Inhibition of epidermal growth factor receptor tyrosine kinase by chalcone derivatives

Design, Synthesis, and Mechanistic Anticancer Evaluation of New Pyrimidine-Tethered Compounds

Background: Despite recent breakthroughs in cancer treatment, non-small cell lung cancer (NSCLC) and breast cancer remain major causes of death from all malignancies. The epidermal growth factor receptor (EGFR) is an important mediator of the pathways involved in cell proliferation, apoptosis, and angiogenesis. Thus, its overexpression triggers several types of cancer, including NSCLC and breast cancer. Methods: In the current study, we synthesized new pyrimidine-tethered compounds (chalcone derivative (B-4), pyrazoline-carbothioamide (B-9), and pyrazoline-thiazole hybrids (BH1-7)). These compounds were then tested for cytotoxicity against A549 NSCLC and MCF-7 breast cancer cells. Results: Of these, B-4 displayed significant cytotoxicity against both cells (IC50 = 6.70 ± 1.02 µM for MCF-7; IC50 = 20.49 ± 2.7 µM for A549) compared to the standard agent lapatinib (IC50 = 9.71 ± 1.12 µM for MCF-7; IC50 = 18.21 ± 3.25 µM for A549). The anticancer potential of B-4 between Jurkat leukemic T cells and peripheral blood mononuclear cells (PBMCs) (healthy) was found to be selective. Mechanistically, 11.9% and 10.2% of A549 and MCF-7 cells treated with B-4, respectively, underwent apoptosis and B-4 produced 46% EGFR inhibition at a concentration of 10 μM. The B-4/EGFR complex obtained after induced fit docking was subjected to 300 ns of molecular dynamics simulation, which confirmed the stability of the complex in a mimicked biological environment. On the other hand, B-4 was shown to have drug-like properties by in silico pharmacokinetic estimation. Conclusions: B-4 is an EGFR inhibitor and apoptosis inducer for future NSCLC and breast cancer studies.

Phloretin inhibits transmissible gastroenteritis virus proliferation via multiple mechanisms

Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, has caused huge economic losses to the pig industry, with 100% mortality in piglets aged 2 weeks and intestinal injury in pigs of other ages. However, there is still a shortage of safe and effective anti-TGEV drugs in clinics. In this study, phloretin, a naturally occurring dihydrochalcone glycoside, was identified as a potent antagonist of TGEV. Specifically, we found phloretin effectively inhibited TGEV proliferation in PK-15 cells, dose-dependently reducing the expression of TGEV N protein, mRNA, and virus titer. The anti-TGEV activity of phloretin was furthermore refined to target the internalization and replication stages. Moreover, we also found that phloretin could decrease the expression levels of proinflammatory cytokines induced by TGEV infection. In addition, we expanded the potential key targets associated with the anti-TGEV effect of phloretin to AR, CDK2, INS, ESR1, ESR2, EGFR, PGR, PPARG, PRKACA, and MAPK14 with the help of network pharmacology and molecular docking techniques. Furthermore, resistant viruses have been selected by culturing TGEV with increasing concentrations of phloretin. Resistance mutations were reproducibly mapped to the residue (S242) of main protease (Mpro). Molecular docking analysis showed that the mutation (S242F) significantly disrupted phloretin binding to Mpro, suggesting Mpro might be a potent target of phloretin. In summary, our findings indicate that phloretin is a promising drug candidate for combating TGEV, which may be helpful for developing pharmacotherapies for TGEV and other coronavirus infections.

Design, In Silico Molecular Docking, and ADMET Prediction of Amide Derivatives of Chalcone Nucleus as EGFR Inhibitors for the Treatment of Cancer

BACKGROUND

Cancer is a devastating disease. Many studies have shown that the primary causes of the aggressive and resistant types of cancer are the overexpression of receptors and growth factors, activation of oncogenes, and the inactivation of tumour suppressor genes. One such receptor is the epidermal growth factor receptor (EGFR), which is used as a drug target for the treatment of cancer.

OBJECTIVE

This study aimed to develop the new chemical entities of amide derivatives of chalcone as EGFR inhibitors using structure-activity relationship (SAR) studies, molecular docking, and ADMET (absorption, distribution, metabolism, excretion, and toxicity) studies.

METHOD

New chemical entities (NCE) were designed based on literature findings. The Schrodinger 13.4 software was used for the molecular docking study. While Quickprop and Pro Tox-II online tools were used for ADME and toxicity prediction, respectively. .

RESULT

In this work, all compounds were subjected to an in-silico ADMET analysis. After pharmacokinetic and toxicity profile predictions, the molecules were further analysed by molecular docking. As a result of molecular docking, molecules AC9 and AC19 showed comparable docking scores compared to standard Afatinib.

CONCLUSION

Molecules AC9 and AC19 showed good docking scores and a promising ADMET profile. In the future, these derivatives can be further evaluated for wet lab studies and determination of their biological activity.

Hydroxy Chalcones and Analogs with Chemopreventive Properties

The aim of this review is to highlight the chemopreventive properties of hydroxy-substituted natural and synthetic chalcones along with a number of their analogs. These products display various biological activities, and have many applications against various diseases. Antioxidant and anti-inflammatory properties of chalcones bearing hydroxy substituents are underlined. The influence of hydroxy substituents located on ring A, B, or both are systematized according to the exhibited biological properties.

