-(3-pyrazolyl)thiazole hybrids 8a-d and 12 ~ 14. The symmetric bis-(2-naphthoyl-pyrazol-3-yl)thiazol-2-yl)hydrazono)methyl)phenoxy)alkanes 18a-c and 21a-c were similarly synthesized from reaction of 6 with the appropriate bis-thiosemicarbazones 17a-c and 19a-c, respectively. The synthesized two series of simple and symmetrical bis-molecular hybrid merging naphthalene, thiazole, and pyrazole were evaluated for their cytotoxicity. Compounds 18b,c and 21a showed the most potent cytotoxicity (IC₅₀ = 0.97-3.57 µM) compared to Lapatinib (IC₅₀ = 7.45 µM). Additionally, they were safe (non-cytotoxic) against the THLE2 cells with higher IC₅₀ values. Compounds 18c exhibited promising EGFR and HER-2 inhibitory activities with IC₅₀ = 4.98 and 9.85 nM, respectively, compared to Lapatinib (IC₅₀ = 6.1 and 17.2 nM). Apoptosis investigation revealed that 18c significantly activated apoptotic cell death in HepG2 cells, increasing the death rate by 63.6-fold and arresting cell proliferation at the S-phase. Compound 18c upregulated P53 by 8.6-fold, Bax by 8.9-fold, caspase-3,8,9 by 9, 2.3, and 7.6-fold, while it inhibited the Bcl-2 expression by 0.34-fold. Thereby, compound 18c exhibited promising cytotoxicity against EGFR/HER2 inhibition against liver cancer.

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.

Design, synthesis, cytotoxic activities, and molecular docking of chalcone hybrids bearing 8-hydroxyquinoline moiety with dual tubulin/EGFR kinase inhibition

The present study established thirteen novel 8-hydroxyquinoline/chalcone hybrids3a-mof hopeful anticancer activity. According to NCI screening and MTT assay results, compounds3d-3f, 3i,3k,and3ldisplayed potent growth inhibition on HCT116 and MCF7 cells compared to Staurosporine. Among these compounds,3eand3fshowed outstanding superior activity against HCT116 and MCF7 cells and better safety toward normal WI-38 cells than Staurosporine. The enzymatic assay revealed that3e,3d, and3ihad goodtubulin polymerization inhibition (IC₅₀ = 5.3, 8.6, and 8.05 µM, respectively) compared to the reference Combretastatin A4 (IC₅₀ = 2.15 µM). Moreover,3e,3l, and3fexhibited EGFR inhibition (IC₅₀ = 0.097, 0.154, and 0.334 µM, respectively) compared to Erlotinib (IC₅₀ = 0.056 µM). Compounds3eand3fwere investigated for their effects on the cell cycle, apoptosis induction, andwnt1/β-cateningene suppression. The apoptosis markers Bax, Bcl2, Casp3, Casp9, PARP1, and β-actin were detected by Western blot. In-silico molecular docking, physicochemical, and pharmacokinetic studies were implemented for the validation of dual mechanisms and other bioavailability standards. Hence, Compounds3eand3fare promising antiproliferative leads with tubulin polymerization and EGFR kinase inhibition.

Synthesis, enzyme inhibition, and molecular docking studies of a novel chalcone series bearing benzothiazole scaffold

This study reports the facile synthesis of a novel series of benzothiazole-chalcones, in addition to their inhibitory profile on important metabolic enzymes including human carbonic anhydrases (hCA-I, hCA-II) and paraoxonase (PON-1). The inhibition parameters, IC₅₀ (concentration for 50% inhibition) and Ki (dissociation constant) values, toward the title enzymes were determined for the studied compounds. As a result, IC₅₀ values of hydratase activity were in the range 4.15-5.47 and 2.56-4.58 μM for hCA-I and hCA-II, respectively. At the same time, IC₅₀ values of esterase activity were in the range 24.91-104.00 and 35.25-97.00 μM, while Ki values were in the range 14.43-59.66 and 26.65-73.34 μM for hCA-I and hCA-II, respectively. In addition, PON-1 enzyme inhibition results showed interesting inhibitory effects, with IC₅₀ values between 13.28 and 16.68 μM. Finally, a comprehensive approach was established for the synthesized compounds based on theoretical calculations, which have been done using B3LYP, PBE0 theories and SVP, TVZP, TVZPP basis sets, followed by docking studies by which the outputs proved the harmonically flows with the experimental results.

