Design, synthesis and biological evaluation of 7-(aryl)-2,3-dihydro-[1,4]dioxino[2,3- g ]quinoline derivatives as potential Hsp90 inhibitors and anticancer agents

Lewis Acid Catalyzed [4 + 2] Annulation of Propargylic Alcohols with 2-Vinylanilines

An elegant Lewis acid catalyzed, protection-free, and straightforward synthetic strategy for the assembly of a series of sophisticated polycyclic quinoline skeletons employing propargylic alcohols and 2-vinylanilines as the substrates in the presence of Yb(OTf)3 (10 mol %) and AgOTf (10 mol %) in tetrahydrofuran has been described. This annulation protocol, which proceeds through a sequential Meyer-Schuster rearrangement/nucleophilic substitution/deprotonation sequence, provides a versatile, practical, and atom-economical approach for accessing quinoline derivatives in moderate-to-good yields.

Molecular Target Interactions of Quinoline Derivatives as Anticancer Agents: A Review

One of the leading causes of death worldwide is cancer, which poses substantial risks to both society and an individual's life. Cancer therapy is still challenging, despite developments in the field and continued research into cancer prevention. The search for novel anticancer active agents with a broader cytotoxicity range is therefore continuously ongoing. The benzene ring gets fused to a pyridine ring at two carbon atoms close to one another to form the double ring structure of the heterocyclic aromatic nitrogen molecule known as quinoline (1-azanaphthalene). Quinoline derivatives contain a wide range of pharmacological activities, including antitubercular, antifungal, antibacterial, and antimalarial properties. Quinoline derivatives have also been shown to have anticancer properties. There are many quinoline derivatives widely available as anticancer drugs that act via a variety of mechanisms on various molecular targets, such as inhibition of topoisomerase, inhibition of tyrosine kinases, inhibition of heat shock protein 90 (Hsp90), inhibition of histone deacetylases (HDACs), inhibition of cell cycle arrest and apoptosis, and inhibition of tubulin polymerization.

Heterocyclic Compounds as Hsp90 Inhibitors: A Perspective on Anticancer Applications

Heat shock proteins (Hsps) have garnered special attention in cancer therapy as molecular chaperones with regulatory/mediatory effects on folding, maintenance/stability, maturation, and conformation of proteins as well as their effects on prevention of protein aggregation. Hsp90 ensures the stability of various client proteins needed for the growth of cells or the survival of tumor cells; therefore, they are overexpressed in tumor cells and play key roles in carcinogenesis. Accordingly, Hsp90 inhibitors are recognized as attractive therapeutic agents for investigations pertaining to tumor suppression. Natural Hsp90 inhibitors comprising geldanamycin (GM), reclaimed analogs of GM including 17-AAG and DMAG, and radicicol, a natural macrocyclic antifungal, are among the first potent Hsp90 inhibitors. Herein, recently synthesized heterocyclic compounds recognized as potent Hsp90 inhibitors are reviewed along with the anticancer effects of heterocyclic compounds, comprising purine, pyrazole, triazine, quinolines, coumarin, and isoxazoles molecules.

Discovery of new pyrimido[5,4-c]quinolines as potential antiproliferative agents with multitarget actions: Rapid synthesis, docking, and ADME studies

A novel series of pyrimido[5,4-c]quinoline derivatives variously substituted at positions 2 and 5 have been synthesized, in good to excellent yields, via rapid base-catalyzed cyclization reaction of 2,4-dichloroquinoline-3-carbonitrile (5) with guanidine hydrochlorides 6a-c. All the synthesized compounds were screened for their in vitro antiproliferative activity. The most active hybrids 26a-d, 28a-d, and 30B were assessed against topoisomerase (topo) I, topo IIα, CDK2, and EGFR. The majority of the tested compounds exhibited selective topo I inhibitory activity while had weak topo IIα inhibitory action with compounds 30B and 28d, showed better topo I inhibitory activity than the reference camptothecin. Compound 30B, the most potent derivative as antiproliferative agent, exhibited moderate activity against CDK2 (IC₅₀ = 1.60 µM). The results of this assay show that CDK2 is not a potential target for these compounds, implying that the observed cytotoxicity of these compounds is due to a different mechanism. Compounds 30B, 28d, and 28c were found to be the most potent against EGFR and their EGFR inhibitory activities (IC₅₀ = 0.40 ± 0.2, 0.49 ± 0.2, and 0.64 ± 0.3, respectively) relative to the positive control erlotinib (IC₅₀ = 0.07 ± 0.03 µM). These results revealed that topo I and EGFR are attractive targets for this class of chemical compounds.