Identification of the structural features of quinazoline derivatives as EGFR inhibitors using 3D-QSAR modeling, molecular docking, molecular dynamics simulations and free energy calculations

Epidermal growth factor receptor (EGFR) is a promising target for the treatment of different types of malignant tumors. Therefore, a combined molecular modeling study was performed on a series of quinazoline derivatives as EGFR inhibitors. The optimum ligand-based CoMFA and CoMSIA models showed reliable and satisfactory predictability (with R²_cv=0.681, R²_ncv=0.844, R²_pred=0.8702 and R²_cv=0.643, R²_ncv=0.874, R²_pred=0.6423). The derived contour maps provide structural features to improve inhibitory activity. Furthermore, the contour maps, molecular docking, and molecular dynamics (MD) simulations have good consistency, illustrating that the derived models are reliable. In addition, MD simulations and binding free energy calculations were also carried out to understand the conformational fluctuations at the binding pocket of the receptor. The results indicate that hydrogen bond, hydrophobic and electrostatic interactions play significant roles on activity and selectivity. Furthermore, amino acids Val31, Lys50, Thr95, Leu149 and Asp160 are considered as essential residues to participate in the ligand-receptor interactions. Overall, this work would offer reliable theoretical basis for future structural modification, design and synthesis of novel EGFR inhibitors with good potency.Communicated by Ramaswamy H. Sarma.

Dihydroconiferyl Ferulate Isolated from Dendropanax morbiferus H.Lév. Suppresses Stemness of Breast Cancer Cells via Nuclear EGFR/c-Myc Signaling

Breast cancer is the leading cause of global cancer incidence and breast cancer stem cells (BCSCs) have been identified as the target to overcome breast cancer in patients. In this study, we purified a BCSC inhibitor from Dendropanax morbiferus H.Lév. leaves through several open column and high-performance liquid chromatography via activity-based purification. The purified cancer stem cell (CSC) inhibitor was identified as dihydroconiferyl ferulate using nuclear magnetic resonance and mass spectrometry. Dihydroconiferyl ferulate inhibited the proliferation and mammosphere formation of breast cancer cells and reduced the population of CD44^high/CD24^low cells. Dihydroconiferyl ferulate also induced apoptosis, inhibited the growth of mammospheres and reduced the level of total and nuclear EGFR protein. It suppressed the EGFR levels, the interaction of Stat3 with EGFR, and c-Myc protein levels. Our findings show that dihydroconiferyl ferulate reduced the level of nuclear epidermal growth factor receptor (EGFR) and induced apoptosis of BCSCs through nEGFR/Stat3-dependent c-Myc deregulation. Dihydroconiferyl ferulate exhibits potential as an anti-CSC agent through nEGFR/Stat3/c-Myc signaling.

Synthesis and studies of anticancer and antimicrobial activity of new phenylurenyl chalcone derivatives

Background:

Phenylurenyl chalcone structures have the potential to act as a scaffold in anticancer drug discovery.

Methods:

N-Phenethyl-N'-{4-[(2E)-3-phenylprop-2-enoyl]phenyl}urea, 4/3-[(2E)-3-substitutedphenylprop-2-enoyl]phenyl}-N-phenylurea,4/3-[(2E)-3-substitutedphenyl prop-2-enoyl]phenyl}-N-methylphenyl urea and {4/3-[(2E)-3-substitutedphenylprop-2-enoyl]phenyl}-N-ethylphenyl urea derivatives(1-35)were prepared and evaluated for their anticancer and antimicrobial activity against A-549 Hep-3B, HT-29, CF-7, PC-3, K-562 NIH-3T3 and Huh-7 cell lines and against Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 9027), Escherichia coli (ATCC 8739) and Candida albicans (ATCC 10231), respectively.

Results:

While compounds 2, 26, 29, and 34 showed moderate cytotoxic activity on cell line Huh 7, compounds 14 (IC50: 6.42 µM), 16 (IC50: 5.64 µM), 19 (IC50: 6.95 µM) and 34 (IC50: 6.87 µM) showed good cytotoxic activity on Huh-7 cell line close to Sorafenib (IC50: 4.29 µM) (as reference). MIC values of compounds 4 and 22 against E. coli were 25 μg/ml, of compounds 3, 14 and 29 against P. aeruginosa 25 μg/ml and of compounds 11 and 33 against S. aureus 25 μg/ml. On the other hand, the minimum inhibitory concentration of all tested compounds against C. albicans was 25 μg/ml.

Conclusion:

N-Phenethyl-N'-{4-[(2E)-3-phenylprop-2-enoyl]phenyl}urea may be a new candidate to be developed as an anticancer compound.

Molecular mechanisms underlying chemopreventive potential of butein: Current trends and future perspectives

Despite extensive efforts, cancer is still often considered as an incurable disease and initiation of novel drug development programs is crucial to improve the prognosis and clinical outcome of patients. One of the major approaches in designing the novel cancer drugs has historically comprised studies of natural agents with diverse anticancer properties. As only a marginal part of natural compounds has been investigated, this approach still represents an attractive source of new potential antitumor molecules. In this review article, different anticancer effects of plant-derived chalcone, butein, are discussed, including its growth inhibitory action, proapoptotic, antiangiogenic and antimetastatic activities in a variety of cancer cells. The molecular mechanisms underlying these effects are presented in detail, revealing interactions of butein with multiple cellular targets (Bcl-2/Bax, caspases, STAT3, cyclins, NF-κB, COX-2, MMP-9, VEGF/R etc.) and regulation of a wide range of intracellular signal transduction pathways. These data altogether allow a good basis for initiating further in vivo studies as well as clinical trials. Along with the efforts to overcome low bioavailability issues generally characteristic to plant metabolites, butein can be considered as a potential lead compound for safe and more efficient cancer drugs in the future.