In vivo Study of Chalcone Loaded Carbon Dots for Enhancement of Anticancer and Bioimaging Potencies

The fluorescent imaging and drug delivery utilizing carbon dots nanomaterials (CDs) have attracted tremendously due to their unique optical ability and outstanding biocompatibility. Herein, we reported a new design of chalcone-loaded carbon dots (Chalcone-APBA-CDs) to serve chalcone transport onto cancer cells and enhance the CDs bioimaging and antitumor activity. The boronic acid was directly introduced to carbon dots (CDs) via pyrolysis process to drive CDs specifically to the cancer cell, and chalcone was mediated on CDs by ultrasonication to perform facile release of the drug delivery model. The successfully synthesized Chalcone-APBA-CDs were proved by their chemical structure, fluorescent activities, in vitro and in vivo analyses, and drug release systems using different pH. In addition, flow cytometry and confocal fluorescent imaging proved CDs' cellular uptake and imaging performance. In vitro analyses further proved that the Chalcone-APBA-CDs exhibited a higher toxicity value than bare CDs and efficiently inhibited the proliferation of the HeLa cells depending on their dose-response. Finally, the performance of Chalcone-APBA-CDs on cancer healing capability was examined in vivo with fibrosarcoma cancer-bearing mice, which showed a remarkable ability to reduce the tumor volume compared with saline (control). This result strongly suggested that the Chalcone-APBA-CDs appear promising simultaneously as cancer cell imaging and drug delivery.

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.

1,3,4-Oxadiazole-naphthalene hybrids as potential VEGFR-2 inhibitors: design, synthesis, antiproliferative activity, apoptotic effect, and in silico studies

In the current work, some 1,3,4-oxadiazole-naphthalene hybrids were designed and synthesised as VEGFR-2 inhibitors. The synthesised compounds were evaluated in vitro for their antiproliferative activity against two human cancer cell lines namely, HepG-2 and MCF-7. Compounds that exhibited promising cytotoxicity (5, 8, 15, 16, 17, and 18) were further evaluated for their VEGFR-2 inhibitory activities. Compound 5 showed good antiproliferative activity against both cell lines and inhibitory effect on VEGFR-2. Besides, it induced apoptosis by 22.86% compared to 0.51% in the control (HepG2) cells. This apoptotic effect was supported by a 5.61-fold increase in the level of caspase-3 compared to the control cells. Moreover, it arrested the HepG2 cell growth mostly at the Pre-G1 phase. Several in silico studies were performed including docking, ADMET, and toxicity studies to predict binding mode against VEGFR-2 and to anticipate pharmacokinetic, drug-likeness, and toxicity of the synthesised compounds.

Chalcone: A Promising Bioactive Scaffold in Medicinal Chemistry

Chalcones are a class of privileged scaffolds with high medicinal significance due to the presence of an α,β-unsaturated ketone functionality. Numerous functional modifications of chalcones have been reported, along with their pharmacological behavior. The present review aims to summarize the structures from natural sources, synthesis methods, biological characteristics against infectious and non-infectious diseases, and uses of chalcones over the past decade, and their structure–activity relationship studies are detailed in depth. This critical review provides guidelines for the future design and synthesis of various chalcones. In addition, this could be highly supportive for medicinal chemists to develop more promising candidates for various infectious and non-infectious diseases.

Two Important Anticancer Mechanisms of Natural and Synthetic Chalcones

ATP-binding cassette subfamily G and tubulin pharmacological mechanisms decrease the effectiveness of anticancer drugs by modulating drug absorption and by creating tubulin assembly through polymerization. A series of natural and synthetic chalcones have been reported to have very good anticancer activity, with a half-maximal inhibitory concentration lower than 1 µM. By modulation, it is observed in case of the first mechanism that methoxy substituents on the aromatic cycle of acetophenone residue and substitution of phenyl nucleus by a heterocycle and by methoxy or hydroxyl groups have a positive impact. To inhibit tubulin, compounds bind to colchicine binding site. Presence of methoxy groups, amino groups or heterocyclic substituents increase activity.