In Silico Exploration of Novel Tubulin Inhibitors: A Combination of Docking and Molecular Dynamics Simulations, Pharmacophore Modeling, and Virtual Screening

Microtubules play a critical role in mitosis and cell division and are regarded as an excellent target for anticancer therapy. Although microtubule-targeting agents have been widely used in the clinical treatment of different human cancers, their clinical application in cancer therapy is limited by both intrinsic and acquired drug resistance and adverse toxicities. In a previous work, we synthesized compound 9IV-c, ((E)-2-(3,4-dimethoxystyryl)-6,7,8-trimethoxy-N-(3,4,5-trimethoxyphenyl)quinoline-4-amine) that showed potent activity against multiple human tumor cell lines, by targeting spindle formation and/or the microtubule network. Accordingly, in this study, to identify potent tubulin inhibitors, at first, molecular docking and molecular dynamics studies of compound 9IV-c were performed into the colchicine binding site of tubulin; then, a pharmacophore model of the 9IV-c-tubulin complex was generated. The pharmacophore model was then validated by Güner-Henry (GH) scoring methods and receiver operating characteristic (ROC) analysis. The IBScreen database was searched by using this pharmacophore model as a screening query. Finally, five retrieved compounds were selected for molecular docking studies. These efforts identified two compounds (b and c) as potent tubulin inhibitors. Investigation of pharmacokinetic properties of these compounds (b and c) and compound 9IV-c displayed that ligand b has better drug characteristics compared to the other two ligands.

Updates on the versatile quinoline heterocycles as anticancer agents

Quinoline motifs have befallen significant molecules due to their assortment of interest in medicine, chemical synthesis, coordination chemistry, also in the field of applied chemistry. Therefore, various researchers have produced these molecules as objective structures and studied their natal potential. The current chapter endows with concise attention about cancer, anticancer agents, sources (natural) of quinoline, and together with an innovative scope of quinoline-related medicines. Further, the present section gives knowledge concerned with the anticancer activity of synthesized quinolines and their derivatives.

Synthesis and biological evaluation of novel quinoline analogs of ketoprofen as multidrug resistance protein 2 (MRP2) inhibitors

Objectives

A new series of quinoline analogs of ketoprofen was designed and synthesized as multidrug resistance protein 2 (MRP2) inhibitors using ketoprofen as the lead compounds.

Materials and Methods

The cytotoxic activity of the compounds was evaluated againt two cancer cell lines including A2780/RCIS (MRP2-overexpressing ovarian carcinoma), A2780, drug-sensitive ovarian carcinoma using MTT assay. Compounds showing low toxicity in MTT test were selected to investigate their MRP inhibition activity. MRP2 inhibitory potency was evaluated by determination of the uptake amount of fluorescent 5-carboxy fluorescein diacetate (5-CFDA) substrate, by A2780/RCIS in the presence of the selected compounds. Mode of interaction between synthesized ligands and homology modeled MRP2 was investigated by MOE software.

Results

Compound 6d, a 4-carboxy quinoline possessing dimethoxy phenyl in position 2 of quinoline ring, showed the most MRP2 inhibition activity among all the quinolines and more than the reference drug ketoprofen. MRP2 inhibition activity of compound 7d was less in comparison to that of compound 6d, indicating that carboxyl group in position 4 of quinoline may interact with MRP2. Docking studies showed that compound 7d methyl ester of 6d, interacted less compared to its parent 6d, which is consistent with biological results.

Conclusion

This study indicates that 6- or 8-benzoyl-2-arylquinoline is a suitable scaffold to design MRP2 inhibitors. The position of benzoyl in quinoline ring is important in inhibition of MRP2. Generally, MRP2 inhibition activity of compound 7d was less in comparison to that of 6d, indicating that carboxyl group in position 4 of quinoline may interact with MRP2.

