N,N-bis-heteroaryl methylamines: Potent anti-mitotic and highly cytotoxic agents

Exploring diverse frontiers: Advancements of bioactive 4-aminoquinoline-based molecular hybrids in targeted therapeutics and beyond

Amongst heterocyclic compounds, quinoline and its derivatives are advantaged scaffolds that appear as a significant assembly motif for developing new drug entities. Aminoquinoline moiety has gained significant attention among researchers in the 21stcentury. Considering the biological and pharmaceutical importance of aminoquinoline derivatives, herein, we review the recent developments (since 2019) in various biological activities of the 4-aminoquinoline scaffold hybridized with diverse heterocyclic moieties such as quinoline, pyridine, pyrimidine, triazine, dioxine, piperazine, pyrazoline, piperidine, imidazole, indole, oxadiazole, carbazole, dioxole, thiazole, benzothiazole, pyrazole, phthalimide, adamantane, benzochromene, and pyridinone. Moreover, by gaining knowledge about SARs, structural insights, and molecular targets, this review may help medicinal chemists design cost-effective, selective, safe, and more potent 4-aminoquinoline hybrids for diverse biological activities.

Recent advances of antitumor leading compound Erianin: Mechanisms of action and structural modification

Erianin, a bioactive compound extracted from Dendrobium, a traditional Chinese medicine, exhibits remarkable anti-cancer properties through diverse molecular mechanisms and has attracted the attention of medicinal chemists. However, the low solubility in water, rapid metabolism and elimination from the body lead to poor bioavailability of Erianin, and greatly hinder its clinical application. The development of new Erianin derivatives is continuously proceed to improve its anticancer effects. In recent years, although important progress in the development of Erianin and the publication of some reviews in this aspect, the mechanism against various cancers, pharmacokinetic study, structural modification as well as structure-activity relationships have not been thoroughly considered. This review is aimed at providing complete picture regarding the above aspects by reviewing studies from 2000 to 2023.06. This review also supplies some important viewpoints on the design and future directions for the development of Erianin derivatives as possible clinically effective anticancer agents.

Design, synthesis and bioevaluation of novel trifluoromethylquinoline derivatives as tubulin polymerization inhibitors

Aim: A series of novel trifluoromethylquinoline derivatives were designed, synthesized and evaluated for antitumor activities. Methodology: All compounds were evaluated for antiproliferative activity against four human cancer cell lines. Results: Among them, 5a, 5m, 5o and 6b exhibited remarkable antiproliferative activities against all the tested cell lines at nanomolar concentrations. Mechanism of action studies demonstrated that 6b targeted the colchicine binding site, potentially inhibiting tubulin polymerization, and further studies indicated that 6b could arrest LNCaP cells in the G2/M phase and induce cell apoptosis. Molecular docking confirmed that 6b could bind to the colchicine binding site. Conclusion: Results suggested that 6b could serve as a promising lead compound for the development of novel tubulin polymerization inhibitors and cancer therapy.

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

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

Advances in antitumor research of CA-4 analogs carrying quinoline scaffold

Combretastatin A-4 (CA-4) is a potent inhibitor of tubulin polymerization and a colchicine binding site inhibitor (CBSI). The structure-activity relationship study of CA-4 showed that the cis double bond configuration and the 3,4,5-trimethoxy group on the A ring were important factors to maintain the activity of CA-4. Therefore, starting from this condition, chemists modified the double bond and also substituted 3,4,5-trimethoxyphenyl with various heterocycles, resulting in a new generation of CA-4 analogs such as chalcone, Flavonoid derivatives, indole, imidazole, etc. Quinoline derivatives have strong biological activity and have been sought after by major researchers for their antitumor activity in recent years. This article reviews the research progress of novel CA-4 containing quinoline analogs in anti-tumor from 1992 to 2022 and expounds on the pharmacological mechanisms of these effective compounds, including but not limited to apoptosis, cell cycle, tubulin polymerization inhibition, immune Fluorescence experiments, etc., which lay the foundation for the subsequent development of CA-4 containing quinoline analogs for clinical use.