Evaluation of 3,5-Diphenyl-2-Pyrazolines for Antimitotic Activity by Inhibition of Tubulin Polymerization

Chalcones have a skeleton of diphenyls connected via an α,β-unsaturated carbonyl group. Many chalcone derivatives have been shown to interact with tubulin. Based on previous reports, chalcones derived by substitution of a carbonyl group with 2-pyrazoline can be expected to inhibit tubulin polymerization. Therefore, 3,5-diphenyl-2-pyrazolines were prepared to investigate their ability to inhibit tubulin polymerization. The clonogenic long-term survival assay showed that derivative 4, 5-(3,5-dimethoxyphenyl)-3-(2-methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide, was the most effective at inhibiting the clonogenicity of HCT116 human colon cancer cells. Derivative 4 induced G2/M cell cycle arrest. In addition, derivative 4 caused dispersed microtubules, a disorganized spherical arrangement of chromosomes, and inhibition of mitotic spindle formation. The binding mode between tubulin and derivative 4 was elucidated by in silico molecular docking. Derivative 4 was superimposed with colchicine and entered the colchicine-binding site well. These results suggest that derivative 4 inhibits tubulin polymerization by binding to the colchicine binding site of tubulin, thus preventing mitotic spindle formation during mitosis in HCT116 colon cancer cells. We propose that derivative 4 could be used as a promising antimitotic chemotherapeutic agent.

Design and Synthesis of Some New Furan-Based Derivatives and Evaluation of In Vitro Cytotoxic Activity

New furan-based derivatives have been, designed, synthesized, and evaluated for their cytotoxic and tubulin polymerization inhibitory activities. DNA flow cytometric study of pyridine carbohydrazide 4 and N-phenyl triazinone 7 demonstrated G₂/M phase cell cycle disruptions. Accumulation of cells in the pre-G1 phase and positive annexin V/PI staining, which may be caused by degeneration or fragmentation of the genetic components, suggested that cell death occurs via an apoptotic cascade. Furthermore, compounds 4 and 7 had a strong pro-apoptotic impact through inducing the intrinsic mitochondrial mechanism of apoptosis. This mechanistic route was verified by an ELISA experiment that indicated a considerable rise in the levels of p53 and Bax and a drop in the level of Bcl-2 when compared with the control.

A Review of the Recent Developments of Molecular Hybrids Targeting Tubulin Polymerization

Microtubules are cylindrical protein polymers formed from αβ-tubulin heterodimers in the cytoplasm of eukaryotic cells. Microtubule disturbance may cause cell cycle arrest in the G2/M phase, and anomalous mitotic spindles will form. Microtubules are an important target for cancer drug action because of their critical role in mitosis. Several microtubule-targeting agents with vast therapeutic advantages have been developed, but they often lead to multidrug resistance and adverse side effects. Thus, single-target therapy has drawbacks in the effective control of tubulin polymerization. Molecular hybridization, based on the amalgamation of two or more pharmacophores of bioactive conjugates to engender a single molecular structure with enhanced pharmacokinetics and biological activity, compared to their parent molecules, has recently become a promising approach in drug development. The practical application of combined active scaffolds targeting tubulin polymerization inhibitors has been corroborated in the past few years. Meanwhile, different designs and syntheses of novel anti-tubulin hybrids have been broadly studied, illustrated, and detailed in the literature. This review describes various molecular hybrids with their reported structural–activity relationships (SARs) where it is possible in an effort to generate efficacious tubulin polymerization inhibitors. The aim is to create a platform on which new active scaffolds can be modeled for improved tubulin polymerization inhibitory potency and hence, the development of new therapeutic agents against cancer.

Synthesis, Molecular Structure, Thermal and Spectroscopic Analysis of a Novel Bromochalcone Derivative with Larvicidal Activity

Chalcones belong to the flavonoids family and are natural compounds which show promising larvicidal property against Aedes aegypti larvae. Aiming to obtain a synthetic chalcone derivative with high larvicidal activity, herein, a bromochalcone derivative, namely (E)-3-(4-butylphenyl)-1-(4-bromophenyl)-prop-2-en-1-one (BBP), was designed, synthesized and extensively characterized by 1H- and 13C- nuclear magnetic resonance (NMR), infrared (IR), Raman spectroscopy, mass spectrometry (MS), ultraviolet–visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction. Further, the quantum mechanics calculations implemented at the B3LYP/6–311+G(d)* level of the theory indicate that the supramolecular arrangement was stabilized by C–H⋯O and edge-to-face C–H⋯π interactions. The EGAP calculated (3.97 eV) indicates a good reactivity value compared with other similar chalcone derivatives. Furthermore, the synthesized bromochalcone derivative shows promising larvicidal activity (mortality up to 80% at 57.6 mg·L−1) against Ae. aegypti larvae.