Design, synthesis and biological evaluation of novel imidazole-chalcone derivatives as potential anticancer agents and tubulin polymerization inhibitors

Novel imidazole-chalcone derivatives were designed and synthesized as tubulin polymerization inhibitors and anticancer agents. The antiproliferative activity of the imidazole-chalcone was assessed on some human cancer cell lines including A549 (adenocarcinoma human alveolar basal epithelial cells), MCF-7 (human breast cancer cells), MCF-7/MX (mitoxantrone resistant human breast cancer cells), and HEPG2 (human hepatocellular carcinoma cells). Generally, the imidazole-chalcone derivatives exhibited more cytotoxicity on A549 cancer cells in comparison to the other three cell lines, among them compounds 9j' and 9g showed significant cytotoxicity with IC₅₀ values ranging from 7.05 to 63.43 μM against all the four human cancer cells. The flow cytometry analysis of A549 cancer cells treated with 9g and 9j' displayed that these compounds induced cell cycle arrest at the G2/M phase at low concentrations and increased the number of apoptotic cells (cells in subG1 phase) at higher concentrations. They have also inhibited tubulin polymerization similar to combretastatin A-4 (CA-4). Annexin V binding staining assay in A549 cancer cells revealed that compound 9j' induced apoptosis (early and late). Finally, molecular docking studies of 9j' into the colchicine-binding site of tubulin presented the probable interactions of these compounds with tubulin.

Tailored Quinolines Demonstrate Flexibility to Exert Antitumor Effects through Varied Mechanisms-A Medicinal Perspective

BACKGROUND

Quinoline is considered to be a privileged heterocyclic ring owing to its presence in diverse scaffolds endowed with promising activity profiles. In particular, quinoline containing compounds have exhibited substantial antiproliferative effects through the diverse mechanism of actions, which indicates that the heteroaryl unit is flexible as well as accessible to subtle structural changes that enable its inclusion in chemically distinct anti-tumor constructs.

METHODS

Herein, we describe a medicinal chemistry perspective on quinolines as anticancer agents by digging into the peer-reviewed literature as well as patents published in the past few years.

RESULTS

This review will serve as a guiding tool for medicinal chemists and chemical biologists to gain insights about the benefits of quinoline ring installation to tune the chemical architectures for inducing potent anticancer effects.

CONCLUSION

Quinoline ring containing anticancer agents presents enough optimism and promise in the field of drug discovery to motivate the researchers towards the continued explorations on such scaffolds. It is highly likely that adequate efforts in this direction might yield some potential cancer therapeutics in the future.

Design, synthesis, and biological evaluation of novel 5,6,7-trimethoxy quinolines as potential anticancer agents and tubulin polymerization inhibitors

Objective(s):

Microtubules have key roles in essential cellular processes such as mitosis, cell motion, and intracellular organelle transport. Increasing interest has been given to tubulin binding compounds after the introduction of taxanes into clinical oncology. The object of this study was synthesis and biological evaluation of novel 5,6,7-trimethoxy quinolines as tubulin inhibitors.

Materials and Methods:

The cytotoxicity of the newly synthesized compounds was assessed against different human cancer cell lines including MCF-7, A2780, MCF-7/MX, A2780/RCIS, and normal cells. Compounds demonstrating the most antiproliferative activity, were chosen to examine their tubulin inhibition activity and their ability to arrest the cell cycle and induce apoptosis. Molecular docking studies and molecular dynamics simulation of compound 7e in the catalytic site of tubulin were performed.

Results:

Most of the synthesized quinolines showed moderate to significant cytotoxic activity against human cancer cells. Compounds 7e and 7f, possessing N-(4-benzoyl phenyl) and N-(4-phenoxy phenyl), respectively, exhibited the most antiproliferative activity more potent than the other compounds and exhibited similar antiproliferative activity on both resistant and parental cancer cells.

Conclusion:

Flow cytometry analysis of A2780, A2780/RCIS, MCF-7, and MCF-7/MX cancer cells treated with 7e and 7f exhibited that these compounds arrested the cell cycle (at the G2/M phase) and induced cellular apoptosis in A2780 cancer cells. These quinolines inhibited tubulin polymerization in a way resembling that of CA-4. Molecular dynamics simulation and molecular docking studies of compound 7e into the binding site of tubulin displayed the probable interactions of 7e with the binding site of tubulin.

Quinolines, a perpetual, multipurpose scaffold in medicinal chemistry

Quinoline is a versatile pharmacophore, a privileged scaffold and an outstanding fused heterocyclic compound with a wide range of pharmacological prospective such as anticancer, anti-inflammatory, antibacterial, antiviral drug and superlative moiety in drug discovery. The quinoline hybrids have already been shown excellent results with new targets with a different mode of actions as an inhibitor of cell proliferation by cell cycle arrest, apoptosis, angiogenesis, disruption of cell migration and modulation. This review emphasized the mode of action, structure activity relationship and molecular docking to reveal the various active pharmacophores of quinoline hybrids accountable for novel anticancer, anti-inflammatory, antibacterial and miscellaneous activities. Therefore, several quinoline candidates are under clinical trials for the treatment of certain diseases, for example ferroquine (antimalarial), dactolisib (antitumor) and pelitinib (EGFR TK inhibitors) etc. Plenty of research has been summarized the recent advances of quinoline derivatives and explore the various therapeutic prospects of this moiety. This review would help the researchers to strategically design diverse novel quinoline derivatives for the development of clinically viable drug candidates for the treatment of incurable diseases.