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.

Cardamonin exerts a protective effect against autophagy and apoptosis in the testicles of diabetic male rats through the expression of Nrf2 via p62-mediated Keap-1 degradation

Cardamonin (CARD) is a chalconoid with anti-inflammatory and antioxidant properties, and it is present in several plants. We sought to explore whether CARD exerts any positive effects against hyperglycemia-induced testicular dysfunction caused by type 2 diabetes and aimed to identify its possible intracellular pathways. Adult male rats were subdivided into six groups: control, CARD, diabetic (DM), DM + glibenclamide (GLIB), DM + CARD and DM + GLIB + CARD. Type 2 DM induced a significant increase in blood glucose and insulin resistance, along with diminished serum insulin, testosterone and gonadotropins levels, which were associated with the impairment of key testicular androgenic enzymes and cellular redox balance. Administration of CARD at a dose of 80 mg/kg for 4 weeks effectively normalized all of these alterations, and the improvement was confirmed by epididymal sperm analysis. After treatment with CARD, the pathological changes in spermatogenic tubules were markedly improved. Significantly, CARD upregulated testicular glucose transporter-8 (GLUT-8) expression and had inhibitory effects on elevated autophagy markers and caspase-3 immunoreactive cells. Furthermore, our results revealed that CARD was able to attenuate damage via activation of Nrf2 through the p62-dependent degradation of testicular anti-Kelch-like ECH-associated protein-1 (Keap-1). In conclusion, this study suggests that CARD provides protection against diabetic stress-mediated testicular damage. The use of CARD with conventional anti-diabetic therapy was associated with improved efficacy compared with conventional therapy alone.

Phloretin, an Apple Polyphenol, Inhibits Pathogen-Induced Mucin Overproduction

SCOPE

Bacterial infection induces mucus overproduction, contributing to acute exacerbations and lung function decline in chronic respiratory diseases. A diet enriched in apples may provide protection from pulmonary disease development and progression. This study examined whether phloretin, an apple polyphenol, inhibits mucus synthesis and secretion induced by the predominant bacteria associated with chronic respiratory diseases.

METHODS AND RESULTS

The expression of mucus constituent mucin 5AC (MUC5AC) in FVB/NJ mice and NCI-H292 epithelial cells is analyzed. Nontypeable Haemophilus influenzae (NTHi)-infected mice developed increased MUC5AC mRNA, which a diet containing phloretin inhibited. In NCI-H292 cells, NTHi, Moraxella catarrhalis, Streptococcus pneumoniae, and Pseudomonas aeruginosa increased MUC5AC mRNA, which phloretin inhibited. Phloretin also diminished NTHi-induced MUC5AC protein secretion. NTHi-induced increased MUC5AC required toll-like receptor 4 (TLR4) and NADH oxidase 4 (NOX4) signaling and subsequent activation of the epidermal growth factor receptor (EGFR)/mitogen-activated protein kinase (MAPK) pathway. Phloretin inhibited NTHi-induced TLR4/NOX4 and EGFR/MAPK signaling, thereby preventing increased MUC5AC mRNA. EGFR activation can also result from increased EGFR ligand synthesis and subsequent ligand activation by matrix metalloproteinases (MMPs). In NCI-H292 cells, NTHi increased EGFR ligand and MMP1 and MMP13 mRNA, which phloretin inhibited.

CONCLUSIONS

In summary, phloretin is a promising therapeutic candidate for preventing bacterial-induced mucus overproduction.

Antiviral properties of chalcones and their synthetic derivatives: a mini review

Chalcones (natural or synthetic derivatives) are aromatic ketones possessing a central backbone that form a core for variety important compounds with different substitutions. Recent scientific advances show that chalcones exhibit different bio-medical activities, including antiviral, which is related to the variety substitutions. This review provides general information on the origin, sources, virucidal and direct antiviral properties of chalcones in vitro, as well as a brief overview of the possible application and molecular modes of action of these compounds. The antiviral effect of chalcones probably results from the disruption of the different stage of viral replication cycle, inhibition of viral or cell enzymes, induction of apoptosis and others. Structural requirements for antiviral activities vary according to the mechanisms of action. Based on the published information, it could be considered that synthetic chalcones are very perspective antiviral candidates and deserve further studies for elucidating of their pharmacological potential.

Molecular targets and anticancer activity of quinoline-chalcone hybrids: literature review

α,β-Unsaturated chalcone moieties and quinoline scaffolds play an important role in medicinal chemistry, especially in the identification and development of potential anticancer agents. The multi-target approach or hybridization is considered as a promising strategy in drug design and discovery. Hybridization may improve the affinity and potency while simultaneously decreasing the resistance and/or side effects. The conjugation of quinolines with chalcones has been a promising approach to the identification of potential anticancer agents. Most of these hybrids showed anticancer activities through the inhibition of tubulin polymerization, different kinases, topoisomerases, or by affecting DNA cleavage activity. Accordingly, this class of compounds can be classified based on their molecular modes of action. In this article, the quinolone-chalcone hybrids with potential anticancer activity have been reviewed. This class of compounds might be helpful for the design, discovery and development of new and potential multi-target anticancer agents or drugs.