Novel chalcone-derived pyrazoles as potential therapeutic agents for the treatment of non-small cell lung cancer

Lung cancer is considered to account for approximately one-fifth of all malignant tumor-related deaths worldwide and is therefore one of the most lethal malignancies. Pyrazole scaffold possesses a wide range of biological and pharmacological activities, which play important roles in medicinal chemistry. The present study reports the synthesis and in vitro biological characterization of nine pyrazoles derived from chalcones as potential anticancer agents for non-small cell lung cancer A-549, H226, and H460 cell lines. Most of the compounds efficiently inhibited the growth of all the tested cancer cell lines at micromolar concentrations. One of the most active compounds (PCH-1) was further evaluated for its effect on cell cycle distribution, apoptosis, migration, epithelial–mesenchymal transition, and oxidative stress. Furthermore, studies on the mechanism of action revealed that PCH-1 disrupts microtubule assembly, leading to cancer cell death. Molecular modeling studies confirmed the potent interaction of PCH-1 with the vinblastine binding site on tubulin. Overall, this study provides novel opportunities to identify anticancer agents in the pyrazole series.

Synthesis and biological evaluation of halogenated phenoxychalcones and their corresponding pyrazolines as cytotoxic agents in human breast cancer

Novel halogenated phenoxychalcones 2a–f and their corresponding N-acetylpyrazolines 3a–f were synthesised and evaluated for their anticancer activities against breast cancer cell line (MCF-7) and normal breast cell line (MCF-10a), compared with staurosporine. All compounds showed moderate to good cytotoxic activity when compared to control. Compound 2c was the most active, with IC₅₀ = 1.52 µM and selectivity index = 15.24. Also, chalcone 2f showed significant cytotoxic activity with IC₅₀ = 1.87 µM and selectivity index = 11.03. Compound 2c decreased both total mitogen activated protein kinase (p38α MAPK) and phosphorylated enzyme in MCF-7 cells, suggesting its ability to decrease cell proliferation and survival. It also showed the ability to induce ROS in MCF-7 treated cells. Compound 2c exhibited apoptotic behaviour in MCF-7 cells due to cell accumulation in G2/M phase and elevation in late apoptosis 57.78-fold more than control. Docking studies showed that compounds 2c and 2f interact with p38alpha MAPK active sites.

A review on synthetic chalcone derivatives as tubulin polymerisation inhibitors

Microtubules play an important role in the process of cell mitosis and can form a spindle in the mitotic prophase of the cell, which can pull chromosomes to the ends of the cell and then divide into two daughter cells to complete the process of mitosis. Tubulin inhibitors suppress cell proliferation by inhibiting microtubule dynamics and disrupting microtubule homeostasis. Thereby inducing a cell cycle arrest at the G2/M phase and interfering with the mitotic process. It has been found that a variety of chalcone derivatives can bind to microtubule proteins and disrupt the dynamic balance of microtubules, inhibit the proliferation of tumour cells, and exert anti-tumour effects. Consequently, a great number of studies have been conducted on chalcone derivatives targeting microtubule proteins. In this review, synthetic or natural chalcone microtubule inhibitors in recent years are described, along with their structure-activity relationship (SAR) for anticancer activity.

Design, synthesis and biological evaluation of novel thiazole-naphthalene derivatives as potential anticancer agents and tubulin polymerisation inhibitors

A novel series of thiazole-naphthalene derivatives as tubulin polymerisation inhibitors were designed, synthesised, and evaluated for the anti-proliferative activities. The majority of the tested compounds exhibited moderate to potent antiproliferative activity on the MCF-7 and A549 cancer cell lines. Among them, compound 5b was found to be the most active compound with IC₅₀ values of 0.48 ± 0.03 and 0.97 ± 0.13 μM. Moreover, mechanistic studies revealed that 5b significantly inhibited tubulin polymerisation with an IC₅₀ value of 3.3 µM, as compared to the standard drug colchicine (IC₅₀ = 9.1 μM). Further cellular mechanism studies elucidated that 5b arrested the cell cycle at G2/M phase and induced apoptosis in MCF-7 cancer cells. Molecular modelling study indicated that 5b binds well to the colchicine binding site of tubulin. In summary, these results suggest that 5b represents a promising tubulin polymerisation inhibitor worthy of further investigation as potential anticancer agents.