Target-based anticancer indole derivatives and insight into structure‒activity relationship: A mechanistic review update (2018‒2021)

Cancer, which is the uncontrolled growth of cells, is the second leading cause of death after heart disease. Targeting drugs, especially to specific genes and proteins involved in growth and survival of cancer cells, is the prime need of research world-wide. Indole moiety, which is a combination of aromatic-heterocyclic compounds, is a constructive scaffold for the development of novel leads. Owing to its bioavailability, high unique chemical properties and significant pharmacological behaviours, indole is considered as the most inquisitive scaffold for anticancer drug research. This is illustrated by the fact that the U.S. Food and Drug Administration (FDA) has recently approved several indole-based anticancer agents such as panobinostat, alectinib, sunitinib, osimertinib, anlotinib and nintedanib for clinical use. Furthermore, hundreds of studies on the synthesis and activity of the indole ring have been published in the last three years. Taking into account the facts stated above, we have presented the most recent advances in medicinal chemistry of indole derivatives, encompassing hot articles published between 2018 and 2021 in anticancer drug research. The recent advances made towards the synthesis of promising indole-based anticancer compounds that may act via various targets such as topoisomerase, tubulin, apoptosis, aromatase, kinases, etc., have been discussed. This review also summarizes some of the recent efficient green chemical synthesis for indole rings using various catalysts for the period during 2018–2021. The review also covers the synthesis, structure‒activity relationship, and mechanism by which these leads have demonstrated improved and promising anticancer activity. Indole molecules under clinical and preclinical stages are classified into groups based on their cancer targets and presented in tabular form, along with their mechanism of action. The goal of this review article is to point the way for medicinal chemists to design and develop effective indole-based anticancer agents.

Recent contributions of quinolines to antimalarial and anticancer drug discovery research

Quinoline, a privileged scaffold in medicinal chemistry, has always been associated with a multitude of biological activities. Especially in antimalarial and anticancer research, quinoline played (and still plays) a central role, giving rise to the development of an array of quinoline-containing pharmaceuticals in these therapeutic areas. However, both diseases still affect millions of people every year, pointing to the necessity of new therapies. Quinolines have a long-standing history as antimalarial agents, but established quinoline-containing antimalarial drugs are now facing widespread resistance of the Plasmodium parasite. Nevertheless, as evidenced by a massive number of recent literature contributions, they are still of great value for future developments in this field. On the other hand, the number of currently approved anticancer drugs containing a quinoline scaffold are limited, but a strong increase and interest in quinoline compounds as potential anticancer agents can be seen in the last few years. In this review, a literature overview of recent contributions made by quinoline-containing compounds as potent antimalarial or anticancer agents is provided, covering publications between 2018 and 2020.

Current status of carbazole hybrids as anticancer agents

The drug resistance and low specificity of current available chemotherapeutics to cancer cells are the main reasons responsible for the failure of cancer chemotherapy and remain dramatic challenges for cancer therapy, creating an urgent need to develop novel anticancer agents. Carbazole nucleus, widely distributed in nature, is a predominant feature of a vast array of biologically active compounds. Carbazole derivatives exhibited potential antiproliferative activity against different cancer cell lines by diverse mechanisms, inclusive of arrest cell cycle and induce apoptosis, and several anticancer agents are carbazole-based compounds. Thus, carbazole derivatives represent a fertile source for discovery of novel anticancer therapeutic agents. Over the past several years, a variety of carbazole hybrids have been developed as potential anticancer agents. The present review focuses on the recent progress, from 2016 until now, in knowledge on anticancer properties, structure-activity relationships and mechanisms of action of carbazole hybrids to provide a basis for development of relevant therapeutic agents.

Discovery of Novel Anti-Breast-Cancer Inhibitors by Synergistically Antagonizing Microtubule Polymerization and Aryl Hydrocarbon Receptor Expression

A series of unreported dual-receptor inhibitors targeting both the tubulin colchicine site and AhR were designed and synthesized, and their anti-breast-cancer activities were evaluated. Compound 12 showed the strongest activity with an IC₅₀ of 0.9 nM in MCF-7 cell lines. Besides, 12 could significantly inhibit cancer growth in MCF-7 xenograft tumor models with no obvious toxic effects and was more effective than the positive control (combretastatin A-4). With the in-depth study, it was found that 12 could induce apoptosis in breast cancer cells by making arrest in G2/M phase, depolarizing mitochondria and inducing intracellular reactive oxygen generation. This evident anticancer effect and the ability to inhibit cell migration were attributed to the synergistic antagonism of 12 on tubulin and AhR. In general, 12 was worthy of further research as an effective and safe anti-breast-cancer drug.

Anticancer properties of indole derivatives as IsoCombretastatin A-4 analogues

In this study, a variety of original ligands related to Combretastatin A-4 and isoCombretastatin A-4, able to inhibit the tubulin polymerization into microtubules, was designed, synthesized, and evaluated. Our lead compound 15d having a quinazoline as A-ring and a 2-substituted indole as B-ring separated by a N-methyl linker displayed a remarkable sub-nanomolar level of cytotoxicity (IC₅₀ < 1 nM) against 9 human cancer cell lines.

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.