A comprehensive review on the biological interest of quinoline and its derivatives

Amongst heterocyclic compounds, quinoline is an advantaged scaffold that appears as a significant assembly motif for the development of new drug entities. Quinoline and its derivatives tested with diverse biological activity constitute an important class of compounds for new drug development. Therefore, many scientific communities have developed these compounds as intent structure and evaluated their biological activities. The present, review provides brief natural sources of quinoline and including a new extent of quinoline-based marketed drugs. This review also confers information about the biological activities of quinoline derivatives such as antibacterial, antifungal, antimycobacterial, antiviral, anti-protozoal, antimalarial, anticancer, cardiovascular, CNS effects, antioxidant, anticonvulsant, analgesic, anti-inflammatory, anthelmintic and miscellaneous activities.

Synthesis and biological evaluation of oxazinonaphthalene-3-one derivatives as potential anticancer agents and tubulin inhibitors

Objectives

In the present study, a new series of oxazinonaphthalene-3-one analogs was designed and synthesized as novel tubulin inhibitors.

Materials and Methods

The cytotoxic activity of the synthesized compounds was evaluated against four human cancer cell lines including A2780 (human ovarian carcinoma), A2780/RCIS (cisplatin resistant human ovarian carcinoma), MCF-7 (human breast cancer cells), and MCF-7/MX (mitoxantrone resistant human breast cancer cells), those compounds which demonstrated the most antiproliferative activity in the MTT test were selected to investigate their tubulin inhibition activity and their effects on cell cycle arrest (at the G2/M phase). Moreover, molecular docking studies of the selected compounds in the catalytic site of tubulin (PDB ID: 4O2B) were carried out to describe the results of biological experiments.

Results

Most of our compounds exhibited significant to moderate cytotoxic activity against four human cancer cell lines. Among them, Compounds 4d, 5c, and 5g, possessing trimethoxy phenyl, showed the most antiproliferative activity with IC50 values ranging from 4.47 to 52.8 μM.

Conclusion

The flow cytometric analysis of A2780 cancer cell line treated with compounds 4d, 5c, and 5g showed that these compounds induced cell cycle arrest at the G2/M phase. Compound 5g, the most antiproliferative compound, inhibited tubulin polymerization in a dose-dependent manner. Molecular docking studies of 5g into the colchicine-binding site of tubulin displayed a possible mode of interaction between this compound and tubulin.

Quinazoline Based HSP90 Inhibitors: Synthesis, Modeling Study and ADME Calculations Towards Breast Cancer Targeting

A new 2-thioquinazolinones series was designed and synthesized as HSP90 inhibitors based on the structure of hit compound VII obtained by virtual screening approach. Their in vitro anti-proliferative activity was evaluated against three human cancer cell lines rich in HSP90 namely; colorectal carcinoma (HCT-116), and cervical carcinoma (Hela), breast carcinoma (MCF-7). Compounds 5a, 5d, 5e and 9h showed a significant broad spectrum anti-proliferative activity against all tested cell lines. They were characterized by potent effect against breast cancer in particular with IC₅₀ of 11.73, 8.56, 7.35 and 9.48 μM, respectively against Doxorubicin (IC₅₀ 4.17 μM). HSP90 ATPase activity inhibition assay were conducted where compound 5d exhibited the best IC₅₀ with 1.58 μM compared to Tanespimycin (IC₅₀ = 2.17 μM). Compounds 5a and 9h showed higher IC₅₀ values of 3.21 and 3.41 μM, respectively. The effects of 5a, 5d and 9h on Her2 (a client proteins of HSP90) and HSP70 were evaluated in MCF-7 cells. All tested compounds were found to reduce Her2 protein expression levels and induce Hsp70 protein expression levels significantly, emphasizing that antibreast cancer effect is a consequence of HSP90 chaperone inhibition. Cell cycle analysis of MCF-7 cells treated with 5d showed cell cycle arrest at G2/M phase 38.89% and pro-apoptotic activity as indicated by annexin V-FITC staining by 22.42%. Molecular docking studies suggested mode of interaction to HSP90 via hydrogen bonding. ADME properties prediction of the active compounds suggested that they could be used as orally absorbed anticancer drug candidates.