Discovery of orally active chalcones as histone lysine specific demethylase 1 inhibitors for the treatment of leukaemia

Histone lysine specific demethylase 1 (LSD1) has emerged as an attractive molecule target for the discovery of potently anticancer drugs to treat leukaemia. In this study, a series of novel chalcone derivatives were designed, synthesised and evaluated for their inhibitory activities against LSD1 in vitro. Among all these compounds, D6 displayed the best LSD1 inhibitory activity with an IC₅₀ value of 0.14 μM. In the cellular level, compound D6 can induce the accumulation of H3K9me1/2 and inhibit cell proliferation by inactivating LSD1. It exhibited the potent antiproliferative activity with IC₅₀ values of 1.10 μM, 3.64 μM, 3.85 μM, 1.87 μM, 0.87 μM and 2.73 μM against HAL-01, KE-37, P30-OHK, SUP-B15, MOLT-4 and LC4-1 cells, respectively. Importantly, compound D6 significantly suppressed MOLT-4 xenograft tumour growth in vivo, indicating its great potential as an orally bioavailable candidate for leukaemia therapy.

Synthesis, biological evaluation and molecular docking investigation of new sulphonamide derivatives bearing naphthalene moiety as potent tubulin polymerisation inhibitors

A new series of sulphonamide derivatives bearing naphthalene moiety were synthesised and evaluated for their antiproliferative and tubulin polymerisation inhibitory activities. These new compounds were evaluated for their in vitro antiproliferative activity against MCF-7 and A549 by using CCK-8 method. Among all the tested compounds, compound 5c with naphthalen-1-yl moiety exhibited the most potent antiproliferative activity against MCF-7 and A549 cell line, with IC₅₀ values of 0.51 ± 0.03 µM and 0.33 ± 0.01 µM, respectively. The results of tubulin polymerisation assay shown that 5c exhibited a significant ability to inhibit tubulin polymerisation with IC₅₀ value of 2.8 μM. Consistent with its antitubulin activity, 5c can significantly arrest the cell cycle at G2/M phase and induce apoptosis in MCF-7 cancer cells. Molecular docking study indicated that compound 5c inhibited tubulin polymerisation through interacting at the colchicine-binding site of tubulin. Furthermore, 5c exhibited low cytotoxic activity on human normal cell line.

Synthesis and biological evaluation of chalcone-polyamine conjugates as novel vectorized agents in colorectal and prostate cancer chemotherapy

The aim of this study was to synthesize chalcone-polyamine conjugates in order to enhance bioavailability and selectivity of chalcone core towards cancer cells, using polyamine-based vectors. Indeed, it is well-known that polyamine transport system is upregulated in tumor cells. 3',4,4',5'-tetramethoxychalcone was selected as parent chalcone since it was found to be an efficient anti-proliferative agent on various cancer cells. A series of five chalcone-polyamine conjugates was obtained using the 4-bromopropyloxy-3',4',5'-trimethoxychalcone as a key intermediate. Chalcone core and polyamine tails were fused through an amine bond. These conjugates were found to possess a marked in vitro antiproliferative effect against colorectal (HT-29 and HCT-116) and prostate cancer (PC-3 and DU-145) cell lines. The most active conjugate (compound 8b) was then chosen for further biological evaluations to elucidate mechanisms responsible for its antiproliferative activity. Investigations on cell cycle distribution revealed that this conjugate can prevent the proliferation of human colorectal and prostate cancer cells by blocking the cell cycle at the G1 and G2 phase, respectively. Flow cytometry analysis revealed a sub-G1 peak, characteristic of apoptotic cell population and our inquiries highlighted apoptosis induction at early and later stages through several pro-apoptotic markers. Therefore, this chalcone-N1-spermidine conjugate could be considered as a promising agent for colon and prostatic cancer adjuvant therapy.