Divergent Synthesis and Evaluation of the in vitro Cytotoxicity Profiles of 3,4-Ethylenedioxythiophenyl-2-propen-1-one Analogues

A new series of 3,4-ethylenedioxythiophene (EDOT)-appended propenones were prepared by condensation reaction and their in vitro cytotoxicity effects were evaluated against five human cancer cell lines. Preliminary structure-activity relationships of EDOT-incorporated 2-propenone derivatives were also established. The EDOT-appended enones demonstrated significant cytotoxicity against human cancer cell lines. The most active analogue, (E)-3-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3 p, GI₅₀ =110 nm), severely inhibited the clonogenic potential of cancer cells, and induced cell-cycle arrest in the G2/M phase and caused an accumulation of HCT116 colon cancer cells with >4 N DNA content. Also, 3 p exhibited weak inhibition of the enzymatic activity of human topoisomerase I. Molecular docking studies indicated preferential binding of the compounds to the ATP-binding pocket of the human checkpoint 2 kinase (Chk2) catalytic domain, thus, identifying a novel diaryl 2-propenone chemotype for the development of potent inhibitors of Chk2.

Substitution at Phenyl Rings of Chalcone and Schiff Base Moieties Accounts for their Antiproliferative Activity

BACKGROUND

In a continuous combat against cancer, which is one of the leading causes of mortality now, chalcone and Schiff bases moieties have been incorporated and their antiproliferative activities and associated mechanisms against liver (HepG2) and breast (MCF-7) cell lines in addition to normal fibroblasts (WI-38) have been examined.

METHODS

Derivatives 4 and 5 of Schiff bases only and chalcone derivatives of Schiff bases 1 and 2 were devoid of any antiproliferative activity. All three compounds (3, 6, and 7) with significant antiproliferative activity were selective and caused no growth inhibition in normal fibroblasts. Derivative 3 was a chalcone only with IC50 of ~20 µM and has a very interesting signature where it enhanced apoptosis in HepG2 by stimulating the expression of downstream execution caspase 3 without affecting neither p53 nor initiator caspase 9. In spite of the structural similarity between compounds 6 and 7, compound 6 discerned itself with a unique IC50 of ~ 10 µM.

RESULTS

The antiproliferative activity of derivative 6 could be attributed to its unique capability of formation of free radicals such as phenoxide radicals which arrested the cell cycle through enhancing the expression of p53 and induced apoptosis by induction of both caspases 9 and 3. It was the only investigated derivative that inhibited the tyrosine kinase activity by 89%.

CONCLUSIONS

The antiproliferative activity of the compounds under investigation considerably depended on the nature of the substituent at position 4 in phenyl rings of both chalcone and Schiff base fragments. Derivative 6 with electron withdrawing chlorine substitution on the phenyl ring of Schiff base fragment and an electron donating methoxy group on the phenyl ring of chalcone fragment was the most active member.

1,3,4-oxadiazole/chalcone hybrids: Design, synthesis, and inhibition of leukemia cell growth and EGFR, Src, IL-6 and STAT3 activities

A new series of 1,3,4-oxadiazole/chalcone hybrids was designed, synthesized, identified with different spectroscopic techniques and biologically evaluated as inhibitors of EGFR, Src, and IL-6. The synthesized compounds showed promising anticancer activity, particularly against leukemia, with 8v being the most potent. The synthesized compounds exhibited strong to moderate cytotoxic activities against K-562, KG-1a, and Jurkat leukemia cell lines in MTT assays. Compound 8v showed the strongest cytotoxic activity with IC₅₀ of 1.95 µM, 2.36 µM and 3.45 µM against K-562, Jurkat and KG-1a leukemia cell lines, respectively. Moreover; the synthesized compounds inhibited EGFR, Src, and IL-6. Compound 8v was most effective at inhibiting EGFR (IC₅₀ = 0.24 μM), Src (IC₅₀ = 0.96 μM), and IL-6 (% of control = 20%). Additionally, most of the compounds decreased STAT3 activation.

Butein suppresses hepatocellular carcinoma growth via modulating Aurora B kinase activity

Aurora B is aberrantly expressed in various tumors and shown to be a promising target for cancer therapy. Butein, a chalcone isolated from Rhus cerniciflua, has demonstrated antitumor activities in different cancers. In this study, we aimed to validate whether Aurora B kinase was the direct target of butein to exhibit its potency in hepatocellular carcinoma (HCC). Comparing with the normal cell line and tissue, Aurora B was overexpressed in all tested HCC cells and the majority of tumor tissue. Knocking down of Aurora B with shRNA substantially inhibited HCC cell proliferation, colony formation and delayed tumor growth in nude mice. Except computer docking, a series of kinase assays revealed butein directly interacted with Aurora B and inhibited its kinase activity. Along with the decrease of Aurora B and histone H3 phosphorylation, HCC cells were induced G2/M cell cycle arrest and subjected to cell apoptosis. Butein-mediated antitumor activities were substantially impaired in Aurora B knockdown cells, suggesting Aurora B was an important target of butein in HCC. Oral administration of butein substantially restrained HCC xenograft growth and the expressions of Ki67 and phosphor-histone H3 were significantly decreased in butein-treated tissue. To the best of our knowledge, our studies revealed that Aurora B was the direct target of butein in HCC.