Colchicine-like β-acetamidoketones as inhibitors of microtubule polymerization: Design, synthesis and biological evaluation of in vitro anticancer activity

OBJECTIVES

In this study a series of novel colchicine-like β-acetamidoketones was designed and synthesized as potential tubulin inhibitors.

MATERIALS AND METHODS

The cytotoxicity of the novel synthesized β-acetamidoketones was assessed against two cancerous cell lines including MCF-7 (human breast cancer cells) and A549 (adenocarcinomic human alveolar basal epithelial cells) employing the MTT test. Tubulin polymerization test was done by using a commercial kit (tubulin polymerization assay kit).

RESULTS

In general, the cytotoxicity activities were highly dependent on the aromatic substitution pattern of phenyl ring at β position of β-acetamidoketones. Based upon, compound 4f possessing the same structural elements of colchicine and chalcone 1, revealed the most cytotoxicity more than the other β-acetamidoketone against the cancerous cell lines and showed moderate antitubulin effect. The tubulin inhibitory effect of 4f, colchicine and chalcone 1 were consistent with their antiproliferative activities. Molecular docking studies of 4f, into the colchicine-binding site of tubulin exhibited possible mode of interaction between this compound and tubulin.

CONCLUSION

The structure activity relationship (SAR) data attained showed that the presence of trimethoxy phenyl attached to carbonyl group of β-acetamidoketones and a methoxy group at para position of the other ring are essential for cytotoxic activity. In general, the cytotoxicity activities were highly dependent on the aromatic substitution pattern of phenyl ring at β position of β-acetamidoketones.

Thermodynamic analysis of interactions of the Hsp90 with adenosine nucleotides: A comparative perspective

Hsp90s are key proteins in cellular homeostasis since they interact with many client proteins. Several studies indicated that Hsp90s are potential targets for treating diseases, such as cancer or malaria. It has been shown that Hsp90s from different organisms have peculiarities despite their high sequence identity. Therefore, a detailed comparative analysis of several Hsp90 proteins is relevant to the overall understanding of their activity. Accordingly, the goal of this work was to evaluate the interaction of either ADP or ATP with recombinant Hsp90s from different organisms (human α and β isoforms, Plasmodium falciparum, Leishmania braziliensis, yeast and sugarcane) by isothermal titration calorimetry. The measured thermodynamic signatures of those interactions indicated that despite the high identity among all Hsp90s, they have specific thermodynamic characteristics. Specifically, the interactions with ADP are driven by enthalpy but are opposed by entropy, whereas the interaction with ATP is driven by both enthalpy and entropy. Complimentary structural and molecular dynamics studies suggested that specific interactions with ADP that differ from those with ATP may contribute to the observed enthalpies and entropies. Altogether, the data suggest that selective inhibition may be more easily achieved using analogues of the Hsp90-ADP bound state than those of Hsp90-ATP bound state.

Design, synthesis, and biological evaluation of 6-methoxy-2-arylquinolines as potential P-glycoprotein inhibitors

Objective(s):

In the present study, a new series of 6-methoxy-2-arylquinoline analogues was designed and synthesized as P-glycoprotein (P-gp) inhibitors using quinine and flavones as the lead compounds.

Materials and Methods:

The cytotoxic activity of the synthesized compounds was evaluated against two human cancer cell lines including EPG85-257RDB, multidrug-resistant gastric carcinoma cells (P-gp-positive gastric carcinoma cell line), and EPG85-257P, drug-sensitive gastric carcinoma cells. Compounds showing low to moderate toxicity in the MTT test were selected to investigate their P-gp inhibition activity. Moreover, trying to explain the results of biological experiments, docking studies of the selected compounds into the homology-modeled human P-gp, were carried out. The physicochemical and ADME properties of the compounds as drug candidate were also predicted.

Results:

Most of our compounds exhibited negligible or much lower cytotoxic effect in both cancer cells. Among the series, 5a and 5b, alcoholic quinoline derivatives were found to inhibit the efflux of rhodamine 123 at the concentration of 10 μM significantly.

Conclusion:

Among the tested quinolines, 5a and 5b showed the most potent P-gp inhibitory activity in the series and were 1.3-fold and 2.1-fold stronger than verapamil, respectively. SAR data revealed that hydroxyl methyl in position 4 of quinolines has a key role in P-gp efflux inhibition of our compounds. ADME studies suggested that all of the compounds included in this study may have a good human intestinal absorption.