Synthesis and biological evaluation of new 2-methoxyestradiol derivatives: Potent inhibitors of angiogenesis and tubulin polymerization

Here, we report the structural optimization of a hit natural compound, 2-ME₂ (2-methoxyestradiol), which exhibited inhibitory activity but low potency on tubulin polymerization, anti- angiogenesis, MCF-7 proliferation and metastasis in vitro and in vivo. A novel series of 3,17-modified and 17-modified analogs of 2-ME₂ were synthesized and investigated for their antiproliferative activity against MCF-7 and another five different human cancer cell lines leading to the discovery of 9i. 9i bind to tubulin colchicine site tightly, inhibited tubulin polymerization and disrupted cellular microtubule networks. Cellular mechanism studies revealed that 9i could induce G2/M phase arrest by down-regulated expression of p-Cdc2, P21 and cell apoptosis by regulating apoptosis-related proteins (Parp, Caspase families) in a dose-dependent manner. Importantly, 9i significantly inhibited HUVEC tube formation, proliferation, migration and invasion. The inhibitory effect against angiogenesis in vivo was confirmed by zebrafish xenograft. Furthermore, 9i could effectively inhibit the proliferation and metastasis of MCF-7 cells in vitro and in zebrafish xenograft. The satisfactory physicochemical property and metabolic stability of 9i further indicated that it can act as a promising and potent anti-angiogenesis, inhibiting proliferation and metastasis of breast cancer agent via targeting tubulin colchicine binding site.

Tubulin Inhibitors: A Chemoinformatic Analysis Using Cell-Based Data

Inhibiting the tubulin-microtubules (Tub-Mts) system is a classic and rational approach for treating different types of cancers. A large amount of data on inhibitors in the clinic supports Tub-Mts as a validated target. However, most of the inhibitors reported thus far have been developed around common chemical scaffolds covering a narrow region of the chemical space with limited innovation. This manuscript aims to discuss the first activity landscape and scaffold content analysis of an assembled and curated cell-based database of 851 Tub-Mts inhibitors with reported activity against five cancer cell lines and the Tub-Mts system. The structure-bioactivity relationships of the Tub-Mts system inhibitors were further explored using constellations plots. This recently developed methodology enables the rapid but quantitative assessment of analog series enriched with active compounds. The constellations plots identified promising analog series with high average biological activity that could be the starting points of new and more potent Tub-Mts inhibitors.

Recent advances in research of colchicine binding site inhibitors and their interaction modes with tubulin

Microtubules have been a concerning target of cancer chemotherapeutics for decades, and several tubulin-targeted agents, such as paclitaxel, vincristine and vinorelbine, have been approved. The colchicine binding site is one of the primary targets on microtubules and possesses advantages compared with other tubulin-targeted agents, such as inhibitors of tumor vessels and overcoming P-glycoprotein overexpression-mediated multidrug resistance. This study reviews and summarizes colchicine binding site inhibitors reported in recent years with structural studies via the crystal structures of complexes or computer simulations to discover new lead compounds. We are attempting to resolve the challenge of colchicine site agent research.

Discovery of novel JAK2 and EGFR inhibitors from a series of thiazole-based chalcone derivatives

The Janus kinase (JAK) and epidermal growth factor receptor (EGFR) have been considered as potential targets for cancer therapy due to their role in regulating proliferation and survival of cancer cells. In the present study, the aromatic alkyl-amino analogs of thiazole-based chalcone were selected to experimentally and theoretically investigate their inhibitory activity against JAK2 and EGFR proteins as well as their anti-cancer effects on human cancer cell lines expressing JAK2 (TF1 and HEL) and EGFR (A549 and A431). In vitro cytotoxicity screening results demonstrated that the HEL erythroleukemia cell line was susceptible to compounds 11 and 12, whereas the A431 lung cancer cell line was vulnerable to compound 25. However, TF1 and A549 cells were not sensitive to our thiazole derivatives. From kinase inhibition assay results, compound 25 was found to be a dual inhibitor against JAK2 and EGFR, whereas compounds 11 and 12 selectively inhibited the JAK2 protein. According to the molecular docking analysis, compounds 11, 12 and 25 formed hydrogen bonds with the hinge region residues Lys857, Leu932 and Glu930 and hydrophobically came into contact with Leu983 at the catalytic site of JAK2, while compound 25 formed a hydrogen bond with Met769 at the hinge region, Lys721 near a glycine loop, and Asp831 at the activation loop of EGFR. Altogether, these potent thiazole derivatives, following Lipinski's rule of five, could likely be developed as a promising JAK2/EGFR targeted drug(s) for cancer therapy.