Synthesis, Evaluation for Cytotoxicity and Molecular Docking Studies of Benzo[c]furan-Chalcones for Potential to Inhibit Tubulin Polymerization and/or EGFR-Tyrosine Kinase Phosphorylation

A series of 2-arylbenzo[c]furan-chalcone hybrids 3a⁻y have been synthesized and evaluated for antiproliferative effects against the human breast cancer (MCF-7) cell line and for its potential to induce apoptosis and also to inhibit tubulin polymerization and/or epidermal growth factor receptor-tyrosine kinase (EGFR-TK) phosphorylation. Most of these compounds exhibited moderate to significant antigrowth effects in vitro against the MCF-7 cell line when compared to the reference standard actinomycin D. The capabilities of the most cytotoxic benzofuran-chalcone hybrids 3b and 3i, to induce apoptosis, have been evaluated by Annexin V-Cy3 SYTOX staining and caspase-3 activation. The experimental and molecular docking results suggest that the title compounds have the potential to exhibit inhibitory effects against tubulin polymerization and epidermal growth factor receptor tyrosine kinase (EGFR-TK) phosphorylation. The modeled structures of representative compounds displayed hydrophobic interactions as well as hydrogen and/or halogen bonding with the protein residues. These interactions are probably responsible for the observed increased binding affinity for the two receptors and their significant antigrowth effect against the MCF-7 cell line.

Inhibitors of dihydrofolate reductase as antitumor agents: design, synthesis and biological evaluation of a series of novel nonclassical 6-substituted pyrido[3,2-d]pyrimidines with a three- to five-carbon bridge

Bridge homologation of the previously reported nonclassical two-carbon-bridged antifolate, 2,4-diamino-6-phenethylpyrido[3,2-d]pyrimidine (wm-5a), afforded the three-, four- and five-carbon-bridged antifolate analogues 3.1-3.5, 4.1-4.2 and 5.1-5.5. The target compounds, with substituents at various positions on the carbon bridges, were efficiently synthesized by aldol condensation or Wittig reaction and followed by reduction. Elongation of the two-carbon bridge to three-, four- or five-carbon bridges, and also saturation of the carbon bridges, provided compounds with good inhibitory activity against recombinant human DHFR (rhDHFR). Analogue 3.5, which has a three-carbon bridge, inhibited the proliferation of HL-60 and HCT116 cells to a greater extent than the other analogues. Compound 3.5 was also the most potent inhibitor of rhDHFR (IC₅₀ = 0.06 μM), and was approximately 38-fold more potent than the two-carbon-bridged lead compound. Docking studies revealed that both the length and flexibility of the saturated carbon bridge in 3.5 were important for high potency. Flow cytometry studies indicated that compound 3.5 arrested HL-60 cells in the S-phase and induced apoptosis. Western blot analysis of HL-60 cells treated with 3.5 showed a dose-dependent upregulation of DHFR protein levels.

Molecular chemotherapeutic potential of butein: A concise review

Butein is a biologically active flavonoid isolated from the bark of Rhus verniciflua Stokes, which is known to have therapeutic potential against various cancers. Notably, butein inhibits cancer cell growth by inducing G₂/M phase arrest and apoptosis. Butein-induced G₂/M phase arrest is associated with increased phosphorylation of ataxia telangiectasia mutated (ATM) and Chk1/2, and consequently, with reduced cdc25C levels. In addition, butein-induced apoptosis is mediated through the activation of caspase-3, which is associated with changes in the expression of Bcl-2 and Bax proteins. Intriguingly, butein sensitizes cells to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis via ERK-mediated Sp1 activation, which promotes the transcription of specific death receptor 5. Butein also inhibits the migration and invasion of human cancer cells by suppressing nuclear factor-κB- and extracellular signal-regulated kinases 1/2-mediated expression of matrix metalloproteinase-9 and vascular endothelial growth factor. Additionally, butein downregulates the expression of human telomerase reverse transcriptase and causes a concomitant decrease in telomerase activity. These findings provide the basis for the pharmaceutical development of butein. The aim of this review is to provide an update on the mechanisms underlying the anticancer activity of butein, with a special focus on its effects on different cellular signaling cascades.

Design, synthesis and biological evaluation of novel pyrazolochalcones as potential modulators of PI3K/Akt/mTOR pathway and inducers of apoptosis in breast cancer cells

Cancer has been established as the "Emperor of all maladies". In recent years, medicinal chemistry has focused on identifying novel anti-cancer compounds; though discovery of these compounds appears to be a herculean task. In present study, we synthesized forty pyrazolochalcone conjugates and explored their cytotoxic activity against a panel of sixty cancer cell lines. Fifteen conjugates of the series showed excellent growth inhibition (13b-e, 13h-j, 14c-d, 15 a, 15 c-d, 16b, 16d and 18f; GI50 for MCF-7: 0.4-20 μM). Conjugates 13b, 13c, 13d, 16b and 14d were also evaluated for their cytotoxic activity in human breast cancer cell line (MCF-7). The promising candidates induced cell cycle arrest, mitochondrial membrane depolarization and apoptosis in MCF-7 cells at a 2 μM concentration. Furthermore, inhibition of PI3K/Akt/mTOR pathway-regulators such as PI3K, p-PI3K, p-AKT, and mTOR were observed; as well as upregulation of p-GSK3β and tumor-suppressor protein, PTEN. Our study indicates that pyrazolochalcone conjugates could serve as potential leads in the development of tailored cancer therapeutics.

Chalcone: A Privileged Structure in Medicinal Chemistry

Privileged structures have been widely used as an effective template in medicinal chemistry for drug discovery. Chalcone is a common simple scaffold found in many naturally occurring compounds. Many chalcone derivatives have also been prepared due to their convenient synthesis. These natural products and synthetic compounds have shown numerous interesting biological activities with clinical potentials against various diseases. This review aims to highlight the recent evidence of chalcone as a privileged scaffold in medicinal chemistry. Multiple aspects of chalcone will be summarized herein, including the isolation of novel chalcone derivatives, the development of new synthetic methodologies, the evaluation of their biological properties, and the exploration of the mechanisms of action as well as target identification. This review is expected to be a comprehensive, authoritative, and critical review of the chalcone template to the chemistry community.