Methylsulfanylpyridine based diheteroaryl isocombretastatin analogs as potent anti-proliferative agents

Isocombretastatins are the not isomerizable 1,1-diarylethene isomers of combretastatins. Both families of antimitotics are poorly soluble and new analogs with improved water solubility are needed. The ubiquitous 3,4,5-trimethoxyphenyl ring and most of its replacements contribute to the solubility problem. 39 new compounds belonging to two series of isocombretastatin analogs with 2-chloro-6-methylsulfanyl-4-pyridinyl or 2,6-bis(methylsulfanyl)-4-pyridinyl moieties replacing the 3,4,5-trimethoxyphenyl have been synthesized and their antimitotic activity and aqueous solubility have been studied. We show here that 2-chloro-6-methylsulfanylpyridines are more successful replacements than 2,6-bis(methylsulfanyl)pyridines, giving highly potent tubulin inhibitors and cytotoxic compounds with improved water solubilities. The optimal combination is with indole rings carrying polar substitutions at the three position. The resulting diheteroaryl isocombretastatin analogs showed potent cytotoxic activity against human cancer cell lines caused by tubulin inhibition, as shown by in vitro tubulin polymerization inhibitory assays, cell cycle analysis, and confocal microscopy studies. Cell cycle analysis also showed apoptotic responses following G₂/M arrest after treatment. Conformational analysis and docking studies were applied to propose binding modes of the compounds at the colchicine site of tubulin and were in good agreement with the observed SAR. 2-Chloro-6-methylsulfanylpyridines represent a new and successful trimethoxyphenyl ring substitution for the development of improved colchicine site ligands.

Cyclic bridged analogs of isoCA-4: Design, synthesis and biological evaluation

In this work, a series of cyclic bridged analogs of isocombretastatin A-4 (isoCA-4) with phenyl or pyridine linkers were designed and synthesized. The synthesis of the desired analogs was performed by the formation of nitro-vinyl intermediates, followed by a Cadogan cyclization. Structure activity relationship (SAR) study demonstrates the critical role of the combination of quinaldine as ring A, pyridine as the linker, and indole as ring B in the same molecule, for the cytotoxic activity. Among all tested compounds, compound 42 showed the highest antiproliferative activity against a panel of cancer cell lines with average IC50 values of 5.6 nM. Also, compound 42 showed high antiproliferative activity against the MDR1-overexpressing K562R cell line; thus, it was 1.5- and 12-fold more active than the reference compounds, isoCA-4 and CA-4, respectively. Moreover, 42 displayed a strong antiproliferative activity against the colon-carcinoma cells (HT-29), which are resistant to combretastatin A-4 and isoCA-4, and it was found to be 8000-fold more active than natural CA-4. Compound 42 also effectively inhibited tubulin polymerization both in vitro and in cells, and induced cell cycle arrest in G2/M phase. Next, we demonstrated that compound 42 dose-dependently caused caspase-induced apoptosis of K562 cells through mitochondrial dysfunction. Finally, we evaluated the effect of compound 42 in human no cancer cells compared to the reference compound. We demonstrated that 42 was 73 times less cytotoxic than isoCA-4 in quiescent peripheral blood lymphocytes (PBLs). In summary, these results suggest that compound 42 represents a promising tubulin inhibitor worthy of further investigation.

Synthesis and Anticancer Properties of Oxazepines Related to Azaisoerianin and IsoCoQuines

In this article, we report the synthesis and biological properties of a series of novel oxazepines related to isoCA-4 having significant antitumor properties. Among them, three oxazepin-9-ol derivatives display a nanomolar or a sub-nanomolar cytotoxicity level against five human cancer cell lines (HCT116, U87, A549, MCF7, and K562). It was demonstrated that the lead compound in this series inhibits tubulin assembly with an IC₅₀ value of 1 μM and totally arrests the cellular cycle in the G2/M phase at the low concentration of 5 nM in HCT116 and K562 cells. Molecular modeling studies perfectly corroborates these promising results.

Developments of isoCombretastatin A-4 derivatives as highly cytotoxic agents

Combretastatin A-4 (CA-4) is a natural anti-cancer agent isolated in 1989 from the African willow tree, Combretum caffrum. Due to its chemical simplicity, this (Z)-stilbene has been the subject of many structural modifications mainly to improve its chemical and metabolic stability. Beside a large number of synthetic analogues, isoCombretastatin A-4 (isoCA-4), has proved to be a solution of choice since this non-natural isomer of CA-4 is stable, easier to synthesize and has equivalent antitumor properties as CA-4. In this review, we will present the structure-activity relationships (SARs) around isoCA-4 since its discovery in 2007. In a first part, we will describe some alternatives to replace the phenol B-ring of isoCA-4, then we will focus on the variations made on the 1,1-ethylene double bond and then, we will evocate very recent exiting results concerning the possible replacements of the 3,4,5-trimethoxyphenyl A-ring of isoCA-4 by suitable heterocycles.