Novel piperidine derivatives as colchicine binding site inhibitors induce apoptosis and inhibit epithelial-mesenchymal transition against prostate cancer PC3 cells

Tubulin polymerisation inhibitors that target colchicine binding site were powerful anticancer agents. Although along the years many colchicine binding site inhibitors (CBSIs) have been reported, few piperidine derivatives were identified as CBSIs. In this regard, we focussed efforts on the piperidine as a promising chemotype to develop potent CBSIs. Herein, novel piperidine derivatives were synthesised and evaluated for their antiproliferative activities. Among them, compound 17a displayed powerful anticancer activity with the IC₅₀ value of 0.81 µM against PC3 cells, which was significantly better than 5-fluorouracil. It could inhibit tubulin polymerisation binding at the colchicine site and inhibit the tumour growth in vitro and in vivo. Further biological studies depicted that 17a suppressed the colony formation, induced apoptosis, and inhibited epithelial-mesenchymal transition against PC3 cells. These results revealed that compound 17a is a promising colchicine binding site inhibitor for the treatment of cancer and it is worthy of further exploitation.

Antiproliferative benzothiazoles incorporating a trimethoxyphenyl scaffold as novel colchicine site tubulin polymerisation inhibitors

Tubulin polymerisation inhibitors exhibited an important role in the treatment of patients with prostate cancer. Herein, we reported the medicinal chemistry efforts leading to a new series of benzothiazoles by a bioisosterism approach. Biological testing revealed that compound 12a could significantly inhibit in vitro tubulin polymerisation of a concentration dependent manner, with an IC₅₀ value of 2.87 μM. Immunofluorescence and EBI competition assay investigated that compound 12a effectively inhibited tubulin polymerisation and directly bound to the colchicine-binding site of β-tubulin in PC3 cells. Docking analysis showed that 12a formed hydrogen bonds with residues Tyr357, Ala247 and Val353 of tubulin. Importantly, it displayed the promising antiproliferative ability against C42B, LNCAP, 22RV1 and PC3 cells with IC₅₀ values of 2.81 μM, 4.31 μM, 2.13 μM and 2.04 μM, respectively. In summary, compound 12a was a novel colchicine site tubulin polymerisation inhibitor with potential to treat prostate cancer.

Design, Synthesis and Biological Evaluation of Novel 4-(4-Methoxynaphthalen-1-yl)-5-arylpyrimidin-2-amines as Tubulin Polymerization Inhibitors

A novel series of 4-(4-methoxynaphthalen-1-yl)-5-arylpyrimidin-2-amines were designed, synthesized, and evaluated for their anticancer activities. Most of the synthesized compounds exhibited moderate to high antiproliferative activity in comparison to the standard drug cisplatin. Among them, 5i bearing ethoxy at the 4-position of the phenyl was found to be the most active on MCF-7 and HepG2 cancer cell lines, with IC₅₀ values of 3.77 ± 0.36 and 3.83 ± 0.26 µM, respectively. Further mechanism study shown that 5i potently inhibited tubulin polymerization, induced cell cycle arrest at G2/M phase and cell apoptosis in MCF-7 cell line. Furthermore, molecular modeling study suggested that 5i probably binds to the colchicine site of tubulin.

A Comprehensive Review of Aminochalcones

Chalcones, members of the flavonoid family, display a plethora of interesting biological activities including but not limited to antioxidant, anticancer, antimicrobial, anti-inflammatory, and antiprotozoal activities. The literature cites the synthesis and activity of a range of natural, semisynthetic, and synthetic chalcones. The current review comprehensively covers the literature on amino-substituted chalcones and includes chalcones with amino-groups at various positions on the aromatic rings as well as those with amino-groups containing mono alkylation, dialkylation, alkenylation, acylation, and sulfonylation. The aminochalcones are categorized according to their structure, and the corresponding biological activities are discussed as well. Some compounds showed high potency against cancer cells, microbes, and malaria, whereas others did not. The purpose of this review is to serve as a one-stop location for information on the aminochalcones reported in the literature in recent years.