Design, Synthesis, and Biological Evaluation of Coupled Bioactive Scaffolds as Potential Anticancer Agents for Dual Targeting of Dihydrofolate Reductase and Thioredoxin Reductase

The dihydrofolate reductase (DHFR) and thioredoxin reductase (TrxR) enzymes are involved in the process of tumor cell growth and survival. The 4,6-diamino-1,2-dihydro-1,3,5-triazine scaffold is well-established as a useful scaffold for DHFR inhibition, while chalcones have been reported to be inhibitors of TrxR. In this study, 15 novel compounds designed by the structural combination of the 4,6-diamino-1,2-dihydro-1,3,5-triazine and chalcone scaffolds via a diether linker were successfully synthesized and characterized. All of the compounds demonstrated dual inhibition against DHFR and TrxR when they were assessed by in vitro enzyme assays. The compounds also exhibited antiproliferative activity against the MCF-7 and HCT116 cells. The more potent analogs 14 and 15 were found to inhibit cellular DHFR and TrxR activities in HCT116 cells. Therefore, this study provided compelling evidence that 14 and 15 could exert their anticancer property via multitarget inhibition at the cellular level.

Butein in health and disease: A comprehensive review

BACKGROUND

The risk of suffering from many chronic diseases seems to have made no improvement despite the advancement in medications available in the modern world. Moreover, the use of synthetic chemicals as medications has proved to worsen the scenario due to the various adverse side effects associated with them.

PURPOSE

Extensive research on natural medicines provides ample evidence on the safety and efficacy of phytochemicals and nutraceuticals against diverse chronic ailments. Therefore, it is advisable to use natural products in the management of such diseases. This article aims to present a comprehensive and critical review of known pharmacological and biological effects of butein, an important chalcone polyphenol first isolated from Rhus verniciflua Stokes, implicated in the prevention and treatment of various chronic disease conditions.

METHODS

An extensive literature search was conducted using PubMed, ScienceDirect, Scopus and Web of Science^TM core collections using key words followed by evaluation of the bibliographies of relevant articles.

RESULTS

Butein has been preclinically proven to be effective against several chronic diseases because it possesses a wide range of biological properties, including antioxidant, anti-inflammatory, anticancer, antidiabetic, hypotensive and neuroprotective effects. Furthermore, it has been shown to affect multiple molecular targets, including the master transcription factor nuclear factor-κB and its downstream molecules. Moreover, since it acts on multiple pathways, the chances of non-responsiveness and resistance development is reduced, supporting the use of butein as a preferred treatment option.

CONCLUSION

Based on numerous preclinical studies, butein shows significant therapeutic potential against various diseases. Nevertheless, well-designed clinical studies are urgently needed to validate the preclinical findings.

Insights from molecular modeling, docking and simulation of imidazole nucleus containing chalcones with EGFR kinase domain for improved binding function

EGFR Kinase domain is a crucial role player cell surface receptor protein activated by specific binding of its ligand like EGFR. Importance of this protein as a therapeutically important drug target towards treating various cancer types has been proven elsewhere in previous literature. In this present study, we have designed a novel series of five compounds and computationally evaluated their potential to act as inhibitors of EGFR kinase domain towards anti-cancer activity. Our docking study shows compounds have the potential to dock into the active site of the EGFR Kinase domain with a binding energy in a range of -5.46 to - 7.32 Kcal/mol, Among all the compounds, compound 2 was found to be the lead like molecule with the binding energy of -7.32 kcal/mol with predicted IC50 value of 4.33 micro molar level. Molecular dynamic simulation studies for this compound 2 in complex with EGFR kinase domain has revealed several interesting molecular interactions with some of the important residues present at the active binding site of EGFR Kinase domain. Conclusively, novel designed compound 2 of the present study have shown promising anti-cancer potential worth considering for further evaluations.

Optimization of Acryloylphenylcarboxamides as Inhibitors of ABCG2 and Comparison with Acryloylphenylcarboxylates

ABCG2 belongs to the superfamily of ATP binding cassette (ABC) proteins and is associated with the limited success of anticancer chemotherapy, given its responsibility for the cross-resistance of tumor cells, known as multidrug resistance (MDR). Several classes of ABCG2 inhibitors were developed for increasing the efficacy of chemotherapy. A series of chalcones coupled to an additional aromatic residue was synthesized and investigated for their inhibition of ABC transporters. In our previous work we determined the preferred position of the linker on the A-ring to be ortho, and found several substitution patterns at the additional ring that improved potency. In this study we investigated whether a methoxy group that improved the inhibitory activity of chalcones would also be beneficial for the acryloylphenylcarboxamide scaffold. Indeed, this modification led to highly potent ABCG2 inhibitors. To support the hypothesis of a beneficial effect of the amide linker, six acryloylphenylcarboxylates were synthesized and investigated for their inhibitory activity. Replacement of the amide linker with an ester group resulted in decreased inhibition. Molecular modeling showed that the conformational preference of both series differs, thereby explaining the positive effect of the amide linker. Several compounds were characterized in detail by investigating their intrinsic cytotoxicity and capacity to reverse MDR in MTT assays and their effect on vanadate-sensitive ATPase activity.