Development of pyridazine derivatives as potential EGFR inhibitors and apoptosis inducers: Design, synthesis, anticancer evaluation, and molecular modeling studies

Novel hybrids of pyridazine-pyrazoline were synthesized aiming to develop new antiproliferative candidates. All compounds were submitted to the National Cancer Institute (NCI), USA, and many were proved to have significant antiproliferative activity. In addition, in vitro studies of the epidermal growth factor receptor (EGFR) inhibition showed that compounds IXn, IXg, IXb and IXl exhibited excellent inhibitory effect (IC₅₀ = 0.65, 0.75, 0.82 and 0.84 μM, respectively) compared to Erlotinib (IC₅₀ = 0.95 μM). The mechanistic effectiveness in cell cycle progression, apoptotic induction and gene regulation were assessed for the promising compounds IXg and IXn due to their significant EGFR inhibition. Flow cytometeric analysis indicated that compounds IXg and IXn result in increased cell numbers in phase G2/M, suggesting cell cycle arrest in phase G2/M in UO-31cells. Furthermore, real time PCR assay illustrated that compounds IXg and IXn elevated Bax/Bcl2 ratio which confirmed the mechanistic pathway of them. Moreover, the apoptotic induction of UO-31 renal cancer cells was enhanced effectively through activation of caspase-3 by compounds IXg and IXn. On the other hand, molecular docking study was performed to investigate binding mode of interaction of compounds with EGFR-PK in the active site with the aim of rationalizing its promising inhibitory activity. Finally, based on the aforementioned findings, compounds IXg and IXn could be considered as effective apoptosis modulators and promising leads for future development of new anti-renal cancer agents.

Synthesis, antioxidant and anti-tyrosinase activity of 1,2,4-triazole hydrazones as antibrowning agents

A series of 1,2,4-triazole hydrazones (1-16) were synthesized, and their inhibitory activities and mechanisms on tyrosinase were investigated by ultraviolet spectrophotometry, fluorescence quenching, molecular docking study, etc. Most of compounds possessed potent tyrosinase inhibitory activity. Thereinto, compound 9 presented the superior activity with IC₅₀ of 0.9 μM, which was markedly lower than the standard kojic acid (IC₅₀ = 64.1 μM). Compound 9 not only interacted with copper ions in the active center of the enzyme but also bound to the enzyme-substrate complex, indicating that it was a competitive-noncompetitive mixed inhibitor. Additionally, it also displayed potent DPPH scavenging activity. Antibrowning test showed that compound 9 effectively reduced the enzymatic browning of fresh-cut potatoes. Furthermore, compound 9 exhibited low cytotoxic activity against human normal cell line with IC₅₀ of 49.9 µM. Overall, the present study suggests that these compounds may serve as lead molecules for developing novel antibrowning agents in food industry.

Cell Cycle Synchronization of the Murine EO771 Cell Line Using Double Thymidine Block Treatment

This study shows that double thymidine block treatment efficiently arrests the EO771 cells in the S-phase without altering cell growth or survival. A long-term analysis of cell behavior, using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) staining, show synchronization to be stable and consistent over time. The EO771 cell line is a medullary breast-adenocarcinoma cell line isolated from a spontaneous murine mammary tumor, and can be used to generate murine tumor implantation models. Different biological (serum or amino acid deprivation), physical (elutriation, mitotic shake-off), or chemical (colchicine, nocodazole, thymidine) treatments are widely used for cell synchronization. Of the different methods tested, the double thymidine block is the most efficient for synchronization of murine EO771 cells if a large quantity of highly synchronized cells is recommended to study functional and biochemical events occurring in specific points of cell cycle progression.

Ultrasounds-mediated 10-seconds synthesis of chalcones as potential farnesyltransferase inhibitors

A broad range of chalcones and derivatives were easily and rapidly synthesized, following Claisen-Schmidt condensation of (hetero)aryl ketones and (hetero)aryl aldehydes using a ultrasound probe. A comparison was made with classical magnetic stirring experiments, and an optimization study was realized, showing lithium hydroxide to be the best basic catalyst of the studied condensations. By-products of the reactions (β-hydroxy-ketone, diketones, and cyclohexanols) were also isolated. All compounds were evaluated in vitro for their ability to inhibit human farnesyltransferase, a protein implicated in cancer and rare diseases and on the NCI-60 cancer cell lines panel. Molecules showed inhibitory activity on the target protein and cytostatic effect on different cell lines with particular activity against MCF7, breast cancer cells.