Butein provides neuroprotective and anti-neuroinflammatory effects through Nrf2/ARE-dependent haem oxygenase 1 expression by activating the PI3K/Akt pathway

BACKGROUND AND PURPOSE

Butein, 3,4,2',4'-tetrahydroxychalcone, has various pharmacological effects. However, no study has demonstrated the specific neurobiological mechanisms of the effects of butein in neuronal cells. The present study examined the role of butein as an antioxidative and anti-inflammatory inducer of haem oxygenase 1 (HO1) in mouse hippocampal HT22, BV2 microglial and primary mouse hippocampus neurons.

EXPERIMENTAL APPROACH

We investigated the neuroprotective effects of butein on glutamate-induced HT22 cell and primary mouse hippocampal neuron death and its anti-neuroinflammatory effects on LPS-induced activation of BV2 cells. We elucidated the underlying mechanisms by assessing the involvement of NF-κB, HO1, nuclear factor-E2-related factor 2 (Nrf2) and Akt signalling.

KEY RESULTS

Butein decreased cellular oxidative injury and the production of ROS in glutamate-treated HT22 cells and primary mouse hippocampal neurons. Furthermore, butein suppressed LPS-induced pro-inflammatory enzymes and mediators in BV2 microglia. Butein inhibited IL-6, IL-1β and TNF-α production and mRNA expression. In addition, butein decreased NO and PGE2 production and inducible NOS and COX-2 expression through the NF-κB signalling pathway. Butein up-regulated Nrf2/ARE-mediated HO1 expression through the PI3K/Akt pathway and this was positively associated with its cytoprotective effects and anti-neuroinflammatory actions.

CONCLUSION AND IMPLICATIONS

Our results indicate that butein effectively prevents glutamate-induced oxidative damage and LPS-induced activation and that the induction of HO1 by butein through the PI3K/Akt pathway and Nrf2 activation appears to play a pivotal role in its effects on neuronal cells. Our results provide evidence for the neuroprotective properties of butein.

The combination of quinazoline and chalcone moieties leads to novel potent heterodimeric modulators of breast cancer resistance protein (BCRP/ABCG2)

During the last decade it has been found that chalcones and quinazolines are promising inhibitors of ABCG2. The combination of these two scaffolds offers a new class of heterocyclic compounds with potentially high inhibitory activity against ABCG2. For this purpose we investigated 22 different heterodimeric derivatives. In this series only methoxy groups were used as substituents as these had been proven superior for inhibitory activity of chalcones. All compounds were tested for their inhibitory activity, specificity and cytotoxicity. The most potent ABCG2 inhibitor in this series showed an IC50 value of 0.19 μM. It possesses low cytotoxicity (GI50 = 93 μM), the ability to reverse MDR and is nearly selective toward ABCG2. Most compounds containing dimethoxy groups showed slight activity against ABCB1 too. Among these three compounds (17, 19 and 24) showed even higher activity toward ABCB1 than ABCG2. All inhibitors were further screened for their effect on basal ATPase activity. Although the basal ATPase activity was partially stimulated, the compounds were not transported by ABCG2. Thus, quinazoline-chalcones are a new class of effective ABCG2 inhibitors.

Potential of butein, a tetrahydroxychalcone to obliterate cancer

BACKGROUND

Despite the major advances made in the field of cancer biology, it still remains one of the most fatal diseases in the world. It is now well established that natural products are safe and efficacious and have high potential in the prevention and treatment of different diseases including cancer. Butein is one such compound which is now found to have anti-cancer properties against various malignancies.

PURPOSE

To thoroughly review the literature available on the anti-cancer properties of butein against different cancers and its molecular targets.

METHODS

A thorough literature search has been done in PubMed for butein, its biological activities especially cancer and its molecular targets.

RESULTS

Our search retrieved several reports on the various biological activities of butein in which around 43 articles reported that butein shows potential anti-proliferative effect against a wide range of neoplasms and the molecular target varies with cancer types. Most often it targets NF-κB and its downstream pathways. In addition, butein induces the expression of genes which mediate the cell death and apoptosis in cancer cells. It also inhibits tumor angiogenesis, invasion and metastasis in prostate, liver and bladder cancers through the inhibition of MMPs, VEGF etc. Moreover, it inhibits the overexpression of several proteins and enzymes such as STAT3, ERK, CXCR4, COX-2, Akt, EGFR, Ras etc. involved in tumorigenesis.

CONCLUSION

Collectively, all these findings suggest the enormous potential and efficacy of butein as a multitargeted chemotherapeutic, chemopreventive and chemosensitizing agent against a wide range of cancers with minimal or no adverse side effects.

Diverse Molecular Targets for Chalcones with Varied Bioactivities

Natural or synthetic chalcones with different substituents have revealed a variety of biological activities that may benefit human health. The underlying mechanisms of action, particularly with respect to the direct cellular targets and the modes of interaction with the targets, have not been rigorously characterized, which imposes challenges to structure-guided rational development of therapeutic agents or chemical probes with acceptable target-selectivity profile. This review summarizes literature evidence on chalcones’ direct molecular targets in the context of their biological activities.

Butein suppresses ICAM-1 expression through the inhibition of IκBα and c-Jun phosphorylation in TNF-α- and PMA-treated HUVECs

Butein (3,4,2',4'-tetrahydroxychalcone), a flavonoid derivative, has been reported to show several biological actions, including anti-inflammatory and anti-cancer. However, the possible molecular mechanisms involved are poorly understood. Treatment of human umbilical vein endothelial cells (HUVECs) with butein significantly inhibited cell surface intercellular adhesion molecule-1 (ICAM-1) expression, ICAM-1 protein synthesis, and mRNA expression induced by tumor necrotic factor-α (TNF-α) and/or phorbol 12-myristate 13-acetate (PMA). Electrophoretic mobility shift assay revealed that butein blocked activation of transcription factors, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), induced by TNF-α and PMA. Moreover, butein abolished TNF-α- and PMA-induced IκBα phosphorylation, which participates in NF-κB activation, and PMA-induced phosphorylation of c-Jun, a subunit composed of AP-1. In vitro, butein inhibited the phosphorylation of c-Jun, binding to GST beads, mediated by JNK isolated from PMA-treated cells. The inhibitory action of butein on the JNK-mediated in vitro c-Jun phosphorylation was abrogated in the presence of ATP. These results indicate that in HUVECs, butein suppresses the expression of ICAM-1 mRNA and protein through the inhibition of the activation of NF-κB and AP-1 induced by TNF-α and PMA, that the inhibitory action of butein on NF-κB activation results from the inhibition of IκBα phosphorylation by IκB kinase (IKK), and that the inactivation of PMA-activated AP-1 by butein is due to the blocking of JNK-mediated c-Jun phosphorylation through the inhibition of ATP binding.

Phytochemicals as Anticancer and Chemopreventive Topoisomerase II Poisons

Phytochemicals are a rich source of anticancer drugs and chemopreventive agents. Several of these chemicals appear to exert at least some of their effects through interactions with topoisomerase II, an essential enzyme that regulates DNA supercoiling and removes knots and tangles from the genome. Topoisomerase II-active phytochemicals function by stabilizing covalent protein-cleaved DNA complexes that are intermediates in the catalytic cycle of the enzyme. As a result, these compounds convert topoisomerase II to a cellular toxin that fragments the genome. Because of their mode of action, they are referred to as topoisomerase II poisons as opposed to catalytic inhibitors. The first sections of this article discuss DNA topology, the catalytic cycle of topoisomerase II, and the two mechanisms (interfacial vs. covalent) by which different classes of topoisomerase II poisons alter enzyme activity. Subsequent sections discuss the effects of several phytochemicals on the type II enzyme, including demethyl-epipodophyllotoxins (semisynthetic anticancer drugs) as well as flavones, flavonols, isoflavones, catechins, isothiocyanates, and curcumin (dietary chemopreventive agents). Finally, the leukemogenic potential of topoisomerase II-targeted phytochemicals is described.

Antirestenosis effect of butein in the neointima formation progression

The development of restenosis involves migration and hyperproliferation of vascular smooth muscle cells (VSMCs). Platelet-derived growth factor (PDGF) is one of the major factors. Butein modulates inflammatory pathways and affects the proliferation and invasion of the tumor. We investigated the hypothesis that butein might prevent the restenosis process via a similar pathway. Our results demonstrated that butein inhibited PDGF-induced VSMC proliferation and migration as determined by BrdU proliferation and two-dimensional migration scratch assay. Butein also concentration-dependently repressed PDGF-induced phosphorylation of PDGF-receptor β, mitogen-activated protein kinases, phosphoinositide 3-kinase/Akt, and phopholipase Cγ/c-Src in VSMCs. In addition, in vivo results showed that butein attenuated neointima formation in balloon-injured rat carotid arteries. These results indicate that butein may inhibit PDGF-induced VSMC proliferation and migration, resulting in attenuation of neointima formation after percutaneous transluminal coronary angioplasty. Our study demonstrates for the first time that systemic administration of butein is able to reduce neointima formation after vascular injury.

The anti-angiogenic and anti-tumor activity of synthetic phenylpropenone derivatives is mediated through the inhibition of receptor tyrosine kinases

Abnormal angiogenesis plays a critical role in the pathogenesis of various diseases such as cancer and chronic inflammation. A variety of pro-angiogenic factors, including vascular endothelial growth factor (VEGF), exert their action through endothelial receptor tyrosine kinases (RTKs). The synthetic phenylpropenone derivatives, used in this study were the following: 1,3-diphenyl-propenone (DPhP), 3-phenyl-1-thiophen-2-yl-propenone (PhT2P), 3-phenyl-1-thiophen-3-yl-propenone (PhT3P) and 1-furan-2-yl-3-phenyl-propenone (FPhP). These derivatives were screened for their inhibitory effect on VEGF-induced angiogenesis in vitro using HUVECs and in vivo using chick chorioallantoic membrane (CAM). The order of anti-angiogenic activity was DPhP>FPhP>PhT3P>PhT2P. The most effective compound DPhP, also known as chalcone, showed weak VEGF receptor tyrosine kinase activity compared with the specific inhibitor, SU4312 (3-[[4-(dimethylamino)phenyl]methylene]-1,3-dihydro-2H-indol-2-one). However, DPhP also inhibited several other receptor tyrosine kinases including Tie-2, epithermal growth factor (EGF) receptor, EphB2, fibroblast growth factor (FGF) receptor 3 and insulin-like growth factor-1 (IGF-1) receptor, as revealed by a receptor tyrosine kinase array assay. In addition, the down-stream signaling, including ERK phosphorylation and NF-κB activation, after receptor activation was significantly inhibited by DPhP. Furthermore, in the HT29 human colon cancer cell-inoculated CAM assay, the tumor growth and tumor-induced angiogenesis was significantly inhibited by DPhP (10μg/ml). These results suggest that the simple flavonoid, DPhP (chalcone), has valuable potential as an antiangiogenic and anti-cancer agent, and its action is mediated through the inhibition of multi-target RTKs including VEGF receptor 2.